Ciz./c : " Digitized by the Internet Archive in 2013 http://archive.org/details/dimensionalmetroOOfull UNITED STATES DEPARTMENT OF COMMERCE • John T. Connor, Secretary NATIONAL BUREAU OF STANDARDS • A. V. Astin, Director Dimensional Metrology Subject-Classified With Abstracts Through 1964 Including linear, angular, and geometrical measurement and in-process control of size and form, but generally not including gages, gaging, and inspection as to limits of size. Compiled by Irvin H. Fullmer National Bureau of Standards Miscellaneous Publication 265 Issued August 1, 1966 For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C., 20402 Price ?3 Abstract This bibliography covers two of the three principal divisions of dimensional metrology, namely (1) linear, angular, and geometrical measurements of solid bodies, and (2) in- process control of sizes. The remaining division is gages, gaging, and inspection as to specified limits of size. There are about 3,600 references classified under main subject headings in 12 sections, which are further subdivided into 102 subsections covering 100 subjects. The 12 main subjects are (1) general metrology, physical and dimensional; (2) length and diameter measurements by interferometry ; (3) length and diameter measure- ments by mechanical methods; (4) calibration of line standards of length, including tapes; (5) dimensional measuring instrument design features; (6) angle measurement; (7) measurements of deviations from geometrical regularity: (8) measurement of profile; (9) measurement of screw threads; (10) measurement of gears; (11) measurement of thickness of thin films ; and ( 12 ) measurement and production techniques for accurate in-process control of size and form. The references in each subsection are arranged chrono- logically and a brief abstract of each is given with few exceptions. The bibliography is an attempt to organize and make more readily available the extensive existing knowledge in the field covered. Library of Congress Catalog Card No. 64-62750 Foreword In the manufacture of modern machines and instruments, an indispensable requirement is the control of the dimensions of parts to within specified tol- erances. Such control makes possible the interchangeability of parts produced in different localities; it also is essential to the proper functioning and relia- bility of the final assembly. Various methods are used to achieve dimensional control. They include (1) control by the production machine or process; (2) application of statis- tical methods of quality control, which involve measurement of samples of parts taken at intervals; and (3) the gaging of in-process or finished parts by means of fixed or indicating gages. All such methods of control require that measurements of the gages or product be made. Thus the underlying basis of such control is the selection and application of measuring techniques whose accuracy is compatible with the gage or product tolerances. This bibliography has been compiled to facilitate the application of exist- ing knowledge regarding measuring methods and equipment. In particular, it is designed to further the development of a series of American Standards by Sectional Commitee B89 on Dimensional Metrology, organized under the pro- cedure of the American Standards Association and sponsored by The Amer- ican Society of Mechanical Engineers. Although the literature of dimensional metrology is extensive in the areas of gaging methods and gages, the present publication, consisting of about 3,600 references, is mostly limited to dimen- sional measurement that yields numerical results. A. V. Astin, Director. in Preface The arrangement of this bibliography was de- termined by the nature of the subject matter treated. A strictly chronological arrangement of all entries would have required an extensive sub- ject index, which was considered economically im- practicable for such a broad subject. Instead, the entries are grouped into sections according to the principal subject treated in each case, and a brief abstract of each entry is given. There are 12 major sections, which are further subdivided into 102 subsections covering 100 sub- jects. Within each subsection, the references are arranged chronologically, so that a reading of the successive abstracts will yield a fairly comprehen- sive picture of the historical development of each subject. There is some, but not extensive, cross- referencing. The order of the sections has only slight rela- tion to their importance. The first section is general and therefore introductory. The section on interferometry is placed next because the in- ternational standard of length is now a wavelength of light from a krypton 86 lamp. From the point of view of historical development, section 4 might have been the second section, followed by section 3. The compiler has not indicated in detail the sources of the abstracts, of which he prepared about 25 percent. He gratefully offers the follow- ing acknowledgments with respect to assistance and sources : To the Engineering Index, Inc., New York, for about 50 percent of the references and abstracts which were copied, by permission, directly from the numerous volumes of the Engineering Index. To Physics Abstracts, London, as the source of about 25 percent of the abstracts. To Dr. Lewis V. Judson, Physicist, NBS (now retired), who had compiled lists of early refer- ences which are embodied in section 4 and sub- section 6.4. To Dr. Werner F. Vogel, Engineering Advisor, NBS (Professor Emeritus of Engineering Me- chanics, Wayne State University, Detroit), for suggestions relative to arrangement and content, particularly with reference to sections 9 and 10. To Dr. Erwin G. Loewen, Bausch and Lomb, Inc., who furnished a list of references not other- wise available to the compiler. To the secretarial staff of the Engineering Me- trology Section, NBS, who over many years pre- pared an extensive card file on this and other subjects of interest to the Section, and for typing and duplicating services. How To Use This Book // you are looking for references on a particular topic: First consult the table of contents and find the subsection that covers your topic. (If the topic is a broad one or is not well defined, it may take more than one subsection to cover it adequately.) Then turn to the page number indicated, where you will find the references of that subsection listed in the order of their dates of publication. // you are looking for publications by a particular author: First consult the author index at the back of the book, where all publications included in this bibliography are listed under the author's name, by subsection number and year of publication. You can then find the references you need by consulting the page numbers given. If there are a great many publications by a single author, you may be able to select those most likely to interest you on the basis of their subsection num- bers (which indicate the topics) and years of publication. A considerable number (a minority) of the papers listed herein are in a file at the Engineering Meteorology Section, NBS, which is keyed to this publication. When articles are not otherwise available to the reader this file may be consulted. Advance arrangement to do so is desirable. Also, authors are invited to send reprints for inclusion in this file. Further hints on the use of the book may be obtained by reading the preface. Also, note the list of abbreviations that follows. VI Bibliographic Abbreviations AAAS American Association for the Advance- ment of Science Abh Abhandlung(en) Acad academie, academy AGMA American Gear Manufacturers Associ- ation. Agric agricultural AIEE American Institute of Electrical Engineers Akad Akademie, akademii Am American An anales Analyt analytical Angew angewandte Ann annales Annu annuaire AOA American Ordnance Association App applied Arch architectural ASA American Standards Association ASHRAE American Society of Heating, Refriger- ating, and Air Conditioning Engineers ASME The American Society of Mechanical En- gineers Assn association ASTM American Society for Testing and Materials ASTME American Society of Tool and Manufac- turing Engineers Astron astronomical, astronomische Astrophys astro physical, astrophysics Austral Australian Automat automation Ber Berichte BIPM International Bureau of Weights and Measures Bldg building Brit British Bros brothers BS British Standard Bui bulletin Bur bureau Can Canadian Cer ceramic Chem chemical, chemistry Chim Chimie, chimique Cir circular Civ civil Co company Conf conference Constr constructional Corp corporation CP circular pitch CR comptes rendus Dept department DIN German Engineering Standard Div division Dokl doklady DP diametral pitch Ed edition Elec electric, electrical Elecn electrician Eng engineering (British Periodical) Engr(s) engineer(s) (British Periodical) Exper experimental Fiz fizika, fiziki FoKoMa Fertigungstechnisches Forschungs- und Konstruktions-Kolloquium Werkzeug- Maschinen und Betriebswissenschaft Fortschr Fortschritte Found foundation Gaz gazette GB Great Britain Gen general, generale Geol geological Geophys geophysics, geophysical Ges Gesellschaft GOST Russian All- Union State Standard Gov government Handb handbook Handl Handlungen Hogsk hogskolans IEEE Institute of Electrical and Electronic Engineers Ilium illuminating IMS Industrial Mathematics Society Inc incorporated Indus industrial, industrielle, industries Ing .. Ingenieur Inst(s) institut, institute (s) Instn institution Instrum(s) instrument(s) InstrumKde Instrumentenkunde Int international IRE Institute of Radio Engineers ISA Instrument Society of America ISO International Organization for Stand- ardization Izmer Tekh izmeritel'naya tekhnika Izv izvestiya J journal K kungliga Lab (s) laboratory (ies) Ltd limited Mach machinist Machy machinery Mag magazine Mar marine Math mathematical Matl (s) material (s) Meas measurement Mech mechanical Mem memoirs, memoires Memo memorandum Met metallurgical, metallurgy Mfg manufacturing Mfr(s) manufacturer^) Mgmt management Mil military Min mining Misc miscellaneous Mitt Mitteilungen Mod modern Monogr monograph Mun municipal Nachr Nachrichten NASA National Aeronautics and Space Admin- istration Nat national Naut nautical NBS National Bureau of Standards NPL National Physical Laboratory, Great Britain Yll Opt optical, optische, optique PA pressure angle PER A Production Engineering Research Asso- ciation of Great Britian Phil philosophical Phys physical, physics, physik, physique Prac practice, practical Prec precision Proc proceedings Prod product, production Progr progress Pt part PTB Physikalisch-Technische-Bundesanstalt Pub public Publ publication Q quarterly Rec record Rech recherche Refs references Refrig refrigerating, refrigeration Rep(s) report(s) Res research Rev(s) review (s), revue Roy royal, royale Ry railway S south SAE Society of Automotive Engineers, Inc. Schweiz schweizerische Sci scientific, scientifique, science Sec section Ser series Sipbldg shipbuilding Shipbldr(s) shipbuilder (s) Shipg shipping Soc soci6te\ society Spektrosk spektroskopiya Stand standard (s) Supp supplement, supplemento Syst system Tech technical, technisshe Technol technology, technological Techn(s) technique (s) Teen technica Tekh tekhnicheskoi Tekn tekniska Telecomm telecommunications Theor theorique Tidskr tidskrif t Trans transactions Trav travaux Univ university VDI Verein Deutscher Ingenieure Vent ventilating, ventilation Verh Verhandlungen Wiss wissenschaftliche Wld world Zeit Zeitschrift Zh zhurnal Ztg Zeitung Vlll CONTENTS Page Foreword •_ iii Preface v How to use this book vi Bibliographic abbreviations vii Section 1. General metrology, physical and dimen- sional 1 1.1. General physical metrology 1* 1.2. General dimensional metrology 6 1.2.1. General 6* 1.2.2. Units of length and angle 10* 1.2.3. Measurements in two- and three- dimensional coordinates 13 1.2.4. Surveying methods applied to large mechanical structures 15* 1.3. Precision, accuracy, uncertainty 17 1.3.1. General 17* 1.3.2. Instrumental errors 19* 1.3.3. Statistical or mathematical treat- ments 22 1.3.4. Personal equation 26 1.4. Temperature effects and measurement 28 1.5. Deformation, deflection, and wear 31* 1.6. Vibration isolation and control 34 1.7. Effects of surface state and texture 36 Section 2. Length and diameter measurements by interferometry 41 2.1. Interferometry, general 41 2.2. Interferometry theory 44 2.2.1. General 44 2.2.2. Method of coincidences- 48* 2.2.3. Aperture correction 50 2.2.4. Refractive index of air 52 2.2.5. Phase change at reflection 53 2.3. Wavelength standards and light sources 56 2.3.1. General 56* 2.3.2. Cadmium 59 2.3.3. Krypton 61 2.3.4. Mercury 63 2.3.5. Helium 65 2.3.6. Atomic beam 65 2.3.7. Lasers 66 2.4. Length and diameter measurements 68 2.4.1. General 68* 2.4.2. Fringe count interferometers and dilatometers 72* 2.4.3. Fabry- Perot interferometers 78 2.4.4. Interference comparators 81* 2.4.5. Measurement of long lengths 84* 2.4.6. Measurement of line standards 86* 2.5. Metrological gratings 87 Section 3. Length and diameter measurements by mechanical methods 91 3.1. Contact length standards 91 3.2. End measuring rods and measurement of long lengths 94* 3.3. External diameters 97* 3.4. Internal diameters. _. 101* 3.5. Measuring machines and bench micrometers- 103* 3.6. Manual measuring tools 108 3.6.1. General 108 3.6.2. Micrometers 110 3.6.3. Vernier instruments 114 3.6.4. Dial and test indicators 114 Pae« Section 4. Calibration of line standards of length, including tapes 117 4.1. Line standards, general - 117* 4.2. Calibration of subintervals 120 4.3. Calibration of tapes 122* 4.4. Measuring microscopes and line compara- tors 123 Section 5. Dimensional measuring instrument de- sign features 129 5.1. Measuring instruments, design principles. _ 129 5.2. Amplification 131 5.2.1. General 131 5.2.2. Electrical 132* 5.2.3. Mechanical 138 5.2.4. Optical 139* 5.2.5. Pneumatic 141 5.3. Dials and pointers 143 5.4. Optical features 143 5.5. Pivots 146 5.6. Slides, stands, and tables 146 5.7. Springs and suspensions 148 Section 6. Angle measurement 153 6.1. Angle measurements, general 153 6.2. Alinement, straightness, and autocollima- tors 157 6.3. Angle gage blocks and polygons 162 6.4. Calibration of graduated circles, dividing heads, and protractors 164 6.5. Angle measurement by interferometry 167* 6.6. Sine bars, plates, and fixtures 169 6.7. Spirit levels 170 6.8. Tapers 172 Section 7. Measurements of deviations from geo- metrical regularity 175 7.1. Planeness measurement 175* 7.2. Parallelism measurement 180* 7.3. Straightness and surface topography 181 7.4. Roundness and concentricity measurement- 185 Section 8. Measurement of profiles 189 8.1. Measurement of radius or profile by me- chanical methods 189 8.2. Contour measurement by optical projection- 193 8.3. Measurement of involute contours 196 Section 9. Measurement of screw threads 197 9.1. General 197 9.2. Lead measurement 202 9.3. Wire and ball measurements of screw threads and other helicoidal features 205* 9.4. Tables for ball, pin, or wire measurements. 212 Section 10. Measurement of gears 213* 10.1. Gear metrology, general 213 10.1.1. Standards and nomenclature 213 10.1.2. Textbooks and handboo s dealing partially with measuring meth- ods 215 10.1.3. Numerical tables 217 10.1.4. Technical papers on gear measure- ment, general 222 10.2. Spur and helical gears 228 10.2.1. Involute form measurement 228 10.2.2. Master gears; composite deviation testing 230 IX Page Section 10. Measurement of gears — Continued 10.2. Spur and helical gears — Continued 10.2.3. Lead measurements 232 10.2.4. Pin and ball measurements of spur gears and spur splines 232 10.2.5. Tooth index position measure- ment 234 10.2.6. Tooth thickness, pitch, and span measurement 234 10.3. Bevel, hypoid, spiroid, and worm gears or drives 238 Section 11. Measurement of thickness of thin films. 241 11.1. Interferometric methods 241 11.2. Polarimetric methods (ellipsometry) 247* 11.3. Miscellaneous methods 249 *One or more additional references relating to this subject are Page Section 12. Measurement and production techniques for accurate in-process control of size and form 257 12.1. General 257* 12.2. Machine tools 259 12.3. Automatic control 262 12.4. Grinding 265 12.5. Lapping 266 12.6. Manufacture of precision measuring tools and components 268 12.6.1. General 268 12.6.2. Scales and gratings 270* 12.6.3. Worms and power screws, includ- ing lead screws 271 12.6.4. Screw thread gages 273 12.6.5. Other gages 274 Author index 277 given in the Addendum at the end of the section. J Section 1. General Metrology, Physical and Dimensional CONTENTS Page 1.1. General physical metrology 1 1.2. General dimensional metrology 6 1.2.1. General 6 1.2.2. Units of length and angle 10 1.2.3. Measurements in two- and three-dimensional coordinates 13 1.2.4. Surveying methods applied to large mechanical structures 15 1.3. Precision, accuracy, uncertainty 17 1.3.1. General____" 17 1.3 .2 . Instrumental errors 19 1.3.3. Statistical or mathematical treatments 22 1.3.4. Personal equation 26 1.4. Temperature effects and measurement 28 1.5. Deformation, deflection, and wear 31 1.6. Vibration isolation and control 34 1.7. Effects of surface state and texture 36 Addendum to Section 1 39 1.1. General Physical Metrology The Progress of Science as Exemplified in the Art of Weighing and Measuring, PROF. Win. HARKNESS, U.S. Naval Observatory. Presidential address before the Phil- osophical Society of Washington, 1887. Smithsonian Re- port, 1888, or *Bul of the Phil Soc of Washington vlO 1887 p 39-86 67 refs. Historical paper dealing partly with length standards. The Theory of Measurement, A deP. PALMER. McGraw- Hill Book Co. 1912 248 p. Chapters 1-7 deal with the general principles that underlie all measurements, nature and distribution of errors, and most probable result ; 8-12, precision of measurements ; 13, methods of physical research. raphy classified under the following heads : 1. General material, theoretical or basic, on physical and mechan- ical instruments. 2. Measurement and production of small linear and angular displacements and distances. 3. Theory and measurement of vibration ; measurement of speeds and time intervals. 4. Frictional and other types of hysteresis and their relation to instrument design and testing ; accuracy, sensitivity and variance. 5. Dynamom- eters, measurement of force (except weighing scales), torque, and accelerations. 6. Measurement and control of temperature and humidity. 7. Weighing scales. 8. Pressure gages, manometers, and aneroid barometers. 9. Engine indicators. 10. Properties and design of springs. 11. Miscellaneous instruments. The Theory of Measurements, L. TUTTLE. Jefferson Lab- oratory of Physics, Philadelphia. 1916 303 p. Some chapter heading are : Angles and circular functions, sig- nificant figures, coordinates in three dimensions, accuracy, the principle of coincidence, measurements and errors, indirect measurements, systematic and constant errors. Republished in expanded form, 1925, Tuttle and Satterly. Mensuration for Marine and Mechanical Engineers, J. W. ANGLES. Longmans, Green and Co. London 1919 162 p. Collection of formulas and tables ; elements of trigonometry ; lengths, taper, speed ; areas of rectilinear figures; areas of circle and ellipse; surfaces, volumes, weights ; surface and volume of cylinder, displacement ; the cone and sphere ; similar figures, Simpson's rule ; weights of machinery. Metrology in the Industries, Proc Phys Soc of London Meeting of Mar 28, 1919 29 p 3 figs. A general discus- sion initiated by Sir R. T. Glazebrook. The International Bureau of Weights and Measures, J. BOYER. Sci Am Monthly v3 n2 Feb 1921 p 105-9 7 illus. An interview with Charles Edouard Guillaume, director. Bibliography for Measuring Instruments, with Special Reference to Instruments and Methods of Metrology used in Mechanical Engineering, F. J. SCHLINK. J Opt Soc Am and Rev Sci Instrum v9 Sept 1924 p 309-21. Bibliog- History of the Standard Weights and Measures of the United States, L. A. FISCHER. NBS Misc Publ n64 1925 34 p. Paper contains a series of photographs of important standards, both ancient and modern. Metorology, W. BLOCK. Eng Progr, v6 Sept 1925 p 283-5 4 figs. Its definition, significance, and fields of appli- cation. Precision Measurements, G. BERNDT. Eng Progr v6 Sept 1925 p 289-91 4 figs. Their significance and utility in engineering ; examples taken from machine construc- tion and instrument making, illustrating great savings achieved by applying precision measuring. Measurement and Calculation, N. R. CAMPBELL. Long- mans, Green and Co., Ltd. 1928 293 p. Chapter headings are: the laws of measurement, number, numerical laws, derived measurement, classification of magnitudes, stand- ards and factors, errors of measurement, errors of numer- ical laws, calculation, and argument from dimensions. Experimental Mechanical Engineering, 1, Engineering Instruments. H. DIEDERICHS AND W. C. ANDRAE. 1930 John Wiley & Sons, Inc. 1082 p. illus. diagrs., charts, tables. Rewritten text based upon Carpenter and Dieder- ich's "Experimental Engineering," for students and prac- ticing engineers ; construction, calibration, and use of instruments for measuring length, etc. ; methods in use described, theory explained and commercial forms of in- struments presented. Eng. Soc. Library, N.Y. ATM Archiv fur Technisehes Messen, R. OLDENBOURG Lieferungen 4-12 Nov-June 1932 Munich and Berlin, 222 p. illus. diagrs. charts tables. Compendium of measuring instruments and methods intending to cover, in 5 vols., whole field of technical measurements; parts are issued monthly, but may be bought singly ; each contains concise 2 to 4-page reviews of dozen instruments or methods, accompanied by references to sources from which account was compiled. Eng. Soc. Library, N.Y. Introduction a l'Etude de la Metrologie Industrielle, P. NICOLAU. Mecanique v20 n269 Nov-Dee 1936 p 235-45. Introduction to study of industrial measurements ; bio- graphical report and cross-sectional view of technique employed in mechanical engineering. Pruefen und Messen als Voraussetzung technischen Fort- schritts, C. RAMSAUER. VDI Zeit v80 n48 Nov 28 1936 p 1429-32. Testing and measurements as prerequisites of technique in engineering progress ; author points to role which precision measurements play in modern engineer- ing, and discusses various fields of application in mechan- ical engineering, aviation, welding, electrical engineering and in factories. Limits of Measurability. W. GERLACH. VDI Zeit v81 Jan 2 1937 p 2-7. The author presents a general review of the importance of precision in measurement and out- lines the methods by which the limits of measurability have been extended. Examples are given of the applica- tion of physical laws to this end, e.g., the application of the theory of interference colours to the determination of thickness. Atomic physics and the quantum theory have extended the attainable limits. The reaction of the measured quantity on the measuring device often imposes a limit on direct measurements. The influence of the Brownian movement is discussed and illustrated in rela- tion to the measurement of very small amounts of energy ; and the measurement of atomic magnitudes is discussed. Tolerances and Their Effect on Physical Measurements, C. DARWIN. Light and Lighting v37 n6 June 1944 p 86 ; Engrs' Digest (Am Ed) vl nil Oct 1944 p 616-8. Author emphasizes that tolerances has become respectable part, not only of engineering practice, but also of fundamental science : among examples cited are manufacture of ma- chine for weighing bullets, theory of sound, and optical measurements ; Uncertainty Principle as limitation to tolerances in nature. From address before Illuminating Engineering Soc. Effect of Tolerances on Measurements, C. DARWIN. Metal Progr v47 n5 May 1945 p 941-6. Discussion of examples showing allowable tolerances, limitations and physical measurements, including importance of subject of errors and tolerances in relation to foundations of physics. Metrologie Genera le (Grandeurs et Unites), M. DENIS- PAPIN, J. VALLOT. Dunod, Paris, 1946 428 p plates I-XLVI tables diagrs. charts. Discussion of measure- ment in general, international system of weights and measures, and symbols and equations of fundamental sys- tems of measurement ; methods of measurement and units described for fields of geometry, geography, mechanics, angular measure, stresses, electricity and magnetism, heat and radiant energy, optics and time as well as for every- day use. Eng. Soc. Library, N.Y. A Discussion of Units and Standards, Staff of NPL. Proc. Royal Soc A vl86 21 Mar 1946 p 149-217 6 figs refs. A discussion of 10 types of physical standards. Symposium on Metrology, J. C. EVANS, Eng vl61 n4189 Apr 26 1946 p 401-2 ; Nature (London) vl57 n3991 Apr 27 1946 p 538-40. Review of symposium held at Royal So- ciety, of short papers dealing with principal units and standards of scientific measurement, read by Director, D. Darwin, and members of staff of National Physical Laboratory. Training In Inspection and Gaging In Mechanical Engi- neering, R. L. GEER. Instrum vl9 nl2 Dec 1946 p 726-8. Need in mechanical engineering curriculum of study of precision measuring techniques ; origin and development of course in measuring instruments for Sibley School of Mechanical Engineering, Cornell Univ. is discussed : pro- gram of lesson topics of course is outlined in detail. Fundamental Concepts of the Technique of Measurement. J. HARTMANN, Rev Sci Paris v85 Apr 1 1947 p 323^ in French. The idea of measurement as a production, anal- ogous to an industrial production, of which the product is an image in figures of the property measured, is de- veloped. The terms, uncertainty (incertitude), error (faute). tolerance, in relation to the production, and in- determinacy, falsification, in relation to the product, are clearly defined. The relationships between these are ex- plained and illustrated by examples. It is shown that the uncertainty of production is manifested by the indetermi- nacy of the product, i.e. by oscillatory deviations from a mean value, whereas the error of production is mani- fested by the falsification of the product, i.e. by a unilat- eral deviation. Limit of Sensitivity, J. L. VAN SOEST, J. L. BOR- DEWIJK. Tijdschrift van het Nederlandsch Radiogen- ootschap vl2 May 1947 p 113-23 in Dutch. A general discussion of sensitivity of measurement and restrictions on the accuracy of measuring instruments and scale readings. Metrologie, son Origine, son Evolution, A. C. PRULIERE. Microtecnic vl n.3 June 1947 p 126-32 (English translation in separate section p 54-7). Origin and development of metrology ; data on metric system and length standards ; review of work done in field of metrology in United States, England, France, Germany and Switzerland. Bibliog- raphy. Precision Measurement Methods and Formulas, J. JOHN- SON. Pitman Publ Corp, New York and London, 1948 181 p diagrs tables, Bridging gap between "school" mathe- matics and practical application theory, book presents actual problems and their solutions ; overall theory behind solution is shown ; solutions are for greater part based on setups requiring simplest of instruments; no special ability other than knowing how to use trigonometric tables is necessary. Eng. Soc. Library, N.Y. Some Applications of Electronics in Metrology, E. J. B. WILLEY. Sci Progr v36 Jan 1948 p 55-65 4 figs 18 refs. A short review article. Electrical gages, surface meters, vibration and acceleration meters, strain gages and ultra- sonic thickness meters and flaw detectors are touched on. Instruments, Physics, and Physicists, G. F. GARDNER. Gen Elec Rev v51 nlO Oct 1948 p 11-3. Good measuring instrument is essentially conveniently arranged physics experiment that can be repeated at will within specified accuracy limits ; historical examples of instrument de- velopment or invention are given. Messung und Darstellung physikalisch-technischer Groessen, W. SPAETH. VDI Zeit v91 nl8 Sept 15 1949 p 471-5. Measurement and presentation of physical- technical quantities ; relation between two coordinates ; practical examples include time and reciprocal of time, hardness and softness, stability limit of rivets, frictional phenomena, coefficient of expansion and melting point, and applications in Bessemer converter. Bibliography. Coup d'Oeil sur la Situation de la Metrologie Industrielle dans le Monde, M. CHALVET. Rev. Gen de Mecanique v34 nl3 Jan 1950 p 18-25. Outline of world status of in- dustrial metrology ; historical background ; types of measuring apparatus; gages, comparators, interferom- eters, etc; illustrations. Neue optische Messgeraete fuer Werkstueck- und Werk- stoffpruefungen, A. METZ. VDI Zeit v92 nl3 May 1 1950 p. 323-31. New optical measuring instruments for testing of workpieces and materials ; different types of microscopes. Atomic Definition of Primary Standards, R. D. HUN- TOON, U. FANO. Nature (London) vl66 n4213 July 29 1950 p 167-8. In view of limits to accuracy with which one can compare any physical quantity with primary standards, possibility of selecting other quantities to serve in place of present primary standards, such as im- mutable properties of atoms or molecules with which other physical quantities can be readily and accurately compared, is considered ; set of working definitions con- sistent with latest values of atomic constants are atomic meter, second, ampere, Newton, Coloumb, and kilogram. Handbook of Measurement and Control, M. F. BEHAR, editor. The Instrum Publ Co. Pittsburgh 1951 291 p. Classisification ; measurables, effects and methods ; static measuring properties ; the response ; the prime relay. Changes of State Caused by the Process of Measurement, G. LUDERS. Ann Phys Leipzig. v8 n5-8 1951 p 322-9 in German. A treatment by v. Neumann (Mathematische Grundlagen der Quantenmechanik, 1932) is critically dis- cussed and an alternative treatment introduced, which permits of a fuller discussion of the concept of the com- patibility of measurements. Units and Standards of Measurement Employed at the National Physical Laboratory. I. Length, Mass, Time; Volume, Density and Specific Gravity, Force and Pres- sure, Dep of Sci and Indus Res. London, H.M. Sta- tionery Office 1951 12 p. This pamphlet describes the standards of the three fundamental units of measure- ment, and definitions of them are given in the inter- national Metric and British Imperial Systems. The derived units are also described, and the values of the standards and bases of measurement employed in work involving these units are given. The absolute value of the acceleration due to gravity at the Laboratory is included. Recent Developments and Techniques in the Maintenance of Standards, London, H. M. Stationery Office 1952 100 p. Proceedings of a symposium held at the N P L on 21st and 22nd May 1951. Reported in Nature (London) vl68 Oct 6 1951 p 594-7. Fluctuation Theory in Physical Measurements, C. W. Mc- COMBIE. Rep Progr Phys vl6 1953 p 266-320. An at- tempt is made to give a coherent, elementary account of the ways in which fluctuation theory has been applied to some of the simpler types of physical measurement. Un- certainties in measurements involving suspended systems are discussed on the basis of simple correlation function arguments, and consideration is given to the methods of measurement appropriate when there are various prac- tical limitations on the parameters of the suspended sys- tem. There follows an elementary development of the mathematical and physical considerations usually em- ployed in treating fluctuations in linear measuring in- struments : remarKs on the status of the random force method as applied to equilibrium systems are included. The circumstances under which there is an absolute limit to the attainable accuracy are discussed. It is shown that, in the case of measurements with a suspended sys- tem, feedback may enable these limits to be attained with a convenient measurement procedure. An account is given of various approaches to the calculation of the limits of accuracy in measurements with radiation detectors. Finally some elementary results are established concern- ing the optimum characteristics of an instrument used to follow a varying signal in the presence of noise. 78 refs. Instrument Engineering. v2 : Methods for Associating Mathematical Solutions with Common Forms, C. S. DRAPER, W. McKAY, S. LEES. McGraw-Hill Book Co., New York, 1st ed. 1953. 827 p. Continuing presen- tation of generalized method of- attack on problems of measurement and control, volume reviews mathematical background and illustrates procedures by actual deriva- tion of quantitative results. Eng. Soc. Library, N.Y. Metrology and the Classification of Measuring Apparatus, A. MOLES. Ann Telecomm v8 July 1953 p 250-3 In French. The precise function of measuring apparatus as transducers of information is recalled and discussed. The distinction between recording and measuring is empha- sized, and the information obtained by Fourier and similar analyses of records is briefly discussed. It is shown that the field of measuring apparatus is limited and in the physical domain is defined by three factors, the scales of frequency /max//min, amplitude Amai/Amm, and precision w. By means of a three-dimensional diagram [diagramme d*equarissage] with coordinates log A, log /, and w the various instruments are classified according to their par- ticular technical field and usefulness. Pratical Calibration Adjustments for Apparatus Which Obeys a Theoretical Law Imperfectly, J. W. HEAD, Elec- tronics Eng v25 Dec 1953 p 499-501. Various empirical methods of adjustment are considered. The nature of the adjustment achieved is fully explained. The object throughout has been to obtain easily a calibration curve which is sufficiently smooth and sufficiently near the ob- served values to satisfy practical requirements, rather than to find the unique curve which satisfies a least- squares or other mathematical criterion of goodness of fit. Concepts in Measurement, D. J. MONTGOMERY. J ISA vl nil Nov 1954 p 51-3. Analysis of some of concepts in physical measurement illustrating modern work in phi- losophy of science and its applicability to problems in in- strumentation ; example of measurement of temperature by means of mercury thermometer, and of measurement of average cross-section area of non-uniform filament by means of vibroscope. The Language of Instrument Calibration and Perform- ance, K. M. GREENLAND. J Sci Instrum v33 n7 July 1956 p 249-54. A critical discussion is presented of the terms used in describing the establishment of instru- ment scales and the performance of measuring instru- ments. Examination of a number of vocabularies and of unrecorded usage shows that many of the important terms have more than one meaning. Arguments are put forward in support of certain unique definitions consistent, wher- ever possible, with the original sense of the words. The discussion takes as a basis the new definitive glossary com- piled by the British Standards Institution (B.S. 2643: 1955). Some Principles of Measurement and Control, J. F. COALES. J Sci Instrum v33 nl2 Dec 1956 p 457-64. Measurements can be divided into two broad classes : those which only have to be observed and recorded and those which are used to control sources of power in order to change some quantity such as position, speed, tempera- ture or pressure. In both cases the principles are the same : there are certain limitations from which all meas- uring instruments suffer, e.g. they all disturb the physical system on which the measurements are being made and they all have inertia and damping to some degree. Also, no measuring instrument is completely stable and all exhibit unwanted fluctuations if the sensitivity is in- creased to the limit of usefulness. These limitations are discussed together with the principles underlying the design of measuring systems to reduce their effect to a minimum. The simple theory of linear control systems is developed, and it is shown that the only real difference between measuring systems and control systems lies in the magnitude of the power required at the output. Nega- tive feedback in a closed-loop system is shown to be the equivalent of the restoring force in an open-loop system. Precise Measurements of the Density of Mercury at 20° C. I. Absolute Displacement Method, A. H. COOK, N. W. B. STONE. Phil Trans A v250 Nov 28 1957 p 279-323. The densities of four samples of mercury at 20° C were measured by finding the mass of mercury displaced by an accurately formed cube of known volume that just sinks in mercury. The cube is of tungsten carbide and was lapped to such an accurate form and good surface finish that the standard deviation of the volume of mercury dis- placed, as calculated from optical interference measure- ments of the dimensions of the cube, is 0.15 parts per million. The weight of mercury displaced had an uncer- tainty of 0.28 ppm but the uncertainty of the density at 20° C is increased by errors of temperature measurement and the effects of residual grease films on the cube to up to 1 ppm. The mean density at 20° C and 1 atm pressure of four samples of mercury from different sources is 13.545 892 g/cm 3 , the range of the four values being 1.1 ppm. The corresponding value at 0° C is 13.595 086 g/cm 3 . The purification, chemical analysis and determination of the isotopic constitution of the samples are carefully dis- cussed. Optics in Metrology, P. MOLLET. Pergamon Press 1960 436 p. Colloquia of the Int. Commission for Optics, 6-9 May 1958. A compendium of 59 papers in three languages. Bases of Measurement, H. BARRELL. Instn Prod Engrs J v37 nl Jan 1958 p 3-18 (discussion) 19-35; Mass Prod v33 nl2 Dec 1957 p 59~65, 120. How standards are com- pared ; comparing end standards by contact measurement in measuring machines ; comparison of primary standards of mass ; defining standard of time or frequency ; 1,200- ton compression machine being used for calibrating 135- ton load standard by buildup from three 50-ton standards. Classification and Nomenclature for Standards of Measurement, A. G. McNISH, NBS. IRE Trans on In- strumentation v7 n3 and 4 Dec 1958 p 371-8. Definitions of units and standards, classification of standards, orders in the prototype category, orders in other categories, nomenclature for other laboratories. Measurement : Definitions and Theories, C. W. CHURCH- MAN, P. RATOOSH. John Wiley & Sons, Inc. 274 p. New York. 1959. I. Some meanings of Measurement. II. Some theories of Measurement. III. Some problems Xi. A method is introduced which does not require prior knowledge of the phase-shift dispersion. For one set of fringes an arbitrary integer, N, is selected and the function tN(\) is found by plotting N\ v. X , (N+l)\i v. Xi, etc. For the set of shifted fringes the function tN(\) is found similarly by plotting N\ ' v. \ \ etc. where the fringe at Xo' has the same order number as that at X . It is shown that the vertical displacement between the two curves is a constant equal to twice the step height. Other uses of the tau function are described. If the tau function is linear with wavelength, the simple expression above can be used without error. Developments in the Comparison of Lengths Using Fringes of Superposition in White Light, A. H. COOK, H. M. RICHARDSON. Proc Phys Soc v73 pt4 Apr 1959 p 661- 70. When two Fabry-Perot etalons are placed one in front of the other, and the length of one is a small multiple of that of the other, fringes are seen in white light and have been used in the past to compare the lengths of etalons. In the study reported in this paper, these fringes have been observed photoelectrically while the optical length of one etalon is varied by changing the pressure of the air inside it. It is shown that the variation of intensity with path difference is the sum of two Fourier integrals involv- ing an intensity function and the phase shifts at the re- flecting surfaces. By forming cosine and sine Fourier transforms these quantities can be obtained separately and a correction applied for the error introduced into the comparison of lengths by the change of the phase shifts with wavelengths. It is shown that phase shifts can be measured more accurately by this method than by other interferometric means. It is possible to compare a metre length with a 20 cm length to about 1 in 10 8 . Effect of Surface Roughness on the Phase Change at Re- flection in Interferometers, B. S. THORNTION. J Opt Soc Am v49 n5 May 1959 p 476-9. The effect of the phase change of light due to surface roughness on the precision measurement of length by interferometry is an important practical problem upon which only little work seems to have been done. This paper investigates the effect from a theoretical and experimental standpoint and shows that the phase loss due to surface roughness is a function of wavelength as well as a function of amplitude and wave- form of the roughness. Phase Shift Effects in Fabry-Perot Interferometry, O. J. KOESTER. J. Res NBS v64A n3 May-June 1960 p 191-200 8 figs 37 refs. A method is demonstrated for utilizing in Fabry-Perot interferometry the data on reflection phase shift dispersion obtained from fringes of equal chromatic order. Unknown wavelengths can be calculated from the Fabry-Perot patterns obtained with a large etalon spacing, even without prior knowledge of the phase shift of the reflecting surfaces. When the theoretical phase shift as a function of wavelength is known approximately, then the correct orders of interference can be determined for both the Fabry-Perot fringes and fringes of equal chromatic order. From the wavelengths of the latter the phase shift dispersion can be measured to an accuracy of about 10A. The method is especially useful for reflectors with large dispersion of phase shift, such as multilayers. Results in the visible spectrum are reported for aluminum films and a pair of dielectric 15-layer broadband reflectors. Phase Dispersion in Interferometry, P. E. CIDDOR. Optica Acta (Int) v7 n4 Oct 1960 p 399-^03. It is shown that the interference equation for interferometers exhibit- ing phase-change effects should take the form M\=2d — \v/w, where v is (/3— ir) and /3 is the phase-change at re- flection for one reflecting surface. Several recent treat- ments of the phase-change on reflection are critically examined and it is shown that the phase-dispersion de- duced from them is inconsistent with generally accepted experimental results for interferometers with silver films. Experimental Determination of Phase Change at Reflec- tion From Glass-Metallic Layer Interface Using a Kosters Interference Comparator, N. BARAKAT, S. MOKHTAR. J Opt Soc Am v53 nlO Oct 1963 p 1153-5. Opaque films of 55 771-846 O — 66 copper and indium have been evaporated on a glass sub- strate, and the phase shift at reflection from the glass- metal interface has been determined both with white light and monochromatic fringes. Helium and krypton spectral lines with a Kosters interference comparator were used. Comparison is made between experimental results and theoretical calculations based on the electromagnetic theory for opaque copper films. Determination of Absolute Phase Change on Reflection at Chromium Films, G. HENDERSON, C. WEAVER Opt Soe Am v54 n8 Aug 1964 p 1052-6. Determination of absolute phase change at chromium film-air interface for thickness up to 400 A at 5461 A wavelength ; compara- tive measurements show Weaver-Hill-MacLeod method is as valid as well tried method of Rouard, although for films thinner than 100 A Rouard method is more suitable. 2.3. Wavelength Standards and Light Sources See also Subsection 1.2.2. 2.3.1. General Wave Length of Sodium as a Standard of Length, A. A. MICHELSON, E. W. MORLEY. J Assn Eng Soc May 1888. Read before the Civil Engineers Club of Cleveland. Gives a method for making the wavelength of sodium light the actual and practical standard of length. Les Methodes Interferentielles en Metrologie et l'esta- blissement d'une Longueur d'Onde Comme Unite Absolue de Longueur ( Interf erometry methods in metrology and the establishment of a wavelength as the absolute unit of length), A. A. MICHELSON. J de Phys v3 m3 1894 p 5- 22. Sur les Sources de Lumiere Monochromatiques (Sources of Monochromatic Light), C. FABRY, A. PEROT. J de Phys 3rd ser v9 July 1900 p 369-82. A series of de- scriptions of the various methods used by the authors for obtaining monochromatic lights of varying degrees of purity. The most useful cases were : (1) Simplification of white light by analysis of spectrum ; (2) emission spectrum of a gas; (3) flames; (4) gases electrically excited by various sources of power ; (5) electric spark ; (6) electric arc in air ; (7) electric arc in vacuo. The final choice was fixed on a mercury arc in vacuo, using the green line chiefly, the other radiations being suppressed by inter- polated solutions of quinine, eosine, etc. Light Waves and Their Uses, A. A. MICHELSON. Univ of Chicago Press 1903. Republished as PSS 514, Phoenix Science Series, Univ of Chicago Press, 1962. Contains a chapter on light waves as standards of length. Die Anwendung der Interferenzen in der Spektroskopie und Metrologie. (The Application of Interference in Spectroscopy and Metrology), E. GEHRKE. Published by F. VIEWEG und SOHN, Braunschweig, 1906. Contents : General introduction; production and theory of a few chosen interference phenonema ; spectral apparatus ; selec- tion of results of the spectroscopic research regarding the mechanism of light ; application of interference to physical measurements in metrology. Bibliography. Some Measurements of Wave Lengths with a Modified Apparatus, LORD RAYLEIGH. Phil Mag ser 6 May 11 1906 p 685-703. Measurements on Cd, Hg, He, Zn, Na. Mesures de Longueurs D'Onde pour l'Etablissement d'un Systeme de Repreres Spectroscopiques (Measurements of Wavelengths for the establishment of a System of Spec- troscopic Spectrum lines), H. BUISSON, C. FABRY. J Phys Ser 4 v7 1908 p 169-95. Introduction, sources of light, methods, description of apparatus, manipulation, measurements, corrections, results. Width of Spectrum Lines and Interference Fringes with Large Path-Difference, C. FABRY, H. BUISSON. CR Acad Sci vl54 May 6 1912 p 1224-7 ; J de Phys v2 Sec 5 June 1912 p 442-64. Formulas for width of line and number of the order corresponding to the limit of visibility of the fringes ; order number for He, Ne, and Kr. Nouvelle Determination du Rapport des Longueurs, d'Onde Fondememtales avec L'Unite Metrique (New Determination of the Relation of the Fundamental Wave Lengths to the Metric Unit), J. R. BENOIT, C. FABRY, A. PEROT. Trav et Mem du BIPM vl5 1913 280 p 23 figs. Part 1, Interference phenomena with silver films: production and properties of fringes of silver films in monochromatic light; theory of coincidences; influence of dispersion phenomena ; phenomena produced by super- position of films ; influence of variations in the refractive index of air. Part 2, Methods and apparatus ; construction and study of the measuring standard ; interferential standards ; cadmium light source. Part 3, Organization, execution, and calculation of the experiments. Part 4, Re- sults and conclusions. Detailed observations. Sur les Etalons de Longueur d'Onde (Wavelength Stand- ards), C. FABRY, H. BUISSON. J Phys Ser 3 v5 Aug 1913 p 613-22. The exactitude of secondary international standards is first discussed. It is seen that many re- searches lead to the conclusion that the values given by interference methods are perfectly correct and identical with those found by means of a grating. The paper then deals in succession with (1) The progress of measure- ments of secondary standards. (2) Variability of wave lengths. (3) Tertiary standards of wave length. (4) The utility of having more numerous secondary standards measured by interference methods 1 . Limit of Interference in the Fabry-Perot Interferometer, M. N. SAHA. Phys Rev vlO Dec 1917 p 782-6. The theory of the Fabry-Perot interferometer has been worked out by Lippich, Rayleigh, and Schonrock. They have shown that when the pressure is small, the critical dis- tance D, or the limit of interference, is connected by the following formula with the wave length \ of the light, the temperature T of the tube, and the mass M of the emission centers: ? = AJ1. \ V T Paper develops an exact value for A which is 1.50x10°. Interference Measurements in the Spectra of Argon, Kryp- ton, and Xenon, W. F. MEGGERS. Sci Papers NBS m414 Aug 1 1921 p 193-202. Gives values of 50 wave lengths in spectrum of argon, krypton and xenon, all of which have been compared with wave length of red radia- tion from cadmium which is international primary standard. Measurement of Meter in Wavelengths of Light, C. SMITH. Machy (London) v28 1926 p 53. F. Determination of the Yard in Wave-Lengths of Light, A. E. H. TUTTON. Roy Soc Phil Trans v230 Sept 1931 p 293-322. The British Imperial Standard Yard has been evaluated in wave-lengths of the red hydrogen line Ha, the yellow line of Ne», and the red line of cadmium Cd r . The author's interferential method was used employing Grayson-ruling fiducial marks of only half-wave-length thickness, the author's interferometer, and the Tutton 5G comparator. Results obtained are tabulated and possible errors discussed. Determination of the Relationship between Wavelength of Light and the Fundamental Standards of Length, J. E. SEARS, Jr., H. BARRELL. Roy Soc Phil Trans v231 "Sept 16 1932 p 75-145. Apparatus and methods developed at the NPL for the establishment of suitable means of realizing a wave-length standard of length and for deter- mining the imperial standard yard and standard meter in terms of it. Measurements can be made either in air under controlled conditions or in vacuum. Interference Measurements in the Spectra of Noble Gases, W. F. MEGGERS, C. J. HUMPHREYS. J Res NBS vl3 Sept 1934 p 293-309 81 refs. Values are given for 3 lines of He, 172 of Ne, 87 of A, 55 of Kr, and 130 of Xe. Many of the lines have been found to be reproducible to 8 fig- ures and are regarded as highly satisfactory standards in spite of objections on account of isotopic hyperfine structure. The Primary Standard of Wavelength, W. F. MEGGERS, NBS. Rev Mod Phys vl4 Apr- July 1942 p 59-63 19 refs. Discusses various spectrum lines and hyperfine structure originating in the isotopic constitution of certain chemical elements. A Method of Cooling Hydrogen Discharge Tubes, H. CHAO-WANG. Rev Sci Instrum vl4 Aug 1943 p 250-3. Experiments are described on cooling by means of rapidly evaporated liquid air. The temperatures were measured with a calibrated Cu constantan thermocouple. Special apparatus was constructed to determine the f.p. of the substances used for calibration. Cooling of the light source to 56 °K. is obtained at low cost. Use of the Fabry-Perot Interferometer for the Study of Feeble Satellites. C. DUFOUR. Rev Opt (Theor Instrum) v24 Jan-Mar 1946 p 11-8 in French. Heavily silvered mirrors are best. Low luminosity due to reflection at the first surface is overcome by having a clear space for entry. The methods of use, and the advantages obtained, are dis- cussed at length. Attention is also given to the use of long tube "end-on" sources. Direct Determination of Wave-Lengths from Fabry-Perot Interferometer Patterns, G. R. HARRISON. J Opt Soc Am v36 nil Nov 1946 p 644-54. Data on measuring and computing engine which determines wavelengths and wave numbers directly from spectrograms made by crossing dispersion of Fabry-Perot interferometer with that of concave diffraction grating; wavelength of spectrum line is determined to six figures from grating dispersion by automatic comparator, and is then converted to wave number by mechanical continuous-function computing arrangement. Bibliography. Relations Entre les Etalons de Longueur Fondamentaux et les Longueurs d'Ondes Lumineuses. (Relations be- tween Fundamental Length Standards and Wavelengths of Light), H. BARRELL, NPL. Rev de MStrologie v25 eer 2e n7 Feb 1947 p 33-44 7 figs 12 refs. Recording Interferometer for Precision Wave-Length De- terminations, W. R. SITTNER, E. R. PECK. J Opt Soc Am v39 n7 July 1949 p 544-6. Precise measurement of angle by means of interferometric measurement of chord length ; application to problem of precise wavelength de- terminations ; possibilities for measurement of rotation of linear displacement as small as one microinch. Use of the Fabry-Perot Etalon for the Wavelength Cali- bration of Monochromators, F. DESVIGNES. CR Acad Sci Paris v229 Nov 15 1949 p 1001-3 in French. The author considers the conditions required for accurate calibration by "Edser-Butler" fringes and gives expres- sions for the fringe width (SX), fringe separation (AX), etalon transmission, and wavelength error (e) due to vari- ation of detector-response with wavelength, as functions of etalon thickness (e) and plate reflection (r). A flint prism monochromator is calibrated up to X=2/t using an etalon with er=18-2/t and r=0-7; the receiver response varied by a factor of not more than 3 from one fringe max. to the next, giving e<0-18AX-SX/AX was equal to 0-057. The calibration obtained agreed with direct measurement of Hg and K lines to the experimental error of about lm/i. Electric Discharge Laboratory Lamps, N. L. HARRIS. Engr vl89 n4906 Feb 3 1950 p 143-6 9 figs. Details of range of Osram laboratory lamps ; thallium vapor lamp and its application to the interference microscope ; other types of discharge tube ; continuous ultraviolet spectrum used in absorption spectroscopy. Light as Standard of Length. Light and Lighting v43 n7 July 1950 p 255-7 2 figs. How wavelength of light can be used as basis of specifications for standard of length ; unit of length is now maintained by bar of platinum iridium of special cross section ; disadvantage is that it cannot be reproduced from specification ; standard based on use of monochromatic light ; use of more precisely defined radia- tion for mercury isotope. A Note on an Automatic Control for Maintaining Constant Intensity of a Light Source, K. C. WIGHT. J Sci Instrum v28 Sept 1951 p 276-7. An electronic arrangement for automatically maintaining constant intensity of a light source using a tungsten filament lamp is described, in which normal electrical components are used. Curves show the stability over a period of some hours and the effect of mains voltage variation. The regulation of in- tensity for the latter, on a percentage basis, is about 150 tol. Calibrating Wavelengths in Region From 0.6 to 2.6 Microns, N. ACQUISTA, E. K. PLYLER. J Res NBS v49 nl July 1952 (RP2338) p 13-6. Wavelength of 20 absorp- tion bands measured on grating spectrometer, several emission lines of krypton also measured in near infrared region ; purpose was to make available additional calibra- tion points for prism instruments. Light Waves, Radio Waves Measure to Millionths, D. E. BROOKS. Can Machy v65 nl Jan 1954 p 108-9, 174. Recent improvements in sources of monochromatic light permit lengths up to 0.5 yd and 0.5 m to be measured with accuracy corresponding to one millionth of inch in 10 in. ; method to be of greatest value in measuring of reference end gages ; possibility of reaching international agreement on specified wavelength to be used as ultimate standard of length. Light Waves and Length Standards, I. C. GARDNER. J Opt Soc Am v45 n9 Sept 1955 p 685-90. A brief history of earlier standards of length and of the standards now in use is given. The plan to substitute a wavelength of light for the present international platinum-iridium pro- totype metre as a standard of length is now under con- sideration by the appropriate international committees. The advantages of the proposed plan, the different isotope sources of monochromatic radiation that have been sug- gested by different countries, and the present status of the proposed change are presented. Wavelength Data and Correction Tables for Length Inter- ferometry, C. F. BRUCE. Australia. Commonwealth Sci & Indus Res Organization-Tech Paper n8 1956 87 p. Sets of tables compiled for use in length interferometry ; in- cluded are all relevant data on wavelengths, refractive indices, and correction factors ; to facilitate reduction of results, additional tables are given of vapor pressures and of wavelength fractions with metric and inch equivalents. 57 Fine Measurements, J. R. ADAMS. J Sci Instrum v33 nlO Oct 1956 p 369-75. The limitations of the existing legal standards of linear measure are considered. The use of light waves as a universal reference of linear measure depends on the availability of a source of truly monochro- matic light and considerable progress has been made using the isotope Hg 198 . Many aspects of engineering require measurements accurate to a few micro-inches and instru- ments capable of meeting such demands have been de- signed. Several typical instruments, together with details of the principles on which they are based, are briefly reviewed. Koesters-Type Interferometer, C. F. BRUCE. J Sci Instrum v33 nl2 Dec 1956 p 478-82. Design and perform- ance of instrument which measures lengths of up to 500 mm directly by interferometry ; isotopic light sources are necessary for measurement of longer lengths, and sources containing mercury 198 and krypton 86, as well as natural krypton and cadmium, have been used; results of some length and relative wavelength measurements given to illustrate performance of instrument in air and in vacuo. Broadening and Shift of Spectral Lines Due to the Pres- ence of Foreign Gases, S. CH'EN, M. TAKEO. Rev Mod Phys v29 nl Jan 1957 p 20-73. This comprehensive review is intended as a sequel to that of Margenau and Watson ( 1936-7 ) and deals with pressure-induced broadening and shifts of atomic and molecular lines in the ultraviolet, visible, infrared and microwave regions by neutral par- ticles. The effects of electron and ion collisions and high temperature broadening are not treated. The following topics are discussed: (A) Causes producing broadening and shift of spectral lines ; (B) Impact theory ; (O) Sta- tistical theory ; ( D ) Theory at general pressures ; ( E ) Fine structure pressure broadening of atomic lines. Ex- perimental Observations : ( A ) Pressure shift and broaden- ing of atomic lines; (B) The fine structure and pressure effect; (C) Narrow diffuse bands of various metals pro- duced by close encounters with foreign particles; (D) Pressure boardening of molecular bands in the infrared region; (E) Pressure broadening of lines in the micro- wave region. Line Shape, R. G. BREENE, Jr. Rev Mod Phys v29 nl Jan 1957 p 94-143. This review discusses the development of the theory of line shape and broadening since Michel- son's original contributions to the subject in 1895. The topics reviewed are: (i) Early line broadening theory; (ii) Stark broadening ; (iii) Statistical broadening ; (iv) Interruption broadening; (v) Resonance broadening; ( vi ) Molecular broadening. Secondary and Tertiary Interferometric Wavelength Standards, in 1.5-2.5 Region, D. H. RANK, A. H. GUEN- THER, J. N. SHEARER, T. A. WIGGINS. J Opt Soc Am v47 n2 Feb 1957 p 144-8. Results of measurement of wave- lengths of three absorption lines relative to Hg 198 green line are; P (1), 002-000 band of HCN, 15,345.2887 A in vacuum; R (15), 01'1-000 band of HCN, 24.700.065 A in vacuum ; R (18) , 2-0 band of CO, 23,150.023 A in vacuum ; 29 lines of 002-000 band of HCN have been measured rela- tive to P (1). Coherent Emission Light Source, R. B. GRIFFITHS, R. H. DICKE, Rev Sci Instrum v28 n8 Aug 1957 p 646-8. Sharp, intense emission line may be obtained by use of resonance radiation coherently scattered from collimated beam of atoms ; coherently scattered light may be separated from exciting radiation by placing atomic beam in one arm of Mach-Zehnder interferometer or by diffraction from sev- eral parallel atomic beam pencils ; technique was tested by observing hyperfine structure in light -coherently scattered from beam of sodium atoms. The Possibility of Using Absorption Lines as a Primary Length Standard, W. G. FASTIE. J Phys Radium vl9 n3 Mar 1958 p 405-8 in French. It is possible to establish conditions of pressure and temperature in an absorbing gas so that its absorption lines are invariant in wave- length, whereas emission lines are subject to wavelength shifts dependent upon the condition of excitation. Ex- perimental limitations have, however, restricted work on the primary length standard to emission lines. The de- velopment of techniques is described which make it pos- sible to achieve comparable measurement accuracy with absorption lines of L vapour at a pressure of 2 n and at a temperature of 250° K. A Hg 198 source was viewed along a variable magnetic field. A quarter wave plate in combination with a polaroid sheet isolated one of the Hg 5461 components which illuminated a long path Fabry- Perot interferometer-monochromator which was scanned by variation of air pressure. When the I 2 absorption tube was placed in the light path, the magnetic field could be adjusted until one of several I 2 absorption lines overlapped the Hg line. The shape of the absorption line was meas- ured photoelectrically by scanning the interferometer. Likewise photographs of the Fabry-Perot patterns in ab- sorption were obtained. The half width of the two lines which have been carefully studied was found to be 0.030 wave numbers, about 2.5 times the theoretical Doppler width, presumably due to the nuclear spin effect of I" 7 . In spite of the width of the lines, their absolute invariance in wavelength makes them appear to be at least compa- rable to presently proposed emission line standards. How- ever, the presence of the nuclear spin effect precludes the possibility of narrowing the lines by molecular beam techniques. Fabry-Perot Fringes in White Light Used as Wavelength Standards, F. S. TOMKINS, M. FRED. J Phys Radium vl9 n3 Mar 1958 p 409-14 in French. The term analysis of the complex rare earth and heavy element spectra re- quires highly accurate descriptions of these spectra in, order to avoid the masking of real regularities with spuri- ous ones, and wavelength accuracy approaching that ob- tainable interferometrically is desirable. Such accuracy can be obtained by photographing white light interference fringes as wavelength markers instead of the iron arc or other conventional standards, without the loss of light attendant on the usual methods of interferometry. The white light fringes provide equally spaced standards of uniform intensity and sharpness, whose wavelength values can be easily calibrated by comparison with a source such as Hg 198 , thus avoiding the deficiencies of the iron lines with respect to accuracy, sharpness, and number. The spacing between fringes is determined by the etalon thick- ness and can be chosen at will. The wavelengths are determined as in the conventional method using a Fabry- Perot interferometer, by measuring the fractional order of the unknown by interpolation between neighbouring fringes, and the whole order number either by counting fringes from a known line or by calculation from the known etalon thickness if the wavelength is already known to approximately 0.1 A. In either case the inter- polation distances actually measured are quite small and errors due to emulsion shrinkage or errors in the focal surface of the plateholder are minimized. Wavelengths accurate to ±0.0003 A can be obtained using this system in the 5th order of the Argonne 30 ft. spectrograph, and typical measurements are shown. Some applications of the method to the calibration of the spectrograph are discussed. Interferometric Calibration of Quartz End Standards, E. ENGELHARD. Zeit Instrumkde v67 n3 Mar 1959 p 59-65 in German. See abstract under 2.3.3. Accuracy of Lightwave Scales in Interferometry, E. ENGELHARD, PTB. NPL Symposium nil 1959, Inter- ferometry. H. M. Stationery Office, London 1960 (Paper 2-1) p 19-47 22 figs 14 refs. Describes investigations dealing with linearity of visible radiation sources. Light- wave scales often have periodic or progressive errors caused by deficiencies depending on spectroscopical con- ceptions such as line width, line asymmetry, line struc- 58 ture, and line shift. Paper illustrates certain errors by some earlier, mostly unpublished measurements as well as by some recent observations made with different kinds of commercial cadmium lamps and with the Krypton- isotope lamp developed at the PTB. An addendum pre- sents line profiles of various Cd and Kr lines and the pres- sure shift of the Kr 60561. line. Discussion. On the Accuracy of Wavelength Comparison, K. M. BAIRD, NRO Canada. NPL Symposium nil, 1959, In- terferometry. H. M. Stationery Office, London. 1960 (Paper 2-2) p 49-66 2 figs 10 refs. Declares that an un- certainty of the order of ±0.00021 to ±0.00031 must be ascribed to determinations of wavelength- values up to the present, but that as far as the sources themselves are concerned agreement in the fifth decimal place should be possible. Discusses pointing on interference fringes and maximum attainable precision of setting. Concludes that with refinement of techniques now being developed some- thing approaching the limit imposed by quantum effects will be reached. Spectral Lines of Narrow Breadth, M. BOTTEMA. Ned- erlands Tijdschrlft voor Natuurkunde (Netherlands) v26 n6 June 1960 p 188-91 in Dutch. A survey of recent work on the production of fine spectral lines using discharge lamps containing pure isotopes. Particular mention is made of the work at the National Bureau of Standards and that of Gardner and Nefflen. The least breadth quoted (the breadth at half the height) is 0.003 cm -1 found for Ca 6S by an atomic beam method and for Hg 188 by the use of a spherical interference filter. Grating Diffraction Spectra as Coherent Light Sources for Two- or Three-Beam Interferometry, A. LOHMANN. Optica Acta (Int) v9 nl Jan 1962 p 1-12. It is common practice in two^beam and three-beam interferometry to obtain coherent light sources by using slits in a coherent field (division of wave-front) or by means of suitable mirror devices (division of amplitude). The purpose of this paper is to show that better coherence properties may be realized if one uses grating diffraction spectra as co- herent light sources. As a result one may use a source larger than that permissible in a conventional slit-inter- ference set-up and thereby gain in photometric efficiency. Further, it is shown that the fringes with slit interference are, in general, inhomogeneously distributed in space. The proposed method of interference between the disturb- ances from the different grating spectra does not suffer from these disadvantages. Also one gets achromatic fringes, and hence the grating interference technique is ideally suited for interferometry in the ultraviolet or in- frared region of the spectrum. The physical reason for the achromatism of the fringes is easy to understand, if one considers the fringes as images of the grating pro- duced by lenses which have no chromatic aberrations. Finally, other interferometric devices are also discussed in terms of coherence. Limiting Precision in Scanning Optical Interferometer, R. M. HILL, C. F. BRUCE. Austral J Phys vl5 n2 June 1962 p 194-222. Interferometer uses photoelectric detec- tion and it is shown that principal noise sources limiting accuracy of detection are shot noise in vacuum photocell and photon noise from light source; from limiting pre- cision of pointing on fringe, limiting precisions of meas- urement of small wavelength shifts and of measurement of wavelengths have been calculated. A Thallium Beam Frequency Standard, J. BONANOMI. IRE Trans Instrum (USA) v 1-11 n3-4 Dec 1962 p 212-5. Following a proposal by Kusch, a thallium atomic beam frequency standard was constructed and put into opera- tion. The main characteristic is that its frequency of 21 310 Mc/s is only very weakly affected by inhomogeneities of the C-field. The construction, which is similar to con- ventional caesium standards, differs from these in the fol- lowing main points: a high (1000° K) oven temperature, high (14000 G) A- and B-fields, an oxidized tungsten fila- ment detector. The interaction length is 90 cm ; the Q factor of the resonance is 160 million. The measurements show that the uncertainty in the Zeeman-shift is negligible, while the error arising from an unsymmetrical cavity is the same as in the case of caesium. Vacuum Wavelength of Kr 86 Hg 198 and Cd ul . K. M. BAIRD, D. S. SMITH, K. H. HART. J Opt Soc Am v53 n6 June 1963 p 717-20. Vacuum-wavelengths values are given for a number of visible lines, emitted by Kr 86 , Hg 198 , and Od m , which are useful spectroscopic and metrological standards. The wavelengths are based on a number of Fabry-Perot interferometer measurements during the past few years ; some of the values have also been confirmed by independent measurements on Michelson interferometers. Perturbations to the wavelengths are discussed. 2.3.2. Cadmium Determination Experimental de la Valeur du Metre en Longeurs d'Ondes Lumineuses (Experimental Determi- nation of the Value of the Meter in Terms of the Wave Length of Light), A. A. MICHELSON. Trav et Mem du B.I.P.M. vll 1895 p 3-85. Appendix, 1, "Determinations Metrologiques" by J. R. Benoit and Ch. Ed. Guillaume, p 86-111. Other appendixes p 112-237. Paper covers in- troduction, theory, description of apparatus, methods of observation, Cd light source, results. Cadmium Lamp for Interference Fringes, M. HAMY. CR Acad Sci. 1897 p 749-52. Michelson's lamp (cadmium vapor in a Geissler tube with aluminum electrodes) does not last well. The author describes a form without inte- rior electrodes, in which the tube is terminated by metal caps lined with black lead, with a sufficient condenser, in derivation, in the induced circuit for the purpose of pre- venting perforation of the glass by sparking. Michelson's Reference of the Meter to certain Wave- lengths of Cadminum Light, P. CULMANN. Zeit fur In- strumtkde v22 Oct 1902 p 293-311. Extract from Bui Soc Enc Ind Nat vlOl 1902 p 146. A description of Michel- son's experiments carried out at Sevres, in which, by an optical interference method, he obtained the meter in terms of certain wavelengths of the cadmium spectrum. According to Guillaume the meter has been obtained to an accuracy of .001 mm in terms of those wavelengths. On Standards of Wave-length, H. KAYSER. Astrophys J vl9 Apr 1904 p 157-61 ; Phil Mag v6 n8 1904 p. 568. Dis- cusses discrepancy between Michelson's and Rowland's values. Nouvelle Determination du Metre en Longueurs d'Ondes Lumineuses (A New Determination of the Meter in Terms of the Wave-length of Light), R. BENOIT, C. FABRY, A. PEROT. CR Acad Sci vl44 May 21 1907 p 1082-6. The authors have redetermined the length of the standard meter in terms of the wave-length of the red line of cad- mium and find that 1 m=1553164.13xx, and X=0.6438, 4702, the measurements being reduced to 760 mm and 15° on the hydrogen scale. Determination of Length of International Meter in Terms of the Red Cadmium Line, N. WATANABE, M. IMAI- ZUMI. Imperial Acad of Japan Proc v4 July 1928 p 350-3 in English. Results of author's determination coincides fairly well to that of Fabry, made 21 years earlier ; change of length of international meter prototype during this time has not been detected ; at same time it has been con- firmed that red cadmium line of Michelson's lamp is quite reliable as standard of length. Settling the Primary Standards Controversy. Black and White, vl n4 Feb 1929 p 22-6. Question of selecting pri- 59 mary standard of measurement is discussed ; wave length of red ray of cadmium light is advocated as primary standard in place of present bar standards whose lengths vary in Washington, London and Paris. Interferential Comparison of Radiations Emitted by a New Cadmium Lamp and the Michelson Lamp, J. E. SEARS, Jr., H. BARRELL. Roy Soc Proc vl39 Jan 2 1933 p 202-18. Comparisons were made by means of a Fabry-Perot interferometer, of the wavelengths of the red radiation emitted by the two sources at a series of path differences. Wavelengths are the same to an accuracy of at least 1 part in 16,000,000. Reversal of the Red Line of Cadmium, A. PERARD. CR Acad Sci vl98 Feb 19 1934 p 727-9. Spontaneous reversal of the cadmium red line has been previously noted in the Hamy lamp, and also, under special circumstances, in the Michelson lamp. The effect is easily observable in the hot- kathode lamp excited by the normal current of 2 amperes, but the reversal is suppressed when the current is reduced to about one ampere. Using a hot-kathode lamp with a constriction at the middle of the discharge tube and a current of 1.15 amperes, the highly intense red line pro- duced is unreversed and is capable of interference over path differences up to 280 mm. Use of Cadmium Red Radiation as a Standard in Metrol- ogy and Spectroscopy, C. FABRY. CR Acad Sci vl98 Mar 5 1934 p 861-4. Objection is raised to a statement by P£rard that the possibility of self -reversal in the red radia- tion of Cd disqualifies it from future use as the funda- mental unit of length. All radiations are reversible, but they can be produced without reversal by suitable control of the conditions of excitation. Discusses adopting a wave- length of light as the international unit of length and pos- sibilities of radiations of Kr and Xe as suitable additional standards. Determinations of Fundamental Standards of Length in Terms of Wavelengths of Light, J. E. SEARS, H. BAR- RELL. Roy Soc London Phil Trans Ser A v233 June 22 1934 p 143-216. Definite determinations have been com- pleted of lengths of yard and meter in terms of wavelength of cadmium-red radiation, both in air and in vacuum, re- sults of these determinations given. Intercomparaisons D'Etalons M6triques au Moyen des Longueurs D'Onde Lumineuses ( Intereomparison of met- ric etalons by means of the wavelength of light), W. ROSTERS, J. E. SEARS, JR. Comity International des Poids et Mesures. Proces-Verbaux des Stances 2d ser vl7 1935 p 113-28 2 figs 3 refs. Contents : Introduction ; in- fluence of phase loss; optical comparison of etalons; re- verification of national prototype meters of England and Germany Nos. 16 and 18 ; repetition of the determination of the wavelength of the red radiation of cadmium by NPL ; correlation by PTR of the red ray of cadmium with the German prototype No. 18 by Rosters and Lampe ; summary. Cadmium Red Line as Standard of Wave-Length, C. V. JACKSON. Roy Soc Proc vl55A June 2 1936 p 407-19. An investigation of the condition necessary to ensure ac- curate reproducibility of the wave-length of the Cd red line from various sources is described. The sources used were Michelson lamps of the original vacuum type, and as modified by Perard containing air at a pressure of about 1 mm., Osram hot-kathode discharge lamps and a Schuler hollow-kathode lamp. Under certain specified conditions all sources give a wave-length identical and reproducible with an accuracy of about ±0.0001 A. The Michelson lamp as modified by P6rard is found to be superior to the original vacuum type, and in the Osram lamp the ex- citing current needs to be limited to a value of 1.1 A, to ensure reproducibility with other sources. Interferometric Wave-Length Comparison of the Red Cadmium Radiation Emitted by Different Sources, W. E. WILLIAMS, D. V. GOGATE. Roy Soc Proc vl6 7A Sept 23 1938 p 509-16. A comparison is made between the wavelengths of the red Cd line 6438 A emitted by a G.E.C. Osira Cd lamp and a Schuler hollow-kathode discharge by photographing the Fabry-Perot fringes due to the two sources side by side in the same horizontal plane by means of a specially designed plate-holder. Interferometer gaps up to 10 cm. were used, and the greatest difference re- corded was less than 1 part in 100x10° or 0.00006 A. Comparison of the Prototype Metre with the Wavelength of the Red Line of Cadmium, M. F. ROMANOVA, G. V. WAHRLICH, A. I. KARTASHEV, N. R. BATARCHU- KOVA. CR Acad Sci URSS v37 n2 1942 p 46-51. Values previously obtained for their wavelength of the red line of Cd are set out, in their original form and corrected to apply to dry air at 15° C. and 760 mm. Hg, containing 0.03% C0 2 . Technique and results obtained in a new com- parison between the std. USSR metre (metre No. 28) and the wavelength of this line are described in detail. The method employed involves the use of a Fabry and Perot interferometer, measurement being made on a flat- ended steel metre bar. Mean values obtained for the red line of Cd were ; normal air, X=6440.2488 A. The mean quadratic error was ±0.0002 A. A Light Source for the Primary Standard of Wave-Length, C. W. HSUEH. J Opt Soc Am v36 Mar 1946 p 160^. A light source for the red Cd line, 6438.4696 A, was devel- oped in which the important objections against the Michel- son type lamp were eliminated. It consisted of a dis- charge tube of two Pyrex bulbs joined by a U-shaped capillary in an electric furnace maintained at a tempera- ture between 300° C and 320° C. The current was 2.5A. The intensity of the standard line was strong, as shown by the short exposure time (30 min) required to produce an interferometer spectrogram. The effective light-emit- ting area was 50x2.5 mm 3 which was large enough to cover most spectrograph slits. The Cd standard line was narrow, as shown by the interferometer spectrograms. The Doppler-effect broadening was reduced by observing the light in a direction perpendicular to that of the dis- charge current. Effect of Change of Argon Pressure in an Electrodeless Discharge upon the Reproduction of Wavelength of the Cd m Red Line, N. R. BATARCHUKOVA, F. B. DUBROV- SKII. Optika i Spektrosk vl n3 1956 p 330-3 in Russian. A spectrum line used as a standard of length should be symmetrical in form and stable to ensure reproducibility and it should have no hyperfine structure. The Kr 84 line has been shown to give a shift in its maximum line under change of pressure. Present authors set out to determine the shift and broadening of the Cd 114 line, with change of argon pressure, in an electrodeless discharge. A Fabry- Perot type interferometer was used set up between the collimator and prisms of a Frish spectrograph. On a length of film photographs were taken of the Cd spectrum over a range of some 40 pressures ranging from 1 to 48 mm Hg. A graph of shift v pressure (roughly linear) is given with an expression for its calculation. Preliminary Report on the Isotopic Structure of the Cad- mium Primary Standard of Wavelength, J. F. WISE, K. L. VANDER SLUIS. J Opt Soc Am v46 n8 Aug 1956 p 587-9. With enhanced samples of the eight isotopes of cadmium in electrodeless discharge tubes, measurements of the centre of gravity line position of \ 6438 have been made to better than one part in 25 million or to about 0.0003 A. The estimated resolution, based on Doppler broadening, was 500,000. The observed shifts, compared to a similar normal cadmium source, have been treated by a least squres analysis of a matrix multiplication by the ORACLE. The preliminary results indicate a difference for the extreme masses of about 0.008 A, which is compa- rable with the half -width of the red line in an atomic 60 beam source. With exception of mass 108, there is a regu- lar increase in wavelength for the even mass numbers. The odd mass isotopes appear to give anomalous shifts, falling near the shift for the adjacent larger even mass. The principal source of error in the procedure is associ- ated with apparent shifts due to differences in density of the patterns. Interferometric Measurements in Metrology, M. F. RO- MANOVA. Optika i Spektrosk v3 n5 1957 p 457-72 in Russian. This review article gives accounts of work on (1) the determination of the wavelength of the standard Cd line; (2) measurement of 1 m length standards; (3) the wavelength of the Cd red line of the isotopes 112, 114, and 116; and (4) a method for finding the velocity of light. Results are given in each section with diagrams of the apparatus used. Some Considerations About the Precision of the Interna- tional Standard of Wavelength, S. Y. CH'EN. Am J Phys v26 n7 Oct 1958 p 464-6. The precision of the accepted value for the wavelength of the red line of Cd is discussed. The uncertainty due to the setting of the end marks by a microscope in the interferometric measurement, the cor- rection for the refractive index of air, and the difficulty in controlling precisely the conditions of excitation of the light source are reviewed with considerations for a new standard of wavelength and a new pair of end marks. Preparation of Hg ies and Cd" 4 Electrodeless Lamp, T. TAKO. Report of the Central Inspection Institute of Weights and Measures, Japan v8 n4 report 20 1960 in Japanese. To obtain the best data to use in the making of the lamp and its operation, several Hg 198 and Cd" 1 elec- trodeless discharge lamps with various amounts of iso- topes and argon or neon of various pressures as carrier gas are prepared. The isotope Hg 198 used is the Atomic Energy of Canada Limited's of which composition is re- ported to be, by mass-analysis, Hg 198 : Hg 189 : Hg 200 =98.74 : 1.19: 0.07% and the sum of the rest is less than 0.01%. An ingenious method for taking a small definite quantity of Hg 198 : say 0.2 mg out of its reservoir is explained. The isotope Cd 114 used is Oak Ridge's and its purity is pub- lished to be 98.2%. The reduction of Cd" 4 from Cd" 4 O is simply carried out by the use of hydrogen. For both cases the procedures in making the lamps are thoroughly ex- plained with figures and photographs. Some considera- tions for these lamps are given. The author adds that the half-value width and broadening of the spectral lines of the lamps are under observation and examination, and their results will be reported in more detail later. Wavelengths of Krypton 86, Mercury 198, and Cadmium 114, C. F. BRUCE, R. M. HILL. Austral J Phys vl4 nl Mar 1961 p 64-88. The vacuum wavelengths and the spectral line profiles for four lines of Kr 88 , four lines of Hg 198 and four lines of Cd" 4 were measured. One line, the radiation 2pio-5d 5 of Kr 86 (6057 A), was used as the refer- ence standard in the wavelength measurement. A vari- able gap Fabry-Perot interferometer with electromagnet - ically controlled plate holders was used throughout under vacuum conditions. The use of photoelectric recording methods and mechanical scanning made it possible to compare wavelengths with an accuracy of better than 1 part in 10 s , and half-intensity widths of lines were meas- ured with an accuracy of 0.5 mK (0.0005 cm" 1 ) . The 6057 A line of Kr 88 was examined under different operating conditions of the Engelhard-type and small wavelength shifts due to variation of temperature, pressure, and cur- rent density were measured. The Doppler shift and in- teratomic Stark shift annul each other if the lamp is viewed in the direction cathode to anode to observer, and is operated in a liquid air bath with the temperature near the capillary surface of the lamp at 63±1°K and with a current density of 0.28±0.05 A/cm a . The Doppler shift under these conditions was found to be +0.014±0.003 m" 1 (— 50±10 nA) and the interatomic Stark shift —0.014 ±0.003 m" 1 (+50±10 /*A). Under these conditions also the half-intensity width is 13.4±0.5 mK, and the wave- length emitted is that for the unperturbed state of the atoms to 2-3 parts in 10 9 . This line is superior to the other lines examined for sharpness and reproducibility and other wavelengths may be established in terms of it to at least 1 part in 10 8 . This is the line that has been recommended as the new primary standard of length. 2.3.3. Krypton Eine neue Methode hochster Genauigkeit zur interfero- metrischen Wellenlangenmessung und ihre erstmalige Anwendung zur Vorbestimmung der fur den deutschen Anschluss des Meters an Lichtwellen vorgesehenen Kryp- tonlinien (A New Method of Highest Precision for Inter- ferometric Wave-Length Measurements and their Primary Application to the Predetermination of Designated Kryp- ton Lines for the German Relation of the Meter to Light Waves) , A. P. WEBER. Phys Zeit v29 Apr 15 1928 p 233- 9 3 figs. (English translation is available). The First Spectrum of Krypton, W. F. MEGGERS, T. L. DE BRUIN, C. J. HUMPHREYS. J Res NBS v3 (RP89) July 1929 p 129-62 6 figs 42 refs. About 200 lines were photographed with concave grating and quartz spectro- graphs. From these spectrograms a new list of estimated intensities and measured wave lengths was obtained. Interference Measurements in the First Spectra of Kryp- ton and Xenon, C. J. HUMPHREYS. J. Res NBS v5 Nov 1930 p 1041-57. Determinations of the stronger arc lines made with the Fabry-Perot interferometer. None of the krypton lines exhibit fine structure under the resolving power employed, and the intensities of any satellites which may exist are too small to influence the wave-lengths. First Spectrum of Krypton, W. F. MEGGERS, T. L. DE BRUIN, C. J. HUMPHREYS. J Res NBS v7 Oct 1931 p 643-57 7 refs. Wave length and intensity data have been improved, several close pairs of lines have been resolved, and total number of lines increased to 460, as the result of a change in technique. Au Sujet de la Recherche d'une Raie Nouvelle comme Etalon de Longueur d'onde Lumineuse (New Line Stand- ard of Wavelength), A. PfiRARD. CR Acad Sci vl94 May 9 1932 p 133-5. By means of the Michelson interfer- ometer comparisons have been made between the provi- sional standard red line of Cd and four Kr lines, and reasons are given at length for adopting KrI (5562.22576 A) as standard. Krypton Vacuum Wavelength Measurements, T. A. LIT- TLEFIELD. Proc Roy Soc A vl87 Oct 22 1946 p220-8. The wavelengths of 31 lines in the spectrum of Kr were compared directly with the red Cd standard using a reflecting echelon in vacuo. Uncertainties connected with dispersion in air are thus eliminated. The values are given to 8 significant figures and this accuracy is justi- fied. For details of the optical apparatus see Abstr. 4466 (1933). Mercury and Krypton Isotope Electric Discharge Lamps, their Applications to Interferometry, N. L. HARRIS. Engr vl90 n4095 Nov 3 1950 p 409-11 5 figs 5 refs. Dis- cusses increased sharpness of interference fringes ; the artificial preparation of Hg 188 isotope; Hg 198 lamps; the use of the Kryton discharge. Isotope Electric Discharge Lamps as Spectral Sources for the Exact Measurement of Length, R. D. KNOTT. Gen Elec Co. J vl8 July 1951 p 169-75. Describes the way in which Hg 198 is made and the factors which affect the sharpness of the spectral lines given by such an isotope. The form of lamp found most suitable for interferometry 61 is a water-cooled cold cathode lamp with large hollow Mo cylinders as electrodes and A at 10 mm pressure as car- rier gas. Lengths up to 20 cm, corresponding to an order of interference of about 350 000, can be measured with such a source. To obtain higher source intensities and minimum line width a water-cooled electrodeless lamp has been developed. Future work includes the development of a Kr 84 lamp, cooled in liquid air to reduce the Doppler broadening effect on the lines. The Present State of a Lightwave Standard of Length, E. ENGELHARD. "Maintenance of standards" sym- posium PTB. Feb 1954 p 13-23 6 figs 8 refs. The proposal to establish a lightwave standard of length is reviewed. The basic problem is two-fold ; the development of ap- paratus for the comparison of the lightwave with the metre, and the development of suitable light sources of the chosen standard wavelength. A new interferometric ap- paratus for the former is described, for the comparison and measurement of end gauges, in which corrections for the refraction of air can be made without the necessity for having the gauges themselves in vacuo. The estab- lishment of a lightwave standard of the required preci- sion and reproducibility is discussed in terms of the causes of line-broadening in spectroscopic sources. In particular, the merits of a source using the isotope Kr 84 cooled to 63 °K are mentioned. Spectral Profile and Causes of Broadening of Certain Highly Monochromatic Radiations of Krypton-86, J. TER- RIEN, J. HAMON, T. MASUI. CR Acad Sci (Paris) v245 nil Sept 9 1957 p 960-3 in French. Interferometric meas- urements were made upon the 5649A and 6056A lines of krypton. They are extremely narrow (~0.01A) and do not suffer from self-absorption effects. The 6056A line in particular, which arises from the 2pi„-5d5 transition, is suggested as a new primary standard of length. In com- parison with the 6438A line of Cd, its wavelength is: 6057 • 8021 X 10 -10 m ±0.0001 X 10- 10 m, the error being in the lack of reproducibility of the Cd radiation. Optical Definition of the Meter, H. BARRELL. Nature (London) vl80 Dec 21 1957 p 1387-8. The Comity Con- sultatif pour la Definition du Metre has recommended that the meter should be defined as equal to 1 650 763.73 times the wavelength in vacuo of the orange — red radia- tion 2pin an aperture behind which there is a photoelectric cell. By adjusting a compensating plane, the phase of the cen- tre of the ring pattern may be set to a standard value and thus lengths may be measured in terms of light wave- .engths. The method is more sensitive than visual or photographic measurements and with it a number of sys- tematic errors should be avoided ; it has been checked by re-determining certain wavelengths in the Hg 198 spectrum in terms of that of the green line 5461 A, the results agree- ing to ±1 X 10"% Measurement of a Profile in Coherent Light, J. C. VIENOT. Rev Opt v35 nlO Oct 1956 p 517-25 in French. The measurement of the diameter of a small object, such as a thread, is difficult with incoherent light because of the out of focus images of the third dimension. The diameter can be measured more precisely from the diffraction fringes formed with coherent light. Conditions are ob- tained for best definition and most accurate measurement. Sample results are quoted. Modified Method of Fizeau Fringes for Thickness Measure- ments, H. OSTERBERG, D. LaMARRE. J Opt Soc Am v 46 nlO Oct 1956 p 777-8. The exit slit of a monochroma- tor is focused upon a pinhole located in the first focal plane of an objective utilized for viewing the multiple- beam fringes formed by interreflections between two in- clined surfaces, one of which is stepped. The step is focused into the plane of an eyepiece whose reticule con- tains a pair of parallel lines between which successive fringes are set and measured by rotation of the wave- length drum. The preferred, and possibly novel, method of interpreting the observations is discussed. Precision Measurement, I. C. GARDNER. Ordnance v41 n222 May-June 1957 p 1099-1100. Reports good progress in producing an interferometric system which gives a pre- cision of 10" 7 in. as a standard for measuring gage blocks. New Techniques in Interferometric Metrology at the National Research Council of Canada, K. M. BAIRD. J Phys Radium vl9 n3 Mar 1958 p 384-9 in French. Deals with some of the new techniques which are being used to assist in the redefinition of the international meter. The first of these is a method of cyclical scanning of the inter- ference fringes formed by the Fabry-Perot etalon. The scanning is done by pressure changes in the atmosphere surrounding the etalon. This method has been applied to the measurement of small wavelength shifts. A modifica- tion of this technique, using a photographic record, en- ables a great many spectral lines to be recorded simul- taneously. An interferometer, based on Michelson's type, makes use of a technique whereby precise determination of the order of interference can be made conveniently ; it enables line standards of length to be calibrated as easily as end standards. New Gauge Interferometer, P. HARIHARAN, D. SEN. J Opt Soc Am v49 n3 Mar 1959 p 232-4. An interferometer for the absolute measurement of the length of end stand- ards is described in which the optical path difference in- troduced between the interfering beams is only half the length of the gage. This permits the direct measurement of gage blocks up to 1 m long with the isotope sources currently available. Other advantages of the instrument are its relatively compact layout and simplicity of opera- tion. Application of Interferometry to the Routine Measurement of Block Gauges, S. P. POOLE, J. H. DOWELL, NPL. Optics in Metrology, P. MOLLET. Pergamon Press 1960 p 405-19 8 figs 2 refs. An interferometer designed at NPL in 1937 deals with twenty gages in one operation. Methods employed are given with a brief survey of sources of error. Interferometer is illustrated with details of im- provements. Introduction to Interferometry, T. J. O'DONNELL. Am Maeh/Metalworking Mfg vl04 nl2 June 13 1960 p 123-46. How interferometers can be used in shop to measure and compare lengths, angles, parallelism, and surface condi- tion. Interferometric Instrument for the Rapid Measurement of Small Diameters, D. H. BLACKBURN. Rev Sci Instrum (USA) v32 n2 Feb 1961 p 137-9. The test fibre is placed between two optically flat surfaces and, using the fibre as a fulcrum, the upper flat is adjusted until the surfaces are parallel ; the absence of interference fringes between the surfaces is used to indicate parallelism. Controlled tilting of the upper flat is obtained by adjusting, with a micrometer screw, a sliding wedge under a lever attached to the upper flat. The fibre diameter is a linear function of wedge position as indicated by micrometer screw set- ting. Spectrophotometric Studies on Inorganic Crystals. II. Measurement of Thickness of Thin Crystals by Interfer- ometry, Y. KONDO. Sci of Light Japan vlO n3 Dec 1961 p 167-75. Two-beam and multiple-beam interference methods are applied to the measurement of thickness of some inorganic mono-crystals and the advantages of the two methods are compared with each other. Although the multiple-beam method has greater accuracy than the two- beam one, the latter is more suitable than the former for microspectrophotometry of rather thick and coloured crystals. Use of monochromatic light from a monochro- mator is advisable, for continuous varying of wavelength simplifies the measurement. In some instances, use of continuous variation of refractive index of medium is advantageous. The relation between interference fringes due to monochromatic light is experimentally investigated. Certain Changes in the Regulations for Checking and Using Block Gauges, L. K. KAYAK. Meas Techn 1961 n6 Dec 1961 p 427-31 1 fig 4 refs. Translated from Izmer Tekh n6 p 1-5 June 1961. Evaluates measurement errors of interferometric methods of measuring gage blocks. Causes of Errors in Interference Metrology, M. CON- STANS. Rev Opt (France) v40 nl2 Dec 1961 p 601-48 in French. The universal use of interference methods in aerodynamics makes evident the need for a systematic study of the errors associated with such methods. These errors are classified into four different types: (1) errors due to the refraction, i.e. to the curvature of the rays owing to the refractive index gradient ; (2) errors altering the gradients themselves (draught, vibrations, change in temperature . . .) ; (3) errors due to the instrument itself and to the adjustment conditions; (4) errors due to the 71 771-846 O— 66- interpretation of results. The first errors due to refrac- tion are theoretically studied for a two-dimensional medium where the refractive index is varied continuously. The calculation was carried out in the second order ap- proximation. Two types of errors may occur ; (a) errors affecting all real objects placed into the jet or up-stream ; Ob) errors affecting only the interferogram fringes. It is shown that the last ones can be cancelled out, provided that the focusing plane is situated at the second third down-stream of the jet. Formulae for an evaluation and correction of errors are given. The values obtained are compared with the accuracy yielded by the measuring in- strument. It is concluded that those errors are very often negligible both in interferometry and in strioseopy. For the experimental checking, the gradients are obtained by diffusion of a hyposulphite crystal into distilled water or by diffusion of a concentrated solution of hyposulphite salt into distilled water. The results obtained concern a zero incidence angle : ( 1 ) The errors affecting the interfero- grams appear to be very small as compared with those re- sulting from the instrument imperfections, wherever the focusing plane may be inside the jet and whatever the thickness of the jet may be ( 100 or 10 mm ) , provided the gradients remain smaller than 5X10" 5 mm -1 . (2) The formulae giving the deformation of a real object are checked for several positions of the object and for several gradient values. Very often the checking corresponds to an accuracy of about 6 or 8%. It is always better than 15%. Errors not resulting from refraction are studied experimentally : the equipment described makes it possible to get rid of them. It consists of a horizontal Mach- Zehnder interferometer realized in silica. Over the whole field (60 x 60 mm) the residual defect is smaller than X/13. By an isothermal jacket the temperature is kept constant to better than 0.03°C in the course of 12 hours. Vibrations are eliminated by means of an elastic suspen- sion. A Method of Measuring Very Small Optical Paths, A. MARECHAL, O. DUPUY, M. RENAULT. Optica Acta ( Int) v9 nl Jan 1962 p 47-54 in French. Describes a meth- od, derived from the three-slit method of Zernike, which permits the measurement of differences of optical path length of the order of 10 A, while giving a much higher luminous flux than the original method. It can be used, for example, for the measurement of phase plates, of very small refractive index differences (in glass, liquids or gases) and it can be used on very small samples. Interferometry in Length Measurement, J. L. GOLD- BERG, R. H. BROOKMAN. Electronic Teehnol v39 n4 5 6 Apr 1962 p 140-4, May p 186-91, June p 238-43. Elec- tronic counting of interference fringes enables automatic and accurate measurement to be made ; problem of ex- tracting useful signal from moving 2-beam interference fringe pattern is discussed ; circuit for amplification of small photoelectric currents encountered in transduction of light output of interferometer by photomultiplier, and subsequent generation of counting waveform by trigger circuit ; application of circuit to reversible counting. Inspection Time Slashed on Parts Adaptable to Coordinate Measuring Techniques, C. H. WICK. Machy (NY) v69 n2 Oct 1962 p 107-9. Inspection time was reduced by about 80% (on applicable parts) and quality control greatly im- proved by means of ShefHeld-Ferranti coordinate measur- ing machine at Plymouth (Mich) Div of Burroughs Corp; hole and surface locations can be quickly and accurately measured on this machine, with dimensions of both X and Y coordinates being displayed simultaneously on direct readout panel; lengthy and laborious bench checks with gage blocks, surface plates, and height gages are no longer required. Methods of Narrowing Spectral Lines for Interference Measurements of Length, A. P. KIRICHENKO. Uspekhi fiz Nauk (USSR) v78 n3 Nov 1962 p 525-38 in Russian. English translation in: Soviet Physics-Uspekhi (USA) v5 n6 p 998-1005 May-June 1963. A detailed review is given of some methods employed for the production of strictly monochromatic radiation having breadth smaller than the Doppler breadth. The methods described are inter- ference monochromatization using a spherical Fabry- Perot etalon, absorption monochromatization in which radiation is transmitted between two close-lying absorp- tion lines produced by Zeeman splitting and an interfer- ence-compensation optical scheme. Laser techniques are only briefly mentioned. Application of Microwave Techniques to Noncontact Precision Measurement, D. H. PARKES. ASME-Paper 63-WA-346 for meeting Nov 17-22 1963 5 p. Developments in application of microwave interferometry in cases where standard gaging equipment is limited either by contact characteristics, or frequency response, or peculiarities of material or gaging situation. Method for Precise Evaluation of Interferograms, G. D. DEW. J Sci Instrum v41 n3 Mar 1964 p 160-2. Photo- electric scanning device is described, capable of evaluat- ing interferograms of 2-beam interference systems to 1/100 fringe or better ; precision is attained with barest mini- mum of equipment. Fringe Pattern of Oscillating Fabry-Perot Interferometer, K. D. MIELENZ. J Res NBS Eng & Instrum v68C n2 Apr-June 1964 p 73-81. Experiments and theory of de- pendence of fringe pattern upon vibration amplitude; if fringes of stationary interferometer are wide, fringe pat- tern tends to disappear at certain values of amplitude; if stationary fringes are narrow, splitting of fringes oc- curs at certain amplitudes; in both cases, stationary pat- tern reappears, with reduced contrast, at intermediate amplitudes; applicability for measurement of vibratioD amplitudes is discussed. Measurement of Fringe Displacement in a Gauge Inter- ferometer, M. J. PUTTOCK. J Sci Instrum (GB) v42 n4 Apr 1965 p 298-9. A description is given of a second de- vice for the measurement of fringe displacements in a gauge interferometer. This device is located in the paral- lel beam of the interferometer whereas the original device was located in a plane conjugate with the lapped surface of the baseplate. 2.4.2. Fringe Count Interferometers and Dilatometers Uber die Ausdehnung starrer Korper durch die Warme (Regarding the Expansion of Rigid Bodies by Heat), H. FIZEAU. Ann der Phys vl28 Oct 3 1866 p 564-89. In- cludes a brief review of the methods of observation apply- ing fringe count methods. These had been previously described in CR Acad Sci May 1864 and Ann Gbim Phys Ser IV T II vl23 p 515. Millimeter and Centimeter Standards, R. BENOIT. Bui Soc Franc Phys n97 1897 p 2-3. Standards, by the Bureau International des Poids et Mesures are described, on the principle of measuring displacements by the travel of cir- cular fringes in a Michelson's refractometer, taking the four cadmium radiations simultaneously ; absolute coin- cidence of the limit of the standard with the plane of reference in the instrument being indicated by certain characteristic fringes. Interferential Calibration of Screws, M. HAMY. CR Acad Sci 126 1898 p 1772-4. A plane mirror, thickly sil- vered, is placed on the carriage of a micrometer or dividing engine, and opposite to it, but attached to the micrometer screw, is placed a lens of very slight curvature, the side nearest the plane mirror being half silvered. Circular in- terference fringes are seen and screw is calibrated by 72 determining variation in number of bands produced as lens is advanced. Application des Phenomenes d'Interference a des Deter- minations Metrologiques (Determinations of Length by Interference), R. BENOIT. J Phys v7 1898 p 57-68. Ar- rangement used toy Michelson to express the length of the meter in terms of wave-lengths of cadmium radiation is used by Benoit for standardizing mm and cm. A Compensated Interference Dilatometer, A. E. TUTTON. Phil Trans Roy Soc A vl91 1898 p 313-64. A form of Fizeau interference dilatometer of increased sensitive- ness. Illuminating and observing apparatus is described, p 324-32. Extensometers, Calibration of an Interference Appara- tus for the Calibration of Extensometers, J. MORROW, E. L. WATKIN. Phys Soc Proc vl9 April 1905 p 365-70 2 figs ; Phil Mag v9 Jan 1905 p 129-35 2 figs. An inter- ference apparatus is described by which extensometers may be accurately calibrated. Specimen tests are given. Interference Extensometer, E. GRUNEISEN. Zeit In- strumKde v27 Feb 1907 p 38-51. Communication from the Phys. Tech. Reichsanstalt. Describes, with illustra- tions, an instrument by which elastic extension of test pieces of metals is measured, using the principle of Hai- dinger's rings. The elastic modulus is given for about 25 various metals and alloys, together with the chemical composition and density, and modulus as observed by transverse vibrations, and in a few cases the modulus found by longitudinal vibrations. A Wave-Length Comparator for Standards of Length : An Instrument for Fine Measurement in Wave-Lengths of Light. With an Appendix on the Use of Wave-Length Rulings as Defining Lines on Standards of Length, A. E. H. TUTTON. Phil Trans Roy Soc A v210 1910 p 1-34 13 figs. Interference comparator constructed for the Standards Dept. of the Board of Trade. Microscope cross-hairs are set on graduations. Differences are measured by counting interference bands as screw is turned. Interferential Contact Lever Experiments Relating to the Elastics of Small Bodies, C. BARUS. Proc Nat Acad Sci vo Feb 1919 p 44-9 9 figs. Apparatus designed by writer in which interferential contact lever measures strain cor- responding to stress imparted by pushing springs. The Use of the Interferometer in the Measurement of Small Dilatations or Differential Dilatations, C. G. PETERS. J Washington Acad Sci v9 May 19 1919 p 281-4. Equations for determining changes in length ob- servable with dilatometer originated by Fizeau. An im- proved form of Fizeau's interferometer consists of three coned pins, 4 mm across the base, 10 mm long. Three conical holes 0.5 mm diam., 0.2 mm deep, 15 mm apart are drilled in the lower surface of the cover-glass plate. The pins rest on the lower glass plate. These holes keep the pins in place and stop any creep of the cover glass, and also serve as reference marks in determinations of the change of length of the pins. The fringes formed by interference are viewed by a Pulfrich interferometer. Simple theory given and uses for small samples. A New Interferential Dilatometer, I. G. PRIEST. Sci Papers NBS vl5 Feb 28 1920 p 667-78 2 figs. Apparatus is designed to measure small changes in length by "change in width" of interference fringes, instead of measuring them by displacement of fringes. The substance whose thermal expansibility is required is used as a pillar to support a glass plate. The other side of the plate is sup- ported by some standard substance, such as glass, quartz, or metal, of known expansibility. A Universal Interferometer, A. E. H. TUTTON. Roy Soc Proc vl04 Aug 1 1923 p 47-62 6 figs. Describes appara- tus constructed for author by Troughton & Simms for measurement of small amounts of motion, slight deforma- tions, short distances, and minute objects, of any nature whatsoever. Instrument provides steadiness and perfect control of the movement of the interference bands ob- tained. The interval between two interference bands is readily divisible into 0.01 parts by a micrometer. An Optical Method of Measuring Small Vibrations, H. A. THOMAS, G. W. WARREN. Phil Mag v5 May 1928 p 1125-30. An interferometer method of measuring small mechanical vibrations is described and its application to the measurement of the vibration of a stiff reed is con- sidered. Interferometer for the Investigation of the Processes of Growth, K. W. MEISSNER. Phys Zeit v30 Dec 15 1929 p 965-71. Paper read before the Deut. Physikertag, Prague, Sept 1929. An interferometer of the Michelson type is described having the following features: (1) In- stead of the usual horizontal mounting the movement is vertical. (2) The one interferometer mirror is movable horizontally by means of a slot and screw, while the second may be moved vertically or by a sensitive Roberval balance arrangement so that it may be moved by very small forces (20—40 mgm. weight), such as those involved in plant physiological problems. (3) In place of the plane inter- ferometer mirror a combination of curved mirrors (con- cave and convex) with a plane mirror is employed. The interference fringes are then concentric Newton's rings. By simple adjustment straight line interference bands may be obtained. (4) With the help of an auxiliary scale achromatic interference fringes may easily be obtained, so that an objective demonstration by projection with white light is easily possible. Quelques Etudes Particulieres au Dilatometre Fizeau (Some Special Studies in Dilatometry ) , A. PERARD. Trav et mem BIPM vl9 1932 127 p 17 figs. Contents : In- troduction ; Principles of the Fizeau dilatometer (and illustrated description) ; execution of the experiments for the determination of those due to the tripod ; determina- tion of the relative expansions of the prototype meters ; refractive index of air ; tables of observations and calculations. Amplifying Lever for Measurement of Small Displace- ments, G. A. FINK, G. W. FOX. Rev Sci Instrum v4 May 1933 p 276-9. System used for measuring piezo-electric deformations of quartz and tourmaline plates, involving use of interference fringes. Arm ratio is 1864 to 1. Der Interferenzmessapparat als Hifsmittel der Kera- mischen Forschung (The Interference Measuring Appara- tus as an Aid in Ceramic Research), H. LEHMAN, M. T. SCHULZE. Zeiss Nachr nlO Jan 1936 p 6-13 6 figs. Con- tains description of Pulfrich viewing device. Contents : The principle of the Fizeau method ; optical path and arrangement of the viewing apparatus ; heating arrange- ment ; measuring process ; test pieces ; computation of air layer thickness. New Type of Interferometer, A. HOYT. J Opt Soc Am June 1936 p 262-6. A description is given of an extremely simple interferometer which is easy to construct and ad- just. It is admirably suited to the measurement of small displacements. It can be adjusted and used with either monochromatic or white light. Each of the small, light mirrors used needs only one optical surface. The sensi- tivity can be increased by using multiple reflections with- out unnecessary loss of intensity, since the surfaces are all fully aluminised. Tests on the interferometer have shown that it is capable of detecting displacements of \/2n where X is the average wave-length of the light used and n is the number of reflections from the moving mir- ror (nearly normal incidence). Under best (easily attain- able) conditions 14 reflections can be obtained, whence a shift of 1 fringe would correspond to X/28. Extreme 73 care in the preparation of optical parts might yield 20 reflections and a displacement sensitivity of X/40 for each fringe shift. A compound multiple reflection interferom- eter is also described which gives twice the sensitivity mentioned above. Improved Interferometric Procedure with Application to Expansion Measurements, J. B. SAUNDERS. J Res NBS v23 July 1939 p 179-95. The Fizeau interferometric meth- od, as applied to thermal expansion measurements, has been studied in order to determine the source of some very serious errors and to find means of reducing such errors. Two types of errors were found to predominate. These may be termed ( 1 ) error caused by tilting of the spacers under mechanical forces, and (2) error caused by varia- tions in air-fllm thickness at the contact points. Such errors often amount to 10% and may, under certain con- ditions, exceed in magnitude 50% of the value sought. In this paper the two types of errors are considered in detail, and a modified procedure is given whereby the errors are reduced to a magnitude comparable to other unavoidable errors, such as those in reading the fringes and in deter- mining the actual temperature of the specimen. Characteristics of Tuckerman Strain Gage, B. L. WIL- SON. ASTM Preprint n94 for meeting June 26-30 1944 10 p. By means of interferometric calibration device used at National Bureau of Standards for calibrating gages and autocollimators, experimental results are secured which indicate variations of calibration factor with dif- ferent conditions of use ; description of autocollimator and strain gage; calibration device; behavior of gage. Interferometer Measurements on the Expansion of Iron, J. B. SAUNDERS, J Res NBS v38 Aug 1944 p 75-86. Sev- eral sets of data, taken on relatively pure Fe by different observers and different procedures, are compared. The results show agreement between data taken with those interferometer methods that are free from tilting of spacers and air-fllm errors, whereas the failure to elimi- nate these two errors produces data that cannot be dupli- cated except by chance. The interferometer data that are free from these errors agree with data obtained by other precision methods. Some investigators claim to have found indications of a characteristic temperature effect in the expansivity curve of iron in the temperature range from 0° to 250° C. When the expansion data are freed from errors of tilting and changes in air films, the in- dications of such effects do not appear. Apparatus for Photographing Interference Phenomena, J. B. SAUNDERS. J Res NBS v3 n35 Sept 1945 (RP 1668) p 157-86, 4 supp plates. Description of photograph- ic instrument designed for recording changes produced in order of interference fringes over long periods and for recording large changes in order of interference; when this instrument is used with interferometric system for studying changes caused in transparent solids by heating, it can be made to yield continuous record of simultaneous changes in temperature, time, index, strain, and density. Bibliography. Optical Method of Determining Thickness of Geiger Tube Windows. F. W. BROWN III, A. B. WILLOUGHBY, Rev Sci Instrum vl9 Nov 1948 p 820-1. The banded spectrum of white light formed by reflection from the mica window with an angle of incidence (r) of 10°, is compared in a direct-vision pocket spectroscope with the Hg spec- trum (of white fluorescent light) and the number (n) of interference fringes between the yellow (\i=577 m/x) and blue (X 5 =436 m/i) Hg lines is counted. Then the surface density of the window, W=[ pXiXglQ- 2/u cos r{\i — X 2 ) w,=0.163 n m/cm", where p=density of mica (2.85 g/cm 3 ), /t=index of refraction (1.58). Multiple-beam Interferometry, S. TOLANSKY. En- deavour v9 Oct 1950 p 196-202. An account is given of the application of multiple-beam interferometry to the study of metals, surface polish, hardness testing, and formation of slipbands in stressed metallic crystals. The technique is also used in studying the mechanism of crystal growth in certain minerals, the hardness anisotropy of diamond undergoing abrasion test, and the modes of oscillation of quartz. A new method of obtaining sharp fringes and the adaptation of an older method for examining defects in mica are described. A Photoelectric Interferometer for Measurement of Di- mensional Changes, R. N. WORK. NBS Tech Rept n5 Oct 30 1950 5 figs 8 refs. Several applications are cited. Photoelectric Recording Interferometer for Measurement of Dimensional Changes, R. N. WORK. J Res NBS v47 n2 Aug 1951 (RP2230) p 80-6. Method for recording of light intensity at reference point in image of interference pattern for automatic plotting of fringe count vs. thermo- couple electromotive force in interferometric dilatometry ; application of technique to measurement of coefficients of expansion and to determination of transition temperature of coefficients of expansion and to determination of transi- tion temperatures in rubber-like materials. Wavelength or Length Measurement by Reversible Fringe Counting, E. R. PECK, S. W. OBETZ. J Opt Soc Am v43 n6 June 1953 p 505-9. Optical and electronic methods for reversible counting of fringes from corner-cube or Michel- son interferometer ; counter operates in either direction at least as fast as 1000 per sec. Electronic Location of Interference Fringes, J. PETERS, G. STROKE. J Opt Soc Am v43 Aug 1953 p 668-72. A device is described which determines a zero reference position in terms of interference fringes and measures any shift to a small fraction of a fringe. It can be used with static or slowly moving fringes, and is based on the principle of superposition of two images of the fringe pattern in polarized light on the single slit of a photo- multiplier tube. By means of a rotating Polaroid as optical shutter an alternating signal is produced of which the amplitude and phase are a function of the displace- ment. A Bidirectional Electronic Counter for Use in Optical In- terferometry, F. H. BRANIN, JR. J Opt Soc Am v43 Oct 1953 p 839-48. A bidirectional electronic counter has been developed for both additive and subtractive counting of electrical impulses in either binary or decimal notation. Using two coherent syncopated sine-wave input signals, such as may be derived from a Twyman-Green interferom- eter with a stepped mirror and two phototubes, direc- tion sensing is obtained by pulse forming and selecting circuits which feed pulses to either the "add" or "sub- tract" channel, depending on the phase relation between the two input signals. In the binary counting circuit, the add and subtract channels each operate separate coin- cidence amplifiers which select the proper phase for trans- ferring the trigger pulses from one binary stage to the next. In the decimal counting circuit, which consists of binary stage followed by a reversible ring-of-five additional coincidence amplifiers determine the direction in which the trigger pulses transfer the count around the ring. Counting rates in excess of 150 kc have been achieved with both circuits and higher rates are possible with proper design. Although the best directional counting circuit was designed primarily for the purpose of elimi- nating the tedium of counting interference fringes visu- ally, it can also be used for differential counting with two separate (incoherent) pulse inputs. A review of con- temporary development in this field is given, along with a discussion on applications of the circuit in interferometry and analogue-to-digital conversion devices. 74 Electronic Fringe Interpolator for an Optical Interferom- eter, R. D. HUNTOON, A. WEISS, W. SMITH. J Opt Soc Am v44 n4 Apr 1954 p 264-9. Electronic fringe counter for use with interferometers; provisions for automatic counting of integral fringes, interpolation to within 1/200 wavelength, and indication of motion direction of inter- ferometer plates. An Optical Dilatometer, J. TERPSTRA. App Sci Res B v4 n6 1955 p 434-46. An instrument is described which enables displacements of 2 X 10" e cm to be determined by means of interference phenomena of monochromatic light. The measuring pin is pushed against the specimen with a force of 4000 dynes. The instrument setting remains Stable for a period of several hours. Interferometric Control of Grating Ruling with Continu- ous Carriage Advance, G. R. HARRISON, G. W. STROKE. J Opt Soc Am v45 n2 Feb 1955 p 112-21. Control method for manufacture of optical gratings; phase of low fre- quency a-c signal produced by interference fringes passing across photoelectric pickup is continuously compared with that of standard signal indicating periodic diamond motion involved in ruling stroke ; blank positioning is con- trolled within *4o of fringe. A Machine for Measuring Interference Fringes, Y. GRI- MOD. Rev. Opt v34 nlO Oct 1955 p 509-11 in French. An automatic photoelectric device is described which com- putes the positions of interference fringes automatically, by means of a photocell. The fringes are then counted on an automatic computing machine. The system has a capacity for counting up to lengths of 100 mm. Fractional-Fringe Measurements with Corner-Cube Inter- ferometer, E. R. PECK. J Opt Soc Am v45 nlO Oct 1955 p 795-7. Extension of fringe counting by interpolation to about 0.01 fringe ; photoelectric method for providing ref- erence reading of position of interferometer carriage to same accuracy as that of interpolation. An Interference Comparator for Evaluating the Differ- ence Between End- Standards, M. DUHMKE. Zeit In- strumkde v65 nl Jan 1957 p 5-17 in German. By employ- ing a difference method against a standard, lengths of slip-gauges (up to 100 mm) can be evaluated to within 0.01/u. The method described enhances the Fizeau-fringe sharpness by multiple reflection. Plucking Millionths Out of Thin Air, J. RITCHIE. Tool- ing & Prod v22 nl2 Mar 1957 p 83-7. Fringe count microm- eter described employs interferometry in combination with electronic digital counting ; instrument is intended to further extend lineal measurement accuracy by referenc- ing dimensions to wavelength of light ; gage blocks or other secondary standards are not needed to set up or calibrate instrument as built-in light source is itself standard. An Algebraic Electronic Counter for Interference Fringes, G. RUFFINO. R. C. Accad. Naz. Lincei v22 v5 May 1957 p 602-5 in Italian. A simple direction-sensitive counter is described, using dekatron tubes to give an immediate display of the fringe count. Details of the electronic cir- cuit are given. Photoelectric Fringe Signal Information and Range in Interferometers With Moving Mirrors, G. W. STROKE. J Opt Soc Am v47 nl2 Dec 1957 p 1097-103. Photoelectric receptors and electronics have greatly increased the ac- curacy and simplicity of interferometric measurements. Theoretical and experimental investigation of instru- mental and light source conditions required to ensure ade- quate information content and "visibility" of fringe signals were made. Mirror parallelism requirements needed to maintain maximum signal modulation and to reduce apparent local displacement errors, for use with equal inclination interferometers, are expressed by the fractional number of equal thickness fringes within the mirror traverse being reducible by decreasing this aper- ture and ensuring best local parallelism. The "effective" length per fringe, determined by photoelectric flux integra- tion over an angular range within the source angular radius a, is approximately (\/n)2(l — a, 2 /4). Theoretical expressions obtained for the fringe "visibility" with simple single isotope lines of Gaussian shape are in good accord with experiments, showing that the fringe amplitude with perfectly adjusted continuously moving interferometers is governed by an expression usable for estimating in- terferometric range with such sources as the green Hg J68 line with an effective Gaussian width of about two Dop- pler widths at room temperatures. The further exten- sion of interferometric range with measurement precisions of 1 part in 10 8 over traverses exceeding 300 mm ap- pears feasible. Length Measurement by Fringe Counting (II), Y. SA- KURAI. Report of the Central Inspection Institute of Weights and Measures, Japan, v7 n2 report 15 1958 in Japanese. The operating principle and the error of an interferometer of which reflecting mirrors are made of a pair of front-surface mirrors so mounted as to form a right angle, were discussed analytically. It was found that when the interferometer was used for the measurements of length by the fringe counting method, the following ad- justments were most important: (1) the positions and dimensions of entrance apertures of phototubes, (2) the linearity of the locus of the moving mirror pair, (3) the angle between the intersection line of the moving mirror pair and the direction of incident parallel light. Interferometric Systems of Continuously Moving Mirrors and Photoelectric Detection, G. W. STROKE. J Phys Radium vl9 n3 Mar 1958 p 415-23 in French. Interfero- metric measurements over the large path distances of several hundreds of millimetres have been recently con- siderably improved and simplified by the use of photo- electric receptors and electronics. Theoretical investiga- tions of the conditions required to ensure adequate information content in the centrifringe range and visibility of the fringe signals in two-beam equal-inclination inter- ferometers permits the examination and separate verifi- cation of (1) mirror parallelism requirements needed to maintain maximum fringe signals and to reduce apparent local displacement errors by minimizing the fraction num- ber of equal-thickness fringes within the mirror aperture and (2) inherent interferometric conditions having to do with the interferometer geometry, the source line shape and photoelectric noise characteristics. Integration of the photoelectric flux within an angular range determined by the source radius and collimator focal length leads in practice to an "effective length" per fringe different from half a wavelength by parts in 10 7 . Theoretical fringe signal amplitude curves corresponding to simple single lines of Gaussian shape, such as the green Hg 198 line, are in good accord with experiments performed over path distances of ±320 mm and serve to estimate range and accuracy in measurements with machines where the causes of improper or variable mirror adjustments have been overcome to a large extent by mechanical perfection and servomechanieal control. Reversible Photoelectric Fringe Counting, R. L. EISNER. Rev Sci Instrum v29 n6 June 1958 p 521-3. Simple modifications of a Fizeau interferometer are shown which give a sense of direction to the passing fringes, enabling a suitable counting system to operate reversibly. Very fast counts can be made accurately using an electronic circuit actuated by four phototubes sighted on four points in the fringe pattern. An oscilloscope display can be used for fractional fringe interpolation. Calibration of Mirror Extensometers by Optical Inter- ferometry, A. F. C. BROWN. Eng vl86 n4S22 Aug S 1958 p 180-2. Types of mirror extensometer ; typical results of calibrations; factors governing behavior of Rhomb type 75 extensometers. Communication from Nat. Physical Lab- oratory. Measurement of Small Displacement by Using Newton's Rings and an Objective Micrometer, I. IKEDA. Mem. Faculty Eng Hokkaido Univ. vlO n46 Oct 1958 p 491-503. Some details are given of the application of Newton's rings methods to the measurement of small displacements. Possible sources of error are examined in detail and a number of examples are illustrated. The method de- scribed is applied to the investigation of the aging of pieces of concrete. Length Measurement by Fringe Counting (3rd Report), Y. SAKURAI. Report of the Central Inspection Institute of Weights and Measures, Japan, v8 n2 report 18 1959 in Japanese. The characteristics of interferometers of which reflecting mirrors are a right angle prism or a pair of front-surface mirrors mounted to form a right angle, are discussed as a continuation of the 2nd report. When the length is measured by means of fringe counting meth- od with those interferometers, it is confirmed quantita- tively that the measured values have the errors essentially in following eases, what has been expected to some ex- tent, (i) The angle between the reflecting surfaces de- viates from the right angle, (ii) The hypotenuse of right angle prism is not parallel to the intersection of its re- flecting surfaces. Length Measurement by Fringe Counting (4th Report), Y. SAKURAI, S. TAKAHASHI, K. OTA, T. YOSHIDA. Report of the Central Inspection Institute of Weights and Measures, Japan, v8 n3 report 19 1959 in Japanese. The experimental apparatus to research the method for calibrating the graduated scales with wavelength of light is shown in this report. The graduated scale to be meas- ured is set on the moving carriage on which one of the reflectors of the corner-cube interferometer is fixed and the lines of this scale are viewed by a photoelectric micro- Scope. The comparisons of mechanical displacement of moving reflector with wavelength are carried out by count- ing the number of interference fringes passing through the field of the interferometer during transference of the moving reflector. To distinguish the direction in which fringes move, two photo-tubes are arranged to view two parts of a fringe pattern where the variations of light intensity resulting from movement of fringes are different in phase by approximately 90°. The outputs of the photo- tubes are transmitted to a reversible electronic and mechanical counter, and a fraction indicator. The num- ber of fringes is given by the indications of these instru- ments. The accuracy of this experimental apparatus was 0.03/i in the length of 20 mm. High-Temperature Rotor Bore Dilatometer Unit, J. WEST. J Sci Instrum v36 nl Jan 1959 p 1-3. The in- strument measures optically the dilation due to centrifugal stresses of the bore of a steam turbine rotor under run- ning conditions. The measurements are independent of vibration of the rotor. Light from an illuminated pin- hole within an autocollimator is collimated on to a system of three mirrors supported kinematically inside a cylin- drical cartridge, which is pushed into the rotor bore of the turbine. Two of the mirrors are fixed to the cartridge, and the third is hinged and connected to a feeler which is spring loaded against the rotor bore. With all three mirrors mutually at right angles, the light is reflected back to the autocollimator in exactly its own path, independent of any relative movement between the dilatometer and the autocollimator. On expansion of the rotor bore, the third mirror is displaced, tilting the returned beam of light. Since the turbine rotor is rotating, the image seen in the autocollimator appears as a circle, the diameter of which gives a measure of the dilation. The preparation of the mirror surfaces enabling them to withstand the conditions inside the turbine is discussed. (Not interf erometric. ) Photoelectric Setting Methods for a Three-Beam Inter- ferometer, P. HARIHARAN, D. SEN, M. S. BHALLA. J Sci Instrum v36 n2 Feb 1959 p 72-5. Some of the photo- electric methods which can be applied to estimate the fractional fringe order in the three-beam interferometer, previously described, are outlined, and their comparative merits are discussed. Experimental measurements show that with the help of such methods settings can be re- peated to better than X/1000, provided care is taken to minimize temperature fluctuations. Estimation of Two Causes of Error in the Photoelectric Observation of Interference Fringes at Infinity with a Michelson Interferometer, J. TERRIEN. J Phys Radium v20 n2-3 Feb-Mar 1959 p 446-8 in French . In an earlier study the author assumed, (1) perfect centering of the receiving aperture on the ring center, and (2) uniform illumination of this aperture in the absence of interfer- ence. The accuracy in centring and uniformity of illumi- nation required to justify these assumptions are here es- timated. To attain an accuracy of 0.001 of a fringe, the error in centring must be less than 0.05 of the aperture diameter and the illumination must not fall by more than 12% from the center of the aperture to its rim. Length Measurement by Fringe Counting, K. HARA, D. S. SMITH. Rev Sci Instrum v30 n8 Aug 1959 p 707-10. Construction and performance of reversible fringe counter with counting rate of 100 fringes per sec over path differ- ence exceeding 20 cm : fringe excess fraction at zero path difference could be determined to 0.001 fringe, and rela- tive precision of about 1 : 10 8 was achieved at path dif- ference of 6.4 cm. Some More Aspects of the Michelson Interferometer With Cube Corners, M. V. R. K. MURTY. J Opt Soc Am v50 nl Jan 1960 p 7-10. In the application of the Michelson in- terferometer for measurement of length by photoelectric methods there is a choice of either plane mirrors or cube-corners as the end reflectors. In the present paper it is shown that the guide on which the moving cube- corner moves needs to be only of moderate accuracy where- as it is known that the guide must be made very accurately when plane mirrors are used. Gage Thin Strip Accurately, J. A. BUZA. Iron Age vl85 n7 Feb 18 1960 p 120-1. Operation and performance of Fringecount Micrometer manufactured by Link Aviation Inc. which compares thickness of metal strip sample with wavelength of krypton light source; strip sample used as standard for maintaining gage tolerance on 26 in. wide foil of variety of alloy steels within 30 millionths of an inch at Wallingf ord Steel Co ; photographs and sketch. Photoelectric Method of Recording Interference Fringes in White Light, T. S. KOLOMITSOVA, I. V. NOVIKOVA. Optics & Spectroscopy (English translation of Optika i Spektrosk) v8 n3 Mar 1960 p 189-92. Photoelectric meth- ods of isolation and recording of central white fringe in system of white light interference fringes were examined ; results of calculations of magnitude of photocurrents are presented, and experimental arrangements and investiga- tions are described ; it is shown that, in principle, automa- tion of measurements on white light interferometers is possible. An Interferometric Measuring Apparatus, P. LEINWE- BER. Mach Tool Eng and Prod News v93 n6 June 1960 p 140-5 10 figs. Translation from Werkstatt und Be- trieb v93 June 1960 p 305-10. Describes an interferometer of the author's design for testing length measuring devices such as mechanical indicating gages. Discusses "uncer- tainty of measurement" at some length. Presents novel fringe-count system. Metodi Electrronici per la Misura Interferometrica delle Lunghezze, G. RUFFINO. Alta Frequenza v29 n3^ July-Aug 1960 p 278-300. Electronic methods for inter- 76 ferometric length measurement ; photoelectric transducer is described transforming illumination of interference pattern into electric signals ; photoelectric interferometric devices classified; advantages of photoelectric method stressed. A Method of Precise Fringe Pointing, D. S. SMITH. Can J Phys v38 n8 Aug 1960 p 983-90. Three methods of photo- electric pointing on an interference fringe are examined theoretically and the expected precision of setting is de- rived for each. An apparatus is described which yielded a precision of 1.2 x 10" compared to the predicted value of 5.8X10°. The reason for this discrepancy is discussed, and modification of the apparatus which would reduce the discrepancy is suggested. Also Oct 1960 p 450. Interference-Fringe Counter for Measuring Small Lengths, V. P. KORONKEVICH, YU. I. TRULEV. Meas Techn 1959 nlO Aug 1960 p 581^1 2 figs 3 refs. Translated from Izmer Tekh nlO Oct 1959. For measuring small lengths (1-2 mm) it was found expedient to construct an interferometer with a fringe counter by using standard instruments. The mean-square error of such an interfer- ometer does not exceed 0.22/*, which is perfectly satis- factory for the majority of measurements in the engineer- ing industry. The interferometer can be easily adapted for measuring micron indicator gages, screws of eyepiece micrometers, for determining coefficients of linear expan- sion and similar operations. Apparecchi Electronici per la Misura Interferometrica delle Lunghezze, G. RUFFINO. Alta Frequenza v29 n5 Oct 1960 p 450-82. Electronic apparatus for interferomet- ric measurement of lengths ; performance principles of ir- reversible and reversible (differential) counters, interfer- ence fringes interpolators and automatic interferometric control ; two methods of interpolation described ; block diagrams of two automatic interferometric control devices which enhance ability of photoelectronic procedures. An Automatic Fringe Counting Interferometer for Use in the Calibration of Line Scales, H. D. COOK, L. A. MARZETTA. J Res NBS v65C n2 Apr-June 1961 p 129- 40. A reversible fringe counting interferometer is described in which mechanical, optical, and electronic ad- justments are maintained stable by servomechanism con- trol or by balancing. Mirror parallelism is achieved by detecting the angular error electronically and correcting by means of barium titanate actuators. An electronic in- terpolator permits recording of the count in digital form to 0.01 fringe without ambiguity. A rate of more than 1200 fringes/sec was achieved over a range of 14 cm. Higher counting rates are possible over shorter ranges. Design factors and details are discussed. A correction factor is derived for the error introduced by finite colli- mation of the interferometer beam. Interference Comparator for Routine Measurement of Length. T. MOROKUMA. Oyo Buturi v31 n3 1962 p 192 22 figs 21 refs in Japanese. English translation available. Theoretical investigation is made on electronic fringe comparator for the purpose of routine measurement of length. (1) A lens and mirror system is introduced as the movable reflector system of the interferometer. This catadioptric system plays the same role as that of a corner cube reflector system when a concave mirror is situated at the focal point of a convex lens. (2) Effects of tempera- ture and atmospheric pressure can be automatically cor- rected if suitable Fabry-Perot etalons are assembled tan- dem to the interferometer and the spacer material of the etalons has the same thermal expansion coefficient as that of the part to be measured. Equal inclination fringes are different from those formed with an ordinary inter- ferometer. (3) Effects are calculated on the visibility of fringes due to optical arrangement of reflector systems and spectral distribution of the light which passed through the etalon. An interference comparator has been con- structed on the basis of theoretical investigation, some results of the investigation were already described in the first part of this paper and the rest are here presented. A pair of interference fringes, having uniform brightness and phase difference of tt/2 rad. is formed in the same field of view by means of a quarter wave length prism analogous to a Fresnel rhomb and they are separated by a Wollaston prism. The direction in which the measuring head moves can be electronically detected from the phase relation between them. Measurement can be performed within the accuracy of 0.03/i with this instrument. An Apparatus for the Determination of the Thermal Ex- pansion of Solids in the Temperature Range 20-1000° C. V. E. MIKRYUKOV, I. K KAMILOV. Pribory i Tekh Eksper (USSR) 1962 n3 p 173-5 May-June in Russian. English translation in Instrum. Exper. Tech. (USA). Describes a compact quartz dilatometer which may be used to measure the expansion coefficient to an accuracy of about 2%. It was used to determine the temperature variation of the expansion coefficient of pure Ni. A dis- continuity was found to occur at the Curie point. Interferometry in Length Measurement — 1. Electronic Counting of Interference Fringes, J. L. GOLDBERG, R. H. BROCKMAN. Electronic Technol v39 n4 Apr 1962 p 140- 4 6 figs 7 refs. A study of the photoelectric detection process applied to a steadily moving two^beam inter- ference fringe pattern. Discusses photomultiplier noise, effect of the aperture in front of the photo-deflector, effect of bandwidth, and experimental details. Interferometry in Length Measurement — 2. Practical Considerations, J. L. GOLDBERG, R. H. BROCK- MAN. Electronic Technol v39 n5 May 1962 p 186-91 10 figs 5 refs. Experimental results are discussed and the effects of imperfections in the transducing system are analysed together with a means of overcoming them. Considers the effects of tilt in the case of Straight fringes viewed through a rectangular aperture, straight fringes viewed with a circular aperture, effects of variation of photomultiplier supply voltage, application to the absolute measurement of a meter line standard, and conclusions. Interferometry in Length Measurement — 3. Waveform Generator Suitable for Reversible Counting, J. L. GOLD- BERG. Electronic Technol v39 n6 June 1962 p 238-43 11 figs 4 refs. Deals with the design of a suitable type of trigger circuit which produces a counting waveform from a noisy fringe signal. Discusses current amplifier, trigger circuit, application to counting, reversible counting. A Versatile Silica Dilatometer, G. G. MATTHEWS, I. H. R. SATTERTHWAITE, C. CAMERON. J Sci Instrum (GB) v40 nl Jan 1963 p 42-3. The dilatometer described here was constructed to make routine measurements of the coefficients of linear expansion of uranium specimens. The dilatometer can be used up to 1000°C or down to liquid air temperatures if required, with suitable dimensional modifications. Interference Dilatometer, A. N. KOROLEVA. Meas Techn 1963 n8 Feb 1963 p 655 1 fig. Translated from Izmer Tekh n8 p 20 Aug 1963. Consists of a telescope with an autocollimation attachment, an interferometer, an electric oven for temperatures to 800°C, and tem- perature regulators. Applies method of coincidences. Fabry-Perot Interferometer Used as a Dilatometer. NBS Tech News Bui v47 n8 Aug 1963 p 131 1 fig. Meas- ures linear displacement as small as 10" 7 em. An Automatic Recording Differential Dilatometer, J. BARFORD. J Sci Instrum (GB) v40 n9 Sept 1963 p 444-5. The apparatus is suitable for the study of the kinetics of phase transformations and precipitation proc- esses in the solid state. Relative length changes between a specimen and a control are measured by means of a variable inductance transducer. The differential system 77 works to better than 1%, over temperature ranges of up to 1000°C. Automatic Measuring Interferometers for the Determina- tion of Length and Angle, A. K. CHITAYAT. ASME Paper n64-Prod-23 Apr 1964 8 p 8 figs. Discusses basic principles, typical utilizations of linear and angular inter- ferometers, establishing zero reference, stability of in- terferometers, monochromaticity and coherence, effect of environmental conditions, utilization of lasers as light sources, high-order laser modes, selection of laser, trace- ability to international standard of length. 2.4.3. Fabry-Perot Interferometer Interference Applied to Metrology, A. PEROT, C. FABRY. Astrophys J v9 1899 p 87-115. The paper is a translation from the original article in Bull Astron vl6, p 5, January 1899 and describes the author's well-known methods of measuring lengths and thicknesses of observing the in- terference fringes produced between silvered surfaces. See also Ann Chim Phys vl2 (7th series) 1897 p 459-501. Sur la Mesure en Longueurs d'Onde des Dimensions d'un Oube de Quartz de 4 cm C6t6 (On the Measurement in Wave-Lengths of the Dimensions of a Quartz Cube 4 cm on a Side), C. FABRY, J. M. de LEPINAY, A. PEROT. CR Acad Sci vl28 1899 p 1317-19. The solid to be meas- ured is placed between two planes of silvered glass, AA', so that the faces a.a' of the solid are parallel to the planes. Results are accurate to 0.1« in 4 cm. Sur un Nouveau Modele d'Interferometre (New Model In- terferometer), C. FABRY, A. PEROT. Ann Chim Phys v22 Apr 1901 p 564-74. Instrument made embodying the improvements suggested by experience. Article contains details of the new instrument. Optical Measurement of Length Standards, A. PEROT, O. FABRY. Ann Ohim Phys v24 Sept 1901 p 119-39. De- tails of special means for applying the interferential method to the determination of the absolute length of standard bars, the system adopted depending on the form of the end of the bar. Sketches of the modifications uti- lized and for the maintenance of uniform temperature are given. Interference Rings Observable by Plates Whose Surfaces Are Absolutely Parallel, LORD RAYLEIGH. Phil Mag vl2 Nov 1906 p 489-93. History of discovery. Distinction between contact rings and plate rings. Effects of double refraction of mica. Quasi-etalon Fabry-Perot Interferometer, H. NAGAOKA. Math Phys Soc Tokyo Proc v9 Feb 1917 p 49-54. Describes arrangement for swift adjustment of mirrors to paral- lelism and not easily deranged. Fine adjustment is pro- vided. Interference Methods for Standardization and Testing Pre- cision Gage Blocks, C. G. PETERS, H. S. BOYD. Sci Papers NBS May 2 1922 p 677-713 21 figs. Use of inter- ference of light waves makes possible detection of errors within a few millionths of an inch. Fabry-Perot inter- ferometer is applied. The Fabry and Perot Parallel Plate Etalon, W. H. J. CHILDS. J Sci Instrum v3 Jan Feb 1926 p 97-103 129- 35 4 figs. A concise account is given of the theory and use of the instrument, together with descriptions of the customary arrangements and the methods of etalon ad- justment. Applications are: Wave-length measurement and detection of small shifts; investigation of resolu- tion and structure ; as a standard of length ; investiga- tion of absorption lines ; determinations of refractive index. Bibliography. Photography of Fabry and Perot Interferometer Fringes by Using a Simple Optical System, S. E. GREEN. Phys Soc Proc v42 Apr 15 1930 p 153-5 ; discussion Apr 15 1930 p 155-6. A simple method of photographing Fabry and Perot interferometer fringes is outlined, and some examples of the results obtained with mercury radia- tion are given. Nomogram for Calculation of Fractional Values of Inter- ference Fringes. A. I. KARTACHEFF. Rev Opt vl4 Sept 1935 p 328-31. A nomogram is described for the graphical determination of the value of the expression (d2—di)/d 2 2 , where d 2 , di are the diameters of successive rings for the fractional part of the order of interference of rings in the pattern produced by a pair of parallel semii^transparent reflecting surfaces illuminated by a con- vergent beam of monochromatic light. A Vacuum Interferometer for Precise Measurements, R. M. ELLIOTT. Rev Sci Instrum vll July 1940 p 235-6. The serious effect of pressure and temperature variations in the use of a Fabry-Perot interferometer is outlined together with a method successfully employed to reduce these variations to a reasonable limit. Fabry-Perot Interferometers in Parallel Arrangement, L. STURKEY. J Opt Soc Am v30 n8 Aug 1940 p 351^. Intensity equation of two Fabry-Perot interferometers op- erated in parallel is obtained and discussed ; it is ob- served that distribution complementary to that of single Fabry-Perot instrument has very significant properties and may be obtained by such arrangement. Interference Spectroscopy, II. K. W. MEISSNER, J Opt Soc Am v32 Apr 1942 p 185-210. The compound Fabry- Perot interferometer and the multiple-interference spec- troscope are described and expressions for their resolving powers and instrumental half^widths evaluated. Appli- cations of the Fabry-Perot interferometer to absorption- line working and to the plotting of line profiles are dis- cussed, and recent work using high resolving power on atomic beams is described. Finally the theory of the re- flection echelon and the methods employed in crossing it with auxiliary dispersion are given. New Contribution to InterferOmetry. Pt I — New Non- Localized Interference Fringes, S. TOLANSKY. London, Edinburgh & Dublin Phil Mag & J Sci v34 n235 Aug 1943 p 555-65. Interference fringes, produced with small source of Fabry-Perot Interferometer, are described ; these extend into space in form of cones, producing sharp rings when allowed to fall upon screen ; properties of rings ex- amined ; striking characteristic is that without lenses sharp rings of great diameter can be produced; possible applications of new fringes. On the Fabry-Perot Interferometer. Importance of Sur- face Defects, C. DUFOUR, R. PICCA. Rev Opt (Theor Instrum) v24 Jan-Mar 1946 p 19-34 in French. A study is made of the effects produced by various instrumental defects — diffusion, plate curvature, surface irregularities. A mathematical treatment is developed and is shown to account fully for the observations. A simple method is indicated for distinguishing between effects due to in- strumental causes (surface defects, diffusion) and spectral causes (nonresolved satellites, continuous background). The Effect of Finite Aperture on the Fringe Intensity Dis- tribution of Fabry-Perot Interferometer. F. E. GEIGER, Jr. J Opt Soc Am v39 Mar 1949 p 249-51. An equation is derived for a square etalon which illustrates clearly the decrease in fringe intensity for increasing angles of inci- dence. The computations show that this effect becomes significant only for hiph reflecting powers and compara- tively large plate separations. The Resolving Power and Intensity Relationships of the Fabry Perot Interferometer with Silvered Reflecting 78 Surfaces, R. J. BRIGHT, D. A. JACKSON, H. KUHN, Proc Phys Soc London A v62 Apr 1949 p 225-36. By the use of a Fabry Perot etalon with very small spacing, the widths of the interference fringes were measured under conditions where the light could be considered as prac- tically monochromatic. In this way, the resolving power which can be achieved with Ag deposits of known optical density was determined for light of 5 different wave- lengths between 6 438 and 3 610 A. The results can be used for selecting the most favourable thickness of silver- ing of etalon plates, namely that which gives the resolv- ing power required for a given purpose without unneces- sary loss of intensity. The application of the results to multiple etalons is discussed. A Mount for a Perot-Fabry Interferometer Without Etalon Ring, H. HABER. Letter in J Opt Soc Am v39 Dec 1949 p 1050-1. The Functioning of the Fabry-Perot Interferometer ; Im- provement in Contrast and Luminosity, C. DUFOUR. J Rech Cent Nat Rech Sci nlO 1950 p 1-16 in French. A discussion of the factors affecting contrast visibility and intensity in various interferometers, particularly the Fa- bry-Perot. By the deposition of alternate layers of cry- olite and ZnS on the silvered surface, considerable increase in resolving power and contrast is obtained. Measure- ments are given and applied also to the thin film inter- ferometric filter. It is concluded that the performance of an etalon is not so much limited by the properties of the thin film but by the surface imperfections. In the F.P. interferometer a practical contrast of 200, permit- ting the detection of a weak satellite of relative strength 1/1000, represents the present limit with a single inter- ferometer. The theory is applied to combinations of etalons in series both with and without intermediate "focalization." It is considered that the F.P. interfer- ometer presents important advantages over other instru- ments. Combinations of multiple etalons are discussed and it is suggested that the usual semi-transparent mir- rors should be replaced by multiple films. Accurate Thickness Measurements With a Fabry-Perot Interferometer, L. G. SCHULZ. Letter in J Opt Soc Am v40 Mar 1950 p 177-8. The Reflectivity of Thin Silver Films and the Performance of the Fabry-Perot Interferometer, H. KUHN. J Phys Radium vll July 1950 p 442^4. By measuring fringe widths in a Fabry-Perot etalon the reflecting coefficient R of the silvered surfaces can be derived. The transmis- sion factors T of the films are measured directly with a photomultiplier tube. The sum R+T is not markedly dif- ferent for different film thicknesses but increases from 0-84 at X3900 to 0-97 at X6400. Direct measurements of R are in agreement with those derived from fringe widths. The data permit selection of the most suitable film thick- ness to give reasonable intensity of fringes. A Note on the Resolving Power of the Fabry-Perot Inter- ferometer, J. H. JAFFE. Letter in Bui Res Coun Israel vl Mar 1951 p 113-14. It is established experimentally with a small-gap Fabry-Perot interferometer that the pre- diction made by Tolansky as to the dependence of resolu- tion on polarization is correct. Direct Method of Measurement of the Characteristics of a Fabry-Perot Interference System, P. GIACOMO. CR Acad Sci (Paris) v235 Dec 22 1952 p 1627-9 in French. The mean transmission factor of an interferometer is a function of 1—R. where R is the coeff. of reflection of one surface. This factor is measured directly by comparing the illumination on a photocell with and without the inter- ferometer interposed. Results obtained for layers of cryolite and ZnS, each \/4 thick, are in good agreement with those calculated from classical Fresnel theory. Resolving Power of the Fabry-Perot Etalon, M. S. SODHA. Letter in Current Sci v 22 May 1953 p 139^0. The Ray- leigh, Sparrow and Abbe criteria for resolution are applied respectively to the case of the prism, the line grating and the Fabry-Perot interferometer. In the case of the Fabry- Perot instrument there is a large difference between the calculated resolution criteria. The three different as- sumptions lead to resolution separations in the ratios 1-49 : 2-72:2-08. Thus this interferometer is ideally suited for deciding between the validity of the three dif- ferent criteria. Influence of the Wavelength on the Sharpness and Bril- liance of the Maxima of the Rings Formed by a Semi- Silvered Fabry-Perot Etalon, J. ROIG, E. COLLET. CR Acad Sci (Paris) v236 May 11 1953 p 1866-8 in French. Measurements are reported for fringe sharpness and in- tensity. Although internally consistent, the absorptions for Ag films appear to be higher than those of other inves- tigators. This is attributed to insufficient pumping speed. Data are reported for eight wavelengths over the range M4500-6800. Some results for Al films are briefly indicated. Selection of Optimal Spacers in Perot-Fabry Interferom- etry, G. V. DEVERALL, K. W. MEISSNER, G. J. ZISSIS. J Opt Soc Am v43 Aug 1953 p 673-80. Contains a gen- eral discussion of the conditions for optimal separation of Perot-Fabry patterns. A convenient graphical method is given which permits the selection of the proper spacer thicknesses for the clear resolution of the components of a pattern even in complicated cases. New Method in Optical Interferometry, K. M. BAIRD. J Opt Soc Am v44 nl Jan 1954 p 11-2. Rapid, accurate method for obtaining order of interference in Fabry-Perot etalon ; apparatus for using method in calibrating end standards; application to wavelength determinations. Fabry-Perot Interferometer Mirrors with Di-electric Multilayers, S, PENSELIN, A. STEUDEL. Zeit Phys vl42 nl 1955 p 21-41 in German. A description is given of the production of multi-layer mirror for Fabry-Perot inter- ferometers using vacuum evaporation. The mirrors are quarter wavelength thick and consist alternatively of the following materials. For 3000 to 4000 A materials are PbCl and MgF 2 C. For wavelengths greater than 4000 A zinc sulphide and cryolite are employed. When freshly prepared films are used reflecting coefficients exceeding 97% are secured with a mean absorption of 0.9% for the zinc sulphide and cryolite combination. Absorption of 1.9% obtains for the lead chloride and the magnesium fluoride combination. Reflectivities are such that the fringe width is determined primarily by errors in the optical flats and not by reflectivity characteristics. Lead chloride layers are protected against the activity of damp- ness with a half-wavelength layer of magnesium fluoride. In the ultraviolet interferometric effects obtained with the multilayers are much superior to those of aluminum mirrors. A Ney Type of Interference Etalon, K. I. TARASOV. Optika i Spektrosk vl nl 1956 p 103-4 in Russian. The apparatus is a modification of the Fabry-Perot etalon in which the plane parallel reflector plates are covered on both sides with interference films of dielectric so that these reflectors individually form Fabry-Perot etalons. The plane parallel layer of air between the plates forms a third intermediate interference space. The interference pic- ture observed in such a triple etalon is substantially dif- ferent from the simple fringe system of a normal Fabry- Perot instrument recalling somewhat what is seen with the multiplex version. The reflection coefficient of each of the glass plates has its maximum value for definite angles of inclination of the incident rays and for other angles it is close to zero. With change of angle incidence there is a complementary change of phase of the reflected 79 ray and this, added to the phase difference of the inter- fering rays (determined by the air inter-layer), leads to much sharper interference rings and greater resolving power than in the normal Fabry-Perot instrument. Sub- sidiary maxima may be readily distinguished from line components for a change of pressure of the air inter-layer causes subsidiary maxima to remain in place while line components will move over the field of view. High-Speed, Direct Recording Fabry-Perot Interferometer, M. A. BIONDI. Rev Sci Instrum v27 nl Jan 1956 p 36-9. An interferometer is described which has a high optical speed and provides a direct tracing of spectral line shapes on a linear scale. A photomultiplier views the centre spot of the interference pattern. The output of the photo- multiplier goes to a vibrating-reed electrometer and then to a pen recorder. The wavelength of the light at the centre of the interference pattern is made to vary with time by changing the index of refraction between the inter- ferometer plates. This is accomplished by enclosing the plates in a gas-tight housing and admitting an inert gas such as argon or helium to the housing. By the proper choice of gas and of the rate of pressure change one ob- tains the desired rate of tracing the line shape. Orders of magnitude reduction in "exposure" time are achieved by eliminating the use of photographic plates. Fabry-Perot Interferometer with Finite Apertures, K. L. VANDER SLUIS, J. R. McNALLY, JR. J Opt Soc Am v46 nl Jan 1956 p 39-46. Closed mathematical expres- sions are developed for the Fabry-Perot interferometer with finite apertures for both noncoherent and coherent illumination. For most practical cases these expressions are substantially equivalent but reveal more serious aper- ture effects than the approximate theoretical treatment of Geiger. The effects expected are of particular impor- tance in problems involving either compound interferom- eters or high reflection coatings. However, even at low reflectivities significant reductions in peak intensity and resolution are to be expected. The conditions for obtain- ing a 99% efficient interferometer are expressed in terms of the reflectivity and aperture parameters. These ex- pressions still limited by the assumptions of smooth, plane parallel films, suggest modifications to the usual applica- tions of the interferometer. Advances in Performance and Applications of the Fabry- Perot Interferometer, A. STEUDEL. Naturwiss v44 n8 1957 p 249-55 in German. This is a general survey of recent improvements which have been published elsewhere. The importance of absorption of the reflecting film is dis- cussed. Dielectric multilayers are surveyed and their reflectivity as a function of wavelength is discussed. Materials discussed include single sulphide-cryolite and PbCl 2 MgF 2 . Registering photoelectric Fabry-Perot spec- trometers are surveyed. A comprehensive literature is reviewed. Properties of a Fabry-Perot Interferometer Whose Mirrors Consist of Interference Filters, R. DUPEYRAT. CR Acad Sci (Paris) v244 nl8 Apr 29 1957 p 2299-302 in French. The device is recommended for the interferometric analy- sis of Raman spectra where troublesome scattering of the exciting radiation takes place, the mirrors of the inter- ferometer being constructed to have a reflectivity very low at the excitation wavelength but high for the Raman rays. A Description of the Fabry-Perot Spectrometer Installed at Bellevue, J. BLAISE. J Phys Radium vl9 n3 Mar 1958 p 335-7 in French. The optical system consists of a Pellin-Broca prism used as pre-monochromator, a Littrow- type spectrograph with a Bausch and Lomb grating, a Fabry-Perot etalon coated with ZnS-cryolite multilayers and a photomultiplier which is liquid nitrogen cooled. The exit slit and the collimating lens of the monochroma- tor are focused respectively on the etalon plates and on the scanning hole. The photocell is coupled to an elec- tronic recorder through an impedance transformer of the cathode follower type (consisting of one tube fed by a dry cell and accumulator). The interferometer mounting allows any spacing of the etalon plates with only a few fused silica spacers. Two different devices for scanning the interference fringe system by changing the air pres- sure in the etalon chamber are described. A Device Permitting the Mechanical Displacement of a Fabry-Perot Flat, R. CHABBAL, M. SOULET. J Phys Radium vl9 n3 Mar 1958 p 274-7 in French. A mechanical device giving a parallel displacement to one of the flats of a Fabry-Perot etalon, which is suspended in a flexible scanning which is linear in cm" 1 , during which the flats remain parallel to a high degree of precision over one order of the etalon. This device is thus useful for saw- tooth scanning, and yields a "definiance" some five times higher than the resolving power. L'Etalon de Fabry-Perot SpMrique (Fabry-Perot Spher- ical Etalon), P. CONNES. J Phys Radium vl9 Mar 1958 p 262-9 7 figs 7 refs discussion. English translation avail- able. A Fabry-Perot interferometer can be made with two spherical surfaces, forming an afocal system. This interferometer can be used in a photoelectric spectrometer ; it has the same transmission, contrast, sharpness free spectral range and theoretical resolving power as a plane Fabry-Perot of double thickness. But the "6tendue" (product of surface by solid angle) of the beam is propor- tional to the resolving power instead of being inversely proportional, and the luminosity of the system becomes greater than that of the plane Fabry-Perot for very high values (several millions) of the resolving power. The spherical Fabry-Perot seems to be useful for studying lines whose width is only a few millikaisers. It could equally be used as a generator of artificial lines narrower than natural ones. See also Rev d'Optique v35 nl 1956 p 37-^43 8 figs 3 refs. Developments in the Comparison of Lengths Using Fringes of Superposition in White Light, A. H. COOK, H. M. RICHARDSON. Proc Phys Soc v73 pt 4 Apr 1959 p 661-70. When two Fabry-Perot etalons are placed one in front of the other, and the length of one is a small multiple of that of the other, fringes are seen in white light and have been used in the past to compare the lengths of etalons. In the study reported in this paper, these fringes have been observed photoelectrically while the optical length of one etalon is varied by changing the pressure of the air inside it. It is shown that the variation of in- tensity with path difference is the sum of two Fourier integrals involving an intensity function and the phase shifts at the reflecting surfaces. By forming cosine and sine Fourier transforms these quantities can be obtained separately and a correction applied for the error intro- duced into the comparison of lengths by the change of the phase shifts with wavelengths. It is shown that phase shifts can be measured more accurately by this method than by other interferometric means. It is pos- sible to compare a metre length with a 20 cm length to about 1 in 10 a . A Vacuum Contact Dilatometer, V. S. GUMENYUK. Pribory i Tekh Eksper (USSR) 1961 n4 p 101-3 July- Aug in Russian. A vacuum dilatometer for work in the region of high temperatures (500-1500°C) is described. An electrical contact device, which is connected to the mobile stage of an IZA-2 comparator, is used for meas- uring the length of specimens at room temperatures as well as high temperatures. The thermal expansion of tungsten was determined, and it was shown that the ac- curacy of the temperature-dependent elongation values that were obtained by means of this dilatometer was in good agreement with data from the literature. [English translation in: Instrum. Exper. Tech. (USA) n4 p 723-5 July-Aug 1961 ; publ Feb 1962.] Double-passed Fabry-Perot Interferometer, P. HARI- HARAN, D. SEN. J Opt Soc Am v51 n4 Apr 1961 p 80 398-9. Increased contrast and resolution can be obtained with the Fabry-Perot interferometer by reflecting the transmitted beams back through the instrument. An arrangement for this purpose is described in which the double-passed interference pattern is isolated by means of a simple polarizing system. Zur Technologie des Perot-Fabry-Interferometers, G. KOPPELMANN, K. KREBS. Optik vl8 n8 Aug 1961 p 358-72. Technology of Fabry-Perot interferometers ; de- rice is limited by departures from perfect flatness of reflecting surfaces and by imperfect parallel adjustment ; photoelectric method is used to investigate these defects and ascertain possibilities for improvement. Cube-Corner Fabry-Perot Interferometer, P. RABINO- WITZ, S. F. JACOBS, T. SCHULTZ, G. GOULD. J Opt Soc Am v52 n4 Apr 1962 p 452-3. Polarized Haidinger fringes were observed in a Fabry-Perot interferometer with one flat replaced by a cube-corner prism. Orien- tation of the polarization planes of the fringes and their relative phase shifts were measured. Some applications are suggested. Construction of a High-Precision Dilatometer. The Dila- tation of Copper, J. L. VERHAEGHE, G. G. ROBBRECHT, E. VAN OUTRYVE. J Phys Radium (France) v23 Suppl n6 June 1962 p 109A-110A in French. A precision direct reading dilatometer for the temperature range from —190 to 700 °C was constructed. The characteristics of the apparatus are described and its possibilities are illus- trated by results obtained on copper. Barium Titanate Ceramics for Fine-Movement Control, J. V. RAMSAY, E. G. V. MUGRIDGE. J Sci Instrum v39 nl2 Dec 1962 p 636-9. Barium titanate transducers are described for use in automatic control of Fabry-Perot interferometer, to achieve parallel displacements of plate to accuracy required in interferometry. Fabry-Perot Mirrors from Dielectric Multilayers for the Spectral Region 2350-20000 A, K. HEFFT, R. KERN, G. NOLDEKE, A. STEUDEL. Zeit Phys (Germany) vl75 n4 1963 p 391-404 in German. The production and the performance of dielectric multilayer mirrors for Fabry- Perot interferometers from 20,000 to 2350A are described. Details of the evaporation apparatus and techniques are given. The optical data, reflection factor, absorption factor and flatness, are represented graphically and dis- cussed. For all wavelengths cryolite served as low re- fractive material. The high refractive materials used were ZnS for wavelengths from the infrared to X>4120 A, Sb 2 3 for \ between 4200 and 3200 A and PbF 2 for the shorter wavelengths to \=2350 A. For PbF 2 an ex- citation band at 2190 A was found. Fabry-Perot Electroptic Modulator, E. I. GORDON, J. D. RIGDEN. Bell System Tech J v42 nl Jan 1963 p 155-79. Analysis of modulation properties of electroptic material placed in Fabry-Perot etalon; power requirements, heat- ing and bandwidth; microwave phase velocity must be matched to that of light in electroptic medium. Some Fringe-Broadening Defects in a Fabry-Perot Etalon, R. M. HILL. Optica Acta (Int) vlO n2 Apr 1963 p 141- 52. Three forms of defect in the surface finish or align- ment of the plates of a Fabry-Perot etalon are considered, and tolerances are assessed where the etalon is used as the resonant chamber of an optical maser, and as a spec- trometer of high resolving power. The defects are a regu- lar polishing error of sinusoidal form, a random polish- ing error of gaussian distribution of amplitude, and a small tilt error between otherwise perfect plates. It is shown that for both uses the plates have to be parallel to about a second of arc, and that if the amplitudes of the error functions are small compared to the wavelength of the emitted or incident radiation the regular sinusoidal function gives the greatest loss in efficiency. Asymmetric line profiles can be obtained if the error in the plates is not symmetrically distributed about the mean planes of the plates. Resolving Power in Near Infrared of Fabry-Perot Inter- ferometer with Gold and with Silver Coatings, D. A. JACKSON, K. NARAHARI RAO. J Opt Soc Am v53 n5 May 1963 p 558-67. Experiments showing how use of Fabry-Perot interferometer with reflecting surfaces of either gold or silver can increase resolving power of spectrometer in region 0.6 to 2Afi, or can increase luminos- ity without decreasing resolving power; optical systems described for these applications of interferometer. Servo-Techiques in Fabry-Perot Interferometry, H. KOBLER. Instn Radio Engrs, Australia— Proc v24 n9 Sept 1963 p 677-84. Servo-system for position control of reflecting surfaces of Fabry-Perot interferometer is de- scribed ; position errors are sensed optically with accuracy of 5x10"° mm ; equipment can compensate for steady er- rors of 4x10"* mm and also reduces amplitude of induced vibrations. Eine magnetische Feinjustierung fuer ein Perot-Fabry- Interferometer (magnetic fine adjustment for Perot- Fabry interferometer), G. KOPPELMANN, H. KRAUSE. Optik v20 n9-10 Sept-Oct 1963 p 475-80. Extremely small (0.001 of light wave length or less) but reproducible changes can be made in relative position of interferom- eter's mirror plates by means of device that uses small permanent magnets ; efficacy of adjustment is discussed. Remote Controlled Fabry-Perot Interferometer, Z. ERDO- KUERTI. Optik v21 n4 Apr 1964 p 167-71. Fabry-Perot type interferometer is described in which both mirror in- clination and distance between mirrors can be varied in small intervals by means of electromagnets ; design ; cali- bration ; testing. Use of Dielectric Coatings in Absolute Wavelength Meas- urements with Fabry-Perot Interferometer, R. W. STANLEY, K. L. ANDREW. Opt Soc Am v54 n5 May 1964 p 625-7. Discussion showing how absolute wave- length measurements can be made with Fabry-Perot inter- ferometer having dielectric coatings in manner that no er- rors attributable to phase change effects can enter into final results ; wavelength corrections are due to dispersion of optical path rather than dispersion of phase change. 2.4.4. Interference Comparators Optical Measurements of Length, A. PEROT, C. FABRY. CR Acad Sci vl26 1898 p 1779-82. Method utilizes inter- ference fringes produced between two lightly silvered glass plates. By having a standard pair of plates which have been accurately calibrated, the fringes produced by them can be matched with those produced in another system the distance between which may be some multiple of the standard. tiber einen Interferenzmessapparat (Regarding an Inter- ference Measurement Apparatus), C. PULFRICH. Zeit fur Instrumtkde vl8 Sept 1898 p 261-7. See also "The K & E Interference Viewing Instrument, 1926." Descrip- tion of Pulfrich interferometer, based on the principle of the simultaneous use of monochromatic lights of different wave-lengths and micrometric measurement of the inter- ference fringes. Sur FApplication de la Chambre Claire de Govi a la Cons- truction d'un Comparateur pour Regies Etalons a Bouts ( On the Application of the Camera Lucida of Govi to the Construction of a Comparator for End Standards), A. LAFAY. CR Acad Sci vl33 Nov 25 1901 p 867-9. New- ton's rings are used as indicators for micrometer settings which are made optically on the ends of the bars. 81 Compensation of Interference and Measurement of Small Thicknesses, G. MESLIN. CR Acad Sci vl38 Apr 18 1904 p 957-9. A ray of light is passed through a thin plate, polarized, received on a plate of crystal (quartz cut paral- lel to the axis), and analyzed. The retardation in the thin, isotropic plate is compensated by that due to double refraction in the crystal, and the method is applied to the measurement of small thicknesses by using plates of quartz, 1, 2, 5, etc. mm. thick for a kind of optical balancing analogous to the use of a box of weights. Advantage lies in being able to compensate the effect of a thin plate by means of a quartz plate some hundreds of times thicker. See also MESNAGER, CR Acad Sci vl38 Jan 11 1904 p 76-7. Interferenzkomparator fur Endmasze (Interference Com- parator for End Measures), F. GOPEL. Werkstattstech- nik Nov 1919 7 p 12 figs. Comparator developed at the Reichsanstalt. Measuring Balls and Plugs by Light-Wave Method, H. L. VAN KEUREN. Machy (NY) v27 Sept 1920 p 14-6 8 figs. Fundamental facts on which method of measuring plain cylindrical plug gages by interference bands pro- duced by light waves is based. Interferenzmethoden zur Untersuchung von Endmassen (Interference Methods for the Investigation of Gage Blocks), G. BERNDT. Betrieb v3 Apr 10 1921 p 389-96 20 figs. Notes on origin of interferences of equal thick- ness and their use in investigation of smoothness of sur- faces and for measurement of differences in length (meth- ods of Bureau of Standards, of Koster, and Gopel) ; ab- solute determination of length with interferences of equal thickness ; interferences of equal inclination and their use in measurement technique. Definition of length of gage blocks. L'Etude des Calibres Industriels au Bureau International des Poids et Mesures (Study of Industrial Gages at Int Bur of Weights and Measures), A. PERARD. Genie Civ v78 June 4 and 11 1921 p 477-80 and 500-3 20 figs. June 4 : Types of gages and comparators employed. June 11 : Calibration of standard gages of Johansson type by means of an interferometer. Gaging by light-interference method. Die Anwendung der Interferenz des Lichtes im Lehrenbau ( The Application of Interference of Light in Gage Work ) , G. BERNDT. Deutsche Optische Wochenschrift vlO n22, 23, 24 June 1, 8, 15 1924 p 265-9, 282-5, 302-8 14 figs. Describes Zeiss interference comparator and its applica- tion in the comparison of lengths of gage blocks. Light- Wave Interference Comparator. Am Mach v62 1925 p 124. A New Interference Apparatus for Testing Haemacytom- eters, C. G. PETERS, B. L. PAGE. Sci Papers NBS v20 n507 June 3 1925 p 221-36. Includes description of an interference comparator by means of which the differ- ence from nominal of the depth of the chamber is indicated by the spacing of the fringes. Method and Device for Examining End Gages, W. KOS- TERS. U.S. Patent 1 561 173 Nov 10 1925. Interference fringes show the difference in length of two gages. An Interference Appliance for the Accurate Comparison of Length Gauges, F. H. ROLT, C. H. KNOYLE. J Sci Instrum v4 Nov 1926 p 42-45 2 figs. Describes an appara- tus for intercomparing two or more length gages, of nom- inally equal length, by interference methods. It consists of a tilting lever, resting on three ball feet, two of which are supported from the base of the apparatus, while the third rests in turn on the various gages to be compared. The lever carries at the top a polished flat steel surface, over which an optical proof plane can be adjusted to give the desired pitch and direction to the interference fringes which appear when the apparatus is suitably illuminated with monochromatic light. The number of fringes which occur within a given space is counted. La Verification des Calibres par les Interferences Lumi- neuses (Standardization qf Gages by Light Interference), E. MARCOTTE. Arts et Metiers v81 July 1928 p 248-9 21 figs. Describes principles which are derived from Fizeau fringes and applied by several constructors to inter- ference measurement of gages ; study of useful rays ; prac- tical operations. Interferometer for Gage Comparison. Am Mach (Euro- pean ed) v75 p 265. This double-ended interferometer is for comparison of lengths, such as master slip gages. It consists essentially of two Michelson interferometers ar- ranged to observe two ends of the gage and measure by wave length of light to avoid mechanical contact with the end faces. By means of this unit lengths can be compared to 0.000001 in. Gauge Comparing and Absolute Length Measuring Inter- ferometers. J Sci Instrum vl6 n5 May 1939 p 163-5 4 figs. Describes two forms, one for comparing gages and the other for measuring absolute length. See also pub- lication by Hilger & Watts Ltd. and British Patent 555,672 Feb 23 1942. Method for Comparing an End-gauge and a Slip-gauge, J. TERRIEN. CR Acad Sci (Paris) v235 Nov 24 1952 p 1288-90 in French. The use of transparent parallel- plane glass or silica end-blocks, the thicknesses of which are determined by interference, is proposed and the ad- vantages are detailed. Interference Comparator of the Test Laboratory of the Conservatoire National Des Arts et Metiers, J. J. HUN- ZINGER. Rev Opt v34 nlO Oct 1955 p 512-19 in French. An interferometric circuit is described which is a polyg- onal variant of the Michelson interferometer. With it two length standards can be compared. The method of adjustment is described in detail, and the manipulation and performance surveyed. Standard gages are exam- ined with this system and comparisons are made. Novel Interferometer Construction, N. O. YOUNG. J Opt Soc Am v46 nil Nov 1956 p 996. An interferometer related to the system of Vaisala is described. A simplified con- struction is used in which the interferometer is built be- tween the jaws of an ordinary small micrometer, the faces of the jaws acting as two parallel mirrors, a strip plate between them being mounted on the yoke. The system is rugged. Ein Interferenzkomparator zur Bestimmung der Differenz von Endmasslaengen (An Interference Comparator for Evaluating the Difference Between End-Standards), M. DUEHMKE. Zeit Instrumkde v65 nl Jan 1957 p 15-7. By employing a difference method against a standard, lengths of slip-gages (up to 100 mm) can be evaluated to within O.Olfi. The method described enhances the Fizeau- fringe sharpness by multiple reflection. Interferometer described has been constructed for comparison of test sample with one that is standard, but can also be used for absolute interferometric measurement. Achromatic Interferometer for Gage Block Comparison, T. R. YOUNG. NBS Cir 581 Apr 1 1957 p 43-50 2 figs; NBS Tech News Bui v40 nl2 Dec 1956 p 176-7. Has many advantages that make it unique as an interference com- parator. It is possible to measure absolute lengths with this interferometer by replacing the white-light source with a monochromatic source. High-Precision Interferometer for Gauge Block Compar- ison. Engr v203 n5287 May 24 1957 p 814-5. Interfero- 82 metric comparator developed by NBS, Washington, D.C., allowing routine comparisons of length to be made to nearest ten-millionth of inch. Design of a Compact Wide Aperture Fizeau Interferome- ter, P. R. YODER, JR., W. W. HOLLIS. J Opt Soc Am v47 n9 Sept 1957 p 858-61. A theoretical investigation of the performance of the Fizeau type interferometer as a function of the collimating lens spherical aberration and the thickness of the air space between the interferometer plates is presented. The theory developed is applied to the determination of the maximum relative aperture per- missible in a simple collimating lens system for use in an interferometer of specified plate separation. It is found that an f/3 lens system consisting of two plano-convex lenses can be used in an interferometer of 10 in. aperture with the plates separated as much as 0.050 in. In such a system, the instrumental error introduced into the fringe pattern is no greater than X/100 for mercury green light. Some Possible Applications of the Interferometer Using Correlated Rays. R. ULLRICH, W. LOCHTE-HOLT- GREVEN. Optik vl4 nil Nov 1957 p 481-9 in German. A discussion of two-beam interferometer systems in which two beams cover a given cycle in opposite directions and then recombine. A difference in space coverage is indi- cated according to whether an odd or even number of reflections is involved. Systems are described for use as (a) a refractometer, (b) an interferometric system in which fringes and object are superposed, and (c) an inter- ference length comparator. Checking Master Gage Blocks with Interferometer. Tool Engr v40 nl Jan 1958 p 115-6. Interferometric compara- tor developed by National Bureau of Standards, which makes routine comparisons of length to nearest 10 mil- lionth of in. ; this instrument will be used to check lengths of master gage blocks that control accuracy of guided missile, jet aircraft, machine tool and similar high preci- sion parts ; design and operation of instrument. Comparator with Photoelectric Detection for Setting on Broad Interference Fringes with Precision, J. M. BEN- NETT, W. F. KOEHLER. J Opt Soc Am v49 n5 May 1959 p 466-7. A comparator with photoelectric detection system is described. Experimental data are reported to demonstrate that the same setting precision of ±0.2 micron is associated with the measured position of a normally exposed two-beam interference fringe, an overexposed two-beam interference fringe, a multiple-beam interfer- ence fringe, and a spectral line. The corresponding set- ting precisions obtained by the usual visual techniques are +6.2±3.0, ±1.1, and ±0.6 microns, respectively. Application of InteTferometry to the Routine Measure- ment of Block Gauges, S. P. POOLE, J. H. DOWELL, NPL. Optics in Metrology, P. MOLLET. Pergamon Press 1960 p 405-19 8 figs 2 refs. An interferometer de- signed at NPL in 1937 deals with twenty gages in one operation. Methods employed are given with a brief sur- vey of sources of error. Interferometer is illustrated with details of improvements. A New Method of Measuring Gage Blocks, J. B. SAUN- DERS. J Res NBS v64C n3 July-Sept 1960 p 173. The parallel testing interferometer is quite applicable, without modifications, to the comparison of lengths of gage blocks. This note described the testing of gage blocks of all lengths, up to several metres, without having to contact them to optical flats. The Double-Passed Fizeau Interferometer, P. HARI- HARAN, D. SEN. J Opt Soc Am v50 nlO Oct 1960 p 999-1001. When the transmitted beams from a Fizeau interferometer are reflected back through the instrument, a new system of fringes is observed in which the intensity distribution undergoes a periodic modulation as the sepa- ration of the plates is changed. Accurate measurements are possible with the help of these fringes, using a photo- metric setting criterion. The mode of formation of these fringes, as well as the theoretical intensity distribution in them under various conditions, are discussed. Study on the Interference Comparator, Y. TOMONAGA. Report of the Central Inspection Institute of Weights and Measures, Japan, vlO n2 report 26 1961 in Japanese. In this paper the author describes the design of a new inter- ference comparator (IC) to be used as precision workshop comparator. Its principle is based on that of Michelson's interferometer for white light. The experiment on this comparator shows that no change of interference colour of white light is observed unless the thickness difference between a glass plate and its compensator is over 3.4/i. Basing upon these data the beamsplitter and the double wedge glass plate are designed. The main body and the column of IC are designed so as to be more rigid than those of Mikrokator (MK), Ultra optimeter (UM) and Projection Optimeter (PM). The measuring spindle is suspended by a pair of parallel sheet springs made of phosphor bronze, and the force necessary to displace the spindle axially by 1 mm is 28.5 gw. The maximum dis- placement of measuring anvil due to clamping is only 0.2/j. For IC the relation between the change of temperature M (deg) and that of indication S 2 (n) is shown to be given experimentally by the following expression : S 2 =0.16A£. In an ordinary conditioned room in which the temperature varies with an amplitude of about ±0.5 deg and with a period of about 30 min. the measuring spindle is to change its length about 0.5/i for one period. As the column is heated by the lamp of light source, the indication of IC changes about 0.02/f in the measurement of 100 mm gauge. But the above mentioned changes of indications do not practically affect the measuring accuracy, so far as IC is used as a comparator, because they give only shift of zero reading. The dispersion of measured values of IC ranges over only 0.01/4 and is proved to be very small. A Contact Interferometer with an Extended Measuring Range, V. P. KORONKEVICH, V. V. SKIDAN, V. A. AFA- NAS'EVA. Meas Techns 1960 n5 Jan 1961 p 373-6 5 figs 8 refs. Translated from Izmer Tekh n5 p 2-5 May I960.. The experimental work carried out makes it possible to conclude that the extended range interferometer can be widely used for accurate measurements of small lengths. The interferometer can be easily adapted for checking microcators, opticators, ultraoptimeters, strain-gauge calibrators, optical micrometer screws, angles of small wedges, for measuring magnetostriction, determining the linear temperature expansion coefficients, and other pur- poses. Double-Passed Fizeau Interferometer. II. Fringe Sys- tems Formed by the Reflected Beams, P. HARIHARAN, D. SEN. J Opt Soc Am v51 n4 Apr 1961 p 400-4. The theoretical intensity distribution in the fringes formed when the beams from a Fizeau interferometer are re- flected back through the instrument is obtained. It is shown that, under certain conditions, the intensity dis- tribution in these fringes exhibits a periodic modulation as the separation of the plates is changed, so that they can also be used for very accurate measurements. Messen eines Keilformigen Endmasses (Measurement of a Wedge-Shaped End-Measure), P. LEINWEBER. Fein- werktechnik v67 nl2 1963 p 469-72 4 figs 5 refs. Describes the application of an interference comparator developed by the author in the measurement of the thicknesses at a series of points of a gage block having a small wedge angle. The process and results are discussed. Interferometer IZK-57 for Measuring the Diameter of Balls, YU. V. KOLOMIITSOV, A. S. EGUDKIN. Meas Techns 1962 nlO June 1963 p 815-8 3 figs 3 refs. Trans- lated from Izmer Tekh nlO p 8-11 Oct 1962. Describes an experimental model of interferometer IZK-57 for pre- cision relative contactless measurements of ball diameters 83 from 1 to 10 mm by comparing them with a reference ball diameter or a block gage. 2.4.5. Measurement of Long Lengths M^thodes Interferentielles pour la Mesure des Grandes Epaisseurs et la Oomparaison des Longueurs d'Onde (In- terferential Methods of Measuring Great Thicknesses and the Comparison of Wave-Lengths ), A. PEROT, C. FABRY. Ann Chim Phys vl6 1899 p 289-338 7 figs. More complete and general than previous papers by authors. Useful in that cross references are given to papers by other workers. Die Anwendung der Lichtinterferenz zu Langenmessungen auf grosseren Distanzen. (Application of Light Inter- ference Methods to Large Distances), Y. VAISALA. Helsinski, 1923. See VAISALA ref under 2.4.1/1927. Standardization of a 25m Jaderin Wire in Terms of the Wave-Length of the Cadmium Red Line, N. WATANABE, M. IMAIZUMI. Imperial Acad Tokyo Proc 5 June 1929 p 223-6. The authors developed a method of Fabry and Perot to measure the length of a long standard using Brewster's white fringe and removing extraneous rays. Standardization was made first for a 6.25 cm. standard and then extended to 1, 5 and 25 m. standards and to the Jaderin wire. It is concluded that the method may be extended without much difficulty to a length of a few hundred metres. Any small variation in length can be traced from time to time by observing the positions of the white fringe in a compensator. The method may find an application in tracing the deformation of the earth's crust and in problems of a similar nature. Application of the Interference of Light in Base Measure- ments, Y. VAISALA. Translated by M. Wurzinger. Publications of the Finnish Geodetic Institute nl4 1930. The method consists in a multiplication based on the ap- plication of the interference of white light. The interval between two parallel mirrors can be copied or multiplied even at great distances, the movement of the air per- mitting. Die gegenwartige Stand der Meter-Definition, des Mete- ranschlusses und seine internationale Bedeutung fur Wis- senschaft und Technik (The Present State of the Meter Definition, of the Meter Determination and Their Inter- national Significance for Science and Technology), W. ROSTERS. Werkstattstechnik und Werksleiter v23 Dec 1938 p 527-33. Describes new Rosters interferometer for long lengths. English translation available. Measuring a Large Displacement by Interferometry, H. BARRELL, M. J. PUTTOCK. Brit J. App Phys vl Apr 1950 p 87-91. A modified form of Michelson interferom- eter is used to calibrate the mechanical displacement sys- tem of an adjustable cavity resonator used to measure the velocity of propagation of electromagnetic waves. For the calibration a linear displacement of 12.7 cm was determined in standard Kr wavelengths to an accuracy of one part in a million, utilizing techniques of fringe obser- vation and calculation which do not involve counting a progression of fringes. Displacements>30 cm can be similarly measured if suitable sources of monochromatic radiations are employed. Two Interferometric Techniques, C. VOLET, N. CA- BRERA. Rev Opt (Theor Instrum) v30 Apr 1951 p 169-73 in French. A multiplication process ( X20) is described whereby a 20 cm Fabry-Perot etalon is multiplied to meas- ure a 4-metre distance between two mirrors. The radia- tion required is that of a single isotope like Hg 188 to meas- ure the etalon, and white light superposition fringes are used in the multiplication. The effect of the dispersion of the phase change on metallic reflection is investigated. This leads to fringe asymmetry. With the method a geodetic standard can be measured to some parts in ten million. The measurement of the metre in terms of light waves is discussed. Some Problems Arising From the Use of Interference for the Precise Measurement of Plane-Ended Gauge Blocks. The Study of Fringes From an Air Wedge, J. TERRIEN. J Phys Radium vl5 Apr '1954 p 6S-8S in French. The length of steel gage blocks can be found by comparison of the two fringe systems formed by interference between beams reflected from a reference glass surface, the upper gage block surface and the surface , plate on which the block is resting. For large gage blocks, an error arises from the different character of the two sets of fringes, that form the upper surface arising from multiple reflec- tions. The error is calculated and a method of measur- ing it is suggested. Optical Interference with a Metre Path Difference, J. TERRIEN, J. HAMON. CR Acad Sci (Paris) v239 n8 Aug 23 1954 p 586 in French. Success has been achieved in obtaining interference over a path difference of 100 cm using a Michelson interferometer ; the source with which this was achieved consists of isolated Kr 8e , operat- ing in the triple point of nitrogen (63 °K). The inter- ference over this long path difference could only be secured in the infrared using the 9856 A. It was not possible to secure fringes over a metre with the shorter wave 8777 and 9752 A. It is now possible to compare in one single operation the length of one metre line standard in terms of light waves. An Interferometric Method of Distance Measurement : Frequency Modulation Radar, G. BROUSSAUD. Rev Opt v35 nil Nov 1956 p 593-603 in French. The equa- tions governing the measurement of distance by optical interference methods are developed to include distance measurement by f.m. radar. This latter method differs from optical techniques not only in the wavelength em- ployed but in the kind of problem which it solves. A Rosters-Type Interferometer, C. F. BRUCE. J Sci Instrum v33 nl2 Dec 1956 p 478-82. The design and performance are described of a Rosters-type interferome- ter which measures lengths of up to 500 mm directly by interferometry. Isotopic light sources are necessary for the measurement of the longer lengths, and sources con- taining Hg 198 and Kr 88 , as well as natural krypton and cad- mium, have been used with this interferometer. Results of some length and relative wavelength measurements are given, to illustrate the performance of the interferom- eter operating in air and in vacuo. Das genaueste Langenmessgerat der Deutschen Demo- kratischen Republik (The Most Accurate Length-Meas- uring Apparatus in the German Democratic Republic), F. SCHILLING. Techn Gemeinschaft n3 1957 p 110-2. Interferentielle Vergleichssmethoden fur Endmasse bis 1000 mm (Interferometric comparison methods for end standards to 1000 mm), M. DUHMKE. Phys Verh Mosbach v8 n5 1957 p 134. A Rosters double prism was used in the interferential comparison of length and paral- lelism of 1000 mm bars mounted horizontally. The meas- urement uncertainty was estimated as a, few hundredths of a micron. Interferenzordnungen fur die Messung langer Parallelend- masse (Interference Methods for Measuring End Stand- ards of Great Length), C. HOFFROGGE, PTB. Zeit In- strumkde v65 n7 July 1957 p 123-5 4 figs 7 refs. The methods are for end standards which are too long to measure directly by optical interference. The overall length is therefore virtually subdivided by the images of reference mirrors, interference fringes being obtained be- tween these mirrors and the ends of the standard. The 84 fractional part of the order of interference of the overall length is equal to the sum of the fractional parts of the orders of the subdivisions. Kbsters double prisms are used as beam dividers. New Gauge Interferometer, P. HARIHARAN, D. SEN. J Opt Soc Am v49 n3 Mar 1959 p 232Ht. Development of interferometer for absolute measurement of length of end standards which utilizes optical arrangement in which path difference introduced between interfering beams is only half length of gage; theoretical principles; experi- mental measurements; advantages include simplicity of operation, compact layout and suitability for measure- ments on comparatively long gages. Interferometrische Kalibrierung von Endmasstaben aus Quarz ( Interf erometric Calibration of End Standards of Quartz), E. ENGELHARD. Zeit Instrumkde v67 n3 Mar 1959 p 59-65 in German. A review is given of the interference methods in use in different countries for the testing and preparation of end standards. The definition of the official meter is discussed. It is considered that the uncertainty in the best cases approximates to 0.1/*. It is estimated that a five times smaller uncertainty could be attained by using the red cadmium wavelength as the standard instead of the standard meter. A ten times smaller uncertainty is attainable using Kr 86. Instruments and Methods for Interference length Meas- urement Developed in the Mendeleev Metrological Insti- tute, A. I. KARTASHEV. NPL Symposium nil, 1959, Interferometry. H.M. Stationery Office, London 1960 (Paper 2-5) p 109-24 6 figs 3 refs. Describes results of research on the design of interferometers for measuring end standards and geodetic bars of fuzed quartz from 100 to 1200 mm in length. Two types were built, one for abso- lute and the other for comparative measurements. De- scribes optical scheme and states advantages of the inter- ferometer. Application of Multiple Beam Interference to the Meas- urement of Long End Standards, J. B. SAUNDERS. J Opt Soc Am v50 n2 Feb 1960 p 183^. A technique is described in which white light fringes of superposition are secured by combining a Fabry-Perot etalon with a Michelson interferometer. Fringes are obtainable for values of the Michelson path which are integral multiples of the Fabry-Perot path. The system can be adapted to the measurement of long end-standards. Interference Fringes with Mercury-198 and a Path Dif- ference of 2000 mm, I. C. GARDNER, K. F. NEFFLEN. J Opt Soc Am v50 n2 Feb 1960 p 184. A Connes type Fabry-Perot interferometer with spherical mirrors sepa- rated by 100 mm was constructed and was used as a monochromator for the Hg green line. It should have given a line width of 0.003 cm" 1 , with which fringes should have been found over a path difference of 3 meters ; in fact fringes were easily visible at 2 meters path difference, the longest obtainable on the available Michelson interferom- eter. Interferometric Length Measurements on Long Parallel End Standards, M. DUHMKE, K. KANTOR, F. HOCK. Optik (Germany) vl8 nl0-ll 1961 p 561-6 in German. A description is given of an interferometer system, essen- tially a combined Fizeau and Michelson system, whereby it is possible to secure interference for end standards ex- ceeding 100 mm in length, up to 1 metre in length. A combined Fabry-Perot and Michelson arrangement is also reviewed. Comment by K. Kantor : It is claimed that by the aid of a sevenfold multiplication of path between semi-transparent mirrors 10 cm apart, linked to a Michel- son interferometer, path-lengths up to 2.8 metres still give good fringes. Comment by F. Hock : A Michelson interferometer system is described in which a polarization beam splitter is in one arm following the normal beam splitter. Thus the two polarization vibrations can be made to traverse different path-lengths. It is shown that this enables paths double the coherence length to be measured. 1-m-Interferenzkomparator, M. DUEHMKE. Zeit In- strumkde v69 nlO Oct 1961 p 267-70. 1 m gage interfer- ometer ; description and operation of instrument for 100- 1000 mm slip gages for comparative measurements ; it can be connected with Fizeau or Michelson interferometers. Wavelength Standard Comparator. Engineer v212 n5519 Nov 3 1961 p 759-60. In accordance with decision of 11th General Conference on Weights and Measures, meter is now defined in terms of wavelength of krypton 86 ; inter- ferometer with photoelectric comparator now being set up at Int Bur of Standards at Sevres will enable meter stand- ards to be compared within one part in 10 8 or better. Metre Interference Comparator. Engr v212 n5527 Dec 29 1961 p 1100-1. Design of instrument invented by Koesters of Physikalisch-Technische Reichsanstalt (PTR) and now commercially produced by Carl Zeiss ; prototype, completed in 1927, has since been redesigned by Engel- hard ; krypton lamp is hot cathode discharge tube sur- rounded by Dewar flask ; sharpness of krypton lines is such that light scales of 800 mm length can be realized, having over 2,000,000 division lines with uncertainty of no more than plus or minus 0.01/t on any point ; diagram. Ein Meter-Komparator fur interferometrische Langen- bestimmungen in Vakuum-Wellenlangen (A meter com- parator for interferometric length determinations in vacuum wavelengths), W. KINDER. Zeiss- Werkzeit- schrift n43 1962 18 figs 10 refs. Describes an in- terferometer developed by the firm of Carl Zeiss with which gage blocks from 4 to 40 in. in length can be meas- ured in vacuum wavelengths of the standard Kr line. This instrument represents an advanced development of the meter comparator described by Kosters in 1938. Radiointerferometer for Measuring Long Lengths, G. S. SIMKIN, I. V. LUKIN, L. I. BIRYUKOV. Meas Techns 1961 nlO Mar 1962 p 780-3 1 fig 7 refs. Translated from Izmer Tekh nlO p 8-10 Oct 1961. Describes a double- beam radio interferometer which operates in the centi- meter waveband and is intended for measuring lengths up to tens of meters in testing end gages and line measures. Long-Path Interferometry Through an Uncontrolled At- mosphere, K. E. ERICKSON. J Opt Soc Am v52 n7 July 1962 p 781-7. An investigation was made of the degree to which the invariance of the relative dispersion of the atmosphere will permit an interferometric separation be- tween geomagnetic path differences and path differences due to atmospheric inhomogeneities. Humidity variations are the most serious. A difference in average humidity of 1% of saturation at 15 °C would affect the comparison of two paths by approximately 2 parts in 10 s . The feasi- bility of photographing interference for long paths through an uncontrolled atmosphere was investigated. Photographs of channel spectrum interference were read- ily obtained for path lengths of 115 m near ground level. A Method for Obtaining Interference With a Great Path Difference, N. R. BATARUCHKOVA, A. I. KARTASHEV. A. P. KIRIOHENKO. Optika i Spektrosk (USSR) vl4 n2 Feb 1963 p 304-5, in Russian. English translation in : Optics and Spectrosc. (USA) vl4 n2 Feb 1963 p 159. Details are given of a spherical Fabry-Perot system for use with an interference monochromator. Interference patterns were easily photographed with path differences of over 2 meters. Measurement of Large Path Differences by Means of an Interference Monochromator, A. I. KARTASHEV, A. P. KIRICHENKO. Meas Techns 1962 n8 Feb 1963 p 630-3 5 figs 2 refs. Translated from Izmer Tekh n8 p 9-11 Aug 1962. Method described which makes it possible to meas- 85 ure large distances without the use of intermediate steps or "multiplier" of the path difference. Interference Monochromator with a Spherical Fabry-Perot Standard, N. R. BATARCHUKOVA, A. P. KIRICHENKO. Meas Techns 1962 n8 Feb 1963 p 633-6 5 figs 2 ref s. Trans- lated from Izmer Tekh n8 p 11-3 Aug 1962. Describes method of narrowing a spectral line and thereby increas- ing coherence length consisting of optical filtering by means of a Fabry-Perot standard with a preset path difference. Comparator Measures up to 40" with Accuracy of 0.4 Microinch, W. KINDER. Instrum & Control Systems v36 n4 Apr 1963 p 123-6. Interferometer type of meter com- parator is described, developed by Carl Zeiss of West Ger- many in collaboration with Physikalisch-Technische Bundesanstalt, Braunschweig; interference problems; path of rays in meter comparator. Tilted-Plate Interferometry with Large Plate Separa- tions, H. W. MOOS, G. F. IMBUSCH, L. F. MOLLEN- AUER, A. L. SCHAWLOW. Appl Optics (USA) v2 n8 Aug 1963 p 817-22. With very highly collimated mono- chromatic light sources, such as optical masers, multiple- beam interference fringes between nearly parallel surfaces are obtained at large separations. Sharp fringes display- ing the surface contours have been observed with separa- tions as large as 20 cm. The requirements and limitations of the device are described, as well as some possible applications. Design of Fabry-Perot Standards with Spherical Mirrors, A. P. KIRICHENKO. Meas Techns 1963 nl Aug 1963 p 25-8 3 figs 10 refs. Translated from Izmer Tekh nl p 18-20 Jan 1963. Deals with the design and manufacture of a Fabry-Perot standard with spherical mirrors used for filtering out spectral lines of single-isotope sources of light. It was possible to observe interference with path differences exceeding 1 m and to measure by the absolute interference method gage blocks up to 1 m long. Interferometric Measurement of End Standards up to 1 m, Y. SAKURAI, H. YAMAMOTO. Bui Japan Soc Prec Eng vl nl Oct 1963 p 17-20 3 figs 3 refs. Contents : Measuring apparatus; factors that affect the accuracy of measure- ment ; results of experiments ; discussions and conclusions. Measuring Distance with the Mekometer, R. H. BRAD- SELL, NPL. New Scientists vl5 p 206-7 1 fig. Instrument measures distances of the order of 50 m using a centimeter wavelength pattern imposed on a light beam. Long Distance Interferometry with He-Ne Laser, F. T. ARECCHI, A. SONA, Nuovo Clmento v32 n4 May 16 1964 p 117-21. Interference fringes have been observed up to optical path difference of 120 m (mirror separation 60 m) without substantial loss of visibility ; He-Ne laser operat- ing at 6328 A has been used. Laser Feedback Interferometer, D. M. CLUNIE, N. H. ROCK. J Sci Instruments v41 n8 Aug 1964 p 489-92. Interferometer consists of He-Ne laser, mirror providing optical feedback, and photodetector ; principle enables interferometry to be performed over path lengths of up to 50 m at either 0.6328 pm or 3.39 /tm ; alignment of instru- ment and detection of fringes is performed at 0.6328 /im ; interferometer may be used to measure length, and also velocities up to at least 80 cm sec" 1 , and produces fringes when only 1% of output is fed back ; applications include machine tool control and measurement of optical path length. Laser Calibrator for Shop. Steel vl55 nl3 Sept 28 1964 p 97. Lengths up to 100 in. are defined to accuracy of one part in one million by instrument called absolute inter- ferometric laser calibator, supplied by Airborne Instru- ments Laboratory Div, New York; construction of cali- brator which has sensor, light reflector and electronic cabinet ; aligning interferometric axis with motion axis of machine and other problems that had to be solved to de- velop accuracy needed. 2.4.6. Measurement of Line Standards See also Section 4 Ruling Line Standards, H. B. LEWIS, C. G. PETERS. Mech Eng v46 mid-Nov issue 1924 p 796-8 7 figs ; Am Mach v61 Dec 11 1924 p 925-8. Method of producing line stand- ards free from measurable error by application of light interference, and end measuring machine upon which they are used. Die Eichung der Drahte: C. Interferenzmessungen (The Calibration of Wires: C. Interference Measurements), E. GIGAS. Handbuch fur die Verwendung von Invardrah- ten bei Grundlinien messungen ; herausgegben von der Trigonmetrischen Abteilung des Reichsamts fur Landes aufnahme, Berlin, 1934 33 figs. Calibration of land sur- veying wires by applying the Finnish geodetic method of Vaisala. Method for Comparing a Line Standard and a Wavelength of Light, J. TERRIEN. CR Acad Sci (Paris) v238 Mar 1 1954 p 1001-3 in French. A discussion is given of a method of using glass plates with a Michelson interfer- ometer so adapted that a line-standard can be converted optically into an end-standard. The method involves the introduction of silvered plates into the path, the plates having lines scratched into the silver and by an inter- changing method the line-standard is converted to an optical end-standard. Ein Interferenzkomparatur fur Strichmasse (An Inter- ference Comparator for Line Standards), C. HOFF- ROGGE, PTB. Microtechnic n6 1956 p 244-8 5 figs 10 refs. Has capacity of 1 m. Accurate Linear Scales Ruled on Grating Engine, D. RICHARDSON, R. M. STARK. J Opt Soc Am v47 nl Jan 1957 p 1-5. Absolute spacing ruled by grating engine is determined by ruling linear scale and using it as dif- fraction grating; angles of incidence and diffraction are measured with spectrometer ; after wavelengths are ad- justed to experimental conditions, average spacing of scale is calculated from grating equation ; wavelength standards are thus used directly for determining line standards of length. On an Instrument for Calibrating Graduated Scales up to 1 m in Terms of Wavelength of Light, Y. SAKURAL. Report of the Central Inspection Institute of Weights and Measures, Japan, v8 n4 report 20 1960 in Japanese. A brief description is given of an interferometric instrument which is designed and constructed in order to evaluate di- rectly graduated scales up to 1 meter in terms of wave- length of light. The graduated scale to be measured is set on the base of the instrument which has the optical parts of the corner-cube interferometer. The lines of the scale are viewed by a photo-electric microscope through an optical system on a carriage which is movable along its way by means of a screw and nut. The carriage also holds the moving reflector of the interferometer at its lower surface, and the position of the reflector is made to be related with that of lines of graduated scale by apply- ing the Eppenstein's principle. The evaluation of relative mechanical displacement of the reflector to the reference corner cube, which is on the same base, are carried out by counting the number of interference fringes which have passed through the field of the interferometer during the transference of the moving reflector. To distinguish the direction in which fringes move, two photo-tubes are ar- ranged to view two different parts of a fringe pattern respectively where the variations of the light intensity 86 resulting from movement of fringes are different in phase by approximately 90°. The outputs of the photocubes are transmitted to a reversible electronic and mechanical counter and a fraction indicator. As the reference corner- cube itself is to displace in the direction of the incident beam, the interferometric instrument is also usable for scales longer than the coherent length of light source. With a view to ensure constancy of temperature, the in- strument is set in an aluminum case with double wall and sandwiched sheets of Molto-pren. The accuracy of this instrument is found to be±0.05/i at its maximum measurable length of 1 meter, and yet a larger part of measuring error, to be caused by the deformation of the body of the instrument due to the transference of the movable carriage. Unmittelbarer Anschuss von Strichmassen an Lichtwel- lenlangen, C. HOFFROGGE. Amtsblatt der PTB 1961 n2 p 192-5; Microtecnic vl4 n2 p 51. An instrument for direct comparison of line standards with wavelengths of light is described. The two principal components are a photoelectric microscope and a modified Michelson inter- ferometer. Computation of lengths by the method of coincidences of excess fractions is used. An Automatic Fringe Counting Interferometer for use in the Calibration of Line Scales, H. D. COOK, L. A. MARZETTA. J Res NBS (Eng & Instr) v65C n2 Apr-June 1961 p 129^0 7 figs 10 refs. Interferometer is described in which mechanical, optical, and electronic adjustments are maintained stable by servo-mechanism control or by balancing. A rate of more than 1,200 fringes per second has been achieved over a range of 14 cm. An electronic interpolator permits recording the count in digital form to 0.01 fringe without ambiguity. On an Instrument for Calibrating Graduated Scales up to 1 Meter in Terms of Wavelength of Light, T. SAKU- RAI. Global Technol Apr 1961 (Digest of original Jap- anese article). Description of an interferometric line standard comparator. The principal components are a photoelectric miscroscope and an interferometer employ- ing a Koster's double prism and corner-cube reflectors. A reversible fringe counter and interpolator is used to determine the order of interference. Interference Comparator for the Calibration of Line Standards Directly in Terms of Standard Wavelengths, K. M. BAIRD. Rev Sci Instrum (USA) v32 n5 May 1961 p 549-54. An interference comparator was built for the routine calibration of line standards or scales by direct reference to the vacuum wavelength of the 0.606/* line of Kr 88 which recently became the international standard of length. The principles of construction and the per- formance of the comparator are given ; it is shown to yield an accuracy of calibration which is mostly limited by the nature of present-day line standards or scales, viz, a few hundredths of a micron in lengths up to one meter. High Speed Interference Calibrator of Standard Scales — 1, Y. DOI, K. SHIMIZU, T. TSUBOI, T. KONO. J Mech Lab Japan vl4 n3 May 1962 p 121-38. Method for cali- brating standard scale with resolution of O.lti ; it requires no longer than 40 min to obtain calibration data for gradu- ated lines ruled at interval of 1 mm for length of 1 m ; photoelectric microscopes are fixed to bed and electric pulses generated at passage of lines across microscope axis ; table motion is measured by interferometer ; pulses from microscopes and interferometer are sent to logical apparatus made of 600 parametrons and calibration data are printed out automatically. In Japanese with English abstract. A Method for Obtaining Interference with a Great Path Difference, N. R. BATARUCHKOVA, A. I. KARTASHEV, and A. P. KIRICHENKO. Optika i Spektrosk (USSR) vl4 n2 Feb 1963 p 304-5 in Russian. English translation in: Optics and Spectrosc (USA) vl4 n2 p 159 Feb 1963. Details are given of spherical Fabry-Perot system for use with an interference monochromator. Interference pat- terns were easily photographed with path differences of over 2 meters. Comparator Measures up to 40" with Accuracy of 0.4 Microinch, W. KINDER. Instrum & Control Systems v36 n4 Apr 1963 p 123-6. Interferometer type of meter com- parator is described, developed by Carl Zeiss of West Ger- many in collaboration with Physikalisch-Technische Bundesanstalt, Brunschweig ; Interference problems ; path of rays in meter comparator. Interference Comparators for Line Standards, K. M. BAIRD. App Optics (USA) v2 n5 May 1963 p 471-80. Reviews progress in the techniques of calibration of scales and line standards by interferometry, techniques that have been under very active development since the redefinition of the metre in terms of an optical wavelength. After a study of some general consideration, specific examples of interference comparators are described, and, finally, the effect of the development of these techniques on the use- fulness of scales as secondary standards is discussed. Interference Measurements of Graduated Standards of Length, M. L. BRZHEZINSKII. Meas Techns 1963 n2 Aug 1963 p 111-3 2 figs 3 refs. Translated from Izmer Tekh n2 p 16-8 Feb 1963. Provides some results obtained from studying the interference comparator and using it for measuring graduated standards of length. Also examines the theoretical peculiarities of its optico-mechanical sys- tem and additional improvements, as a result of which the precision and objectivity in evaluating graduated linear measures has been substantially raised. Line Standard Interferometry, K. H. HART. Int Prod Eng Res Conf Proc Sept 9-12 1963 p 619-24. Published by ASME. Fundamental aspects of interferometer design are presented which are required to achieve accuracy of 0.1/u in meter ; problems of convection and refractive index of air are discussed ; results of measurements made with interferometer developed at Nat Research Council in Canada are presented ; instrument, which is equipped with photoelectric microscopes, is capable of measuring scales up to 1 m in length, to accuracy approaching hundredth of micron. Automatic Calibrating Apparatus for Standard Scales by Counting Interference Fringes, Y. DOI, K. SHIMIZU, T. TSUBOI, T. KOUNO. App Optics v3 n7 July 1964 p 817- 23. New device is described with which calibration of standard scale up to 1000 mm long can be made in terms of interference fringes in 1 hr run with accuracy of plus or minus 0.1 /* ; position of uniformly moving scale is con- tinuously measured by fixed photoelectric interferometer, while instant of transit of every graduation over definite point is detected by array of photoelectric microscopes; data are processed in data-handling circuit 2.5. Metrological Gratings Interference Phenomena, C. BARUS. Sci vl2 1900 p 617-27. Considers interferences observed on viewing one coarse grating through another, and on the projection of one piece of wire gauze by a parallel piece. Moire Micrometer, F. BURMISTROW. Techn Phys USSR v2 n6 1936 p 640-56 in German. A description of an instrument using diffraction phenomena for the meas- urement of (a) thickness, and (b) structure of woven textiles. The idea is not new, such an instrument having appeared some years ago in Czecho-Slovakia. The present paper employs a photographic reproduction of an engine- ruled plate with a varying number of lines per in. from one end to the other. Such a plate is superposed on the 87 771-846 0—66 «H3 silk stocking or other article to be tested and the shift and configuration of the interference lines is used for determinations of structure and thickness. The appara- tus is described and its theory discussed. An Apparatus for the Measurement of Small Differential Expansions and Its Use for the Study of Fused Silica, R. W. DOUGLAS, J. O. ISARD. J Sci Instrum v29 Jan 1952 p 13-15. The differential expansion is magnified by an optical lever, the sensitivity of which is increased by an arrangement of two graticules, the image of one acting as a vernier to the other. Changes of length of 10" 6 cm can be determined. The apparatus has been used to measure differences in the thermal expansion of samples of fused silica which had been given different heat-treatments. Interferometer Action of Parallel Pair of Wire Gratings, J. P. CASEY, JR., E. A. LEWIS. J Opt Soc Am v42 nl2 Dec 1952 p 971-7. Transmission of electromagnetic waves by pair of wire gratings is treated as boundary value prob- lem, including oblique incidence, arbitrary separation be- tween gratings, and ohmic losses ; relative merits of gratings and conducting films in interferometers ; in nu- merical example peak transmission of grating is shown to be about 8000 times larger. Measure Motion to 0.0001 Inch Without Friction or Wear, J. H. BROWN. Control Eng v2 n4 Apr 1955 p 50-2. De- scribes automatic measurement of lineal motion using optical gratings. The Interference Systems of Crossed Diffraction Gratings. Theory of Moire Fringes, J. GUILD, NPL. Oxford Univ Press 1956 152 p. Contents: General background; fun- damental considerations ; two gratings in series ; charac- teristics of the fringe system ; metrological characteris- tics ; influence of grating defects on Moire fringes. Mechanical Interference in Measurement of Strain, J. R. LINGE. Aircraft Eng v29 n337 Mar 1957 p 70-4. Details of simple extensometer with gage length of 0.50 in. which uses mechanical interference of two sets of parallel straight lines to measure displacement and hence strain ; interference effect exhibited by two pieces of Dufaycolor reseau placed in surface contact is employed for develop- ment purposes. An Elementary Introduction to the Use of the Grating Interferometer, V. RONCHI. Atti Fonderie Ronchi vl3 n5 Sept-Oct 1958 p 368-403. The elementary theory of the grating interferometer is presented for the benefit of those who want to apply the Ronchi test in practice, with- out being concerned with the intricacies of the exact theory. A Review of the Application of Gratings to the Study of Optical Aberrations, C. MORAIS. Atti Fonderie Ronchi vl3 n6 Nov-Dec 1958 p 546-602 in Italian. A review of the theory of the Ronchi fringes and their use in measuring aberrations. The work of previous authors is unified into a complete account of the effects of the Seidel aberrations. The evaluation of the Seidel sums from the fringe patterns is demonstrated and sample photographs illustrate the principal results. Long Path Interferences (Moire Patterns) of Electron Waves as Abbe "Objects," O. RANG, H. POPPA. Zeit Phys vl53 n5 1959 p 643-52 in German. Bragg reflection of electrons by overlapping crystal lattices can give rise to a moire pattern in the electron microscope, and additional spots in the diffraction pattern. These may be thought of as primary and secondary interference images in the Abbe sense. This is demonstrated by bright and dark field patterns of gold crystals. The Moire Fringe System as a Versatile Test-Object : Photoelectric Measurement of Aberrations, A. LOHMANN. Optica Acta v6 nl Jan 1959 p 37-41 in German. Proposal for a device in which two gratings in relative rotation provide a moire pattern of variable spacing which is imaged by the lens under test on to a slit backed by a photomultiplier. At the same time the gratings produce a diffraction pattern, consisting mainly of three coherent maxima, which scans across the lens aperture as the grat- ings rotate. An a.c. signal is obtained in which the ampli- tude is related to the Twyman-Green pattern of the lens. Other applications of the device as an analogue Fourier transformer, for thin film measurements and for spectro- photometry are suggested. A Simple Method of Calculating Moire Patterns, G. L. ROGERS. Proc Phys Soc v73 pt 1 Jan 1959 p 142^. The calculation is done by means of simple relations between the reciprocal-space transform of the moire pattern and the transforms of the two grating patterns. Method of Measuring Displacement Using Optical Grat- ings, D. L. A. BARBER, M. P. ATKINSON. J Sci Instrum v.36 nl2 Dec 1959 p 501-4. A method using three diffrac- tion or shadow gratings for accurate linear measurement. Comparison between the gratings produces two alternat- ing signals, and the change of phase difference between the signals is proportional to the distance measured. New Measuring System. Machy (London) v96 n2461 Jan 13 1960 p 103-6. New system of measurement which can be employed either for linear or angular displacements has been developed by Paton Hawksley Electronics, Rock- hill Laboratories, Bristol, largely as result of work in- volved in producing divided circles and diffraction and metrological gratings ; system has family resemblance to well known arrangement of fixed and moving diffraction grating which is employed to produce moire fringe effect ; how microscope in which system has been incorporated is employed for measuring spacing of transverse holes in spool. Diffraction Gratings as Measuring Scales, J. GUILD, NPL. Oxford Univ Press May 1960 208 p. An exposition of detailed information on practical moire fringe equipment that can be adapted in the course of design. Contents : General information, linear measurement, fringe counting, fractional interpolation, gratings, and application to angu- lar measurements. Moire Fringe Reading Head for Use With a Fine Grating, D. A. PALMER. J Sci Instrum v37 n8 Aug 1960 p 261-2. In the usual moire fringe measuring system, practical diffi- culties arise in the use of very fine gratings. An optical system is described in which the use of a separate index grating is avoided, the moire fringes being formed between the scale grating and the image formed by its reflection in a concave mirror. This arrangement has the particular advantage that the sensitivity is doubled. A working model has been constructed to demonstrate the principle. Production and Performance of Metrological Diffraction Gratings, V. W. STANLEY, R. G. N. HALL. Prod Eng v40 nl Jan 1961 p 38-44. Technique for producing diffrac- tion gratings for use as scales for measurement, particu- larly for machine tool control ; superposition of two grat- ings to produce moire fringes ; lathe performance and control for generation of fine helices ; preparation of grat- ings by plastic replica and photographic processes ; grating errors. Precision Diffraction Gratings for Metrologic Purposes, G. N. RASSUDOVA, F. M. GERASIMOV. Optics & Spec- troscopy (English translation of Optika i Spektroskopiya) vll n2 Aug 1961 p 136-7. Method for preparing trans- mission diffraction gratings by etching reflection gratings ruled on layers of aluminum by ruling engine; gratings could be used for very accurate measurement of linear displacement by means of moire bands. 88 Concerning an Error in the Method Using Moire Fringes, A PONCE. Bol Fac Ingen Montevideo (Uruguay) v7 nl6 Dec 1961 p 553-66 in Spanish. Moire fringes have been used to determine distortions of a plane surface, for example in elasticity experiments. There are two pos- sible sources of error inherent in the simple theory, the larger due to the slope of the distorted surface, the smaller due to lateral displacements. These errors are calculated and illustrated in a typical case. Extension de la Methode du Moire a des Problemes Ther- miques — Etudes des Deformations Remanentes d'un Metal au Voisinage d'un Cordon de Soudure, P. DANTU. Rev Francaise de Mecanique n2-3 1962 p 117-18. Exten- sion of fringe (moir6) method to thermal problems; study of residual deformations in weld seam zone ; raster design of 400 points/sq mm was engraved on plates to be welded ; after completion of welding, photograph of deformed raster was superimposed with photograph of reference raster ; fringe pattern formed permitted measurement of deformations with accuracy reaching 5xl0~ 5 . Before Second International Conference on Stress Analysis, Paris 1962. In French. Multi-Sectional Gratings for Linear Measurement, G. D. DEW, NPL. J Sci Instrum v39 Apr 1962 p 141-4 6 figs 2 refs. Describes recent improvements in the techniques of preparing multi-sectional gratings for moire-fringe measuring applications. The system enables adjacent sections to be phased with accuracy of 5-10 pin. and is applicable to gratings of the finest pitch employed in this work. A method of evaluating the phasing errors at the junctions is also described. Moire Fringes — Powerful Measuring Device, P. S. THEO- CARIS. App Mechanics Rev vl5 n5 May 1962 p 333-9. In recent years moire fringes have found increasing ap- plication as measuring device ; their applications may be classified either for measurement, as such, or for auto- matic tool control or monitoring; information obtainable from moire 1 fringes ; application to metrology ; measure- ment of topographic irregularities. 85 refs. Widening Applications of Diffraction Gratings for Meas- urement and Control, W. H. P. LESLIE. Int J Mach Tool Design & Res v2 n4 Oct-Dec 1962 p 393^11. Construc- tion of radial gratings having between 90 and 32,400 lines photographed on to plate glass disks of 12 in. diam or less are described ; errors less than plus or minus 3 sec of arc are obtained ; applications of radial and linear gratings to various machine tools are described ; in gear hobbing machine errors were reduced to %o for worm/table rota- tion and to % in actual cut gears of 20 in. diam ; circuits for phasemeters for servo and for measuring purposes are contrasted, and new techniques for using batching coun- ters with gratings described; typical applications to gear measurement and gearboxless lathe are mentioned. Numerical Control of Machine Tools, H. OGDEN. Indus Electronics vl n2 Nov 1962 p 59-64. Ferranti moire fringe measuring system (Brit Patent Nos 760,321 and 810,478) comprising two optical diffraction gratings superimposed at slight relative angle, producing moving light (moire) patterns during relative grating motion, and photoelec- trically converted into digital length indications of high accuracy for direct display or print-out; applications of Ferranti coordinate positioning system to inspection and control. Metrological Applications of Diffraction Gratings, J. M. BURCH. Progress in Optics v2, North-Holland Publish- ing Co, Amsterdam, 1963 p 73-108 54 refs. Theory of formation of moire fringe signals by means of diffraction gratings; description of moire system metrological equip- ment comprising photographically replicated gratings, vis- ual and photoelectric reading heads, and electronic devices for handling moire fringe information ; advantages offered by fringe method measurements over other methods of machine tool control are discussed. Angular Measurements by Means of a Ronchi Ruling, J. R. MEYER-ARENDT, E. D. MINER, App Optics (USA) v2 nl Jan 1963 p 77-8. It is shown that a simple optical lever gives an angular accuracy of 2 sec of arc if it is combined with a Ronchi ruling. The system described is simpler than the two-grid method utilized by Jones. Light is sent through a grid onto the goniometer and re- turns back through the grid, to be viewed by a telescope. The advantages are reviewed. A grid of 133 lines per inch is best. Angular range is about 3°. Recent Developments in Moire Fringe Measuring Systems for Machine Tool Control, A. T. SHEPHERD. Int J Mach Tool Design & Res v3 nl Jan-Mar 1963 p 47-59. Basic principles of measuring system ; operating condi- tions discussed including optical arrangements, factors affecting fringe contrast, working gaps and prismatic grating optics ; gratings ; fringe subdivision ; circuit check- ing facilities. Measuring Displacement with Diffraction Gratings, S. HANDEL. Meas & Control v2 n2 Feb 1963 p 51-6. Prin- ciple of moire fringe method of measuring relative dis- placement of rapidly moving parts ; application of displace- ment detectors based on this technique to various types of machine tools where positioning can be carried out with accuracy of 1 part in 10,000. Use of Reflecting Diffraction Gratings in Interference Sys- tems for Measuring Linear Shifts, I, G. N. RASSUDOVA, F. M. GERASIMOV. Optika i Spektrosk (USSR) vl4 n3 Mar 1963 p 406-13 in Russian. English translation in : Optics and Spectrosc (USA) vl4 n3 Mar 1963 p 215-19. Reflecting and transparent diffraction gratings are com- bined and used to obtain interference moire bands, react- ing to the shift of one of the gratings in its plane. General properties of such a system are examined. It is shown that in systems with reflecting gratings, unlike in those of similar purpose but with two transparent gratings, the fringe contrast for certain conditions appears to be inde- pendent of the distance between the gratings, angular dimensions of the source and the wavelength interval used. Use of Reflection Diffraction Gratings in Interference Systems for Measuring Linear Shifts, II, G. N. RASSU- DOVA, F. M. GERASIMOV. Optika i Spektrosk (USSR) vl4 n4 Apr 1963 p 559-63 in Russian. English translation in: Optics and Spectrosc (USA) vl4 n4 Apr 1963 p 295-7. The results of experimental investigations of three varia- tions of an interference system consisting of a reflection grating and a transparent grating are given. Systems are also examined in which one reflection grating is used and a semitransparent plate or Wollaston prism is employed as a beam splitter. The properties of different systems are compared. Moire Patterns, G. OSTER, T. NISHIJIMA. Sci Am v208 n5 May 1963 p 54-63. A study of the basic properties of the Moire patterns produced when figures with periodic rulings are made to overlap. Long Range Measurements, R. KIMBLE. ASME Paper n63-PROD-18 May 7 1963 7 p 8 figs. Discusses partic- ularly a system incorporating optical/electronics utilizing transmission or reflective gratings. Optical Gratings in Measurement and Control, S. HAN- DEL. Meas & Control v2 n6 June 1963 p 242-6. It is shown how use of moire fringes for machine tool position control, originally developed for continuous path, has been extended to coordinate positioning of machine tool tables ; system is employed in Ferranti coordinate inspection machine, specially developed to facilitate rapid inspec- tion of machined parts. Photoelectric Analogue-Digical Converters for Length and Angle Measurements. Firm of Dr. Johannes Heidenhain, 89 Traunreut. July 1963 23 p 15 figs. Presents data regard- ing the operating characteristics of both incremental photoelectric encoders and coded encoders. These are mechanical to electrical converters and thus permit the use of mainly digital electronic means of measurement. Moire Patterns Formed with X-Rays. NBS Tech News Bui v47 n9 Sept 1963 p 160-1. During an NBS survey of techniques for studying microstructure, it was found that Moire patterns formed in an X-ray microscope by structures which act as crossed diffraction gratings may reveal detail below the projection imaging power of the instrument. Digital Measuring Systems, A. H. McILRAITH. Int Prod Eng Res Conf Proc Sept 9-12 1963 p 585-91. Published by ASME. Critical survey is made of digital transducers most commonly used in machine tool control and in me- trology ; properties of crossed diffraction gratings are dis- cussed and means whereby greatest accuracy is obtained from them. Observation en Incidence Oblique des Phenomenes de Moire par Reflexion sur une Plaque Gauchie ( Observation in oblique incidence of moire fringes obtained by reflection on deflected plate) , J. EBBENI. Acad Roy de Belgique — Bui de la Classe des Sciences v50 n2 1964 p 114-24, 2 plates. Moire fringes are obtained by super-imposing ref- erance grating on identical deformed grating ; this allows measurement of deformations ; observation of fringes in oblique incidence permits determination of deflection at every point of tested plate. Moire Fringe Interpolator of High Resolution, A. H. Mc- ILRAITH. J Sci Instruments v41 nl Jan 1964 p 34-7. Interpolator capable of dividing one fringe into thousand equal parts is described ; 2 photoelectric signals in phase quadrature are derived from grating system and applied to sine-cosine potentiometer; grating displacement is de- termined from setting of potentiometer at which its out- put vanishes. Theoretical Interpretation of Moire Patterns, G. OSTER, M. WASSERMAN, C. ZWERLING.— Opt Soc Am v54 n2 Feb 1964 p 169-75. General mathematical method for solution of moire patterns produced by overlapping of two figures ; application to combinations of figures involving parallel lines, radial lines and concentric circles ; theory of measurement of refractive index gradients by moire method ; analysis showing how moire patterns are analogs of problems in physical optics, hydrodynamics and electro- statics. 16 refs. Interpolation Arrangement to Improve Sensitivity of Dif- fraction-Grating Measuring System, G. S. K. WONG. Int J Machine Tool Design & Res v3 n4 Apr 1964 p 211-7. De- scription of diffraction-grating electronic interpolation ar- rangement, supported by short mathematical treatment of its logic; some possible errors are considered and their maximum possible magnitudes are expressed in terms of equivalent displacement of measuring system ; arrange- ment described was developed for particular diffraction- grating measuring system (Ferranti 4-fold counting sys- tem), but with some modifications it may be applied to other systems of similar nature. Moire Phenomenon, M. STECHER. Am J Phys v32 n4 Apr 1964 p 247-57. Simple mathematical analysis using shad- ow method predicts shape,. disposition and spacing of moir6 fringes produced by 2 parallel line grids; method is ex- tended to grids of regularly spaced closed-nested-plane figures and to repeated cell structures ; for any species of grid "moir6 magnification" results ; moire fringes are sen- sitive tool for positioning or for measuring very small dis- placements and rotations; moire patterns are visual aid for engineering and teaching of physics. Moire Fringes as Visual Position Indicators, L. O. VAR- GADY. App Optics v3 n5 May 1964 p 631-6. Summary of main known forms of moire fringes for visual metrological applications is given ; to observe and track displacements of moving fringe in conventional moir6 system presents certain difficulties, as individual fringes have distinctive character ; new types of moire fringes were found and are discussed, where recognizable unique fringe indicates also unique position of grating displaced relative to its stationary counterpart. Quality Digital Readout Measuring, O. MOLSTEAD. Tooling and Prod June 1964 7 p 10 figs. Describes ma- chine for X-Y coordinate measurements using Moire fringe system. The grating system and other units are described in detail. An Optical Micrometer Suitable for Use at High Speed, M. C. CAREY and M. R. PIGGOTT. J Sci Instrum (GB) v42 nl Jan. 1965 p 43-4. If a transmission grating is moved across a narrow beam of light the number of oscil- lations of intensity of the transmitted light measures the distance moved. A micrometer based on this principle can measure movements with a sensitivity to about 10"" in. at speeds of up to 10 ft sec" 1 , while being sufficiently robust to withstand shock loading. It can also be used at very low speeds. Moire-Sehattenverfahren zur quantitativen Untersuchung schnell verlaufender Oberflachendeformationen von Fest- korpern (Moire Shadow Procedures for the Quantitative Investigation of Rapidly Changing Surface Deformation of Solid Bodies) . E. HAUSELER and J. POLLOK. Optik (Germany) v22 nl 1965 p 12-23 9 figs 10 refs in German. The four possible moire procedures are investigated from the point of view of their suitability for the measurement of rapidly changing surface deformations. It is shown that only one procedure is practicable for materials with a high E-modulus. The resulting moire lines correspond in this case to the differential of the deformation profile. A function generator is used to convert these curves into analogue electrical voltages and to perform the integra- tions. The procedure is illustrated by the case of the dynamic voltage field of a perspex disk which results when a duralumin bullet is fired into it. Addendum to Section 2. 2.2.2. Method of Coincidences Application des Phenomenes dTnterference a des De- terminations Metrologiques (Application of Interference Phenomena to Metrological Determinations), R. BENOIT. J Phys ser 3 v7 1898 p57-68 2 figs. Describes measure- ment of length using four Cd lines and the method of coincidences. 2.3.1. Wavelength Standards and Light Sources , — General Note on the Effect of Pressure upon the Series in the Spectrum of an Element, J. S. AMES, W. J. HUM- PHREYS. Phil Mag ser5 v44 nl66 July 1897 p 119-21. Discusses shifts in wavelengths of spectrum lines when the pressure on the arc varied. See also other articles by HUMPHREYS, MOHLER, and HUFF : Astro-Phys J v3 1896 p 114-37, v4 1896 p 175-81 and 249-52, v6 1897 p 169- 232, vl4 1901 p 41-8. Uber die Interferenz des Lichtes bei mehr als 2 Millionen Wellenlangen Gangunterschied (Regarding the Inter- ference of Light with more than Two Million Wavelengths Path Difference) O. LUMMER, E. GEHRKE. Verh Deutschen Phys Gesellschaft v4 nl4 Oct 17 1902 p 337-46 5 figs 7 refs. Describes a method, based on multiple re- ( Continued on p. 276) 90 Section 3. Length and Diameter Measurements by Mechancial Methods CONTENTS Page 3.1. Contact length standards 91 3.2. End measuring rods and measurement of long lengths 94 3.3. External diameters 97 3.4. Internal diameters 101 3.5. Measuring machines and bench micrometers 103 3.6. Manual measuring tools 108 3.6.1. General 108 3 .6.2 . Micrometers 110 3.6.3. Vernier instruments 114 3.6.4. Dial and test indicators 114 Addendum to Section 3 116 3.1. Contact Length Standards Standards of Length and Their Subdivision, G. M. BOND. J Franklin Inst 3d ser vll7 April, May 1884 p 281-95 357-67. Early history of length standards in England and America. Development of metric standards. Mo- lecular dimension. Methods of comparing standards. Length comparators. The Rogers-Bond Comparator. Standards of Length as Applied to Gage Dimensions, G. M. BOND. J Franklin Inst 3d ser vll7 May 1884 p 368-86. Illustrates end standard, Whitworth measuring machine, bench micrometer, plug and ring gage, and snap gage. Discussion of accuracy, tolerances, etc. Standards of Length and Their Practical Applications. Pratt and Whitney Co., 1886 180 p. A resume covering the methods employed for the production of standard gages to insure uniformity and interchangeability in every department of manufacture including the reports of Prof. W. A. ROGERS; the Committee on Standards and Gages, A.S.M.E. ; the Committee of the Master Car Builders Assn. ; and including also the report of the spe- cial committee appointed by the Franklin Institute April 1964. Edited by G. M. BOND. Comparaisons des Regies dans le Comparateur Brunner (Comparison of Standards in the Brunner Comparator), O. J. BROCH. Trav et Mem du BIPM v7 1890 p B3-B146. Contents : The comparator ; bending of the standard placed on two supports ; causes of errors in the comparison of standards ; comparison of measuring etalons belong- ing to the Bureau ; tables ; observations. Measurements of End-Standards of Length, P. E. SHAW. Roy Soc Proc Ser A v84 Feb 15 1911 p 589-95. Deals with bar gages having flat ends, particularly to recently made superior Johansson gages. Curves are plotted showing the variations in the readings for different points distrib- uted regularly over the faces. Some improvements of the measuring machine are described. A Silica Standard of Length, G. W. C. KAYE. Roy Soc Proc Ser A v85 Aug 15 1911 p 430-47. A criticism of materials used in making primary standards of length reveals objection to (1) copper alloys, (2) platinum, (3) iridioplatinum, (4) nickel, (5) invar. Fused silica, how- ever, has a remarkable combination of good qualities (a) very small thermal expansion, (b) very small thermal hys- teresis, (c) cheapness, (d) comparative low elasticity, and (e) slight solubility in water can be treated as neg- ligible when, as in the case of the primary standard, only skilled operators handle it. The present meter standard, the first of its kind, consists of a tube of silica with horizontal slabs of the same material fused into its end. Adherence of Flat Surfaces, H. M. BUDGETT. Roy Soc Proc Ser A v86 Dec 22 1911 p 25-35. Experiments on specially made steel blocks showed (1) that at least 75% of the adhesions is caused by the presence of a liquid film; (2) that not more than 25% is due to atmospheric pressure; (3) that adhesion practically vanishes when no film is present. Breakage occurs in liquid itself and not between liquid and steel, only 4% of force required to rupture film is due to surface tension. Tensile strength of water may amount to 60 atmos. Adhesion is 300 to 900 lbs. per sq. in. Large Comparator, W. ROSTERS. Kaiserl. Norrnal- Eichungs Kommission. Wiss Abh n8 1912 p 87-109. De- scribes at length, with numerous illustrations, the con- struction and use of the large comparator used by the above commission. Mesures des etalons Johansson par une Methode Optique (The Measurement of Johansson Gages), A. PERARD, L. MAUDET. CR Acad Sci vl54 June 10 1912 p 1586-8. Johansson gages of length varying from 100 mm to 1 mm were measured by being inserted between the faces of •other Johansson gages and were thus measured in the usual way by the method of differences. The gages were in no case wrong by more than 0.2 micron. Further tests of planeness and parallelism resulted in showing the ex- cellence of the gages in shape. Einfacher Komparator zum Priifen von Endmassen bis zu 5 m Lange (Simple End Comparator for Checking End Standards up to 5 m Length ) , W. BREITHAUPT. Zeit InstrumKde v33 n7 July 1913 p 226-7 2 figs. Les Determinations des Etalons a Bouts (Determination of End Standards of Length), C. E. GUILLAUME. Rev Gen d'Elec v4 Aug 10 1918 p 171-8. A historic account. 91 brought up to date, of methods of comparing end stand- ards and line standards. The old practice was to observe by microscope the point of contact of a point and its image reflected in the polished square end of the end standard. Later Benoit and Guillaume improved this method by having a fine thread stretched horizontally on the squared faces of the ends. Still later, about 1900, a method was used at Sevres in which specially prepared sphere-ended agate contacts were brought by known con- stant pressure against the ends of the standards. Dis- crepancy of 4(i between contact and optical methods was discovered. Cause found to be lens aberration, and op- tical method was henceforth discredited. Two modern methods are described. Advantages of sphere-ended and plane-ended standards are considered. Les Calibres Industriels de Longueur (Industrial Length Standards), C.-E. GUILLAUME. Bui Soc Francaise des Electriciens v8 Dec 1918 p 383-400 5 figs. Development of present principles of gaging ' comparisons of various standards : gaging machines of the Soeiete Genevoise. Writer believes advisability of ascertaining from manu- facturers their experience with the various metals used in manufacture of gages and deciding from study of re- ports on a standard which will satisfy all requirements. Types of End Standards, R. L. RANKIN. Iron Age vl04 Dec 25 1919 p 1331-2 5 figs. Relative value of flat, cylin- drical, spherical and other end standards. Comparator, Millionth. The National Physical Labora- tory — Slip Gauge Comparator. Eng vllO July 2 1920 p 19-20. Detailed description. See also Dictionary of Ap- plied Physics, R. GLAZEBROOK, p 385-6. Precision Measuring and Inspection Devices, R. J. WHIBLEY. Machy ( N. Y. ) v27 Oct 1920 p 135-9 10 figs : Nov 1920 p. 242-5 6 figs. Minimeter and gage compara- tor used by National Physical Lab., England, for inspect- ing precision gage-blocks. Devices permit readings to accuracy of one millionth of an inch. Genauigkeiten der Messzeuge (The Accuracy of Measuring Instruments) , R. P. SCHRODER. Betrieb v4 Feb 11 1922 p 269-74. Notes on gage blocks, initial comparative, trial and working gages. Measurement of work-pieces. Comparator for Checking Precision Gage-Blocks, F. D. JONES. Machy (N.Y.) v28 May 1922 p 689-93 6 figs. Extremely sensitive mechanical apparatus, which has proved very effective at plant of Pratt & Whitney Co. for testing accuracy of precision gage blocks, shown in Figs. 3, 4, 5, and 6. End Measuring — Bars and Slip Gauges, A. J. C. BROOKES. Machy (London) v25 Nov 20 1924 p 244-9 3 figs. How to check them ; recommendations. Etudes sur les Etalons a Bouts. Deuxieme Memoire : Etalons a Bouts, Plans (Study of End Standards. Sec- ond Report: Flat End Standards), A. PERARD, L. MAUDET. Trav et Mem du BIPM vl7 1927 95 p 34 figs 2 appendixes. Description of Johansson gage blocks and their metrological properties; comparison with line standards using ruled auxiliary blocks; interferometric method ; study of one block ; measurement of block combi- nations ; mechanical and optical contact ; phase disper- sion; experimental verification of Hertz formulas for deformation. Contact of Flat Surfaces, F. H. ROLT, H. BARRELL. Roy Soc Proc vll6 Oct 1 1927 p 401-25. Lubricants, such as vaseline oil and ordinary lubricating oil, form wringing films between polished surfaces of steel and glass of thicknesses of 0.007^ and 0.008/t respectively, when artificial means of spreading them between the surfaces is applied. The contact between flat surfaces which are wrung together can be repeated with an accuracy of about 0.01 to 0.02/i. This does not represent the thickness of the part of the film separating the planes containing the high regions on the surfaces. Lapped surfaces of gages show evidence of wear during repeated wringings. Beitrag zur Entwicklung von Dehnungsmessern kleiner Messlange (Contribution to the Development of Extension Instruments for Measuring Short Lengths), K. BOTT- CHER. Zeit Instrumkde v48 Mar Apr May June 1928 p 116-25, 178-87, 234-47, 285-92 21 figs. After a brief survey of known instruments for measuring short lengths, the author discusses a series of requirements which such instruments should possess. A modification of the double lever indicator is found to be more accurate than the Okhuizen apparatus, the average error being about 25X10" 8 mm. Experiments are described whereby the efficiency of the new instrument is calibrated. Millimicro Comparator and Gage Blocks. Am Mach v73 Dec 4 1930 p 901-2. A precision measuring instrument claimed to be accurate within half a millionth of an inch has been announced. This device is mechanical and posi- tive in its measurements and may be readily used by an inexperienced operator. The instrument employs an ad- justable, corrugated anvil to support the work. A vertical plunger carrying an extremely hard contact point is raised and lowered by a slight pressure on the operating lever. Motion of this point is transmitted to a pointer viewed through a microscope. This comparator is claimed to be suited to checking the size and parallelism of flat surfaces such as those of shop gage blocks. Apparatus for Comparison of Length of Gages, C. MOON. J Res NBS vlO n2 Feb 1933 p 249-55 1 supp sheet. Design and operating principles of apparatus for comparing spherical-ended gages of quartz having very small thermal expansion with standard flat-ended gages of steel which have relatively large coefficient of expansion ; sensitivity permits repetition to within 0.1 micron or 1 part in 1,000,000 on gages 10 cm long. A Studv of Glass Surfaces in Optical Contact. LORD RAYLEIGH. Roy Soc Proc vl56A Aug 17 1936 p 326-49. The method of getting glass and silica plates into optical contact and the behaviour of scratches in hindering con- tact are discussed. Scratches made v-ith a cutting dia- mond or steel wheel cutter raise a ridge on the glass while those made with a writing diamond (splinter) do not. A method to determine the mechanical work done in separat- ing two contacted glasses is given, and of the value found, 70 ergs/cm. 2 , half can be recovered on recontacting. Very variable results are found for the pull required to separate two contacted glasses, the maximum being 4.5 X10 7 dynes/ cm 2 . Reflection from the interface between two contacted wedges of glass or silica is slight but measurable and varies from one specimen to another. The reflecting power is not affected by pressure, but the cause of varia- tion is not known. Reflection between silica glass and a liquid of equal index depends on the method of prepara- tion of the surface and is being investigated. End-Gauge Comparator of High Sensitivity, A. TURNER, F. H. ROLT. Eng vl46 n2787 Aug 12 1938 p 183-5. Illus- trated description of comparator designed at National Physical Laboratory, principal aim being to produce in- strument with magnification factor at least equal to that of larger of two existing millionth comparators (30,000 to 1), and of such form that several block gages up to 5 in. in length could, in turn, be readily stood or slid into posi- tion under measuring head. Measuring Millionths of Inch in Gage Room, M. C. COFF- MAN, C. H. BORNEMAN. Gen Elec Rev v41 nil Nov 1938 p 502-3. Higher standards of precision in length measurements are now possible through recent application of new General Electric electric gage head to tailstock of Pratt and Whitney measuring machine in Schenectady Works Tool and Gage Department; machine originally U-2 built to measure mechanically to 0.00001 in. lengths of gage standards up to 80 in. Care of Gage Blocks, K. F. KIRCHHOFER. Tool & Die J \1 nil Feb 1942 p 27-9 and 34. Suggestions concerning correct procedure in handling gage blocks ; correct method of wringing blocks ; testing and checking micrometer with help of blocks. Care and Use of Slip Gauges, N. A. ESSERMAN, E. E. ADDERLEY. Austral Council Sci & Indus Res J vl6 n2 May 1943 p 57-68. Slip gages known as block gages in America ; deals with corrosion, burrs, accessories and wringing. Master Disks. NBS Commercial Stand (CS(E) 124-45 1945 8 p. Standard covers major essential requirements for master disks (American Gage Design) from above 0.105 in. to and including 8.010 in. "Microptic" Vertical Measuring Machine. Eng vl59 n4133 Mar 30 1945 p 246-8 ; Indus Power & Prod v21 n235 May 1945 p 229, 231, 234. Illustrated description of instru- ment which embodies new principle in precision measure- ment of gage blocks, small parts, etc. ; there are no multi- plying devices whatever, actual movement of measuring contact being read directly by means of microscope ; it is manufactured by E. R. Watts and Son ; accuracy of instrument may be relied upon under any conditions to within 0.0001 in. Measurement of Long End-Gauges by Comparison with Precision Line Standards. C. E. ARREGGER. Can J Res F v23 p 185-91 May 1945. The comparison of end- gauges is made by "wringing" short blocks to each end, with lines to convert them to line-gauges. 20-in. and 10-in. end-gauges were compared in turn with a meter standard, using a microscope line comparator as a trans- fer. Precautions to ensure max. accuracy are detailed. The greatest deviation from the mean measurement was less than 2/t. Comparisons between the rules agreed to within 10" 5 in. Das Messen mit Ednmassen und Messcheiben, W. GROTH. Werkstatt und Betrieb v81 nl2 Dec 1948 p 353-8. Preci- sion measurement of distance between two points, parallel axis or product plane surfaces by parallel limit gages, cy- lindrical rods and wheels ; angle measuring by limit gage, sinus and tangent rulers ; conic surface measurement by rulers and Johansson and Fritz Werner clamps ; drawings. Comparison Measurement of Slip Gauges, A. W. MUSK. Machy ( London ) v75 nl940 Dec 29 1949 p 919-24. Anvil of transparent material developed by Taylor, Taylor & Hobson, Ltd. Leicester used for checking comparative dimensions of slip gages against reference gages ; it makes it possible to check almost simultaneously comparative size and degree of flatness ; calibration procedure described. Importance of Surface Finish as Applied to Gage Blocks. H. J. CHAMBERLAND. Western Machy & Steel Wld v41 nl2 Dec 1950 p 64-6. General discussion of finish standards and practices ; new technique removing all amorphous metal or wire edge on gage blocks protects their surface finish through introduction of second para- bolic curve blending original radius with finished surface of gage. A New Method of Measuring the Depth of Haemaey- tometer Counting Chamber Cells, L. O. C. JOHNSON. J Sci Instrum v29 Apr 1952 p 130. The depth of a hae- macytometer counting chamber is measured by means of a rocker, supported by the base of the chamber, with two arms which may be rested in turn on the flanking sur- faces to the left and right of the chamber. The angular displacement of the rocker between these two positions of rest is measured by an autocollimator. The accuracy of measurement is about ±0.2/*. Adhesion and Contact Error in Length Metrology, C. F. BRUCE, B. S. THORNTON. J. App Phys v27 n8 Aug 1956 p 853-9. Studies of nature of strong adhesive con- tact between finely finished steel and glass surfaces when trace of liquid exists between them ; these surfaces are of kind that are of practical use in length metrology where such adhesive action or "wringing" is of consider- able importance, for example, in use of slip gages ; how presence of liquid introduces dimensional contact error. Pneumatic Slip Gauge Comparator, P. J. SIM. Machy (London) v94 n2425 May 6 1959 p 1009-15. Reference made to direct jet type of pneumatic comparator devel- oped by National Standards Laboratory, C.S.I.R.O., Chip- pendale, Australia, in which there is no gaging contact to cause wear or damage; after period of satisfactory operation of instrument in calibrating slip gages, design has been prepared for improved version which is to be built as single unit ; construction and use of prototype described. On the Use of Slip Gages (Gage Blocks), P. V. DENISOV, Meas Techns 1958 n2 Aug 1959 p 127-31 3 figs 6 refs. Translated from Izmer Tekhn n2 Mar-Apr 1958 p 7. The physico-chemical processes taking place on the working surface of slip gages which substantially affect the wring- ing are completely ignored. The underestimation of the role played by the physico-chemical processes causes stick- ing and results in premature wear of the gages. Article describes investigation of adhesive and frictional forces and develops six rules for the use of gage blocks. Gage Blocks of Superior Stability : Initial Developments in Materials and Measurement, M. R. MEYERSON, T. R. YOUNG, W. R. NEY. J Res NBS Eng & Instrum v64C n3 July-Sept 1960 p 175-207 ; see also similar unsigned article in Iron Age vl85 n20 May 19 1960 p 152-3 ; Machy (London) v97 n2503 Nov 2 1960 p 1025-8. Processes, technical aspects and techniques involved in development of three sets of gage blocks are explained, and future research indicated ; blocks are made from treated 410 and 52100 stainless steel, and have shown dimensional sta- bility of 1X10" 7 in./in./yr over one year period. 20 refs. Stability of Block Gauges, A. Z. POLKOVA. Meas Techns 1959 nl2 Sept 1960 p 932-3 2 refs. Translated from Izmera Tekhn nl2 Dec 1959 p 8. Discusses methods of measuring instability and tolerances on stability. Development of More Stable Gage Blocks, M. R. MEYER- SON, T. R. YOUNG, W. R. NEY. Matls Res & Stand vl n5 Mav 1961 p 368-74 ; see also abstract in Metal Treat- ment & Drop Forging v28 nl93 Oct 1961 p 407-9, 418. Long range research program aimed at accuracy of one part in 10 million in gage block length calibrations is underway at US Bur of Standards, to meet need for greater precision in production for atomic and space age ; development of steel gage blocks with maximum dimen- sional change of 0.2/* in./in./yr is described ; observations for one yr on 2 steels (410 stainless and 52100) given total of 14 treatments are reported. Investigation of the Wring Capacity of Block Gauges. L. CH'AO-TSENG, A. S. AKMATOV. Meas Techns 1960 nlO July 1961 p 839-43 8 figs 6 refs. Translated from Izmer Tekhn nlO p 19-22 Oct 1960. The authors aimed at investigating: (1) the effect of the microgeometrical profile, the metal structure and its defects, hardness, the physical nature of the metal (the grade of steel), mechani- cal properties, and the physico-chemical purity of the sur- face; (2) the volumetric physicochemical properties of the lubricant, the physical properties of its molecules, their atomic structure, isomerism, intramolecular mobility, polarizability, polarity, and chemical activity; (3) the method of obtaining an intermediate lubrication layer, it* 93 "training," "thickness," physical condition, structure, mechanical properties, and the nature of intermolecular interactions. Search for Ideal Gage Block Material, R. A. GIERLICH. ISA Proc Preprint 2.3.62 for meeting )ct 15-8 1962 5p. Developments of recent years are discussed from stand- point of gage block makers who must somehow reconcile his methods with findings of US Bur Standards and re- quirements of his customers, if ultimate gage block is to become working tool in laboratories of industry. The Parallelism of a Length Bar with an End Load, D. 0. WILLIAMS, NPL. J Sci Instrum v39 Dec 1962 p 608-10 2 figs 3 refs. The flexure of an engineer's length bar supported horizontally at two positions with a flat wrung to one end is analyzed. Formulas are given for support positions which do not introduce errors in parallelism of the ends. The effect of the flexure on the length of the bar is shown to be negligible. Checked Your Gage Blocks Lately'?, H. EASTMAN. Am Mach/Metalworking Mfg vl07 n5 Mar 4 1963 p 56-8. Rec- ommendations on how to conform with government con- tracts which require adequate gage surveillance programs, with special emphasis on "pedigree" of measurement standards ; calibration laboratories ; importance of meas- uring technique and what should be done to minimize uncertainties ; preparing blocks ; checking flatness ; tem- perature stabilization ; light contact pressure of compara- tor recommended ; blocks of different materials ; equip- ment maintenance. The Effect of Micro- and Macro-Configurations of Block- Gauge Measuring Surfaces on Their Wringing Capacity, Z. I. KREMEN'. Meas Teehns 1963 n2 Aug 1963 p 114-7 4 figs 3 refs. Translated from Izmer Tekhn n2 p 19-21 Feb 1963. Among factors affecting the wringing capacity an important part is played by the quality of the meas- uring surfaces ( height, shape and position of microirregu- larities) and by their geometrical precision (their flatness in the lapped and free condition). This article deals with investigations into the effect of the above factors on the wringing capacity. Variation in Contact Error Between Repeatedly Wrung Surfaces, E. G. THWAITE, R. T. LESLIE. Brit J App Phys vl4 nlO Oct 1963 p 711-3. A controlled experiment is described for determining the variability of contact error between highly flat steel surfaces when repeatedly "wrung" together ; this led to an estimated standard deviation of 0.292 Xl0" 6 in. for the distribution of the con- tact error and an "on the average" tolerance limit about the mean at the 90% level of ±0.52 X10 -6 in. A linear increase of length with serial order of wringing of approxi- mately 0.08X10" 6 in. per wringing was observed and has been attributed to a progressive formation of asperities on the surface. Gage Block of Superior Stability — 2. Fully Hardened Steels, M. R. METERSON, W. A. PENNINGTON. ASM— Trans v57 nl Mar 1964 p 3-25. Possibility of obtaining temporal dimensional stability of 1 to 2 X 10 -7 in./in./yr in through-hardened steels with high hardness levels was studied ; effects of various fabricating tech- niques and stress-relieving temperatures on the surface residual stresses were established and results correlated with observed trends in stability patterns ; presence of surface compressive residual stresses was effective in reducing rate of contraction in 52100 steel on submicro- inch level ; quantitative relationship between dislocation content and length changes was established and tentative finding of instability of carbides noted ; it was found that hardened structure of 52100, or of similar conventionally hardened steels without secondary hardening peaks, can- not be fully stabilized at hardness level of RC 65 even with extended tempering. Gage Blocks of Superior Stability — 3. Attainment of Ultrastability, M. R. MEYERSON, M. C. SOLA. ASM— Trans v57 nl Mar 1964 p 164-85. Materials and tech- niques required to produce degree of temporal dimensional stability of 0.1 to 0.2 /dn./in./yr (ultrastability) and surface hardness of Re 65 minimum are described ; 3 categories of materials and processes included in study are steels with annealed cores and hardened surfaces, steels with partially hardened cores and hardened sur- faces, and cermets and ceramics ; 9 of 11 types had surface hardness of Re 65 or greater; at or above these hardness levels, dimensional stability obtained with best surface hardened steels exceeded that of through-hardened steels ; 2 titanium carbide types were ultrastable. 3.2. End Measuring Rods and Measurement of Long Lengths Rotary Comparator, J. PERNET. Archives Neerlan- daises v5 1900 p 395-406. The form of transverse com- parator which is least subject to errors produced by bending is that of Wild, in which the rods to be compared are mounted in a frame in a vertical plane and are lifted vertically into sight. This form of comparator fails when the rods are to be immersed in liquids. The author con- structs a rotary comparator which admits of exchange with extreme smoothness and simplicity. A stout cyl- inder rotates about its own axis which is placed vertically. The cylinder carries a table in the form of a leminscate, on each of the leaves of which one of the rods is mounted, and supported at y 2 and % of its length. Full details are given. Metres a Bouts (Meter End Standards), J. R. BENOIT. C. E. GUILLAUME. Trav et Mem du BIPM vl2 1902 123 p 13 figs. Describes the comparisons of Tresca sec- tion end standards and a vertical comparator of special design. Two methods of measurement were applied, one optical and the other mechanical. Some Gaging and Measuring Methods at the Works of the Westinghouse Machine Co. Am Mach v27 Aug 4 1904 p 1013-5. Illustrates instruments and describes methods of using them. Large inside and outside micrometers, and large calipers. An Analysis of General Flexure in a Straight Bar of Uni- form Cross-Section, L. J. JOHNSON. Trans Am Soc Civ Engrs v56 Feb 1906 p 169-96. States the problem and gives the solution. Some Gaging and Measuring Methods in American and British Shops. Am Mach v30 p 328 1907. Methods of using exceptionally large micrometer calipers. Premieres Determinations des Etalons a Bouts ; Execu- tees au Bureau International ( First Determinations of End Standards), C. E. GUILLAUME. Trav et Mem du BIPM vl5 1913 31 p 3 figs. Method ; measuring instru- ments ; expansion of steel standards ; correction of the elastic deformations including bending and compression ; principal measurements of 100, 200, 400, and 1000 mm. Etudes sur les Etalons a Bouts. Premier Memoire Broches et Calibres, (Study of End Standards. First Report of Calibration of End Standards), A. PERARD. Trav et Mem du BIPM vl5 1913 170 p 54 figs. Various forms of end standards; measurement of absolute value; 94 instruments ; measurement by longitudinal displacement ; measurement by transverse displacement. The Hart- mann comparator, its functions, study of the comparator, principal measurements, carried out with the comparator. Recent determinations of decimeter standards. Con- " elusions relative to the constancy of standards. Comparator for a Base Unit at Potsdam, F. KUHNEN. Zeit InstrumKde v33 Jan 1913 p 1-9. An elaborate com- parator of the usual type for comparison of 4 meter and 5 meter standard bars with 1 meter standards. Drawings and photographs. Few details. No results to indicate accuracy are given. Large Measuring Machines Constructed by Societe Gene- voise. Eng v98 Sept 11 1914 p 323-6. One of these is adapted to measure a gage of even 3 m long. One new feature in the machine is a rolling foot, allowing that change in temperature shall produce no strain along the length of the bed. The most accurate of the machines described measures to 1 micron. The reference scale, in- stead of being fixed, is placed at the horizontal level of the micrometer screw and moves with it. The advantage here is that a cosine error, instead of as usual a sine error, is introduced. Comparators for the Indian Government. Eng vlOO Aug 20-27 and Sept 3 1915 p 179-82, 208-11, 232-5. A com- parator of 24 m. divided into six sections, and a separate 4 m. comparator ; latter used for comparison of length and determination of coefficient of expansion. Measuring in Millionths of an Inch. Practical Engr v68 Nov 16 1923 p 273-4 2 figs ; Engineer v 136 Oct 5 1923 p 363. Describes generator comparator used by makers, Pitter Gage & Precision Tool Co., Ltd., Eng., in process of manufacturing end gage bars; readily adapted to do all measurements which can be performed in ordinary anvil type of horizontal measuring machines. Application of Micrometers in Railway Shops, M. H. WILLIAMS. Ry Mech Engr v98 1924 p 481 553. tiber die genaue Messung grosser Durchmesser (Regard- ing the Accurate Measurement of Large Diameters). H. SCHMIDT. Maschinenbau v7 1928 p 720. (English translation is available.) Sets forth the conditions nec- essary for accurate measurement of large diameters, par- ticularly when micrometers are used, both by direct meas- urement and by indirect measurement wherein the height of arc corresponding to a certain length of chord is measured. Messung an sperrigen Werkstuecken, P. KUEHNE. Maschinenbau vl6 n7/8 Apr 1937 p 207-11. Measurements of unwieldy parts of locomotives, railroad cars, and air- planes ; measurements during manufacture, after com- pletion and in operation ; illustrations of equipment meas- ured and equipment used. Accuracy in Large Roller Bearings, E. T. COBB. Steel vl02 nl4 Apr 4 1938 p 44-7 and 78. Accuracy of large measurements maintained by Bantam Bearings Corp., South Bend, Ind., based upon measuring machine which measures directly up to 80 in. in increments of 0.00001 in. and is periodically checked against Johansson blocks and special long gage pins ; factors entering into accuracy of bearings, from raw material to finished product, discussed. Einteilung der Endmasse (Division of End Gages), R. P. SCHRODER. Werkstattstechnik und Werksleiter 1939 n6 p 173. Beitrag zur Aufstellung und Herstellung langer Massstabe (Support and manufacture of long measuring rods), A. JOTZOFF. Zeit Instrumkde v60 Apr 1940 p 112-6. After description of the measurement technique and difficulties of fabrication of long measuring rods a proposal is dis- cussed which yields simultaneously a higher measuring accuracy and reduced manufacturing cost. Das Vermessen von Lokomotivrahmen (Measurement of Locomotive Frames), K. HUPE, Tech Mitteilungen Krupp- Tech Ber v9 1941 p 33. Messgeriite fur grosse Langen (Measuring Devices for Large Lengths), H. SCHMIDT. Werkstattstechnik und Werksleiter v36 1942 p 278. Various items of gaging and measuring equipment are described, including a measuring machine for measuring lengths to 7 m (23 ft.) with usual parallel-end standards and longer lengths with special end standards. Messen grosser Werkstucke ; Messgerate ; Passungssystem fiber 500 mm ( Measurement of large workpieces ; measur- ing equipment; systems of fits over 500 mm), N. N. SA- WIN. Skoda-Mitteilungen v6 1944. English translation is available as paper No. 31 of the Symposium on Engineer- ing Dimensional Metrology, NPL, October 1953. Ad in- terpretation (in German) of the standards proposal, by Dr. Ing. Leinweber, is available. Stick Micrometer. Engr vl78 n4619 July 21 1944 p 52-3 ; J Sci Instrum v21 n9 Sept 1944 p 163-4; Eng vl58 n4109 Oct 13 1944 p 286. Brief illustrated description of instru- ment made by Pitter Gauge and Precision Tool Co. consists of micrometer head reading in increments of one one- thousandth of an inch, 1-in. spherical end piece, and 1, 2. 3, 5, 12, and as many 24-in. pieces to make up any length required. Measurement of Long End Gauges by Comparison With Precision Line Standards, C. E. ARREGGER. Can J. Res v23 sec F n3 May 1945 p 185-91. Operation of comparing end standard of length with reference line standard is carried out by method which is simple in principle, but which demands careful experimental technique; in opera- tion described two Johansson type gages of 20 in and 10 in. length, were compared with line standards which them- selves had been compared directly with legal Canadian standard metre. Bibliography. Constant-Length Bar for Outdoor Use, H. I. ANDREWS. Eng vl63 n4226 Jan 10 1947 p 25-6. Bar used as stand- ard of length in measuring small changes in length (few thousandths of inch) in railroad ties; design chosen con- sists of steel tube ; below one end of bar is attached small cylindrical reservoir heated internally by means of insu- lated electric heating element. In a research in the U.K. on concrete and other forms of railway ties it was neces- sary to measure small changes in length, of a few thou- sandths inch in ties approximately 8 ft. long, in very exposed positions under all weather conditions and temper- atures varying from 20 to 90 °F. The standard bar of con- stant length, 9 ft. 3 in. long, consisted of a closed steel tube 2 in. in diameter. Below one end was attached a small cylindrical reservoir which communicated with the interior of the tube. The system was evacuated, sealed, and charged with 2 pounds of liquid sulfur dioxide. When in use the reservoir was heated internally by an insulated electrical heating element. A bimetallic ther- mostat was provided. As the SO? began to boil the vapor pressure increased, and the vapor condensed on the inner walls of the tube, flowing back to the reservoir. Con- tinuous circulation thus established maintained a constant temperature of 94±0.1 °F at which the thermostat was set. Considering all sources of error, the maximum error in any gage length was never likely to exceed 0.00015 in. By using an invar instead of a steel tube this could be re- duced to 0.000013 in. Measuring Large Precision Parts, N. N. SAWIN. Machy ( London ) v71 nlS29 Nov 13 1947 p 541-4. Tests to estab- lish system of tolerances for measuring large pieces over 'JO 500 mm during and after machining processes ; factors in- volved in production of large components within pre- scribed tolerances ; departures from geometrical form, elastic deformation during machining, effects of tempera- ture, inaccuracies of measuring tools, and errors in meas- uring; measurements and calculation for ring and wheel assembly given. The Coordinate Setting Machine, as Sponsored by the U.S. Air Force, published by Fairchild Aircraft Division, Hagerstown, Md., Apr 1952. Contents : Introduction ; its background ; establishing the collimation line ; setting the machine to dimensions ; setting a typical fitting ; the universal positioner ; optical rectangle ; conclusion ; specifications. The Precise Establishment of Long Coordinates in Fac- tories, O. S. READING, U.S. Coast and Geodetic Survey. Paper No. 30, Symposium on Engineering Dimensional Metrology, NPL, Oct 1953 p 485-93, H.M. Stationery Of- fice, London. Report of an Investigation for the British Standards In- stitution into the Accuracy with Which the Industry Measures Large Dimensions, P. W. HARRISON. Paper No. 32, Symposium on Engineering Dimensional Metrology, NPL, Oct 1953 p 527-36, H.M. Stationery Office. London. A progress report covering the investigation conducted in U.K. Up to that time the workpieces had been meas- ured by thirteen firms and organizations and repeat checks had been made by NPL. Instrumentation and Measuring System Employed to Posi- tion Some Features of the Harwell B.E.P.O. Pile Over Distances up to 30 Ft., V. B. HESSEN. Paper No. 34, Symposium on Engineering Dimensional Metrology, NPL, Oct 1953 p 563-76, H.M. Stationery Office. London. In- cludes establishing on the floor of the pile a normal plane from which all vertical dimensions could be taken ; posi- tioning of the tubes ; description and principle of applica- tion of a tape gage for measurements up to 20 ft. Investigation into Accuracy of Industrial Measurements of Sizes up to 80 Inches, P. W. HARRISON. Instn Mech Engrs Proc vl69 n47 1955 p 977-85 (discussion) 985-92. Need to formulate proposals for extension of Int Stand- ards Assn system of Limits and Fits above 500 mm has required improved knowledge of accuracy of industrial measurement of such sizes ; in investigation by National Physical Laboratory this information was obtained for diameters up to 2000 mm ; it was found that industrial measurements tend to be too small, especially at larger diameter. Combination Length Bar Standards, L. W. NICKOLS. Machy (London) v89 n2284 Aug 24 1956 p 473-9; (Mach Shop May-Sept 1956). Influence of screwed joints upon overall length ; determination of torque used when screw- ing length bars together by hand ; measurement of changes in overall length caused by screwing together length bars made in accordance with British Standard 1790 : 1952 ; development of new type of screwed connection where change in length per connection is negligibly small and is independent of assembly torque. Messdraht-Liingenmesser, eim neues Gerate zum messen grosser Abmessungen im Maschinenbau (Wire Length Measurement. A New Apparatus for Measurement of Large Dimensions in Machine Construction), M. BOGUS- LAWSKI, L. K. KAYAK (Moscow). Feingeriitetechnik v5 nlO p 431 Oct 1956. Designs for both external and in- ternal measurements are described. Errors are from 10 to2xl0" 7 parts. How to Measure Large Dimensions, H. W. SCHMIDT. Am Mach vlOO n26 Dec 3 1956 p 145-7. Large bores, long dimensions, and other large work can now be accurately measured without special single purpose gages ; long gage blocks, or gage bars are combined up to 50-ft. length ; any wanted dimension split into 0.0001 in. can be built up by normal and long gage blocks, cutting gage costs. Eine Laengenmessmaschine fuer Messlaengen bis 6000 mm, G. DIETTRICH, K. KAATZ. Werkstattstechnik und Maschinenbau v48 n5 May 1958 p 276-81. Machine for measuring lengths to 6000 mm ; construction and opera- tion of optical machine to measure length of large inter- changeable dynamo parts at Siemens-Schuckert works, Berlin ; critique of accuracy. Die Genauigkeit der Messung grosser Laengen in der Werkstatt, H. SCHMIDT. Werkstattstechnik und Ma- schinenbau v48 n6 June 1958 p 309-15. Accuracy in meas- uring great lengths (500-10,000 mm) in workshop; results of measurements made in England, Italy, and Germany at request of subcommittee ISO/TC3/SC1 ; discussion of methods and instruments. Report on Accuracy of Measurement of Large Dimensions. Report read by I. H. FULLMER at meeting of Standards and Metrology Division, AOA, Jan 14 1959 11 p 9 figs 10 refs. Gives results and analysis of measurements of 30, 50, and 80 in. castings. Contents : Review of past practice, similar investigations abroad, measurement program, sources of data, results of measurement, analysis of results. How to Measure Long Pin Gages, F. H. ROLT, G. GOD- FREY, S. C. BOTTOMLEY. Am Mach vl03 nl8 Sept 7 1959 p 126-7. Machines developed by Hilger & Watts, London that are capable of measuring gages up to 30 ft. long ; design and operation of two machine types ; read- ings can be obtained to 0.00005 or 0.0001 in. Measurement of Large Dimensions, F. P. VOLOSEVICH, Meas Techns 1958 n4 Dec 1959 p 396-9 10 figs. Translated from Izmer Tekhn n4 July-Aug 1958 p 12. Article de- scribes equipment developed for measuring dimensions, including: lightweight external dial micrometers with widened anvils ; minimeter with an extended column ; gage block with foot ; horizontal optical comparator for 3.5 m range ; device for measuring by means of gage blocks ; internal micrometer ; scribing slide gage. Specification for Length Bars and Their Accessories. Brit Stand Instn— BS 1790 1961 33 p. Standard relates to length bars of cylindrical type, in inch sizes up to 48 in. and metric sizes up to 1200 mm, having parallel end faces finished by lapping, while longer bars are to conform to certain clauses ; provision is made for 2 designs, one with complete plane faces and other with annular faces sur- rounding internally threaded hole at one end or both ends of bar ; 4 grades of bar accuracy are reference, cali- bration, inspection, and workshop. Universal Measuring Comparator Type IKU-2, N. F. DELYUNOV, E. I. ROZENBERG, E. P. SMIRNOVA. Meas Techns 1961 n8 Feb 1962 p 601-4 2 figs 2 refs. Trans- lated from Izmer Tekhn n8 p 1-3 Aug 1961. A com- parator having a mm scale with range up to 500 mm. The instrument is intended for direct and differential measurements of internal and external linear dimensions of various articles. The differential dimensions are meas- ured by comparing the measured article with block gauges, templates or reference details. Utilization of Wood for Making Large-Size Measuring Devices. I. P. VAGANOV. Meas Techns 1961 n8 Feb 1962 p 607-10 1 fig 6 refs. Translated from Izmer Tekhn n8 p 7-9 Aug 1961. Wood diameter-measuring caliper gauges are convenient to use, provide more efficient and accurate measurements as compared with the best metal gauges and micrometers, and the ambient air temperature vir- tually has no effect on measurement results. Wooden measuring equipment has a number of advantages as corn- DC. pared with metal equipment, providing the peculiarities of wood are taken into account. Parallelism of Length Bar with End Load, D. C. WIL- LIAMS. J Sci Instrum v39 nl2 Dec 1962 p 608-10. Flexure analysis of engineer's length bar standard sup- ported horizontally at 2 positions with flat wrung to one end ; formulas for support positions which do not intro- duce errors in parallelism of ends ; effect of flexure on length of bar is shown to be negligible. Vertical Type Comparator for Measurement of End Standards, P. HOLMES, E. R. HARRISSON. Micro- tecnic vl7 nl Feb 1963 p 8-14. Illustrated description of instrument constructed at Defense Standards Labora- tories, Australia, for measurement of end standards up to 40 in. long ; measuring head employs electromagnetic pick- up which is rigidly connected to datum platen ; special attention was given to reduction of heating effects due to presence of observer ; discrimination of instrument is 0.1/i in. ; method used to calibrate instrument is described. Long Range Measurements, R. KIMBLE. ASME — Paper 63— Prod-18 for meeting May 7-9 1963 7 p. Prob- lems of greater flexibility and range of measurement in gage manufacture to cope with environmental problems of chips, coolant, and space limitations ; concepts of toler- ances and repeatability, readability and response in meas- urement techniques are reviewed ; use of system incor- porating optical/electronics is reported to offer potential in long-range measurement field. Gauge Blocks for Large Sizes, I. P. VAGANOV, N. M. SHCHIPACHEVA. Meas Techns 1963 n8 Feb 1964 p 649-50. Translated from Izmer Tekhn n8 p 15-6 Aug 1963. Gives results of various experiments to evaluate several parameters. 3.3. External Diameters See also Subsection 3.5 New Measuring Machine, F. GOPEL. Zeit InstrumKde v34 June 1914 p 180-3. Communicated from the Phys Techn. Reichsanstalt. This is to measure the diameter of a cylinder carrying a coil of wire. The measuring parts are light and, being provided with slide movements, can be easily moved to various parts of the cylinder. The latter is so mounted that it can be rotated on its axis when between the contacts of the measuring machine. Micro- scopes are used to measure the position of the contact rods, which have pointed ends. Mesure Mecanique d'une Aire Spherique. Les Spheri- metres (Mechanical Measure of a Spherical Surface; Spherometers ) , P. V ANET. Genie Civ v74 Feb 1919 p 96 6 figs. Principle of planimeter applied to measurement of area of closed figure drawn on a spherical surface. Zwei Schnellvergleicher fur zylindrisehe und platten- formige End-masse (Two Rapid Comparators for Cylin- drical and Flat Gage Blocks), F. GOPEL. Werkstatts- technik vl4 Dec 15 1920 p 625-9 10 figs. Describes com- parator designed by author for rapid and very accurate relative measurements of cylindrical gage blocks, and one based on same principle for measurement of flat gage blocks up to 100 mm. Pratt and Whitney "Super-Micrometer." Machy (N.Y.) v29 Sept 1922 p 68-9. Also Am Mach v57 Aug 31, 1922 p 355. Has a capacity up to 8 in. diam. and settings are made by use of standard inch blocks. Head is graduated to 0.0001 in., and is driven by a belt connected to a knurled handwheel, slippage of which indicates proper contact pressure. Work supports of various forms are provided. Federal Dial Comparator. Am Mach v58 May 24 1923 p 782. Dial indicator mounted on an arm extending over a base. Supplied with a fixture for holding round work. Societe Genevoise Bench Micrometer. Am Mach v59 Nov 29 1923 p 823-4. Equipped with test comparator tube which serves as pressure indicator. Can be read to 0.00005 inch. Carl Zeiss Optimeter. Am Mach v61 Oct 2 1924 p 560. Incorporates optical method of measurement that elimi- nates all moving parts except a small mirror. Optical system is housed in a right-angle tube, adjustably mounted in an arm on a sturdy column. Vertical optimeter is shown in fig. 1 and optimeter with horizontal measuring attachment is shown in fig. 2. The Measurement of Fine Wires, G. A. TOMLINSON. J Sci Instrum v4 Dec 1926 p 74-5. A mechanical method of measuring fine wires is described. The measurement is made at a point and with a very light pressure so that no deformation occurs. The accuracy of the measure- ment is 0.00001 in. Measurement of Very Fine Quartz Suspension Fibers, G. A. TOMLINSON, H. BARRELL. J Sci Instrum v4 Oct 1927 p 410-3. The paper describes two indirect methods of measurement. One is purely mechanical and involves a measurement of the elastic strain under a known tension, from which the mean cross-section can be found. The other method depends on the observation of certain diffraction phenomena produced in white light. In a set of fibers measured, the diameter varied from 3.3 to O.Qfi. The optical method is found to become unreliable when the diameter falls below about three wavelengths. Mikrotast-Feindrahtmesser (Microtast Fine Wire Meas- urer), M. BARTHOLDY. Zeit fiir Feinmech und Prazi- sion v35 Oct 12 1927 p 250-1. Microtast mounted on column for measuring diameters of small wires. New Zeiss Projection Optimeter. Instrum vl May 1928 p 257-8 4 figs; Am Mach v68 1928 p 123. Outstanding feature is visible reading of scale by both eyes instead of by microscope ; more valuable in mass inspection ; table has serrated surface; range of scale to plus and minus 0.005 in. ; scale gradationed 0.00005 in. t'ber die genaue Messung grosser Durchmesser (Accurate Measurement of Large Diameters), H. SCHMIDT. Maschinenbau v7 nl5 Aug 2 1928 2 figs. Comparison be- tween direct measurement with a micrometer and indirect measurement (height of arc). Demonstration of large errors of the indirect method. English translation avail- able. Ein optisches Mikrometer (Optical Micrometer for Meas- uring Fine Threads), I. RUNGE. Zeit fiir Techn Phys v9 nl2 Sept 28 1928 p 484-6 8 figs. Describes an optical system in which the distance between diffraction bands produced by the thread, related to the dimensions of the apparatus, gives the diameter of the thread with an ac- curacy of above 0.25% when the diameter is of the order of 10 to 80 microns. Inspection of Micrometer Spindles at the Zeiss Works, H. SIMON. Am Mach v70 n4 Jan 24 1929 p 175-6 3 figs. Testing lead of Zeiss micrometer spindle thread to 0.00005 in. by combined linear and angular measurements is de- scribed ; Zeiss micrometers are guaranteed not to vary more than 0.000125 in. in 1-in. length ; details of Zeiss lead-testing machine. 97 New Amplifying Comparator. Instrum v2 n8 Aug 1929 p 281-2 1 fig; Am Mach v69 Nov 29 1928 p 866. Ames amplifying comparator described eliminates horizontal stresses and strains and consequent differences in read- ings on same piece of work when shifted about under measuring point; all readings are positive and positively repeat, regardless of direction in which work is passed under point. Elektromechanisches Messgeraet fuer Feindraehte (Elec- tromechanical Measuring Equipment for Fine Wires), M. BARTHOLDY. Kruppsche Monatshefte vlO Nov 1929 p 184-5 1 fig. Equipment has been designed in order to overcome disadvantages of measuring with calipers by which errors result from deformation and motion of meas- uring spindle ; wires can be measured from to 0.05 mm ; size is indicated electrically on scale graduated in 50 sec- tions, each representing 0.001 mm with 0.0001 mm ex- actitude. Optical Measuring Machines, Eng (London) vl29 n3344 Feb 14 1930 p 236-7 11 figs. Measuring machine made by C. Zeiss, of Jena, dispenses with use of micrometer screws and gage blocks, which are subject to slow molecular changes, and of hydraulic feelers, which must exert some pressure, and is based upon comparator principle ; optical system of optimeter is explained by diagram. Bausch and Lomb Optical Comparator. Am Mach v72 Mar 20 1930 p 508. Accuracy to within 0.00005 in. is em- bodied in the optical comparator for comparison and measuring purposes on parts with flat surfaces, balls, or cylinders. The instrument is built into a strong steel casing. The optical comparator is supplied in two models, the first of which has an eyepiece which is inclined 60 deg. to the measuring axis, and the other with a 90-degree eyepiece. It is also possible to supply an instrument with a projection attachment. The range of the calibrated scale is plus or minus 0.004 in. Objects up to 6 in. in height can be compared. Soeiete Genevoise Micro-Indicator Stand. Am Mach v72 Apr 24 1930 p 706-7. A stand to make use of the micro-indicator tube is being manufactured by the Soeiete Genevoise d'Instruments de Physique, Geneva, Switzer- land. By its use the micro-indicator tube can be con- verted to a comparator. The base and column of the stand are of very heavy construction, the total weight being 48 lb. The table for supporting the pieces tested is 5 x 7 in., and is made flat within 0.0001 in. This table is provided with six T slots, which serve for securing two angle plates in any position or a V-block for the support of cylindrical pieces. The micro-indicator itself is supported in a heavy arm secured to the column by a strong clamp. The axis of the indicator is 3% in. from the column. It is possible to measure flat pieces as large as 12 in. in width. The vertical capacity of the apparatus is 6 in. when using a spherical contact point. Beitrag zur Methodik der Fasermessung (Fiber Measure- ment), B. SCHULZE. Papier-Fabrikant v29 nl Jan 4 1931 p 4-5 1 fig. Easily constructed apparatus employed for direct determination of dimensions of fibers by meas- urement of projection. Soeiete Genevoise Model U-3 Micro-Indicator Stand. Am Mach v74 May 28 1931 p 843. This stand is designed for use with the fanshaped micro-indicator. It has an oval-shaped base 10 in. long x 7% in. wide and rests on three rubber feet. A socket is bored to provide for the interchangeable mounting of different types of lower anvils or tables. The tatole is hardened and lapped opti- cally flat. It is 1% in. in diam. Arm movement is 6 in. The micro-indicator unit itself is mounted in the arm through an adjustment ring on the upper part of the supporting arm. The stand is 13% in. high and weighs 32 lb. Tables for Soeiete Genevoise Micro-Indicator Stand U-3. Am Mach v75 Sept 10 1931 p 435. A modification of micro- indicator stand U-3 comprises a V-block as the table adapt- ing it to the support of small cylindrical pieces from % to 2 in. Pieces up to 6 in. can be checked on a large flat table of 4% in. diameter. An adjustable square is also furnished for attachment to the column of the stand and serves as a stop. Pratt & Whitney Electrolimit External Comparator. Am Mach v76 Jan 28 1932 p 151. The "Electrolimit" external comparator provides fast and accurate means for inspec- tion of production. Maximum distance between anvil and spindle is 4 in. The anvil has a serrated surface 1% x 3% in. The anvil can be removed easily, and on the reverse side is a V-block. This equipment can be plugged into a 110-volt, 60-eycle line. Standard magnification of the circuit will cause the needle to travel about %6 in. for each 0.001 in. variation in size. Measurement of Fibre and Yarn Diameters by Diffrac- tion Method, J. A. MATTHEW. J Textile Inst v23 n3 Mar 1932 p T55-T70 1 supp plate. Introduction and sum- mary ; theory, method, calibration and performance of diffraction method ; details of other applications. Bibliography. Standardization of Micrometers, A. KUTAY. Vestnik Standardtizatziyi n2 (50) Mar-Apr 1933 p 43-8 in Rus- sian. Micrometer standards developed by Gage and Measuring Instrument Board of U.S.S.R. ; micrometer errors ; methods of determining deviations of surfaces from level and parallel ; factors affecting micrometer errors, particularly scale graduation. British Standard Specification for Micrometers (Exter- nal). Brit Stand Instn— BS Specification n870 1939 18 p. Specification applies to: external micrometers having frame holding micrometer spindle and nut on one side opposite anvil on other with individual measuring ranges of 1 in. up to 11 to 12 in., and 25 mm up to 275 mm to 300 mm ; setting gages for micrometers above 1 in. or 25 mm. O.M.T. Omtimeter. Eng vl50 n3909 Dec 13 1940 p 477 ; Mech Wld vl09 n2819 Jan 10 1941 p 21-2. Illlustrated description of Omtimeter, particular feature of which is projection attachment permitting instantaneous viewing at normal reading distance; range of scale of instrument is 0.005, and graduation in divisions of 0.00005 ; greatest height of work that can be accommodated is 7 in. and largest diameter is 6 in. Draft Specifications for External Measuring Compara- tors. Eng vl51 n3929 May 2 1941 p 358. Specification issued by British Standards Institution being circulated for technical comment ; comparator is defined as measur- ing tool, consisting of measuring head on rigid stand over work table. Engineers' Comparators for External Measurement. Brit Stand Instn — BS nl054 — 1942 9 p. General construction ; work table ; adjustments for size of work and for zero setting ; measuring contact ; operating pressure ; stops to mechanisms : pointer ; scale ; accuracy of performance ; protection during transport ; marking. Optical Comparators. J Sci Instrum vl9 p 141-2 Sept 1942. Two models of the "optigage" are described. Both are for direct visual comparison of work with a stand- ard, employing mech. and optical magnification. In one model the magnification is X 1,000, with a range of 0.001 in. ; estimations to within 0.00002 in. are claimed. The second model has a magnification of X100, with a scale of ±0.01 in., allowing estimations to 0.0001 in. A pivoted lever engages a fixed prism, rotation of which is shown optically. Drawings and details are given. !»K Accessories for Mechanical Comparator. Eng vl56 n4044 July 16 1943 p 47-8 ; Engr vl76 n4565 July 9 1943 p 37-8. Illustrated description of some new attachments for use with "Sigma" vertical comparator; first type is adjustable locating stop designed to facilitate placing of cylindrical work with its diameter exactly in line with plunger; sec- ond attachment is designed to facilitate checking of diam- eters of internal bores. Mechanical Comparator. Eng vl61 n4190 May 3 1946 p 414. Illustrated description of comparator manufac- tured by Sigma Manufacturing Co., intended for finer measurement ; it has reading range of 0.002 in., or 0.001 in. on each side of zero line. Large Cylinder and Taper Comparator for Gauge Meas- urement, R. H. FIELD. Can J Res v25 n3 (sec F) May 1947 p 238-41, 3 supp plates. Illustrated description of comparator for accommodating cylinders or cones with maximum diameters of 12 in. and lengths up to 48 in. designed and constructed during war at National Re- search Laboratories, Ottawa. Le Comparateur, son Emploi son Fonctionnement, B. HUMBERT. Microtecnic vl n5, 6, Oct 1947 p 241-4, Dec p 290-9. Comparator, its use and operation ; illustrated description of various types, including some recent in- struments manufactured in Switzerland. ( In French and English. ) Measuring Diameter of Fine Wire, R. W. CARSON. Wire & Wire Prod v22 nl2 Dec 1947 p 967-71, 995 (dis- cussion) v23 nl Jan 1948 p 63. Discussion of advantages and limitations of various types of diameter measuring instruments ; analysis of effect of anvil pressure on ac- curacy of measurement ; electronic micrometer is illus- trated and described. Before Wire Assn. Electronic Inspection. Aircraft Prod vlO nll2 Feb 1948 p 52--4. Principles and applications of Cornelius com- parator. Tool for Measuring Large Diameters, C. BARNES. Eng Inspection vl4 nl Spring 1950 p 36-9. Difficulty of meas- uring diameters of large gear blanks during process of turning with giant calipers or large vernier gages ; prin- ciples of instrument devised to simplify such measure- ments, which comprises, essentially, accurately constructed welded frame mounting dial gage and contact blocks ; maintenance and use of gage. Reprinted from Machine Shop Magazine. Dimensional Control on Automatics, Machy ( London ) v76 nl966 June 29 1950 p 925-6. Method developed by Sigma Instrument Co. Ltd., Letchworth, employing one vertical comparator in conjunction with range of suitable fixtures of simple design and so constructed that all dimensions on component can be measured, as distinct from being gaged, without resetting comparator; instrument and in- spection sequence are described and illustrated. The Diffraction of Electromagnetic Wave on a Dielectric Cylinder as a Method of Thickness Measurement for Quartz Threads, E. EBERHARDT. Zeit Angew Phys v3 n7 1951 p 242-6 in German. Theory is developed and ex- perimental apparatus described for a comparative method of measurement of quartz threads. An experimentally obtained group of curves gives the relation between dif- fraction phenomenon and thread diameter. The ac- curacy and usefulness of the method is verified by data obtained with an electron microscope. The measuring ac- curacy of 7% is claimed for threads in the range 10-0.5/1. A Simple Method for the Measurement of the Thickness of Very Thin Fibres and Threads, W. VOIGT. Optik vll nil p 509-10 1954 in German. A microscope attachment is described which allows the diameter of a fibre to be calculated. The fibre is in contact with another fibre or foil, whose movement is determined as the test piece is rotated. Examples of the method are given. How Optics Replace Costly, Time-Consuming Inspection, J. P. WRIGHT. Am Mach v98 n8 Apr 12 1954 p 168-9. Application at Brown & Sharpe Mfg. Co. of optical method of measuring alignment errors in micrometers; interpretation of spindle relationship to anvil by relative position and motion, of their images on collimator reticle ; operation with angle comparator can be carried out by unskilled inspectors more accurately in less than 2 min ; micrometers can be manufactured more accurately than before. Precise Measurement of Diameter of Fine Wires, I. G. MORGAN. Engr v200 n5206 Nov 4 1955 p 646-7; Eng vl80 n4686 Nov 18 1955 p 703; Machy (London) v87 n2242 Nov 4 1955 p 1097-9. Apparatus for measuring diameters of wires to within 0.00001 in. ; angle of tilt is measured by mirror and autocollimator and diameter of wire may thus be determined; apparatus developed in Metrology Division of National Physical Laboratory. Comparator for Measuring Average Diameter of Work Which Has Nominally Circular and Uniform Cross- Section, L. W. NICKOLS. Machy (London) v88 n2251 Jan 6 1956 p 43-5; Engineer v200 n5214 Dec 30 1955 p 933-4. Comparator enables rapid measurements to be made and is particularly suitable for work in which de- partures from circular cross section may be appreciable, provided that these departures do not include any re- entrant curves ; construction of comparator ; its setting and operation ; range of measurement is from 1 to 2 in. diam ; under favorable conditions error may be about plus or minus 0.001 in. Communication from NPL. Measurement of Diameter of Opaque Cylinders by Scan- ning Microscopy, J. A. DOBROWOLSKI, W. GODFREY, P. N. SLATER, W. WEINSTEIN. J Opt Soc Am v47 n2 Feb 1957 p 186-90. Experiments show that for cylinders of diameter near optical resolution limit, scanning micro- scope gives too large size estimate ; variation of error with aberrations and numerical aperture of scanning ob- jective, and with wavelength and state of polarization of light were determined. Precision Comparator for Small Cylindrical Work, J. C. EVANS, W. F. ATKINS. Engr v203 n5285 May 10 1957 p 716-7; Machy (London) v90 n2321 May 10 1957 p 1074-6 ; Eng vl84 n4770 Aug 9 1957 p 182-3. Simple com- parator designed at National Physical Laboratory, to en- able diameters of small cylinders to be measured by simple technique to accuracy with plus or minus 0.00001 in. ; by use of wedge, effect of errors of micrometer screw are reduced tenfold. New Instrument for Precise Measurement of Fine Wire Diameters, L. AV ALTER. Wire & Wire Prod v33 n5 May 1958 p 543, 583-5. Equipment developed in National Physical Laboratory in Great Britain provides means of measuring wire up to about 0.01 in. diam to accuracy of 0.00001 in. or better ; principal design feature is use of very light contact load at measuring anvils, thereby re- ducing to minimum errors of measurement due to com- pression of wire. Messunsicherheit beim Messen von Durchmessern fiber 500 mm ( Measurement Uncertainty in the Measurement of Diameters over 500 mm), L. WIZENEZ. Werkstattstech- nik v49 n6 1959. 99 Measurement of Fibre Diameter Variation by Optical Diffraction, W. J. ONIONS. B. ELLINGHAM. Brit J App Phys vlO n7 July 1959 p 328-32. A theory is de- veloped relating the intensity of light refracted at any given angle by a parallel array of opaque fibres of un- equal diameters with the mean diameter and the coefficient of variation of fibre diameter. The ratio of the inten- sities of the first minimum and the first maximum is shown to depend upon the coefficient of variation of fibre diameter. This affords an opportunity of measuring fibre diameter variation. The possibilities and limitations of the method in practice are explored. Beriihrungloses Messen grosserer Aussen und Innen- durchmesser (Contaetless Measurements of Large External and Internal Diameters), K. RANTSCH, E. LEPPER. 4 FOKOMA Munich Oct 6-7 1959 p 1959-10. Contaetless measurement is an acute problem of the progressive finishing technique to the metrologist. This problem is solved electrically, pneumatically, and opti- cally. The explanations of this paper are concerned only with optical contaetless measurements, especially for ex- ternal and internal diameters. Next the demands placed on new equipment are set forth for larjje measurements. An especially remarkable such measuring equipment is the flawless, contaetless indication response of the cylinder surface. For this the field of surface indication is espe- cially treated. Optical indicators of known and of newer kinds are systematically arranged and closely elucidated. Two principal groups of indication responses are thus developed. These chief groups are further classified. Thereby the application possibilities of the single in- dicators may be recognized. From this knowledge con- clusions are derived for practical application in metrology. The already obtained experimental information presents a prospect of future flawless measuring methods. An Image-Splitting Microscope for Accurate Measure- ment, J. DYSON. Nature (London) vl84 Nov 14 1959 p 1561. Describes how, by fitting in the eyepiece a suit- able image splitting device, the two images may be sheared across each other until edge-to-edge contact is obtained. By reversing the shear until edge-to-edge con- tact is again obtained, the diameter of the object may be measured. The technique is illustrated by application to blood corpuscles. Systematik und Kennwerte von Laengenmessgeraeten fuer Bohrungen und Wellen mit Durehmessem ueber 500 mm (Systematic and Characteristic Values of Length Measuring Equipment for Holes and Shafts with Diam- eters over 500 mm) , L. WIZENEZ. Werkstattstechnik v50 n8 Aug 1960 p 424—30. Design equipment, construction and materials employed for principal components of length measuring instruments for bores and shafts with diam- eters of over 500 mm : physical and technological char- acteristics ; it is proposed that system of classification of instruments according to their measuring accuracy be established. Tentative Methods for Measuring Diameter or Thickness of Wire and Ribbon for Electronic Devices and Lamps. American Society for Testing and Materials, ASTM Stand Part 2 F16-61T p 1495-501 5 figs. Describes procedures for measuring the diameter or thickness of round and flat wire (ribbon) 0.060 in. (1.524 mm) maximum, used in electronic devices and lamps. Mechanical measuring methods are based on the use of a sensitive measuring head with calibrated force settings, shaped measuring anvils to reduce errors caused by material curvature or waviness, and a method for presetting the anvil spacing by means of gage blocks or cylindrical master standards. Fehlermogliehkeiten beim Messen Zylindrischer Teile mit Kugeligen Messflachen (Possibility of Errors in the Meas- urement of Cylindrical Parts with Spherical Measuring Surfaces), O. NIEBERDING, S. TROST. Zeit fur Prac- tische Metallbearbeitung v55 p 163 1961. Optische Praezisionsgeraete fuer die Drahtmessung (Optical precision instruments for measurements on wire), A. METZ. Draht yl2 n4 Apr 1961 p 153-4. De- scription of following Leitz instruments and their use : "Tolerator" for checking thickness tolerances within 1/j; two types of "Ultra-Projectometer" for checking toler- ances with l/i and 0.1/*, respectively ; measuring micro- scope, for instance, for determination of wall thickness of insulation of cable. A Machine for the Precise Measurement of External Diam- eter, I. G. MORGAN, F. R. TOLMON, NPL. Machine Shop Mag v23 p 463 Aug 1962; Machy (London) vlOl n2595 Aug 8 1962 p 295-301. Machine constructed at NPL has capacity from 0.2 in. to 3 in. and employs pneu- matic measuring system ; design requirements ; principle of operation; mechanical details and pneumatic system described ; method of use ; performance results ; new ma- chine is capable of reproducing comparison between cylinder and slip gage to accuracy of about plus or minus 2/i in. New Method of Measuring Diameters of Balls to High Precision, S. P. POOLE, NPL. Machy (London) vlOl n2605 Oct 17 1962 p 904-7 ; Am Mach/Metalworking Mfg vl07 nl2 June 10 1963 p 159-61 ; Machine Shop Mag v23 nil Nov 1962 p 618-21 3 figs 2 refs. Equipment described was designed to improve accuracy of measurement for balls of sizes below 0.2 in. in diam. by eliminating errors introduced through imperfect measuring faces; measure- ments are made under very small measuring loads and true sizes of balls, i.e., diameters in uncompressed state, can therefore be accurately derived ; equipment, method of measurement and measuring force described. It is used in conjunction with the NPL-type slip gage interferometer and embodies a 5 mm parallel faced quartz block as the standard of reference. The sizes of balls below 0.2 in. diameter are measured by reference to the quartz block standard in terms of wavelengths of monochromatic light. A Machine for the Precise Measurement of External Diameter, I. G. MORGAN, F. R. TOLMON, NPL. Quality Engr v26 n4 1963 8 p 6 figs 1 ref. The machine is de- signed for the measurement of diameter of standard cylinders from 0.2 to 3 in. to an accuracy of ±5jx in. The cylinder is compared with gage blocks by means of a caliper having spherical steel anvils whose displacements are detected by a pneumatic measuring system. The an- vils exert contact forces of only 3 g so that elastic deforma- tion is negligible. The cylinder and gage blocks rest in close proximity and are not handled during measurement. Compensated Electrical Instrument for Remote Measure- ments of Displacements, M. I. BELYI. Meas Techns 1962 n8 Feb 1963 p 641-2 1 fig 2 refs. Translated from Izmer Tekh n8 Aug 1962 p 17-9. Instrument uses a method of compensating two emfs for direct measurement of linear displacements over large distances with an error not exceeding 10fi. Instrument for Automation of Large Diameter Testing, V. A. TRUTEN'. Meas Techns 1963 n6 Nov 1963 p 465-70 2 figs 7 refs. Translated from Izmer Tekh n6 p 9-13 June 1963. From examination of existing methods it was found that instruments based on the decimal system and the rolling principle meet the requirements for precise and objective measurements, high efficiency, easy handling, and mechanical strength. 100 3.4. Internal Diameters The Measurement of Large Internal Diameters, G. W. BURLEY. Prac Engr Jan 30 1913. Describes the rod . gage and its use. Length Gage, D. R. GALLAGHER. Machy (N.Y.) v26 Sept 1919 p 74; also May 1920 p 849. Describes a pin gage comprising a wooden handle and two wood screws. Gages of this type have been used successfully on work up to 60 inches in diameter. Tapered Ring Gages, V. E. AYRE. Machy (N.Y.) v26 June 1920 p 971. Gives formulas for measuring tapered ring gages by means of balls. New Light on Internal Measurements, J. BATH. Am Mach v54 June 30 1921 p 1110^ 4 figs. Forms of con- tacts for measuring cylindrical surfaces. Results induced by presence of oil on surfaces in contact. Holes meas- ured by line contact. Measuring surfaces cleaned with soap and water. The holding film as a detector of ir- regularities. Interference bands in a ring produced by oil film. Neue Optische Messverfahren fur den Werkzeug and Maschinenbau (Zeiss Internal Measuring Machines), A. STEINLE. Maschinenbau v3 Jan 24 1923 p 244-9 15 figs. Description of Zeiss measuring machines and ap- plications. Measuring the Internal Diameter of Transparent Tubes, J. S. ANDERSON, G. BARR. J Sci Instrum vl Oct 1923 p 9-15. Two methods : ( 1 ) Immersing the tube in a suit- able liquid and varying the wavelength of the illuminating beam until equality of refractive index is attained so that, the system now being homogeneous, the diameter can be measured directly; (2) taking an X-ray shadow photo- graph of the tube and measuring the image found. Be- tween the two methods accurate measurements can be effected no matter what the outside shape of the tube may be. "Zeiss" Inside Measuring Attachment for Horizontal Optimeter. Am Mach v65 Aug 5 1926 p 264. To facili- tate the work of measuring bores, both absolute and rela- tive. Accuracy of 0.00004 in. claimed. Societe Genevoise Comparator for Small Internal Diam- eters. Am Mach v66 Mar 3 1927 p 389-90 1 fig. Made by Societe Genevoise d'Instruments de Physique of Geneva, Switzerland, for use in measuring internal diam- eters of small size. Range 0.16 to 0.24 in. Comprises a rectangular table and a comparator tube. "Standard" External and Internal Comparators. Am Mach v74 June 11 1931 p 925. The external gage is avail- able with a dial indicator or a fan-shaped scale. The dial- scale is graduated to 0.0001 in. in widely spaced divisions, whereas the fan-shaped scale is graduated to 0.00005 in., and may be fitted with tolerance markers. Optically flat 4-in. tables with serrated surfaces are furnished with the external gages. Pieces up to 6 in. in height can be ac- commodated under the direct-acting dial plunger. The internal gage is for exploring holes for bell mouth, taper, and out-of-roundness. Ball racings and bushings can be quickly checked for the above conditions. The dial is graduated to 0.0001 in. The work is slipped over two arms projecting from the body. Comparators for bores from y 2 to 3 in. and up to 3 in. in length are available. Internal Attachment for Zeiss Vertical Optimeter, G. SCHERR CO. Am Mach v76 Aug 31 1932 p 983. Measure- ment of bores from % to 4 in. to within 0.00005 in. ac- curacy can be done with an adjustable internal attachment, which is now available for the Zeiss vertical optimeter, an optical precision amplifying gage. Means are also provided for determining taper and for finding both minimum and maximum diameter of the bore. The attachment slips over the vertical post of the optimeter. Optische Pruefung von Hohlraeumen und langen Bohrun- gen (Optical Testing of Hollow Spaces and Long Bores), G. ZIEHER. Maschinenbau vl6 nl3/14 July 1937 p 347-50. In order to obtain required exactness of modern produc- tion methods special measuring tools have to be designed ; equipment for measuring bores, wall thickness, tapering, parallel alignments, etc., described. Electric Indicator Gauge. Machy (London) v54 nl397 July 20 1939 p 504-6 and v55 nl416 and 1417 Nov 30 1939 p 213-7 and Dec 7 p 241-3. Illustrated description of gage or comparator developed by AEG, Berlin in coopera- tion with Bauer & Schaurte, which can be used for both external and internal measurements ; gage comprised mechanical and electric units, together with indicating equipment. Rachenlehrenpruefung mit Innenmessgeraeten, H. SCHORSCH. Werkstattstechnik und Werksleiter v34 n2 Jan 15 1940 p 21-5. Testing of jaw type gages by aid of internal measuring disk according to DIN and ISA speci- fications, described. Internal Micrometers. Brit Stand Instn — BS n959 — 1941 15 p. Specification applies to internal micrometers com- prising measuring head, extension rods with or without spacing collars, and in smaller sizes, handle ; provision made for three sizes of measuring heads in both inch and metric units. "Three-point method" of Measuring Bores, C. C. STREET. Instrum vl4 ptl nl Jan 1941 p 6-7. Principle of method is that of determining change in altitude of isosceles tri- angle that can be contained in bore under inspection ; mathematical discussion shows manner in which such gage can give true difference in diameter between master setting ring and bore under inspection. Bohrungsmessung mit Zwei- und Dreipunkt-Geraeten, G. BERNDT. Zeit Instrumkde v 61 n3 Mar 1941 p 69-82. Second part of discussion on principles, methods, and ad- vantages of "two-point" and "three-point" instruments for measuring bores ; formulas for evaluating required dimensions from measured values for point, ball and rounded gages. Method for Measuring the Internal Area of Section of a Glass Tube, D. J. BEHRENS. Phil Mag v31 Mar 1941 p 199-203. The external and apparent internal radii at the section are determined from 3 microscope readings and the determination repeated at intervals at 30° around the section. The author gives the theory, which is ap- plicable whether the internal or external sections are concentric or not, so long as the external section is cir- cular and the internal section is everywhere concave. Electrical Tube Gauge, E. PAWSSETT. Eng vl56 n4057 Oct 15 1943 p 301-2. Illustrated description of electro- mechanical instrument for measuring internal diameter of long tubes, which is capable of being used by semi- skilled labor, particularly women, in quickly checking internal diameter of air heater tubes in position. Electric Gaging to High Accuracy, AY. F. ALLER. Elec Mfg Feb 1944. Describes Sheffield internal-external meas- uring instrument. Electrolimit Internal Comparator. Western Machy & Steel Wld v35 n3 Mar 1944 p 10S-9. Some applications of Pratt & Whitney Electrolimit internal comparator are presented; series of photos and brief description given. 101 Size Control. Automobile Engr v34 n454 Oct 1944 p 397- 400. Reasons for use of end standards are discussed, with special reference to end standards produced by Pitter Gauge and Precision Tool Co. ; description also given of two devices developed by this Company, stick micrometer for internal measurements and Universal Measuring Block. Bore Inspection, A. E. THOMAS, T. E. JONES. Aircraft Prod vlO nll6 June 1948 p 187-8. Fine measurement of interrupted and soft surfaced bores ; new method evolved at AID Test House, Harefield ; application to measure- ment of rotor subassembly for high pressure fuel pump; method gives accuracy to within 0.00002 in. and with appropriate modification of anvils and stylii, it might satisfactorily be applied to other problems of internal measurement. Comparator Gauge for Internal Measurement®, L. SANTER. Commonwealth Engr v35 nil June 1 1948 p 435-6. Principles of dial instrument developed during investigations on creep in timber at split ring and shear plate connector joints; based on Scott-Russell straight line motion, gage eliminates personal error in setting, allows much greater number of readings to be recorded in limited time, is much easier to read and requires less skilled operators. Rings and Plugs Checked to Hundredth of a Thou, M. J. PUTTOCK, NPL. Mach Oct 16 1948. Describes method of using an electric gage for the precision measure- ment of circularity, concentricity, and straightness of plain and tapered rings and plugs. Comparator for Measuring Diameters of Small Holes. E. R. DYMOTT, W. O. JENNINGS. Machy (London) v73 nl878 Oct 21 1948 p 590-1. Experimental apparatus assembled for measuring diameters of ring gages and holes from 0.5 in. (13 mm) down to 0.1 in. (2.5 mm) by comparison with slip gages; comparator gives results accurate to plus or minus 0.00003 in (0.0008 mm). Bore-Measuring Micrometer. Eng vl67 n4339 Mar 25 1949 p 272 ; Engr vl87 n4860 Mar 18 1949 p 312. Matrix Micro- Maag internal micrometer introduced by Coventry Gauge and Tool Company is suitable for measuring bores be- tween 1 and 2 in. diam and up to 15 in. deep, to within 0.0001 in. ; photographs, drawings. Odd-Sized Holes to Millionths, E. J. TANGERMAN. Am Mach v93 n24 Dec 1 1949 p 77-80. Steps taken at Bryant Chucking Grinder Co., Springfield, Vermont, toward achieving superprecision finishing of odd sized holes by grinding ; special electronic gage produced by company ; correct assembly of gage blocks, and new developed heavy duty clamp considered as most important factors in attain- ing standard within ±0.000002 and in transferring dimension to hole within 0.000008. Measurement of the Internal Diameters of Metallic Capil- lary Tubes, C. T. COLLETT, J. C. HUGHES, F. C. MOREY. J. Res. NBS v45 p 283-8 Oct 1950. The uni- formity of the internal diameters of some metallic capil- lary tubes was studied by means of a small thread of mercury, using X-ray technique, following the method of Fisher. Eight tubes out of a group of twelve were selected as suitable for use in an absolute viscosimeter, and flow constants were computed. The tubes studied were about 15 ft long, with an internal diameter of about 0.015 in. Maximum deviation from the average diameter in most cases was about 1.5% or less. Matrix Micro-Maag as Internal Gauging Standard, M. MAAG. Microtecnic v6 nl 1952 p 26-9. Set of gages comprising internal micrometers, and assortments of reference rings, measuring needles and various adjuncts; internal micrometer is three-point contact instrument with accuracy of 1 micron permitting detection of out of roundness; particulars of various types of Micro-Maag sets for use as workshop reference standards. New Precision Internal Measuring Machine, C. O. TAYLERSON, A. TURNER, NPL. Symposium on Engi- neering Dimensional Metrology Proc. 1953 p 73. Measures ring gages from 0.1 to 1.5 in. to ±0.0001 in. by comparison with gage block combinations. Diffraction Patterns in Circular Aperture Less Than One Wavelength in Diameter, S. L. ROBINSON. J App Phys v24 nl Jan 1953 p 35-8. Measurements of diffraction patterns from 0.2 to 1.0 wavelength in diameter with plane polarized electromagnetic wave incident normally ; microradiation relative to that of unperturbed beam determined at points along electric and magnetic diam- eters of apertures ; data disagree with calculations from Young's circuited form. Shardlow Imicro Internal Micrometer. Machy (London) v82 n2112 May 8 1953 p 879-80. Micrometers introduced by Tesa, S. A. Renens-Lausanne, Switzerland, are pro- duced in many ranges by British company ; construction of micrometer and method of operating anvils described. Pneumatic Gaging Applied to the Measurement of the Bore of Tube, R. CHITTLEBURGH, E. F. POWELL, G. F. MORTON. J Sci Instrum v31 p 20-2 Jan 1954. A method is described which enables the bore of a tube to be measured accurately at all positions along the length of the tube. The method is particularly suited to the measurement of the bore of tube manufactured to close tolerances. With a method of amplification incorporated into the system, it is possible to determine whether the bore of tube having large tolerances, e.g., % in. bore with a tolerance of +%2 in., lies within those tolerances. A steel ball is placed within the tube and held in position by an electromagnet. The ball serves as the second con- striction in a pneumatic system, air at constant pressure being supplied to one end of the tube through a first con- striction of fixed size. The pressure developed between the two constrictions is a measure of the gap between the steel ball and the inner wall of the tube. Measurement of Small Holes, I. A. GRIGOR'EV. Dept of Sci and Indust Res. Her Majesty's Stationery Office, London 1956 137 p. Discusses contact devices and methods as well as eontactless methods. Measurement of Small Holes, L. A. GRIGOR'EV. GB Dept Sci & Indus Res 1956 137 p. Study of possibility of applying limit plug gages in sizes below 1 mm ; series of tolerances for holes between 0.1 and 18 mm diam ; con- tact devices and eontactless methods; application of internal gages with taper pin, spring type internal gage, and other mechanical means of measuring small holes. Translated from Russian. Internal Measuring Machine. Engr v203 n5274 Feb 22 1957 p 304. Machine made by Coventry Gauge and Tool Company stated to be capable of measuring diameters of finely ground or lapped bores to accuracy of plus or minus 0.00001 in. or less ; it is basically comparator using high precision slip gages as reference standards. Prototype Instrument for Measuring Diameters of Very Small Bores, P. W. HARRISON, G. M. SEVERN. Machy (London) v94 n2428 May 27 1959 p 1210-3. Instrument developed at National Physical Laboratory is capable of measuring bores down to 0.03 in. diam, with lengths up to 1% in. to accuracy of about 0.00002 in.; principle of operation ; contact sensing device ; measuring stylus ; ap- paratus described ; observational procedure. Machine for Precise Measurement of Internal Diameter, I. G. MORGAN, F. R. TOLMON. Machy (London) v95 n2451 Nov 4 1959 p 941-6. Prototype machine built by National Physical Laboratory ; existing equipment, pri- marily Zeiss universal measuring machine, was used to 102 save initial expense, and measuring range is therefore lim- ited to diameters between 1.5 in. and 3.5 in. ; diameter of ring to be measured is established by comparison with known size of reference standard of box form built up from slip gages and lapped steel endplates ; measuring equipment and procedure ; performance tests. Machine for Precise Measurement of Internal Diameter, I. G. MORGAN, F. R. TOLMON. Microtecnic vl4 nl Feb 1960 p 14-20. Prototype machine for precise measure- ment of internal diameter; machine was developed for confirming performance of existing machines for diam- eters up to 6 in. (150 mm) and investigating possibility of improving upon accuracy of measurement at present obtained ; comparative tests show agreement between ma- chines and that accuracy of plus or minus 5/t in. (plus or minus 0.125yu) can be obtained. Minutes of Meeting No. 3 on Internal Diameter Calibra- tions and Measurements of the Measurements Research Conference, NBS June 15 1960. Contains schematic draw- ings of various commercial measuring devices. Verfahren zum Erfassen der Umkehrpunkte Beim Messen grosser Bohrungen und Wellen, L. WIZENEZ. Werk- stattstechnik v50 n7 July 1960 p 363-70. Methods for determining "reversal points" in measuring large bores and shafts; errors occurring in sensing of cylindrical bodies ; three different sensing methods, their advantages and disadvantages described. Measurement of Dimensions in Inaccessible Places, I. A. KUPTSOV. Meas Techns 1959 nl2 Sept 1960 p 939 1 fig. Translated from Izmer Tekh nl2 Dec 1959 p 13. The universal lever instrument with dial gage is being widely used in measuring the deviation of holes from a common axis, the thickness of walls at a considerable depth in small holes, the direction of teeth and internal grooves of small diameters, and other similar dimensions. Instrument for Measuring Verv Small Bores, P. W. HAR RISON, G. M. SEVERN. Engr v210 n5460 Sept 16 1960 p 467-9. Modifications and additions made to prototype at National Physical Laboratory ; electric motor now drives worm shaft and relay halts stylus ; smaller stylus, 0.014 in. ball on tungsten stem, extends range down to bores of 0.02 in. diam ; holes down to 0.0008 in. diam have been made. Further Development of NPL Prototype Instrument for Measuring Very Small Bores, P. W. HARRISON, G. M. SEVERN. Machy ( London ) v97 n2497 Sept 21 1960 p 699- 700; Quality Engr v24 n6 Nov-Dec 1960 p 181. Refer- ence made to instrument previously described by authors (see Engineering Index 1959 p 665) ; circuit for instru- ment modified ; construction of even smaller stylus com- prising ball of 0.014 in. diam mounted on tungsten stem. A Method of Measuring Internal Diameters of Pipes by Means of an Electrical Hole Gauge, D. E. ROKHMAN, V. R. TYR. Meas Techns 1960 n2 Nov 1960 p 94-5 1 fig. Translated from Izmer Tekh n2 Feb 1960 p 6. The in- strument here described is intended for measuring pipe diameters over their entire length for research purposes ; yet, a further improvement of its design and, in partic- ular, its equipment with a centering device, will convert this instrument into an engineering tool for checking the internal diameter of pipes. If required, the variations of the internal diameter values can be recorded on an oscilloscope film. End-Pieces for Internal Measurement Devices, I. S. VASILENKO. Meas Techns 1960 n2 Nov 1960 p 95 2 figs. Translated from Izmer Tekh n2 Feb 1960 p 7. In the case of internal grooves or stepped diameters it is often difficult to measure dimensions accurately. For such measurements attachment IZO-1 to micrometer UIM-21, with an end-piece which has a large diameter sphere, can be used. Measurement of the Internal Cell Length of Glass Measur- ing Cells, H. MORET. Rev Sci Instrum (USA) v33 n2 p 241-3 Feb 1962. The paper describes a novel method, which would appear to be of general application. An accuracy of a few microns is claimed. A brief descrip- tion indicates how the method can be extended to deter- mine the cell length over the whole cell window area. Measuring Small Internal Dimensions on an Optimeter, P. U. MARKOV. Meas Techns 1961 nlO Mar 1962 p 790-1 5 figs. Translated from Izmer Tekh nlO p 16-7 Oct 1961. A measuring method was developed based on the utiliza- tion of a horizontal optimeter and brackets redesigned for the purpose of measuring small holes. Eine neue Messmaschine fuer Innendurchmesser. \V. KIRCHNER, G. BRAUNE. Werkstattstechnik v52 n6 June 1962 p 291—4. New measuring machine for inside diameters ; design and construction of machine used in particular for bores of ring gages ; it operates according to principle by Abbe and has range from 3 to 120 mm ; measuring inaccuracy is only plus or minus 0.1/* in. Some Inside Facts on Inside Measurement, L. O. HEINOLD, JR., ISA Proc Preprint 2.4.62 for meeting Oct 15-8 1962 6 p. New standards for equipment perform- ance, ring geometry and laboratory reporting are sug- gested which must be acted upon before state of art can move forward. Measurement of Small Holes by Means of the "Magic Eye," B. Ya. VERKHOTUROV. Meas Techns 1962 n9 Apr 1963 p 726-8 4 figs 1 ref. Translated from Izmer Tekh n9 p 12^ Sept 1962. "Magic eye" is a tube 6E5 attachment to a universal microscope. When the probe touches the measured hole the shadow in the tube spreads, thus in- dicating a contact. The component with the hole under test is placed on the microscope stage. The probe is in- serted to a certain depth into the hole, the position of the diameter plane is found and the diameter of the hole d=~L+d v is determined, where L is the difference in the readings of the microscope scale, d P is the diameter of the probe. Een nieuwe meetmachine voor het Meten van Inwendige Diameters. (New machine for measuring internal diam- eters), J. M. MULLER. Polytechnische Tijdschrift vl9 nil May 27 1964 p 464-7. Design and operation of ma- chine developed by Kugelfischer Georg Schaefer & Co, Schweinfurt, West Germany ; special design features which were made necessary by high requirements to be met by measuring machine ; illustrated description of some components which are particularly important for accuracy of machine. 3.5. Measuring Machines and Bench Micrometers The Whitworth Measuring Machine. Proc Inst Mech Engrs 1856 ; Am Mach v47 1918 p 189. Measuring Machines, Cornell. Am Artisan November 1874 ; Am Mach v29 May 17 1906 p 655-6. The Whitworth (Millionth) Measuring Machine, T. M. GOODEVE, C. P. B. SHELLEY, 1877. Standards of Length as Applied to Gage Dimensions, G. M. BOND. J Franklin Inst 3d ser vll7 p 318-86 May 1884. Illustrates end standard, Whitworth measuring machine, bench micrometer, etc. Discusses accuracy, tolerances, etc. Standard Measurements in Machine Construction, F. J. MILLER. Am Mach vl5 9 Jan 7, 21 1892 14 figs. Prof. Sweet's bench micrometer is shown in Fig. 5. 103 771-846 O — 66 The Army Gun Factory Comparator, J. E. HOWARD. Notes on the Construction of Ordnance n63, Ordnance Of- fice, Washington Oct 13 1893 10 p 10 figs. Describes a transfer comparator, designed for laying off the distances defined on a line standard bar, and establishing definite distances between or over the ends of contact points for the adjustment of end measures, either for interior gage rods and measures or for exterior diameter calipers. Its capacity is from to 70 in. for gage rods and from 5 to 75 in. for exterior calipers. Automatic Recording Instrument for End Measurements, L. HARTMANN. CR Acad Sci vl20 1895 p 1024-9. Briefly describes (without illustrations) an instrument which measures to 0.001 mm. lengths by comparison with end standards. Instrument records measurements. Can be used for measuring diameters of cylinders, etc. An Electric Micrometer for Laboratory Use, P. E. SHAW. Phys Rev vl6 Mar 1903 p 140-57 6 figs. An instrument of considerable adaptability having delicacy of 0.0001 mm or less, accuracy, and great length of scale. A New English Measuring Machine. Am Mach v26 July 2 1903 p 964-5 5 figs ; Eng vl08 p 104-5 July 25 1919. A description of the Newall Measuring Machine, having a tilting level indicator. The Improved Electric Micrometer, P. E. SHAW. Proc Roy Soc A v76 Aug 4 1905 p 350-9. Limits to its practical sensitiveness (4X10"" 8 cm) have been reached. Paper states in detail the form, peculiarities, and limitations of the apparatus. First used for the measurement of the amplitude of a telephone diaphragm. Recent Improvements in the Newall Measuring Machine. Am Mach v28 Nov 30 1905 p 734-5 3 figs. Illustrates and describes the new features recently introduced and the increase in size, the latest machine having a capacity of six feet. Discussion, J. E. STOREY, Am Mach v29 Feb 8 1906 p 183, Applications of the Newall correcting device to precision lathes. Six-foot Measuring Machine. Constructed by the Newall Engineering Co. Ltd. Eng v81 Jan 19 1906 p 78-9 6 figs ; Am Mach v29 Apr 12 1906 p 488-9. Designed for use with contact or line standards. Has spirit-level indicator. The English Precision Lathe and the Newall Measuring Machine, J. E. SWEET. Am Mach v29 Feb 8 1906 p 172- 3 5 figs and discussion, J. E. STOREY, April 12 p 488-9, and J. E. SWEET, May 17 p 655-6. Design of screws and nuts for precision work. Includes description and illustration of the Cornell measuring machine with references. An Electrical Measuring-Machine for Engineering Gages and Other Bodies, P. E. SHAW. Eng v81 June 29 1906 p 865-8 13 figs. Abstracted from the Proc. Roy. Soc. A v77 Dec 1 1905 p 340-64 10 figs. Describes a method having the advantage of being more sensitive than the old method, and giving an illustrated description of the machine. See also Sci. Am. Supplement Apr 7 1906. Transverse Comparator, W. ROSTERS. Wissenschaft- liche Abh der Kaiserlichen Normal-Eichungs Commission, v8. Julius Springer, Berlin, 1908. A Measuring Machine of- Simple Construction, O. E. PER- RIGO. Am Mach v31 Aug 20 1908 p 271-2 6 figs. A work gaging machine with sliding contact plunger and multiplying levers for moving the indicator pointer over a graduated arc. The Picard and Colomb micrometer, Am Mach v32-2 Oct 7 1909 p 620-1 2 figs. Report of the Committee of Economic Arts of the French Society of Encouragement for National Industry on micrometer measuring machine, for measurement of objects with parallel sides or the diameters of cylinders. Has hydraulic indicator. An Electro Micrometer, G. J. MURDOCK. Am Mach v32 Dec 16 1909 p 1025-7. Illustrated description of a tool for accurate measurements, general testing, and compari- son. Especially adapted for obtaining accurate measure- ments of the inside diameter of bushings and other work when held in a chuck, where the hole is so small that the common inside micrometer cannot be used. Messmaschine von H. Hommel, D. GOPEL. Mech Ztg 1910 p 1-5. Automatic Micrometer Calipers. Mech Engr (GB) v26 Aug 26 1910 p 248-51 17 figs. Illustrated description of a series of automatic calipers made in England. Fig. 1, auto calipers, 1 inch between jaws, divided in .01 in. and Vie in- to %28 in. Fig. 2, do. Fig. 3, large auto calipers with from 6 to 38 in. reach. Fig. 4, large auto calipers, with base to screw to bench, for measuring leather or large metal, etc., sheets. Figs. 5, 6, 7, types of graduated dials. Fig. 8, autocalipers, divided to 0.001 inch. Fig. 9, Imperial auto wire gage, to give direct readings in W.G. Nos. 1 to 30. Fig. 10, Vulcan patent plate gage. Fig. 11, auto sliding calipers, to measure up to 6 in., dial marked every 1 mm. Fig. 12, Auto sliding calipers with one dial in mm and 1 in inches. Fig. 13, large auto micrometer with 5 in. dial to measure % in., marked in 0.0005 in. Fig. 14, large auto micrometer with handle. Fig. 15, large auto micrometer. Fig. 16, large auto micrometer with 7 in. dial for quickly measuring large quantities of samples. Fig. 17, auto micrometer with large reach of frame for measuring thick- ness of sheets of felt or similar materials. A Standard Measuring Machine, P. E. SHAW. Roy Soc Proc Ser A v87 Oct 31 1912 p 385-90. Gives an outline of the scope of an improved type of machine constructed by the author on the principle of electric touch (Science Abstract No. 1116, 1906) and now installed at the NPL. Details and results to be given later. The Reinecker Measuring Machine, A LEMAN. Zeit In- strumkde Beib4 Feb 15 p 33-9 and Mar 1 1913 p 45-8 ; D Mech Ztg ( Berlin ) 1913 p 33 and 45. Communication from the Phys-Techn Reicchanstalt. The peculiarity of this machine as compared with the usual mechanical touch machine invented by Whitworth, is the indication of con- tact shown by the rise of a dilute solution of alcohol in a capillary glass tube. Sectional drawings are given and some methods of adjustment are indicated. Electrical Measuring Machine, P. E. SHAW. Inst Mech Eng Proc v2 Mar-Apr 1913 p 579-629 ; Elect Rev v73 July 25 1913 p 127 ; Electrician v72 Oct 10 1913 p 9-11. A new measuring machine is described founded on the principle of electric touch ( See Sci. Abs. 1116-1906 and 718-1911 ) . Applicable to measurement of cylindrical, spherical, or parallel-faced bodies. The present machine embodies improvements. Unit of measurement is 0.0001 mm. Large Measuring Machines Constructed by Societe Gene- voise. Eng v98 Sept 11 1914 p 323-6. One of these is adapted to measure a gage of even 3 m long. One new feature in the machine is a rolling foot, allowing that change in temperature shall produce no strain along the length of the bed. The most accurate of the machines described measures to 1 micron. The reference scale, in- stead of being fixed, is placed at the horizontal level of the micrometer screw and moves with it. The advantage here is that a cosine error, instead of as usual a sine error, is introduced. 104 Slocomb Bench Micrometer. Machy (N.Y.) v21 Mar 1915 p 591. Range to 6 in. Graduated to 0.0001 inch. Methods of Measurement, D. T. HAMILTON. Machy (N.Y.) v22 Oct 1916 p 100-8 18 figs. A survey of measuring machines and comparators. The following types of universal measuring machines are shown : Fig. 8, Brown & Sharpe measuring machine. Figs. 12, 13, Slocomb standard measuring machine; Figs. 14, 15, Societe Gene- voise measuring machine; Figs. 16, 17, 18, Newall stand- ard type of measuring machine ; Fig. 20, Reinecker meas- uring machine. A Length Comparator for Determining Linear Coefficients of Expansion, W. L. DE BAUFRE. J Am Soc Naval Engrs Nov 1916. Construction and operation with method of calculating. Mikroskop Fiihlhebel fur Schrauben-Messmaschinen (Microscopic Indicator on Measuring Machines), F. GOE- PEL. Zeit InstrumKde v37 July 1917 p 142-5. From the Phys Techn Reichsanstalt. The anvil end of the measuring machine is controlled as usual by a spring. On being pressed back, when a gage is being measured, the far end of the anvil bears against a sensitive lever by which any movement is multiplied 30- or 40-fold. The end of the long lever-arm carries an illuminated index mark, which is viewed by a low-power microscope. The unit is 0.0001 mm. The Taft-Peirce Measuring Machine, E. J. BRYANT. Am Mach v47 Nov 22 1917 p 913-4; Inspector, vl p 9 and 17 Aug 15 1919. A Simple Form of Measuring Machine. Engr vl25 Apr 5 1918 p 302 1 fig; Iron and Coal Trades Rev, March 8, 1918. Measuring machine made by Armstrong, Whit- worth and Company, Ltd., is adaptable to a variety of gage measurements. Cylindrical feeler is used. Specially shaped anvils are provided for various classes of work. Major, pitch, and minor diameters of screw thread gages can be measured. Coats Precision Fluid Gage. Am Mach v49 Sept 5 1918 p 451. Describes Prestwieh amplifying comparator hav- ing a diaphragm which actuates fluid in a capillary tube. A Universal Measuring Machine. Am Mach v53 July 8 1920 p 49-53 14 figs. Engr vl29 May 7 1920 p 472-3 and p 476 9 figs partly on 2 supp plates. Construction and method of operation of universal measuring machine made by Societe Genevoise and designed for accurate measure- ment of pieces of all shapes. Machine is intended as primary standard of measurement for use chiefly for measuring gages or parts of all descriptions, for measur- ing screw threads and as a rapid comparator. All meas- urements are made with reference to a standard scale mounted in a case, shown at the left side on top of the bed, it being read by means of a microscope, never coming in contact with the object being measured. The axes of the scale and of the work being measured are directly in line, thus reducing the chance of error. The headstock at the right contains an indicator to enable the obtaining of the same pressure for each measurement. The fixture in the center is for use when measuring screw threads. Precision Measuring and Inspection Devices, R. J. WHIB- LEY. Machy (N.Y.) v27 Oct 1920 p 135-9 10 figs. Opti- cal methods developed at British National Physical Labo- ratory, for facilitating inspection. Leonard Optical Comparator, 12 in. Am Mach v53 Oct 1920 p 88. The machine is intended to register accu- rately length measurements up to 12 in. within a limit of 0.0005 in. It has a heavy-section box bed, on the ma- chined top surface of which are mounted two headstocks. one fixed and one adjustable. Each headstock carries an anvil, the measurement being made between the anvils. The fixed headstock carries a light box and the optical element, also the amplifying mechanism. The amplify- ing mechanism is so designed that any slight movement of the main body adjusts the ratio between the two sides of the first lever, maintaining the ratio of 7 to 1. The smallest lever is the most important feature of the whole unit, as any slight error on this causes considerable alteration to the scale. A total magnification of 1,000 can be obtained. Neure Feinmessgerate fur die technische Liingenbestim- mung (Modern Measuring Instruments for the Technical Determination of Lengths), G. BERNDT. Zeit VDI v65 June 18 1921 p 639-43 19 figs. Discusses improvements in comparative measurements with gage blocks and meas- uring machines. Almost the same accuracy can be ob- tained with mechanical and optical lever gages, such as minimeters, optimeters, microscopic lever gages, etc., which are described. Details of Gopel and Kosters inter- ference comparators, used for finer measurements. Sum- mary of all measuring machines in which the order of fineness has been changed from 0.00001 to 0.000001 inch. Describes the following briefly and critically : 1 Pratt and Whitney, 2 the German form which employs a liquid indi- cator, 3 Geneva Society with microscope and later for use with indicator, 4 machines with indicators by Eden and Sears, 5 machines using indicators by Gopel, 6 Zeiss optimeter, 7 Shaw's electric micrometer, 8 the interfer- ence comparator of the Reichsanstalt, 9 other less well known forms. An Extensometer Calibrating Device, R. L. TEMPLIN. Chem and Met Eng v25 Aug 10 1921 p 248-51 5 figs. De- scribes various instruments and methods of operation. Accurate End Measurement on Measuring Machines Using a Screw, H. BAKER. Engr vl34 July 28 1922 p 81-3 6 figs. Experiments relating to attempts to measure correctly to one ten-thousandth of a millimeter. Description of ma- chine used and methods. Using a machine of the Societe Genevoise make, with the endeavor to attain consistent work to .1 micron the author finds many precautions nec- essary, which are enumerated. Experiments with oil film in micrometer screw, with dry screw, high tension, etc. The Pratt and Whitney Supermicrometer. Am Mach v57 Aug 31 1922 p 355 ; Machy (N.Y.) v29 Sept 1922 p 68 ; Am Mach v66 Mar 31 1927 p 552 ; Eng vl24 Dec 9 1927 p 747. Instrument which occupies position intermediate between ordinary micrometer calipers and an elaborate measuring machine, is intended for general use by tool makers, in- spectors and mechanics, in shops where measurements of 0.0001 in. are required. Has a capacity of 8 in. and settings are made by use of gage blocks. Has controlled measur- ing force and work support of various forms. Messmaschinen und ihre Bedeuting fur den modernen Betrieb, H. SCHULTZ. Prazision v2 May 1923 p 104. Transversal und Longitudinal — Komparatoren fiir Langen- masse (Transverse and Longitudinal Comparators for Length Measurements) , W. KOSTERS. Prazision v2 1923 pl68. The Wickman Gauge Measuring Machine. Engr vl35 Mar 9 1923 p 266-8 8 figs. Machine for verification of workshop gages, to be carried out quickly and accurately. Measurement of Thin Elastic Plates, C. CHENEVEAU. J. CALLAME. CR Acad Sci vl77 Nov 5 1923 p 872-1. Describes a form of apparatus devised to measure accu- rately the thickness of a thin plate of elastic material. A vertical rod, bearing a fiducial mark, rests on the plate so that the pressure is constant and as small as possible. The height of the mark is measured by means of a microscope. The pressure may be altered, if desired, by placing weights on a pan carried at the top of the rod. 105 Bethel-Player Measuring Machine and Comparator, Am Mach v61 nl3 Sept 25 1924 p 521 1 fig. Uses gage blocks as standards and a tilting level as an indicator. Technische Messgerate (Technical Measuring Instru- ments), W. BLOCK. Maschinenbau v3 Nov 13 1924 p 1036-8. Discusses basic difference of scientific and technical measuring, independence of foreign instruments, simplification of existing instruments, etc. Universal Measuring Machine. Machy (N.Y.) v31 Jan 1925 p 387-8 5 figs. Improved machine known as Hanson- Whitney universal type, which is in part a comparator and in part direct measuring machine using precision screw and large graduated measuring wheel and vernier for ob- taining accurate measuring. Two multiplying lever in- dicators are embodied in the machine. End Measuring Machine at the National Physical Labora- tory. Machy (London) v26 Apr 28 1925 p 113-4 2 figs. Special micrometer head stock and indicating tailstock form essential parts of machine. Measurement of short gages and of thermal expansion of short gages by inter- ference methods. High Precision Measuring Machines, T. TODD, Am Mach v63 Sept 10 1925 p 420. Discussion of article by J. K. WOOD, Am Mach v62 p 945. Deals with measuring pres- sures of workmen. An Electrically-Controlled Micrometer Caliper, C. MOON. J Opt Soc Am and Rev Sci Instrum vll Oct 1925 p 453-8. A description of a special micrometer caliper fitted with electrical control for remote operation. The headstock and tailstock are supported by a heavy ring frame. The headstock screw is driven by a very small electric motor, and in the tailstock there is a mechanism which auto- matically stops the motor by opening a set of electric con- tacts when the critical measuring pressure is reached. The caliper was designed for measuring the diameter of a precision single-layer inductance coil while both coil and caliper were in a constant temperature enclosure. Thickness Measurements of Compressible Materials, R. W. BROWN. India Rubber Wld v76 July 1 1927 p 197-8 5 figs. It is believed that appreciable increase in accuracy of measuring compressible materials will be realized with more general recognition of effect on such measurements of linear accuracy, foot size, foot pressure, and parallelism of feet ; standardization of these factors would eliminate confusion existing at present. The Hilger "Tenthou" Comparator, C. F. SMITH. Machy ( London) v31 Dec 1 1927 p 263 2 figs. Brief account of op- tical gage or comparator which measures differences to accuracy of 0.0001 in. (0.00254 mm) ; designed to meas- ure depressions in rubber ; projects bright line on white scale 10 in. length, divisions of which measure to 0.05 in. ; total difference of 0.02 in. measured directly to 0.0001 in., and by estimation to 0.00005 in. ; small constant pressure applied to object by contact point ; only one moving part. Motor Micrometer of Glasgow Transit-Circle, L. BECKER. Monthly notices Roy Astron Soc v88 May 1928 p 604-6. An electrically driven micrometer, running 280 rev. per sec. without appreciable variation by means of which greater accuracy could be obtained than by another mode of observation. The Calibration of Extensometers, R. K. TEMPLIN. ASTM Preprint v96 for mtg June 25 1928 8 p 3 figs. De- tails of new design of calibration device suitable for cali- brating extensometers arranged for measuring deforma- tions on gage lengths varying from % to 10 in., inclusive ; device indicates total deformations to nearest 0.000002 in. ; errors due to temperatures, design, workmanship, and manipulation are discussed ; calibration data pertaining to micrometer screw are included together with results obtained on few different types of commercial extensom- eters. Carl Zeiss Precision Measuring Machine, G. SCHERR. Instrum vl Nov 1928 p 483^ 2 figs ; Am Mach v69 Oct 4 1928 p 561-2 ; Machy (London) v27 Mar 18 1926 p 815-6 5 figs; Western Mach Wld v20 329-30 Sept 1929 4 figs. Construction is based on _ entirely new optical principle, whereby micrometer screws as well as devices for con- trolling their rather excessive measuring pressure have been eliminated entirely ; in their stead only glass scales are being used together with optical indicator ; these glass scales will not wear and therefore retain their orig- inal accuracy indefinitely. Scale is accurate to 0.00005 in. An Instrument for the Measurement of Thickness of Com- pressible Solids, M. C. MARSH. J Sci Instrum v6 Dec 1929 p 382-5 4 figs. Instrument combines sensitivity and robustness, for measurement of thickness of compressible fabrics over very wide range of pressures. Ames Dial Gage for Thin Materials. Am Mach v73 Aug 7 1930 p 266. Rapid and accurate measurement of thin materials can be effected by the dial gage illustrated. The dial reads to 0.000025 in. Any size of contact points can be furnished. The gage is finished in black crystalline lacquer. Grid-Glow Micrometer, R. W. CARSON. Electronics v4 June 1932 p 191 and 204. Hand micrometer with electri- cal means of indicating instant of contact between mi- crometer and center of ribbon failed ; satisfactory measurements of elastic hysteresis effects were finally made by using Westinghouse DKU-612 grid-glow tube. Microlux Optical Micrometer. Eng vl34 July 15 1932 p 79. Micrometer manufactured by Fritz Werner, Berlin, for gaging finished parts within fine limits ; fundamental features are that manual touch is replaced by constant mechanical pressure, reading is very greatly magnified, and it can be distinguished without aid of eyepiece. Van Keuren Light-Wave Micrometer, VAN KEUREN CO. Am Mach v76 Aug 3 1932 p 920. An accurate bench mi- crometer, the instrument has a 6-in. measuring wheel graduated in 0.0001 in., permitting readings of 0.00001 in. An optical flat is held in contact with a 3-in. steel flat with spring pressure and is connected by a tension rod to the arm supporting the micrometer head. Bending of the arm is detected by movement of the light-wave inter- ference bands. Messmaschinen, G. BERNDT. Archiv fuer Tech Messen v2 nl7 Nov 1932 p T167 (2p). Layout and operating characteristics of length and thickness measuring ma- chines with particular regard to designs by Societe Gene- voise dTnstrum entes de Physique and Zeiss. Screw Micrometer Gages for Rubber Specimens, W. L. HOLT. J Res NBS vlO RP549 May 1933 p 575-82. Screw micrometers combined with an electrical contact indicating device have been adapted to measuring the dimensions of soft rubber parts. Three types of gages have been built. Two of these are vertical gages for thickness measurements and the other is a horizontal gage for dimensions, such as the width of test specimens and the diameter of cylindrical or spherical parts. Measure- ments made with the micrometer gages are compared with (1) the thickness or diameter computed from the volume and (2) those made with the usual type of dial gages. The micrometer gage measurements agree very closely with the computed values due to the precision of the micrometer screw and the fact that there is little compression of the rubber at points of contact. Extensometer Comparator, A. H. STANG, L. R. SWEET- MAN. J Res NBS vl5 n3 Sept 1935 (RP822) p 199-203, 106 1 supp plate ; Mech Wld v98 n2550 Nov 15 1935 p 473-4. Comparator for calibration of extensometers, compres- someters, micrometer dials, and strain gages described ; comparator has given satisfactory results in calibrating length-measuring instruments used for materials testing. Jig Borer Measuring System. Eugr vl64 n4255 July 30 1937 p 135. Method of measurement used for setting table of Newall jig boring machine; illustrated descrip- tion of micrometer device, known as "Micro Locator," lsed for positioning table and trains of rollers with micrometer attachment in position for setting longitudi- nal slide. Society Genevoise Measuring Machine. Machy (London) v53 nl369 Jan 5 1939 p 429-31. Universal measuring machine developed by firm in Geneva, Switzerland ; ar- rangements permit of great diversity of operations on single unit ; weight of carriage supported on ball bearings, with result that wear of guidew T ays is eliminated ; in addi- tion to two micrometer microscopes, goniometric micro- scope is provided. Neuere optische und elektrische Geraete und Verfahren zur Laengenmessung, F. MUELLER. Maschinenbau vl8 nl3/14 July 1939 p 339-40. Recent optical and electric equipment and methods for measurement of lengths ; illustrated description of equipment. Convenient Electrical Micrometer and Its Use in Mechani- cal Measurements, R. GUNN. Trans ASME (J App Mech) v7 n2 June 1940 p A— 19-52. Simple micrometer of mechanical and electrical stability ; electric current out- put from micrometer is accurately proportional to im- pressed mechanical displacement. Zero drift, hysteresis, temperature, and pressure variations reduced to less than 1%. Special circuits described which permit indication of sums, differences, ratios, or products of mechanical displacements. Measuring to 0.000025 in. Without Pressure, R. W. CAR- SON. Elec Mfg v40 Oct 1941 p 80-4 164-70 9 figs. De- scribes micrometer in which contact at the micrometer produces operation of a relay which lights indicating lamps. Unit responds to changes of no more than 4/*" at the contact point. Unit makes consistently repeatable measurements of soft, flexible or compressible materials as well as hard metal parts. Calibrator for Strain Gauges and Extensometers, D. A. MORRELLI. Commonwealth Engr v29 nl2 July 1 1942 p 290-1. Instrument evolved by author has proved very satisfactory in use being robust, steady and easy to use ; it involves no close clearances, or exceptionally precise machine work, and will handle large or smallest extensom- eters with equal ease. A Note on Electromagnetic Induction Micrometers, In- cluding a Novel Circuit, Incorporating Metal Rectifiers, R. J. COX. J Sci Instrum vl9 Aug 1942 p 117-20. Uti- lizes changes in inductance of iron cored coil produced by changes in lengths of air gaps in its magnetic circuit. Verwendung ueblicher Messgeraete zu Sondermessungen (Use of Ordinary Measuring Instruments for Special Measurements), L. TSCHIRF. Werkstattstechnik und Werksleiter v36 n23/24 Dec 1942 p 491-4. Illustrated description of test apparatus for control of small calipers ; measurement of surface thicknesses and symmetries ; con- trol of spaces between holes. Proving-in Paper Micrometer, J. M. FINCH. Bell Lab Rec v21 Jan 1943 p 121-2. It has been proposed that a dial micrometer would be a satisfactory alternative in- strument to pressure-adjusted machinists' micrometers and more easily manipulated ; to determine the compara- tive merits of these devices, tests were undertaken and the results are discussed. Precision Measurement. Automobile Engr v33 n434 Mar 1943 p 123-5. Developments exhibited by E. H. Jones (Mach Tools) Ltd; various new designs for making some form of measurement comparison ; trend is towards evolu- tion of fine precision apparatus that is not too complex or too delicate for use by comparatively unskilled operators. Micrometer for Long End-Measurements. Eng vl58 n4109 Oct 13 1944 p 286 ; Engr vl78 n4619 July 21 1944 p 52-3 ; J Sci Instrum v21 n9 Sept 1944 p 163-4. Brief illustrated description of PVE stick micrometer for making measure- ments of this kind, manufactured by Pitter Gauge and Precision Tool Co. "Microptic" Vertical Measuring Machine. Eng vl59 Mar 30 1945 p 246-8. A new type of vertical measuring ma- chine is described in which no multiplying devices are em- ployed, the actual movement of the measuring contact be- ing read directly by means of a microscope. Its normal capacity covers measurements from zero to 4 in., the read- ing being made directly to within 0.00005 in. and by esti- mation to 0.00001 in. For consistent and accurate read- ings, temperature control is necessary. The main scale is engraved on a block of glass and a graticule scale gives readings to 0.01 in., a micrometer scale, visible in one half of the microscope field, giving the figures in the next 3 decimal places. Das Komparatorprinzip und sein optisches Aequivalent, K. RAENTSCH. Optik v2 n3 Aug 1947 p 235-42. Prin- ciple of comparator and its optical equivalent ; Abbe's comparator principle applied to sliding gage, micrometer screw and apparatus for longitudinal measurements; de- scription of "Zeiss" apparatus built on Eppenstein's opti- cal principle ; photographs, diagrams. Improved Ultramicrometer According to Dowling's Meth- od, G. GUSTAFSSON. Aeronautical Res Inst Sweden— RSAB (Roy Swedish Air Board— Translation n6) 1948 6 p. Principles of length measurement by determining variations in capacity from corresponding changes in anode current of electron tube ; though requiring only one tube and very simple components this type of ultra- micrometer offers comparatively high degree of sensitivity and shows good reproducibility ; design details and sensi- tivity data. English translation from Ann Phys 1935. Zeiss Measuring Machine. Machy (London) v75 nl908 May 19 1949 p 660-2. Standard of reference and optical compensating system employed on new 2m measuring machine. Abstract from BIOS Report No. 1809. Der Perflectokomparator (The Perflectocomparator), R. SCHULZE. VDI Zeit v93 n2 p 41-4 Jan 11 1951. Very accurate measuring instrument for calibration of gages and workpieces. Very wear resistant ; photographs, dia- grams. Micro-Inch Micrometer of One-Tenth Inch Range, E. B. BAKER. Rev Sci Instrum v22 n6 June 1951 p 373-5. It is pointed out that many instruments exist which will mag- nify small displacements to almost any degree desired but always at expense of range ; while micrometer screw is notable exception, it does not give electrical output ; construction details of device which combines lever, mi- crometer screw, sensing element, and servomotor to achieve desired purpose. Machine for Testing Dial Gauges, D. C. BARNES, C. BARNETT. Engr vl98 n5150 Oct 8 1954 p 496-7. Con- tinuous machine developed at National Physical Labora- tory to speed up testing of gages and to give more detailed record of their errors ; if errors are present, they are shown by movements of indicating pointer, and magnitude of errors may be observed by relation to two fixed refer- ence lines. Communication from NPL. 107 ^~ New Comparator for Measuring Pitch Errors of Root Ser- rations on Gas Turbine Blades, L. W. NICKOLS. Machy (London) v86 n2218 May 20 1955 p 1085-8; Aircraft Prod vl7 n6 June 1955 p 212-4. New comparator constructed at National Physical Laboratory measures pitch of pressure flanks of serrations, and may be easily adapted to measure pitch of centers of grooves ; principle of operation ; work- holder, turret, setting fixture and other components de- scribed; setting and operating comparator. Gerat fur die Priifung von Zeigerlehren (Apparatus for the Testing of Dial Gages). Feingeratetechnik v5 nlO p 436-7, 471. In the National Physical Laboratory, Tedding- ton, a continuous working apparatus was developed, which makes possible a quick calibration of dial gages. Some Instruments Developed Recently by Carl Zeiss, Jena. Machy (London) v89 n2291 Oct 12 1956 p 851-4. Instruments described include large toolmakers' micro- scope, 3-meter capacity length measuring machines, Zeiss recording hob testing machine, and electrolytic polisher, which incorporates microscope whereby progress of polish- ing operation can be observed. A Critical Evaluation of High-precision Electromechani- cal Linear Measuring Systems, F. BROWER. Elec Mfg Aug 1957 p 128-41 28 figs 8 refs. Summarizes the advan- tages and limitations of commercially tried approaches to closed-loop machine tool position-measuring, some con- ventional, some off-beat and some proprietary, with a frank discussion of the accuracy, linearity, resolution, and sources of error of each. Untersuchungen an handelsublichen Feinmessgeraten, D. LOBELL- Werkstattstechnik und Masehinenbau v48 n2 Feb 1958. Gives results of experiments relative to the de- pendence of measuring force on measuring travel ; the relationship between measuring force and scatter of mi- crometer instruments ; also result from rambles. Technische Feinmessgerate, Weg und Ziel ihrer Gestaltung (Technical Fine Measuring Equipment, Manner and Aim of Their Design), H. PLESSE. Fourth Res and Construc- tion Colloquium. Mach Tools and Factory Sci, Munich vl p B67 Oct 6-7 1959. Electronic equipment, independ- ent or as construction elements. The article gives a spe- cific description of electronic fine measuring equipment with a classification according to the different methods of work, whereby single processes are accurately set forth. Technische Feinmessgerate, Weg und Ziel ihrer Gestaltung (Technical Fine Measurement Apparatus, Manner and Aim of Their Design), H. SCHORSCH. Fourth Res and Construction Coloquium. Mach Tools and Factory Sci, Munich vl p B63 Oct 6-7 1959. Recently the economy of measurement has been added to the previously deter- mined technical viewpoints as to the design of measuring apparatus. Proceeding from this the necessary measuring times and automation are simultaneously investi- gated as to the relative positions of absolute and compara- tive measuring equipment and the action of these rela- tive changes appraised on the future relative positions of single and multiple purpose equipment. Komparatorsystem und Werkzeug Maschine ( Comparator System and Machine Tools), K. RANTSCH. Fourth Res and Construction Colloquium, Mach Tools and Factory Sci, Munich vl p B55 Oct 6-7 1959. The comparator principle in its classical form is in general not satisfac- tory with machine tools. A few possibilities for the less- ening of measuring errors of the first order with length measuring machines are presented. Finally its transla- tion to machine tools is discussed, and indeed takes place for machines with which the workpiece may be measur- ably shoved in one direction as well as for such with which the measurable di s Pl ac e m ent is in two crossed directions. The described knowledge may give stimula- tion for the measuring technique of practicable equipment of modern machine tools. Length Measurement Using Dynamic Technique, R. G. N. HALL, V. W. STANLEY. Machy (London) v97 n2502 Oct 26 1960 p 959-64. Principle of linear measurements as function of time which is of particular value where dynamic calibration of scale or machine is required ; description of apparatus and of technique which has many applications ; its use in calibration of particular lathe which has servo-control system, using grating as reference scale. SIP Type CLP-10 Photo-electric Longitudinal Compara- tor, A. W. ASTROP. Machy (London) v99 n2554 Oct 25 1961 p 944-62. Details of new length measuring and comparing equipment of outstanding accuracy and design recently developed by Societe Genevoise d'Instruments de Physique, Geneva, Switzerland ; theoretical metrology on which instrument is based ; mechanical, electrical and optical design features; special premises which are re- quired to house comparator and its associated equipment. What Makes a Good Gage Block Comparator? J. H. WORTHEN. Quality Assurance vl nl Oct 1962 p 45-7. Discusses gage block calibration, repetitive accuracy, test technique, calibration accuracy, and other considerations. Slow-Motion Micrometer Drive, F. R. TOLMON. Machy (London) vlOl n2607 Oct 31 1962 p 1016-7. Prototype "4-in. drum" micrometer with slow motion drive developed by NPL in Great. Britain ; design and operation of instru- ment which has now been in constant use for more than year for calibrating various types of displacement sensi- tive devices of high magnification and short range ; graph shows result of calibration of pneumatic measuring system using slow motion micrometer drive. A Slow-Motion Micrometer Drive, F. R. TOLMON, NPL. Mach Shop Mag v24 nl Jan 1963 p 35-7 2 figs. Designed for calibration of displacement sensitive devices. Vertical Type Comparator for Measurement of End Standards, P. HOLMES, E. R. HARRISSON. Microtecnic vl7 nl Feb 1963 p 8-14. Illustrated description of in- strument constructed at Defence Standards Laboratories, Australia, for measurement of end standards up to 40 in. long ; measuring head employs electromagnetic pickup which is rigidly connected to datum platen ; special atten- tion was given to reduction of heating effects due to pres- ence of observer; discrimination of instrument is 0.1/iin. ; method used to calibrate instrument is described. A New Instrument for Measuring Radial Internal Clear- ance of radial ball bearings, S. AOKI, M. YOSHITSUGU. Bull Japan Soc Prec Eng vl nl Oct 19«3 p 9-12 10 figs. Contents : causes of errors involved in conventional meas- uring methods and methods for minimizing such errors ; GML's proposal ; development of the new instrument. 3.6. Manual Measuring Tools 3.6.1. General Small Instruments of Measurement, J. HORNER. Cas- sier's Mag May 1905. Illustrates and describes various small instruments of precision, giving some account of the care needed in their manufacture and their uses. Note sur Quelques Jauges et Calibres (Notes on gages and measuring appliances), G. RICHARD. Rev Meca- nique vl9 n2 Aug 1906 p 124-51 65 figs. With illustra- tions of a variety of micrometer and vernier cali- pers, and a discussion of precise measurements in the shop. 108 Calipers and the Art of Calipering, F. A. STANLEY. Am Mach v30 Mar 7 1907 p 327-62. Contributed and editorial articles dealing with various phases of the subject. Evolution of the Spring Caliper. Am Mach v30 Mar 7 1907 p 327-8. Some interesting particulars regarding this tool. Aids in Setting Calipers to a Steel Scale. Am Mach v30 Mar 7 1907 p 358-9. Accurate results obtained by means of adjustable stops on steel scales for setting calipers. The Side Play of the Calipers. Am Mach v30 Mar 7 1907 p 359-61. Making allowances when boring holes for run- ning, shrink, and press fits. Gages and Interchangeability in Small-Scale Manufac- ture, F. A. HALSEY. Am Mach v32 June 10 1909 p 960-1. Illustrates and describes applications of the indicating beam caliper, explaining its advantages. New Machinists' Tools. Am Mach v32-l June 3 1909 p 943-4 10 figs. Describes machinists' tools brought out recently by the Brown & Sharpe Mfg. Co., including a universal surface gage, tempered steel rules with beveled edges, tempered steel rules with figure graduations, test indicator, tubular inside micrometer gages, height gage attachment, heavy micrometer calipers, improved tool- makers' clamp, hardened square with beveled edges, and heavy automatic center punch. Measuring Tools. Machinery's Reference Book n21 1910. History and development of standard measurements : calipers, dividers, and surface gages ; micrometer measur- ing instruments, miscellaneous measuring tools gages. Height Gages for Inspecting, A. C. LINDHOLM. Machy (N.Y.) vl7 Sept 1910 p 51-2 2 figs. An indicating height gage having two columns is shown in Fig. 1. An instru- ment for measuring the height gage settings is shown in Fig. 2, which consists of a vertical series of notched size blocks and a micrometer suitably mounted on a base. Pioneer Steps Toward the Attainment of Accuracy, L. D. BURLINGAME. Am Mach v41 Aug 6 1914 p 237-43. Work done at Brown & Sharpe plant in developing accu- rate machinists' tools including standard rules, wire gages, cylindrical and caliper gages, and micrometer calipers. Also machine tools and shop methods. A.n Exact Method of Setting Dividers. A. L. CONATY. Machy (N.Y.) v25 May 1919 p 859. Describes vernier caliper provided with holes for setting calipers. Shop Use of Octaval Notation in Shop Measurements, A. WATKINS. Mech Eng v41 Nov 1919 p 870-1 and 905 4 figs. Advocates adoption of octaval notation to denote British binary inch fractions in workshop and on work- shop measuring instruments. Octaval rule, simple ver- nier calipers, double vernier calipers, single-screw microm- eter, and two-screw micrometer using octaval notation are described and discussed. Use of Precision Balls for Accurate Measurements, R. L. RANKIN. Machy (N.Y.) v26 Nov 1919 p 236-8 6 figs. Machy ( London) vl5 Nov 27 1919 p 273-4 7 figs. Practice of U.S. Bureau of Standards in use of precision balls as attachments for machines and for taking direct measure- ments in inspection of gages. New Precision Measuring Device. Machy (N.Y.) v27 Mar 1921 p 657-8 2 figs. Device for measuring within hundred- thousandth part of an inch by use of only six precision measuring blocks, designed by B. M. W. Hanson, Hartford, Conn. Sliding parallels actuated by micrometer. Steel Balls as an Aid in Measuring, R. H. KASPER. Am Mach v54 Apr 21 1921 p 696-7. Describes applications in finding center line of hole, locating position of hole, meas- uring depth of hole having rounded bottom, measuring thickness of bushing wall, measuring thickness of double concave web. Schoop "Out Slide Mikes" for Measuring Diameters. Am Mach v58 Mar 22 1923 p 462. A tape having special grad- uations and vernier, which is wrapped around the object whose diameter is to be measured. Modern Precision Measuring Instruments, W. L. WHIT- MARSH. Army Ordnance v4 May-June 1924 p 381^, 400 8 figs. Describes standard types, including micrometer caliper, vernier calipers, vernier betvel protractor, fluid gage, etc., and their functioning and use. Zeiss Fine Measuring Tools. Machy (London) v26 Apr 30 1925 p 144-8 12 figs. Describes measuring tools placed on market by Carl Zeiss, Jena, Germany, including depth gages, micrometers, dial indicator, passameter twist drill gage, geartooth caliper, and optical dividing head. See also p 334. The Development of Automatic Measuring Devices and the Use of Optical Methods, E. BUCKINGHAM. Am Mach v69 nl8 Nov 1 1928; ASME Trans v51 n4 Jan-Apr 1929 p 5-6. Development of Measuring Devices, Primarily Manual. J. A. HALL. Machine-Shop Practice (ASME Trans) v51 n4 Jan-Apr 1929 p 13-6 and discussion 16-7. History of development of devices for making linear and angular measurements ; go and not go gages ; length standards ; Johansson and Hoke gage blocks ; use of comparators : difficulties in fine measurements ; discussion by E. Oberg covered practical use of measurements. Am Mach v69 nl8 Nov 1 1928. Circumstantial Evidence from Hairs and Fibers, C. A. MITCHELL. Chem and Industry v49 May 30 1930 p 451—4. For purpose of evidence in criminal courts, it is necessary that any evidence given should be capable of verification ; very useful measuring instrument is Kew micrometer ; for accurate measurement of width of hairs and fibers, Zeiss standard measuring glass with glass mi- crometer in circular or linear measurements will be found trustworthy ; identification of isolated hairs ; distinctive human hairs ; hairs of animals ; fibers of furs ; vegetable fibers. Grundlagen, Mittel und Beispiele zweckmaessiger Werk- stattmessverfahren, T. DAMM. (Berichte ueber betriebs- wissenschaftliche Arbeiten. bd. 6.) Berlin. VDI Verlag, 1931 31 p Illus. Principles that underlie various measur- ing instruments used in machine shops, accuracy of these instruments and proper methods of using them. Eng. Soc. Library, N.Y. "Crescent" Tape-Rule. Am Mach v74 June 25 1931 p 997. This 6-ft. tape-rule has an accurate steel tape that auto- matically winds into a sturdy case 2 in. in diameter and yet when completely withdrawn is rigid because it is of tempered steel, stiffened by special forming. The rule is nickel-plated and has prominent dark markings in inches to 16th for the No. 696, and in lOths and lOOths of a foot (engineers' measure) for the No. 696D. The rule blade is returned automatically by pressing the center button. Stanley Flexible Rigid Steel Rules, Stanley Rule and Level Plant, New Britain, Conn. Am Mach v76 May 19 1932 p 656. These pull-push rules with a 6-ft. steel blade, coiled in a watch-size case, are graduated in sixteenths. The rule is a concave steel strip that may be bent as desired and yet is ordinarily rigid. 109 Messen von Bohrungen, G. BERNDT. Werkstattsteehnik v28 nil June 1 1934 p 217-9. Shortcomings of fixed bor- ing calipers with respect to control of forms and thei^ efficiency ; for this reason they are supplanted by test indi- cators and micrometers ; fundamental design principles ; advantages and disadvantages. Beitraege zur Bestimmung der Masse von Rachenlehren, G. BERNDT. Werkstattsteehnik und Werksleiter v29 nl8 Sept 15 1935 p 359-63. Contribution to determination of dimensions of micrometers ; rules for design and shap- ing of micrometers and test calipers. Improved Equipment for Toolroom, R. HARRIES. Machy (London) v64 nl647 May 4 1944 p 477-83. Illustrated de- scription of some designs for measuring equipment and methods of construction ; extending range of micrometer ; built-up sine bar ; radial setting arms ; vernier height gages from steel rules ; bench micrometers for long measure- ments. Precision Instruments and Their Application, J. TITSCH. Technique vl9 n6 June 1944 p 390-3. Discussion of cali- pers, micrometers, verniers, indicators and other com- mon precision instruments. Size Control. Automobile Engr v34 n454 Oct 1944 p 397- 400. Reasons for use of end standards are discussed, with special reference to end standards produced by Pitter Gauge and Precision Tool Co. ; description also given of two devices developed by this Company, stick micrometer for internal measurements and Universal Measuring Block. Braille Instruments Aid Blind Inspectors. Iron Age vl57 n21 May 23 1946 p 56-7. Brief description of special braille marked gaging instruments developed in Great Britain as aid to rehabilitation of war wounded ; instruments now available include vernier calipers and height gages, and micrometers reading to 0.0001-in. ; operating and setting procedures explained. Pitch-Checking Instrument and Micrometer Slip Gauges. Eng vl68 n4367 Oct 7 1949 p 380. Matrix screw thread pitch checking instrument and set of slip gages for check- ing micrometers, known as "Matrix Mikechex" introduced by Coventry Gauge & Tool Co. Srodki Zwiekszajaco Dokladnosc Odczytan na Wzorcach Kreskowych, A. TOMASZEWSKI. Mechanik vl22 nl2 Dec 1949 p 461-3. Means of increasing accuracy of linear scales ; diagrams. Know Your Measuring Tools, H. E. LINSLEY. Am Mach v95 n7 Apr 2 1951 p 101-12. Common measuring tools used at bench, layout table and machine, are discussed ; scales and tapes ; simple and vernier calipers ; micrometer cali- pers ; squares and protractors ; height and surface gages ; miscellaneous gages ; how to read vernier and micrometer. Common Gage Types, R. H. WILCOX. Mill & Factory v51 n2 Aug 1952 p 97-101. Details of main gaging devices cur- rently in industrial use ; with exception of pneumatic, elec- tronic and electrical ; rules and tapes ; calipers ; height, depth, and surface gages ; micrometers ; thread gages. Linear Measurements — Instruments & Apparatus. ASME Power Test Codes PTC 19.14 1958 Supp ASME, New York, 1958 14 p. Types of instruments and methods of linear measurement likely to be required by ASME Power Test Codes ; instruments which determine their range of application. A Set of Measures and Instruments for Mobile Automobile laboratories, B. N. VOROXTSOV. Meas Techns 1959 nil Sept 1960 p 849-51 2 figs. Translated from Izmer Tekh nil Nov 1959 p 13. Describes a set of measuring devices con- veniently portable and especially suited for mobile labora- tories. These are designed for checking universal linear measuring instruments, instruments for measuring the hardness of metals, and for checking dial inside calipers. Universal Measuring Block, R. D. PURVIS. Machy (Lond) vl03 n2662 Nov 20 1963 p 1154-7. Equipment described, meeting requirements of accuracy and also those of full utilization of instrument, consists basically of block of close grained cast iron which has accurately ma- chined central vees and locating pads on base, sides and ends ; these pads allow block to be set in any of 5 positions while maintaining squareness, parallelism and symmetry with central vees to high degree of accuracy ; applications indicated ; equipment was found to be extremely useful for toolroom and experimental machine shop applications. Classification and Comparison of Measuring Instruments, T. BUSCH. Tool & Mfg Engr v54 nl Jan 1965 p 53-5. Tabulation of linear measuring instruments ordinarily used in manufacturing gives range, precision, sensitivity linearity and reliability for scales, vernier, micrometer, gage blocks, indicators, comparators, flat and squares. 3.6.2. Micrometers New Brown & Sharpe Measuring Instruments. Iron Age Sept 27 1900. An illustrated description of micrometer calipers and gages. The Use of Micrometer Calipers for Regular Machine Shop Gages, J. T. SLOCOMB. Am Mach v24 May 2 1901 p 494-^5. An illustrated article explaining the uses made of the micrometer caliper in the machine shop. New Micrometers, W. WEICHOLDT. Zeit InstrumKde v6 Mar 15 1902 p 53-5. These are made with wheel and lever motions, and the length is given by the reading of a pointer on a circular scale, the instruments reading di- rectly to from 0.02 mm to 0.0001 mm. Periodic Errors of Micrometer Screws, H. ROSENBERG. Zeit InstrumKde v22 Aug and Sept 1902 p 246-54 and 269-75. Mathematical treatment. Instruments de Mesure de Haute Precision (Measuring Instruments of High Precision), A. GALASSINI. Rev Mecanique vl3 July 31 1903. Especially describing the micrometers of Bariquand and Marre, as adapted for precise measurements in the workshop. Micrometer Gages, A. L. MONRAD. Am Mach v26 Oct 29 1903 p 1524—6. Convenient tools described, includ- ing micrometer surface gage, micrometer height gage and micrometer beam caliper. The Improved Electric Micrometer, P. E. SHAW. Proc Roy Soc A v76 Aug 4 1904 p 350-9. Limit to its practi- cal sensitiveness (4xl0~ 8 cm) has been reached. States in detail the form, peculiarities, and limitations. First used to measure the amplitude of a telephone diaphragm. Some Micrometer Measuring Instruments, A. L. MON- RAD. Machy (N.Y.) vll Sept 1904 p 41-4. Illustrated description of the writer's own designs of micrometer surface gage, micrometer square, micrometer lathe tool, small inside micrometer, micrometer depth gage, and micrometer lathe stop. A New Type of Micrometer, W. C. DURFEE. Harvard J Eng June 1906. Describes what is called a rolling lens micrometer and its chief merit is said to be its ease of manipulation. Accuracy of Modern (Optical) Micrometers, M. D. EWELL. Proc Am Phil Soc v46 Jan-Mar 1907 p 187-90. Eight modern scales on glass by different makers have been compared, and two older ones (of 25 years ago) . No 110 advance in precision is shown, the results not even equal- ling those of the early period. Exceptionally good re- sults are, however, shown by a glass scale by Leitz and a photograph by Moller. On the other hand the maximum -(7 and — divergence in a glass scale by Watson is 4.6/i in 0.1 mm, and in one by Bausch and Lomb 2.8/j. Some Gaging and Measuring Methods in American and British Shops. Am Mach v30 Mar 7 1907 p 328-32. Large micrometers and other calipers ; their use by inspec- tors and machinists ; gaging big work. Standard Gages and Micrometers in the Shop. Am Mach v30 Mar 7 1907 p 332-4. Micrometers of special design are illustrated. Discussion regarding fits. Micrometers. Am Mach v30 Mar 7 1907 p 351-6 361-2. Early history of the micrometer caliper ; calibration of two Brown & Sharpe micrometer screws ; a micrometer made in a Chinese shop; the use of micrometer calipers for regular shop gages, some modern micrometer calipers. Radius Micrometer, W. A. FARRAR. Machy (N.Y.) vl4 Sept 1907 p 56-7 5 figs. Two forms of radius micrometer for setting turning or boring tools are described. Two micrometer heads are so mounted that the ends of the spindles just coincide with the axial line joining the cen- ters when the barrels register zero. Micrometer Attachment for Reading Ten-thousandths, P. L. L. YORGENSEN. Machy (N.Y. ) vl4 Feb 1908 p 399. Disk mounted on barrel having 250 graduations. Sensitive Indicating Micrometer. Machy ( N.Y. ) vl5 Sept 1908 p 31. Uses a mercury column in a glass tube and supported by a diaphragm as an indicator. An Electro Micrometer, G. J. MURDOCK. Am Mach v32 Dec 16 1909 p 1025-7. Illustrated description of a tool for accurate measurements, general testing, and comparison. Especially adapted for obtaining accurate measurements of the inside diameter of bushings and other work when held in a chuck, where the hole is so small that the com- mon inside micrometer cannot be used. Ball Point versus Anvil Type Thread Micrometers. Machy (N.Y.) vl6 Mar 1910 p 564 3 figs. Points out that the anvil type detects drunken threads whereas the ball type does not. Plant Inside Micrometer Caliper. Machy (N.Y.) vl7 Nov 1910 p 237-8. A set of two inside micrometers for meas- urements from V 2 to 2 in., each of which is provided with handle perpendicular to the micrometer axis w 7 hich may be rotated to lock the setting of the instrument. Some Uses of the Micrometer, G. W. BURLEY. Mech Wld Feb 23 1912. Explains the value of this precision tool and describes uses to which it can be applied. An Electric Micrometer, B. THIEME. Zeit InstrumKde v32 Oct 1912 p 322-5. A fine micrometer screw is mounted on a rigid frame and can be rotated by gearing. Readings of 0.1/i can be obtained. Electrical contact is employed using a galvanoscope as indicator. Slocomb Direct-reading Micrometer. Machy (N.Y.) v21 Dec 1914 p 326-7. Micrometer caliper for measuring the size of wire, having a deep frame provided with a disk dial at the end of the thimble on which the size of wire is given in steel wire gage, decimal equivalent of an inch, and iron wire gage. Howe We Came to Have the Micrometer Caliper, L. D. BURLINGAME. Machy (N.Y.) v21 June 1915 p 778-88. Development of fundamental principles and improved features. How We Came to Have the Slocomb Shop Micrometer, J. T. SLOCOMB. Machy (N.Y.) v21 Aug 1915 p 990-1000. Account of the designing of the micrometer caliper. Common and Special Micrometer Calipers, F. SERVER. Machy (N.Y.) v21 Nov 1917 p 231^5 16 figs. Describes and illustrates tube micrometer, thread comparing mi- crometer (cone anvil and spindle), plate micrometer, paper micrometer, ball anvil-micrometer with relieved frame, heavy type micrometer, micrometer with inter- changeable anvils for large work, beam micrometer, mi- crometer for measuring three-sided piece, micrometers with special points, depth micrometers, thread micrometer. The Micrometer Head in Tool Work, H. F. PUSEP. Am Mach v48 Jan 10 1918 p 59. Cites examples of lathe work, measuring equipment for the milling machines, boring a jig leaf, etc. Ten applications are illustrated. Ball Point Attachments for Micrometer, G. C. HANE- MAN. Machy (N.Y.) v25 Mar 1919 p 645. Describes some methods of attaching balls to the contact points of micrometers. Micrometer Height Gage, H. KIEHNE. Am Mach v51 Aug 7 1919 p 258. The Effect of Finger-Heat upon the Micrometer Gauge, L. PYLE. Sci Am Supp v88 Sept 20 1919 p 185 3 figs. Illustrates right and wrong ways to handle a micrometer caliper and gives curve showing expansion with time as the micrometer is held in the hand. The Davenport-Slocomb Direct Reading Micrometer. Am Mach v52 Mar 4 1920 p 528-9. Counting wheels are mounted on a sleeve that runs concentric with the spindle. Reads from to 999 thousandths. Brinnell Indentation Micrometer. Am Mach v52 Apr 29 1920. A micrometer for measuring the diameter and depth of the indentation made in applying the Brinnell test. As may be noted from the illustration the instru- ment will register both horizontal and vertical measure- ments as separate graduations are provided. The dimen- sions of the impression can be read to 0.01 mm and the hardness value quickly determined by reference to tabu- lated data. Testing the Accuracy of Micrometers in Common Use, C. A. HUBBELL. Am Mach v53 July 29 1920 p 209-10. Sum- mary of results of test carried out on large number of micrometers in commercial use. Ueber die Messgenauigkeit von Schublehren und Mikrome- tern (The Accuracy of Sliding Gages and Micrometers), O. KIENZLE. Werkstattstechnik vl4 Aug 1 and 15 1920 p 426-8 and 442-5 13 figs. Points out that faults occur- ring in all measuring instruments are inaccuracy of con- struction, wear and tear on measuring surface, faults due to different temperatures, to different pressure when measuring, and to faulty readings. Normung der Mikrometer (The Standardization of Mi- crometers), R. P. SCHRODER. Betrieb v3 Nov 25 1920 p 97-100 4 figs. Discusses gradation of size, accuracy, and gap. Notes on limit gages. Bath Internal Micrometer and Master Ring Gages. Am Mach v54 Mar 31 1921 p 578-9. Micrometer is provided with four jaws fitted to inclined dovetail grooves in the body, and movement of the jaws is controlled by an accu- rate micrometer screw. Bath Micrometer Plug Gage. Machy (N.Y.) v27 Apr 1921 p 795-7 5 figs. The gage has four measuring jaws provided with true cylindrical contact surfaces and held in perfect alignment with the sliding member by means of closefitting dovetailed slots. The measuring jaws are 111 expanded or contracted when the slide is moved back and forth through the operation of a micrometer screw. It is claimed that, as the movable jaws fit tightly in the dove- tailed grooves of the slide and are controlled by an accu- rate screw without backlash, an instrument is obtained which is as rigid as a solid plug. Die Aufbiegung von Schraubenmikrometern (The Spread- ing of Micrometer Frames), G. BERNDT. Betrieb v3 June 25 1921 p 574-81 12 figs. Results of experiments with a number of screw micrometers by different firms. Formula for calculation of semi-circular frames. Tables of permissible amounts of spreading of frame and weights for rectangular cross-section frames. Checking the Accuracy of Micrometer Measurements, E. SHELDON. Am Mach v55 Oct 6 1921 p 562-4. Notes on close measurements with micrometer; possibilities of error due to mechanical defects. Genauigkeitsanspriiche an Mikrometer und Fiihlebel (Ac- curacy Requirements of Micrometers and Lever Gages), G. BERNDT. Betrieb v4 Feb 11 1922 p 280-4. Relation between measuring and reading accuracy of screw mi- crometers. Suggestions for increasing accuracy of lever Inside Micrometer and Height Gage (Comb.). Iron Age vllO July 13 1922 p 84. Tool made by Reed Small Tool Works. Combination set comprises a micrometer head, adjusting wrench, 5 rods and % in. spacer for capacity 2 to 7 in., 5 additional 5 in. spacers, and height- gage base attachments of two different forms. Sloeomb Inside Micrometer. Am Mach v58 Apr 5 1923 p 532b. Provided with an auxiliary cap for measuring large diameters. Measuring Threads Accurately with Micrometers. Can Machy v31 May 1 1924 p 31-2 and 51 6 figs. Hints on accurate use of micrometers. Proper Care Essential to Micrometer Accuracy. Can Machy v32 July 24 1924 p 25-6 6 figs. Hints on use and care of measuring instruments. Sloeomb Tube Micrometer. Am Mach v61 Sept 18 1924 p 480. Micrometer caliper of standard construction ex- cept frame is designed to support a stud extending at a right angle to the spindle and forming the anvil. Mikrometer und Messapparate (Micrometers and Meas- uring Instruments), P. DUCKERT. Zeit InstrumKde v44 Oct, Nov and Dec 1924 p 443-53, 483-94, and 547-55; and v45 Apr 1925 p 176-85. A description, with numerous illustrations and diagrams, of various types of microme- ters. For a comprehensive treatment of the theory of the various instruments the author refers to the treatise by E. Becker in Valentiner's Dictionary of Astronomy, 3, Sec 1. Brown & Sharpe Direct-Reading Micrometer No. 26. Am Mach v63 Oct 1 1925 p 567; Eng vl21 Jan 8 1926 p 60. Direct reading feature consists of a set of num- bered dials which are actuated by the movement of the measuring screw through steel indexing gears. Wear of Micrometer Screws. Machy (London) v27 Jan 14 1926 p 521-22 2 figs. Report of series of experi- ments made at Zeiss plant. Screw Thread Micrometer Calipers, H. BENTLEY. Indus Mgmt (London) vl3 June 1926 p 261-2 2 figs. Application of micrometer calipers to measuring V-type screw threads. Brown & Sharpe No. 11 Micrometer. Am Mach v67 July 28 1927 p 173. Has enlarged opening in frame and small size of the frame at its anvil end, designed to measure odd-shaped pieces. The Meter-Inch Micrometer. Model Engr & Light Machy Rev v57 Sept 1 1927 p 202-3 3 figs. Combination of metric and inch micrometer instrument which as a whole is considered accurate within satisfactory limits; calibra- tion of screw for progressive error at intervals of 0.1 in. over its 1 in. of length showed it to be within 0.0001 of inch total, and within 0.003 mm by metric measure. Brown & Sharpe Nos. 90, 91, and 92 Micrometers. Am Mach v68 Apr 26 1928 p 714. Combined range 12 to 24 in. Each tool is provided with four interchangeable anvils of different lengths. Micrometer for Measuring Diameter of Quartz Fibers. Eng vl25 June 1 1928 p 655 2 figs. Capacity .020 mm. Galvanometer serves as an indicator. Brown & Sharpe Micrometers. Am Mach v68 June 28 1928 p 1063-4. Nos. 60 and 62 micrometer calipers, range 1 to 2, and 2 to 3 in. Inside micrometer No. 276 provided with 10 changeable anvils. Brown & Sharpe Blade-and-Disk-Anvil Micrometers. Am Mach v69 Sept 27 1928 p 521-2. Special micrometers for measuring forming tools. Thin blades on the ends of anvil and spindle permit them to enter the narrow slots and grooves of forming tools. Starrett No. 210 Micrometer for Comparing Screw Threads. Am Mach v69 Oct 25 1928 p 668. Lufkin Direct-Reading Micrometer. Am Mach v73 July 24 1930 p 187. This direct reading micrometer gives the total measurement without difficult and often incorrect additions. This reading is shown at a glance by an in- genious arrangement of the figures on the sleeve. The hub markings are the same as on the regular type of micrometers. Hundredths of thousandths are indicated by a long line. The three shorter lines indicate 0.025, 0.050, and 0.075, and are arranged so that they appear as a group of three. Mischker Square-barrel Micrometer. Am Mach v73 Nov 13 1930 p 796. Quick setting by means of a ratchet to within 0.025 in., and then final measuring by means of a graduated barrel, are features of this square-barrel micrometer. The measuring stem with its square barrel is removable and is intended for use with a set of frames of varying sizes. The stem is provided with a short thread sufficient for one complete turn or 0.025 in. move- ment. An inside stem is provided with the set. Neo-Micrometer. Eng vl31 n3413 June 12 1931 p 775 2 figs. Instrument is made in two forms, smaller instrument having range of from zero to 12 in. between gage points, and corresponding range for larger instrument being from zero to 40 in.; each can be used for both internal and external measuring. Starrett Thimble-Friction Micrometer Caliper. Am Mach v75 Dec 10 1931 p 900-1. A friction-stop mechanism eliminates the inconvenience of reaching beyond the thimble to operate the stop. Since the stop disengages at exactly the same pressure each time, the operator is as- sured of uniform contacts. Range of the instrument is to 1 in. by thousandths or, for an extra charge, by ten-thousandths. Starrett Micrometers with Tungsten-Carbide Tipped An- vil and Spindle. Am Mach v76 Jan 28 1932 p 150. The anvil and spindle of micrometers are now available with facings of cemented tungsten carbide to give greater wear resistance. The frame is cut away to facilitate use 112 in places where the ordinary micrometer cannot be inserted. Brown & Sharpe Micrometer Calipers with T. C. Surfaces. Am Mach v76 June 23 1932 p 800. Micrometer calipers (1-in. size) in several styles have the ends of the spindle and anvil faced with tungsten carbide, useful where the micrometers are subjected to unusual wear. Laengenmessung mit Sehraublehren, G. BERNDT. Archiv fuer Technisches Messen v2 nl5 Sept 1982 p T137 (2 p). Principal factors contributing to errors in length meas- urements with screw calipers. Starrett #700 Inside Micrometer Caliper. Am Mach v76 Nov 23 1932 p 1175. Dimensions between 0.200 and 1 in. can be measured directly in thousandths. The micrometer combines the sliding jaws of a slide caliper and the easy reading thimble and sleeve arrangement of a micrometer caliper. One jaw is fixed and the other is attached to the sleeve. Micrometers. Mech Wld vl04 n2712 Dec 23 1938 p 611-2. Specification applying to micrometers having bow-shaped frame holding micrometer spindle and nut on one side opposite anvil on other with individual measuring ranges otf 1 in. to 11 to 12 in., and 25 mm up to 275 mm to 300 mm and to setting gages for micrometers above 1 in. or 25 mm. One of series of Brit Standards Instn. Speci- fications in course of production for engineers' precision tools. Take Good Care of Micrometers. Mill & Factory v32 n3 Mar 1943 p 108-20. Tool craftsmanship charts pointing out some of more common abuses to which micrometers are subjected ; preventive measures. Improved Micrometer Allowing Lateral and Rotary Ad- justment. Indus Power & Prod v21 n232 Feb 1945 p 90. New micrometer head comprises easily operated means of locking thimble in new rotary and lateral positions on spindle, after insertion of shim or shims between flange on spindle and internal flange on thimble. Micrometers and How to Use Them, G. W. DAWSON. Motor Service July 15 1946 p 124, 154, 157, 218. Microme- ter measurement reading and interpretation explained, including recommendations for care and handling. Multi-Purpose Micrometer. Engr vl82 n4729 Aug 30 1946 p 196. Brief description of new form of micrometer introduced by E. H. Hones ( Machine Tools ) , Ltd. designed for use on wide range of work not adapted to measure- ment by standard type of instrument ; consists of stand- ard micrometer barrel at base of sleeve on which is mounted block instead of usual frame. How to Read Micrometers and Verniers, J. FOSTER. Power Generation v52 n3 Mar 1948 p 81-3. Instructions for use of typical micrometer as used in machine shops ; principle of operation ; English type micrometer ; metric type micrometer ; vernier micrometer ; vernier caliper ; universal bevel protractors. Measurement of Close Tolerance Parts. Matls & Methods v29 n4 Apr 1949 p 79, 81. Method of correcting observed micrometer readings to obtain actual dimensions of part of standard temperature (68 °F). External Micrometers. Brit Stand Instn— BS n870— 1950 19 p. Provisions for micrometers with measuring ranges of to % in. and from 12 to 24 in. ( with their correspond- ing metric equivalents) ; requirements relating to microm- eters with interchangeable anvils and various measuring ranges up to 24 in. (600 mm ) . Measurement of the Thickness of Capacitor Paper, W. SOUDER, S. B. NEWMAN. NBS Cir n532 10 p 1952. The definition of thickness must be carefully analysed before choosing an instrument for such measurements. Three methods are available: (1) by direct observation across an edge section by means of a micrometer micro- scope, (2) by measuring the separation of two geometric- surfaces between which one or more specimens are placed, and (3) by determining the mass of a definite area of sample and computing the thickness, using the density parameter. Measurements have been made on some commercial thin capacitor papers, using the interferom- eter, micrometer microscope, mechanical micrometers, and the surface analyser. These data have been analysed. It has been found that the precision dial micrometer or the precision screw micrometer may be used for such measurements. The size and type of contact and the load to be applied will depend on the needs of the manu- facturer and user of the paper. Micromaster. TESA, Ltd., Switzerland, Bui 28 Nov 1952 3 p 7 figs. Micrometer giving a partial digital readout with graduations on thimble and sleeves arranged side by side. Longitudinal play is eliminated by use of differen- tial screw threads. Micrometer with Setting Shown Numerically. Eng vl77 n4590 Jan 15 1954 p 87. "Micromaster" micrometer de- veloped by Tesa, Ltd, Switzerland, is similar to normal micrometer, but divisions are more widely spaced and setting is indicated by numerals. New Design of Height Gauge, H. A. CHIVERTON. Machy (London) v87 n2235 Sept 16 19>55 p 695-6. Gage developed by author is based on micrometer principle in- stead of usual vernier scale, and affords number of advantages, including low cost of manufacture, and excep- tional robustness ; design details. A Universal Test-Piece for Use with Micrometers of Throat over 100 mm, A. N. DOLGUSHEV. Meas Techns 1959 n2 Feb 1959 p 97-8 1 fig. Translated from Izmer Tekh n2 Feb 1959 p 14. A test piece having ball tips for checking parallelism of faces. Modern Measuring Instruments — Electric and Electronic Gages, F. W. WITZKE. ASTME Tech Papers v60. book 1, paper No. 245. Electronic gage heads now pro- vide extreme precision and accuracy for standards labora- tory use. Performance specifications are listed. A Device for Checking Micrometers for Dimensions over 100 mm, YU. F. AKSYUK, YA. P. VOLOSIN. Meas Techns 1959 n5 June 1960 p 311 1 fig. Translated from Izmer Tekh n5 May 1959 p 9. The proposed device per- mits the checking of micrometers with a wide measure- ment range (over 100 mm) by means of length standards with the maximum size of the block equal to 25 mm. thanks to the presence of an auxiliary adjustable stopper. Evaluation of the Measuring Efforts in Micrometer Instru- ments, A. I. SUVOROV. Meas Techns 1962 n4 Sept 1962 p 278-9 2 figs. Translated from Izmer Tekh n4 p 8-9 Apr 1962. Relates measuring effort to stability of mi- crometer readings and methods of its measurement. An Improved Precision Height Gage, L. B. VALE, Ames Research Center. NASA SP-5001 Nov 1963 12 p 3 figs 4 patent refs. For sale by Office of Tech. Services, Dept. of Commerce, Washington, D.C., 20230'. price 50 cents. Describes a wedge parallel actuated by a micrometer which yields performance and accuracy superior to those of previous devices. It may be accurately set to a desired height without auxiliary measuring devices, there is no lost motion in the movement of the upper block, and the resolution is improved. 113 3.6.3. Vernier Instruments See also subsection 4.2 The Reading of Verniers. Am Mach v25 Apr 3 1902 p 474-5 5 figs. An explanatory article. The Reading of Verniers. Am Mach v30 Mar 7 1907 p 349-51 5 figs. Explains the reading of verniers. Inside and Outside Caliper Gage, H. E. CURTIS. Am Mach v32-2 Nov 4 1909 p 786. A vernier beam caliper having inside measuring jaws. Vernier Height Gage, Machy (N.Y.) v23 Feb 1917 p 546. Slide Gage. Jeweler's Circular Jan 7 1920 p 143. caliper having special features is described. A vernier Brown & Sharpe Nos. 465A and 465B Height Gage In- struments. Am Mach v69 Aug 30 1928 p 374-5. Die Genauigkeit der Ablesung an einem Nonius bei feinen Kreisteilungen (Exactitude in Reading of Vernier on Small Circular Divisions), K, LUDEMANN. Zeit In- strumKde v49 n5 May 1929 p 238-48. Tabulation of observations on reading with and without magnifying glass ; summary of existing literature. Bibliography. British Standard Specification for Vernier Calipers. Brit Stand Instn— BS Specification n887— 1940 14 p. Specifica- tion applies to calipers, with internal and external meas- uring faces, and having ranges of measurement in inch units up to 48 in., graduated to read 0.001 in., in metric units up to 1 mm, graduated to read 0.02 mm, and in both inch and metric units with above graduations. Choix et Determination d'un Vernier, A. LABORDE, C. TURLAN. Technique Mod v38 n9-10 May 1-15 1946 p 106-11. Study of theory of vernier, its intervals and method of observation ; circular verniers ; charts and tables presented. Some Variables Influencing Vernier Acuity, I. Illumina- tion and Exposure Time. II. Wave-length of Illumination, K. E. BAKER. J Opt Soc Am v39 p 567-76 July 1949. Functions relating vernier acuity to illumination have been obtained for two different exposure times and at 8 regions of the visible spectrum. An apparatus providing the necessary stimulus controls has been described in de- tail and the procedure is fully explained. Single Element Verniers Reading Two or Three Dimen- sions, R. E. LEWIS. Rev Sci Instrum v21 p 647-9 July 1950. By superimposing concentric radial elements on rectangular co-ordinate rulings, vernier systems may be constructed reading in two or three dimensions without the necessity of any particular angular orientation. A two-dimensional vernier may consist of one transparent element ruled with concentric circles. The observed tan- gencies of the circles, with regard to a rectangular grid placed in contact, provide the reading of the additional decimal of the co-ordinates of the fiducial centre of the circles on the grid. A three-dimensional vernier system may be established by means of a binocular optical system presenting images of spheres concentric with the locating point and images of co-ordinate boxes in the same space. The tangency of a vernier sphere and co-ordinate plane indicates the last decimal of the reading. Angular orien- tation may be indicated by radial lines near the points of tangency. Precision Vernier Calipers. TESA, Ltd., Switzerland Bui 21 Feb 1951 4 p 15 figs. Discusses important factors in manufacture and use of vernier calipers, including accuracy of graduation, thickness of lines, errors of interpretation, influence of the measuring pressure, de- formation of beam and jaws, and objective and subjective influences on measuring accuracy. Modernized Slide Gauge. L. D. SHCHUKIN. Meas Techns 1962 nl June 1962 p 18 2 figs. Translated from Izmer Tekh nl p 15 Jan 1962. Modified vernier caliper for measuring internal dimensions. Making Parts for Vernier Calipers, P. A. SIDDERS. Machy (London) vlOl n2604, 2606 Oct 10, 1962 p 800-8, Oct 24 p 924—32. Methods employed for production of new instrument, type 600 calipers, developed by James Chester- man & Co., Sheffield ; it was designed to meet need for relatively inexpensive calipers with acceptable standard of accuracy ; operation ; induction hardening jaws ; grind- ing external measuring jaw ; finish broaching operation ; milling operations on beam ; surface grinding operations ; operations on triggers ; inspection trolley specially built to facilitate inspection work ; grinding ends of scales and ends of depth gage blades. Chesterman-Sogenique Electronic Height Gauge. Machy (Lond) vl05 n2706 Sept 23 1964 p 761-2. Gage described has dial indicator to ensure predetermined stylus pressure and digital indicating equipment ; it is designed to enable accurate measurements to be made rapidly, and to elimi- nate possibility of slight errors in reading instruments of vernier type. 3.6.4. Dial and Test Indicators See also subsections 5.2.3 and 5.3 New Micrometers, W. WEICHOLDT. Zeit InstrumKde v6 Mar 15 1902 p 53-5. These are made with wheel and lever motions, and the length is given by the reading of a pointer and circular scale, the instruments reading directly from 0.02 mm to 0.0001 mm. The "Just It" Lathe Test Indicator. Machy (N.Y.) vl3 Dec 1906 p 225 2 figs. Pivoted-finger type of test indicator. Toolmakers Universal Test Indicators, J. D. STRYKER, Am Mach v30 Sept 19 1907 p 411-2 9 figs. A test indicator of the plunger-pin type. Inspecting Tools with the Test Indicator, J. H. BOULET. Am Mach v30 Oct 17 1907 p 537^11, Nov 14 1907 p 773. Illustrates and describes a number of methods of testing and measuring various classes of tools by means of indi- cator of the author's invention. Dial Gages for Accurate Measurements. Machy (N.Y.) vl4 Dec 1907 p 264-5 3 figs. A Test Indicator and Some of Its Applications. Am Mach v31 Aug 27 1908 p 303-5 9 figs. An instrument of plunger- pin type, for setting and testing lathe, miller, shaper, and surface plate work. Made by Henry Koch and Son. Var- ious applications are illustrated. Compact Form of Dial Indicator, L. HAAS. Machy ( N.Y. ) vl5 Aug 1909 p 966-7. Plunger-pin type indicator using spiral and multiplying lever combinations. Dial Indicators, p 2059-60. Zeit Practische Maschinenbau v45 1910 A Novel Fine-Measuring Machine — "Hirth Minimeter", A. GRADENWITZ. Am Mach v33-l Apr 14 1910 p 696-7 8 figs. Various adaptations of "Hirth" Minimeter for gag- ing are illustrated. Fig 1, the minimeter lever, pointer, and scale ; Figs. 2, 4, and 8, the minimeter mounted as an amplifying comparator ; Figs. 3, 5, 6, and 7, the minimeter mounted to gage rings. 114 Automatic Micrometer Calipers. Mech Engr v26 Aug 26 1910 p 248-51 17 figs. Describes a series of dial microm- eters, or auto calipers, made in England. A Test Indicator and Comparator, H. F. ATKINS. Am Mach v34 Aug 31 1911 p 407-9 19 figs. Illustrated de- scription of a simple indicator of almost universal appli- cability. The principle on which the indicator depends is the magnifying of the movement of a plane surface by transferring it to a roller, held between the movable plane and a fixed plane, and causing the roller to swing a pointer over a graduated sector. Test Indicators and Their Uses, G. W. BURLEY. Mech Wld Dec 1 1911. Explains uses to which they are applied and illustrates and describes types. A Universal Indicator, H. V. PURMAN. Machy (N.Y.) vl8 Jan 1912 p 341-2 4 figs. Diagrams and descriptions of indicator of pivoted-finger type, designed by F. A. Turner. Test Indicator. Machy (N.Y.) vl8 Apr 1912 p 648-9. Pivoted finger type of indicator made bv American Watch Tool Co. Universal Test Indicator. Machy (N.Y.) vl8 July 1912 p 898. Pivoted-finger type of indicator made by Alvan Mfg. Co. Lowe "Last Word" Indicator. Machy (N.Y.) v20 Mar 1914 p 610 2 figs. Fig. 1 shows Lowe test indicator carried on ball-joint toolpost shank ; Fig. 2 shows Lowe indicator mounted on the needle of a surface gage. Also Machy (N.Y.) v22 Nov 1915 p 248 3 figs. Contact point is pro- vided with a friction joint at the pivot. Toolmakers' Test Indicator, D. BAKER. Machy (N.Y.) v23 Nov 1916 p 246-7 3 figs. Pivoted finger type of indi- cator designed by Warren Dunbrack. Ausbau der Fuhlhebelmessung (Development of Lever- Gage Measurement), M. KURREIN. Werkstattstechnik vl6 Oct 15 1922 p 613-6 8 figs. Describes new measuring tools of the Fortuna Works, Stuttgart-Cannstatt. Ger- many, exhibiting at Leipzig Exhibition. A Study of Commercial Dial Micrometers for Measuring the Thickness of Paper, P. L. HOUSTON, D. R. MILLER. Tech Papers NBS n226 Dec 29 1922 p 125-52. For abstract see Subsection 5.4. Federal Micrometer Dial Gage. Am Mach v58 Apr 26 1923 p 643. See also p 889. Consists of a bench stand for holding dial indicator at any desired angle and a pair of micrometer jaws. Federal Dial Indicators, Models D and DD. Am Mach v58 June 14 1923 p 889. Show 0.04 in. per revolution. D-10 "Last Word" Test Indicator. Am Mach v61 July 31 1924 p 211. For specially accurate work. Range 0.016 in. Magnifies 300 times. Toleranzmesser, Flachen und Winkelprufer (Tolerance Measurer, Surface and Angle Measurer), W. EWALD. Deutsche Opt Wochenschrif t vl2 n36 Sept 1926 p 466 4 figs ; vl2 n34 Aug 1926 p 441 1 fig. Describes mechanical indi- cating instrument for measuring thicknesses and angle de- viations. Produced by Askania. A Convenient Indicating Device for Dividers, Calipers and Compasses. Instrum vl Mar 1928 p 165-6 1 fig. Device designed to eliminate tiresome and slow operation of tak- ing measurements directly from scale or rule ; disk is grad- uated in V ei and %oo in. ; dial performs function of ver- nier ; can be provided with dial for direct indication of any desired units. Ames Dial Micrometer. Am Mach v72 Feb 6 1930 p 281. Easier reading to thousandths by means of widely spaced dial graduations is the chief feature of this dial indicator micrometer. Two dials are employed. The smaller indi- cates the revolutions of the larger pointer, each graduation of the small dial representing 0.1 in. The large dial has 100 widely spaced graduations around the dial, each rep- resenting 0.001 in. The range is to 1 inch. By operating the spindle lock, the tool may be used as an adjustable snap gage. Apparatus for Measurement of Very Small Displacements, H. WHITAKER. J Sci Instrum v8 n8 Aug 1931 p 251-8 6 figs. Apparatus consisting of accessory device, which can be fitted to standard type of microscope ; method con- sists in using fine quartz pointer as lever which multiples small displacement to be measured. Japanese Scientists Develop Simple Optical Indicator, P. N. HELDT, Automotive Industries v70 n26 June 30 1934 p 813-4. Details of optical indicator developed by F. Naka- nishi, M. Ito, and K. Katamura. Frictional Forces in Dial Gauges, C. F. BRUCE. Eng vl67 n4335 Feb 25 1949 p 169-71. Investigation of "sticki- ness" in movement of plunger on anvil of gages for dial indicators of type which are mounted on surface gage and used mainly for leveling of surfaces ; frictional forces in gage may amount to as much as 50% of max operating force on gage, as measured when gage is lightly tapped ; photographs, charts. How to Get Your Money's Worth Out of Dial Indicators, I. A. HUNT. Am Mach v93 nl2 June 12 1949 p 93-100. Construction and maintenance recommendations includ- ing standard dimensions and types of dials ; checking of indicators ; their correct mounting ; when and how to use indicators. Les Defauts des Comparateurs a Cadran, G. MICHALET. Pratique des Indus Mecaniques v32 n9, 10, 11, Sept 1949 p 279-87, Oct p 318-21, Nov p 359-63. Defects in dial com- parators of %oo mm ; results of study conducted at Laboratoire Central de l'Armement ; discussion of differ- ent defects, their causes and remedies ; degree of accuracy which can be expected ; different types of comparators : illustrations. The Deming Test Indicator. Precision Measurement in the Metal Working Industry. 1952 ed. Syracuse Univ. Press. Described on p 108 and illustrated in Figs. 164 and 165. (No other published description has been found, but it was very popular during the First World War and subse- quently. ) Is graduated to 0.0005 in. It has a spring- pivoted compound lever system and a number of replace- able ball points for reaching into small holes, slots, and recesses. Messuhren. G. BERNDT. Dresden. Technische Hoch- schule Wiss Zeit v3 nl 1953-4 p 63-70. Dial gages ; formu- lation of standards and determination of errors. New Dial Indicator Design Features Only Four Moving Parts, R. C. SOUERS. Machine & Tool Blue Book v49 no May 1954 p 193-200, 202. Nilcoid indicator now in stage of production at Nilsson Gage Co., Poughkeepsie. N.Y. will reduce disadvantages of gear train indicator without sacrificing any of advantages ; design details of indicator which is claimed to retain its accuracy longer than gear train type. Stable Wide-Range DC Amplifier, F. F. OFFNER. Rev Sci Instrum v25 n6 June 1954 p 579-86. Versatile high gain amplifier for biological applications ; features include differential push pull operation with rejection ratio greater than 1000; response from zero to beyond 30 kc has maximum gain of about 2.5X10 a ; optical control of 115 high and low frequency cutoff is provided ; other features ; circuit diagram. Dial Gauge, H. W. BAKER. Eng vl86 n4841 Dec 19 1958 p 804-6. Investigations carried out to obtain precise information about reliability of both new and nearly new gages, and to shed light upon factors which should re- ceive special attention from manufacturers or users. Fullv Transistorised Frequency Modulated Indicator for Field Tests, R. S. ROBSON, A. GOODIER, R. G. PENN. Engr v207 n5380, 5381 Mar 6 1959 p 374-7, Mar 13 p 412-14. Indicator for translating mechanical parameters into elec- trical ones, developed by Thornton Research Centre, Chester ; thermionic valves have been replaced by transis- tors and crystal diodes; it will replace most indicators used by Shell Research. The Accuracy of the Dial Indicators of D-Type Shore Hardness Testers, K. YAMAMOTO, K. IIZUKA. Report of the Central Inspection Institute of Weights and Meas- ures, Japan, vll nl report 28 1962 in Japanese. A method for testing the accuracy of the dial indicators of D-type Shore hardness testers is devised. By means of this meth- od 10 indicators are inspected : two made by Shore In- strument & Manufacturing Co., U.S.A. and eight by do- mestic manufacturers. The results show that one division of the scales of the indicators does not correspond to the height of rebound of 0.1238 mm which would be the stand- ard value when the same definition as C-type testers is applied for the scale of D-type testers but corresponds to about 0.13 mm, and show that most of the indicators have a periodic deviation of 0.020-0.045 mm and random deviations of 0.025-0.040 mm from the mean pitch of the graduation. The cause of the periodic and random errors is investigated and it is concluded that the former error arises from the eccentricities of both the scale plate and the pinion to the center of rotation of the pinion and can be cancelled out by adjusting the magnitudes and phases of two eccentricities, whereas the latter one is due to the error of teeth form of the rack and pinion and deter- mines the ultimate accuracy of the hardness readings, which is assumed to be 0.2-0.3 units in Shore scale for the testers. 4-m-Endmasskomparator • ( 4-Meter End-Measure Com- parator), M. DUHMKE in collaboration with G. GEORGI and W. FISCHER. Feinwerktechnik v66 1962 p 369-72 3 figs 4 refs. With this comparator parallel end measures over 200 to 4000 mm in length are compared with stand- ards of equal length by mechanical contact. The meas- ures lie on two-dimensionally applied ball bearings and are hydraulically controlled from the outside of a temperature shield surrounding the measuring apparatus. Device for Checking Dial Gauges and Indicating Hole Gauges, E. M. EVICH. Meas Techns 1962 n6 Dec 1962 p 463-4 1 fig. Translated from Izmer Tekh n6 p 15 June 1962. Equipment was made from an old height gage ; its measuring device consists of a zero class micrometer, and a collet chuck is used for fixing the dial gauge or bending limiter of a hole gauge tubular stem. More Reliable Testing of the Precision of Dial-Type Gauges, A. N. KARTASHOVA. Meas Techns 1963 n3 Sept 1963 p 185-8 1 fig 5 refs. Translated from Izmer Tekh n3 p 4-7 Mar 1963. Describes a newly-developed testing technique for dial gages which provides higher reliability of testing with lower expenditure of labor. Addendum to Section 3 3.2. End Measuring Rods and Measurement of Long Lengths Combined Micrometer and Sensitive Indicator Unit, W. F. ATKINS. Machy (London) vl05 n2697 July 22 1964 p 271-2 ; Machine Shop v25 n8 Aug 1964 p 398-400. To overcome difficulty when measuring work pieces of large diameter, design was produced at National Physical Lab- oratory in which micrometer and fiducial indicator are combined in single unit that can be mounted on machine ; external and sectional views of unit are described ; unit was fitted to diameter measuring machine used at NPL for checking API screw plug gages. 3.3. External Diameters by Mechanical Methods Superposition Spherometer Type IZS-8, S. D. GOLOD, V. A. NIKITIN. Meas Techns n8 Mar 1965 p 679-81 2 figs. Translated from Izmer Tekh n8 p 19-21 Aug 1964. The new superposition spherometer IZS-8 is suitable for meas- uring convex and concave spherical surface radii in the range of 80 to 40 000 mm. As compared with spherom- eters made abroad the IZS-8 spherometer has several advantages which are : high precision provided by large- diameter carrier rings for measuring the radii of curva- ture in large components, the replacement of supporting- bands used in foreign spherometers by ball bearings over which the carrier rings can be turned as they become worn, direct measurement of the spherical segment curva- ture deflection by comparing it with a certified instrument scale, as against indirect measurement used in foreign spherometers which require reference glass spheres. A. Study of Errors in the Measurement of Microscopic Spheres, C. P. SAYLOR, NBS. App Optics v4 n4 Apr 1965 p 477-86 11 figs 6 refs. Uncertainties in the micro- scopical measurement of small spheres as influenced by index of refraction of the mount, focus, aperture, and resolution have been variously reported and denied. The present study was conducted with large spheres in order to disclose the basic phenomena, but with such optical conditions as would ordinarily be used for much smaller objects. The reality of each reported error is verified. The principal uncertainties originate in the geometrical optics of thick bodies, but these effects tend to be confused by limitations in resolving power. See also F. Ehrenhaft, p. 10. 3.4. Internal Diameters by Mechanical Methods Investigation of Contact Methods for Measuring Internal Sizes of Components with Stationary Instruments, G. B. KAINER. Meas Techns nil Apr 1965 p 945-9 4 figs 1 ref. Translated from Izmer Tekh nil p 8-11, Nov 1964. The research revealed the basic components of the error pro- duced in measuring internal sizes with stationary instru- ments. The process was investigated by means of a recorder with induction transducer which was mounted on an instrument with a metering device (for instance, an optimeter) in such a manner that all the displacements of the component together with support table could be recorded in the course of measurements. (Continued on p. 151) 116 Section 4. Calibration of Line Standards of Length, Including Tapes CONTENTS Page 4.1. Line standards, general 117 4.2. Calibration of subintervals 120 4.3. Calibration of tapes 122 4.4. Measuring microscopes and line comparators 123 Addendum to Section 4 128 4.1. Line Standards, General Comparaisons des Metres dans L'Air a la Temperature Ambiante (Comparisons of Meters in Air at Ambient Temperature), M. J. PERNET. Trav et Mem du BIPM v4 1884 273 p 10 figs. Description of Brunner transverse comparator ; measurement of temperatures ; calibration of thermometers ; measurement of lengths ; calibration of op- tical micrometers ; method of comparisons and reduction of data ; results ; tables ; observations. Standard Measures, E. A. GIESELER. J. Franklin Inst Aug 1888 p 115-33 ; Eng News Sept 8 1888. Gives brief history of the development of standards of length, de- scribes the present standards of the United States, and methods adopted to compare them with other standards. The New Standards of Weight and Measure. The Na- tion Oct 24 1889. An interesting letter from Paris, de- scribing the methods used in preparing the standard meter bars and standard kilograms for the International Bureau of Weights and Measures. Nouvelles Determinations des Metres Etalons du Bureau International (New Determinations of the Meter Stand- ards of the International Bureau), J. R. BEXOIT, C. E. GUILLAUME. Trav et Mem du BIPM vll 1895 87 p. Discusses comparisons of several standards made in 1884. 1892, 1894 and other years by various observers ; derives equations for their temperature coefficients ; defects of the microscopes of the Brunner comparator ; observations. On the Comparison of Line and End Standards, L. A. FISCHER. Bui Phil Soc Washington vl3 p 241-50. Read before the Phil. Soc. of Washington May 28, 1898. Precision in Determinations of Length. J. R. BENOIT. Int Phys Congress at Paris Rept 1 1900, p 30-77. A re- sume of the practice and progress in different countries as to the standard and measurement of length. France, Eng- land, Russia, and Germany are dealt with, and the ex- tension of the metric system noted. The best form for standards of length is discussed and the tests they should bear are described. The probable error of a single com- parison in comparing 30 standard meter bars is calculated to be ±0.12/1. The permanence of the standards and their variations with temperature are also treated. Methods of Testing Flat-End Gages and Standards. Great Britain NPL Rept 1906 p 39-42. Flat-end gages are tested by an optical method, involving the reflection of light from them. A method of measuring an end standard by means of a line standard is to apply two or more end standards (preferably flat ends) and draw a line near the middle of each. All possible combinations with a line standard are measured. Standards of Length, H. T. WADE. Sci Am Mar 10 1906. Information concerning the two meter bars in the custody of the National Bureau of Standards at Washington, and the care given them. Also the uses to which they are applied. Methods of Comparing Standard Measure Bars, L. A. FISCHER, NBS. Am Mach v29 Oct 25 1906 p 547-8. De- scribes a simple process for deriving the yard from the meter bar. Verification of International Meter Standards, C. E. GUILLAUME. CR Acad Sci vl73 Dec 27 1921 p 1438-43. Results of recomparison of various national standard me- ters with the international protype meter. fiber Metermasstiibe mit Striehteilung und ihre Genauig- keit ( Regarding Meter Measures having Line Division and their Accuracy) , K. LUDEMANN. Der Betrieb v4 n9 Feb 11 1922 p 292-8 13 figs. Proposal for a standard meter measure with line divisions required in mechanical metrology. Matters of Special Interest in Precision Metrology, A. PERARD. Rev Opt v2 Dec 1923 p 506-11. Precise defini- tion of the exact method of making a setting with a micro- scope on a line graduation might be "to set the microscope so as to obtain equality of the luminous area between the line of the microscope graticule and the edges of the line upon which the setting is made". Discusses personal er- rors, fogging of objectives and torsional forces on bars. Testing of Line Standards of Length. NBS Cir n332 May 13 1927 22 p 2 figs. Method used in comparison and stand- ardization of line standards of length and basis of such measurements in United States : apparatus used and pre- cautions necessary for precise work : information regard- ing testing of line standards and of metal tapes, includ- ing shipping directions. Optical Instrument Demands Unusual Precision, H. SI- MON. Am Mach v68 Mar 8 1928 p 421-3 6 figs. Scribing and checking of half -inch line on blade used in Zeiss meas- uring microscope ; accuracy within plus or minus 0.00002 in. must be maintained ; high-precision dividing engine and apparatus used to check its work ; testing device per- mits readings to be made correct within limits of about 0.000008 in., plus or minus. Skalen fuer Messgeraete ( Scales for Measuring Instru- ments), G. KEINATH. Archiv fiier Tech Messen v3 n32 Feb 1934 p T20-1 ( 4 p) . Scales for measuring equipment ; comparative study of various standard types ; illustra- tions. 117 Gestaltung von Instrumenten zum Zwecke der Verein- faehung Messtechnischer Aufgaben (Design of Instru- ments for the Purpose of the Simplification of Technical Measurement Problems), R. SEWIG. Zeit Instrumkde v56 n9 Sept 1936 p 349-57. Design of instruments with view to simplifying practical problems of measurements ; psychotechnical and phototeehnical form and character of scales discussed. Homogeneous Scales for Pointer Instruments, H. MAU- RER. Zeit InstrumKde v57 Jan 1937 p 26-9. In certain types of pointer instruments it is necessary to read the position of the pointer in terms of divisions of a non-homo- geneous scale, owing to the mode of operation of the meas- uring device. Thus a similar change of the measured quantity a at different parts of the scale corresponds to dissimilar changes of angular position w of the pointer, where w is some non-linear function of a. It is possible to find curves on which the lengths of the intercepts be- tween two positions of the pointer are linearly proportional to the difference between the corresponding indicated quantities, so that accurate linear interpolation between scale divisions becomes possible. For practical purposes a scale of circular form is retained but the fiducial marks are shown on a zig-zag line. Improvements in Definition of International Standards of Length and in Comparison of Standards, A. PERARD, C. VOLET. CR Acad Sci v208 Jan 23 1939 p 263-5. An ac- count of the state of certain copies of the standard metre. It was decided to renew the scales on five of these, and this was done satisfactorily as regards definition, thick- ness of the lines reduced to 3.5/i and other points of im- provement. There has taken place also an Improvement in the observing instruments. The redrawn standards will be compared with the international metre and its latest copy. Permanence of Standards of Length, T. H. FIELD. Can J Res vl7 Sec A May 1939 p 71-6. A few reasons are presented for believing that the fundamental standards for the metre and the yard, and also the legal Dominion standards of length, are not changing appreciably. On the other hand, measurements of a number of laboratory nickel-iron rules show progressive shortening which is still taking place, through periods up to 20 years. Comparaison au Prototype metrique de ses Temoins et des Metres d'Usage du Bureau International des Poids et Measures, A. PERARD, C. VOLET. CR Acad Sci v212 n2 Jan 13 1941 p 71-3. Comparison of metric stand- ard with its reference replica and with meters used by International Bureau of Weights and Measures ; report on comparisons made by four independent observers, with improved optical comparator. Comparison of Etalons of Length, C. VOLET. Rev Opt (Theor Instrum) v21 1942 p 168-75 in French. Analyses the systematic errors liable to be encountered in the com- parison of standard metres, etc., when observations are made on grooves or scratches. The effects of the shape of the groove and of the illumination are discussed. The method of comparison by means of reversible microscopes is advocated and a Societe Genevoise instrument of this type is described. Premiere Verification Periodique des Metres Prototypes Nationaux et Determination de Quelques Nouveaux Proto- types (The First Periodical Verification of the National Prototype Meters and Determination of some New Proto- types), A. PERARD, L. MAUDET, C. VOLET. Trav et Mem du BIPM v20 1944 86 p 7 figs. 7 refs. Characteristics of the Prototype Meters ; revision of the early measures, — actual values of dilatations and equations ; instruments and methods, — Brunner comparator, thermometers and temperature, manner of checking a line, organization of the measurements ; periodic verification, — the prototype of the Bureau, the national prototype meters, prototype meters verified several times, table of results, conclusions ; deter- mination of changing prototype meters. An Adjustable Scale for Measuring Instruments, W. KOCH. J Sci Instrum v22 May 1945 p 94-5. A method is described for constructing and using a scale which compensates for calibration errors. The principle in- volves the use of 3 fixed points ; the appropriate scale read- ing is determined by the intersection of a movable line with an arc passing through each point of the scale. The line is adjusted by reference to the fixed points. Metres and Comparators, C. VOLET. Microtecnic v2 n4 Aug 1948 p 138—43. Comments on substitution and dis- placement methods used for comparison of graduated length standards ; description of improvement which made it possible to avoid instrument errors when using sub- stitution method ; construction principles and choice of good standard discussed. Measuring Instruments — the Division on Glass of Grad- uated Areas of Instruments, F. DELHOMME, J. MARTIN, CR Acad Sci Paris v227 Aug 2 1948 p 335-7 in French. The technique of making scales on glass by depositing by evaporation of thin homogeneous layer of Pb or Al, ruling with a dividing engine, and coating with a protecting layer of varnish is fully described. New Method for the Calibration of Line Standards. Soc Gen d'Inst Phys May 31 1950. Micrometer Eyepieces, H. BECKER. Microtecnic v5 n2, 3 Mar-Apr 1951 p 59-65, May-June p 108-13. Limita- tions of eye in respect to its optical resolution in reading very fine scale division ; problems connected with use of magnifying eyepiece or microscopes on micrometer in- struments ; reference made to some German patents in this field ; typical optical systems for precision readings ; factors important in manufacture of micrometer eyepieces. Human Factor in Instrument Design, L. S. BEALS, JR. Instrum v24 nil Nov 1951 p 1290-1, 1337-9. How aviation or other instrument dials and control knobs can be im- proved and made more useful by careful analysis and design of size, resistance to motion, grouping, direction of motion, numbers, letters, pointers, and scale division. Bibliography. New Comparator of High Precision for Measurement of Line Standards of Length, J. S. CLARK, L. O. C. JOHN- SON, V. W. STANLEY. J Sci Instrum v28 nl2 Dec 1951 p 357-64. 1-m comparator having two heat insulated tanks designed to contain line standards of length and to bring them in turn under pair of micrometer microscopes rigidly fixed at distance apart equal to nominal length of stand- ards to be compared ; instrument can be used to compare lengths of two standards or to determine their coefficients of thermal expansion. Les Metres Prototypes du Bureau International. Notes Historiques. Renovation. Etude. (The Prototype Meter of the International Bureau. Historical Notes. Restora- tion. Study ) , A. PERARD, C. VOLET. Trav et Mem du BIPM v21 1952 156 p 36 figs. 46 p of historical notes. Re- view of measurements prior to 1937. Study of new sources of errors. Restoration of the meter and the Brunner com- parator. Determination of the meter retraced. Examina- tion of the progress realized. Conclusion. Note on a study of the subdivisions. Graticules for Engineer Optical Measuring Instruments, A. G. THOMSON. Mech Wld vl33 n3402 Jan 1953 p 26-7. Processes developed by Brit Sci Instrum Res Assn, which have enabled graticules for optical instruments to be made with accuracy which, in general, enhances precision of instrument ; graticules are produced by photography and etching on glass, and by vacuum evaporation of films of chromium, aluminum, platinum, palladium, rhodium, etc. 118 The Possibility of Comparing Line Standards of Length Photographically, A. H. COOK. Proc Roy Soc A v219 Oct 7 1953 p 500-15. Line standards can be compared visually to about one in ten millions. It seems possible that in a photographic comparison appreciably higher precision could be attained with less labour. Photographs of the lines on some line standards have been examined with a densitometer to determine the accuracy with which the distance between two photographic images of such lines could be measured. With suitable definition of line position a single measurement of this distance should have a standard deviation corresponding to less than 0.05/n. Provided the temperature of the bars is known with suf- ficient accuracy it should be possible to compare two line standards to much better than one in ten millions in less than half the time taken by present visual methods. A machine for measuring the photographs is suggested. The characteristics of photographs of some lines are given in an appendix. Novel Devices for Checking Graduated Scales and Tapes, C. HOFFROGGE, Microtecnic v9 n5 1955 p 247-52 7 figs. Devices are described which make possible the checking of graduated scales and tapes with an uncertainty of some ±0.01 mm. The standard can be moved longitudinally in order that coincidence readings can be carried out on the graduations to be compared. The displacement is given by a dial comparator or a micro-indicator. The devices can be used with particular advantage for tolerance measurements. Calibration of Meter Line Standards of Length at the Na- tional Bureau of Standards, B. L. PAGE. J Res NBS v54 nl Jan 1955 p 1-14. The results of the intercomparisons of the total lengths of several meter bars and of calibra- tions of the subintervals of some of these bars for the past twenty years are reported. Information both on the degree of stability of these standards and on the preci- sion with which such measurements can be repeated was obtained. The results are critically analyzed and com- ments made as to the precautions necessary in the preci- sion comparisons of line standards of length. Machine Tool Scales with Optical Reading Devices, C. GODFREY, S. C. BOTTOMLEY. Microtecnic vl3 n4 Aug 1959 p 154-61. Use of precision scales on machine tools, especially when viewed by optical projection, has many advantages ; they are unaffected by wear, can be magni- fied, and permit subdivision of main scale ; review of vari- ous types covers micrometer projectors, vernier projectors, circular scales, and "rnicroptic" scale reader ; photographs. The Manufacture, Testing, and Application of Precision Glass Scales, G. MEISTER, J. CICHON. (Zeiss, Jena) 1960. An example of automation in precision-measuring technology by means of photoelectronic methods. Con- tents : On the state of dividing techniques ; basic methods for the objective photoelectronic localization of graduation marks ; instrument technology ; application of glass scales ; automation of photoelectronic reading of glass scales. De l'lmportance de la Qualite d'une Regel-Etalon, P. MAR- TIN. Optics in Metrology, P. MOLLET. Pergamon Press 1960 p 57-62 8 figs. The coming change in the definition of the meter and its consequences ; line standards on glass and on metal, advantages and disadvantages; factors of errors ; precision ; definition of the line ; factors influencing the good definition of the line ; appropriate materials for good scales ; lines with round edges ; the Volet effect ; the retracing of the prototypes. Survey of Development of Line Standard Metrology, J. PETAVEL. Microtecnic vl4 nl Feb 1960 p 1-13. Meth- ods used by Bureau of Weights & Measures, and standards Laboratories for intercomparison of line standards and their comparison with international standard ; micrometer microscopes enable meter to be defined with relative un- certainty of one part in 10 7 ; photoelectric microscopes have enabled uncertainty to be reduced to one part in 10 s . Calibration of Line Standards of Length and Measuring Tapes at National Bureau of Standards, L. V. JUDSON. NBS Monogr nl5 May 1960 11 p. Methods used in cali- brating line standards of length and measuring tapes sub- mitted for standardization ; equipment used is described briefly ; there is discussion of some considerations that should be given as to whether or not standard should be submitted to Bureau ; instructions are given for submit- ting items to Bureau for calibration ; appendix contains useful information on use of steel tapes. Unmittelbarer Anschuss von Strichmassen an Lichtwellen- langen (An Instrument for Direct Comparison of Line Standards with Wavelengths of Light), C. HOFFROGGE, Amtsblatt PTB 1961 n2 p 192-5. See abstract under 2.4.6. An Automatic Fringe Counting Interferometer for Use in Calibration of Line Scales, H. D. COOK, L. A. MAR- ZETTA. J Res NBS v65C n2 Apr-June 1961 p 129-40. A reversible fringe counting interferometer is described in which mechanical, optical and electronic adjustments are maintained stable by servomechanism control or by balanc- ing. An electronic fringe counter and interpolator per- mits recording of the count in digital form to 0.01 fringe. Design factors and details are discussed. On an Instrument for Calibrating Graduated Scales up to 1 Meter in Terms of Wavelength of Light, Y. SAKURAI. Global Technol Apr 1961 (Digest of original Japanese ar- ticle). Description of an interferometrie line standard comparator. The principal components are a photoelectric microscope and an interferometer employing a Koester's double prism and corner-cube reflectors. A reversible fringe counter and interpolator is used to determine the order of interference. Interference Comparator for the Calibration of Line Standards Directly in Terms of Standard Wavelengths, K. M. BAIRD. Rev Sci Instrum v32 n5 May 1961 p 549-54. An interference comparator for routine calibration of line standards or scales by direct reference to the vacuum wavelength of Kr 86 . Principles of construction and per- formance characteristics are given. Method of exact frac- tions used to determine the order of interference. Case Histories of Methods to Achieve Cost Reduction Through Optical Tooling, A. W. YOUNG. ASTME Crea- tive Mfg Seminars Tech Paper SP63-120 Feb 1963 7 p. Eleven examples are described dealing with alignment of machine tools, checking out rotational error of rotary tables, transfer of angular measurement in shops, use of telescope and clinometer mounted in one fixture, etc. The Calibration of Linear Scales by the Method of Hansen- Perard. E. G. THWAITE, R. T. LESLIE. Austral J' Phys vl6 nl Mar 1963 p 82-107. The exact least-squares solutions are obtained by matrix inversion. These sets of equations correspond to the "simple calibration" and the "cross calibration," of linear scales by the method of Han- sen-Perard. Tables are given of the inverses of the co- efficient matrices of the normal equations for most prac- tical cases and expressions are derived for the variance to be associated with any interval between calibrated scale graduations. Positioning System Spaces Lines to Within Vio Microinch, E. G. LOEWEN. Control Eng vlO n5 May 1963 p 95-8. Author, associated with Bausch & Lomb Inc., explains op- eration and control of ruling engine that scribes up to 100,000 uniformly spaced lines per inch on diffraction grating. Magneto-Optic Positioning, R. J. MELTZER. IEEE Trans Indus Electronics vIE-10 nl May 1963 p 46-56. For accu- rate production of scales and grids it was necessary to 119 771-846 O — 66- develop device which could locate lines with precision better than 1/dn. ; system is described that accomplishes this by forming image of line with polarized light, whose angle of polarization varies with position of line. High-Precision Linear Scales. Firm of Dr. Johannes Heidenhain, Traunreut. Oct 1963 19 p 21 figs. Describes advantages of scales manufactured by the patented Diadur process. Describes detail features of high-precision glass rules, metal rules, grating bars, and coded rules. Recommendations for Design of Scales and Indexes. Brit Standards Instn— Brit Standard 1449 pt 1 1964 44 p. Rec- ommendations in this part are intended to be generally applicable to quantitative instruments of bold presenta- tion and designed for rapid reading, intended to be read to resolution of about 1 to 2% of scale range and are par- ticularly concerned with relating scale dimensions to max- imum reading distance ; they are only applicable to single scale instruments having dials with full circle, part circle or straight scales as defined. 4.2. Calibration of Subintervals Note. The more important articles are indicated by an asterisk (*) *Traite de Thermometre (Treatise on Thermometry), HENNERT, 1758 (Book.) Chwolson in his Traite de Physique v3 p 42 states that the method generally ascribed to Gay-Lussac was first given by Hennert. Gay-Lussac is credited by very many writers on this subject with having given the first method of calibration. Some have, how- ever, given evidence to prove that he did not originate the method. An outline of the method of Gay-Lussac is given in many treatises on experimental physics and in books on thermometry but without reference to Gay-Lussac's de- scription of his method. Anmerkningar angaende thermometrars fortfardigande och Bruk. Hallstrom, G. GABRIEL, Abo, 1823 Akad Dis- sertation. A very early method of calibration, concerning which there seems to be considerable difference of opinion, although the Hallstrom method is often referred to in the literature. In a footnote to an article by Hallstrom in the Ann Phys Chem in 1836, Poggendorf states that, as the method is the same as that already published by Bessel, to save space it is not repeated, although included in Hall- strom's manuscript of the article. Rudberg later pointed out some slight differences. The committee of the British Association (see under Stewart) put the method in an entirely different classification from that of Bessel. The original dissertation unfortunately has not been available for consultation in the preparation of this bibliography. Methode die Thermometer zu berichtigen ( Method of Cor- recting the Thermometer ) , F. W. BESSEL. Pogg An Phys v6 1826 p 287-308. A method of calibration in which the various lengths used are not multiples of the smallest or unit interval. Untersuchungen fiber das Thermometer : V. Die stereo- metrischen Verhaltnisse der Glassrohre (Investigations of the Thermometer : V. The Stereometric Proportions of the Glass Tube), P. N. C. EGEN. Pogg An Phys und Chemie vll p 529-36 1827. A method of calibration which is a slight modification of that of Bessel. Allusions are sometimes found in the literature to Egen's method with- out any journal reference being given. Uber die Konstruktion des Thermometers ( Regarding the Construction of the Thermometer), F. RUDBERG. Pogg An Phys v40 1837 p 562-82. A method of repeated sub- division ; for instance, first divide the total length in half, then compare the three-thirds of the total length, then divide the total into twelfths, etc. *Bestimmung der Teilungsfehler eines gradlinigen Mass- stabes (Determination of the Graduation Errors of a Rectilinear Scale). P. A. HANSEN. Abhandlungen der Mathematisch-Physikalischen Klas.se der KSniglich Sach- sisehen Gesellschaft der Wissenschaften vl5 1879 p 525- 667. The basic memoir on which present-day methods of calibration of scales are founded. It discusses the cali- bration of a single scale. Methods of double calibration are a later development. t'ber das KalJibrieren von Thermometern (Regarding the Calibration of Thermometers), M. THIESEN. Carl's Repertorium fiir Experimental-Physik vl5 1879 p 235-99. The author points out that Lambert in his "Pyrometrie" published in 1779 had used (p 31, 43) the method of cali- bration commonly attributed to Gay-Lussac, and that it was known even earlier. An application to thermometry of this method is briefly outlined by Thiesen. It is stated that Rudberg's method is only a special case of Hall- strom's, but that it has the disadvantage that the correc- tions to the divisions obtained in the component parts of the calibration are not well coordinated to make a unified system of corrections. *t T ber die Anwendung der Methode der Kleinsten Quad- rate auf die Kalibrirung der Thermometer (Regarding the Application of the Method of Least Squares to the Cali- bration of the Thermometer), W. J. MAREK. Carl's Re- pertorium fiir Experimental-Physik vl5 1879 p 300-19. Method of calibration of a thermometer (applicable also to a scale) for cases of division into 2, 3, 4, 5, and 6 parts with a brief statement of the general case. Corrections to the intervals are obtained by the solution of the normal equations obtained by least squares methods. These equa- tions are given a form especially applicable for ready numerical solution. Numerical examples exemplifying the method in the calibration of thermometers are given, together with formulas for obtaining the probable error of the results. See also reference to article by Benoit, p 121. Lber das Kalibrieren von Thermometern, inbesondere fiber die wahrscheinlichen Fehler der Kaliberkorrektion (Regarding the Calibration of Thermometers, Especially Regarding the Probable Error of the Calibration Correc- tion), M. THIESEN. Carl's Repertorium fiir Experi- mental Phys vl5 1879 p 677-81. By a consideration of the probable errors, the feasibility of an abbreviated method of calibration is shown. There is a saving of time com- pared with the rigorous least squares method proposed by Marek. The artifice used by Thiesen had been pro- posed by F. E. Neumann in the case of another set of equa- tions similar to those involved in this work, and the method of calibration is sometimes known as the Neumann- Thiesen method. Report of the Committee Appointed for the Purpose of Re- porting on the Methods Employed in the Calibration of Mercurial Thermometers. B. STEWART ; RUCKER ; T. E. THORPE. Report of the Brit Assn for 1882 p 145-204. Discussion with illustrative examples using the following methods : Gay-Lussac, Hallstrom, Rudberg, Thiesen, Marek, Bessel (as modified by von Ottingen and improved by Thorpe and Rficker). These methods are also applicable, with certain modifications to the cali- bration of divided scales. Four classes of methods are distinguished by this committee. (1) "Step by step," ex- ample, Gay-Lussac's method; (2) "Principal points," ex- amples, Hallstrom, Thiesen, Marek; (3) "Repeated divi- sion," example, Rudberg; (4) "Distributed points," examples, Bessel and the modification by von Ottingen. 120 ♦Calibration of Thermometer Green 5280 by Hansen's Method, C. C. BROWN. Van Nostrand's Eng Mag v29 1883 p 1-7. One of the few expositions in the English language of Hansen's method. Mesures de Dilatation et Comparaisons de Regies Metrique. 13 Thermometres-Correetions de Calibrage (Measurement of Dilation and Comparison of Metric Scales. 13 Cali- bration Corrections of Thermometers), J. R. BENOIT. Travaux et Mem du BIPM v2 1883 p C35-C48. Method of Marek as used in the calibration of thermometers. This article is in French ; Marek's original article was in German. ♦Etudes Thermometriques (A Study of Thermometry), C. E. GUILLAUME. Trav et Mem du BIPM v5 1886 92 p 5 figs. Comprises study of thermometers, variations of thermometers, and concordance of thermometers. Note sur l'Etalonnage des Sous-Divisions d'une Regie, sur l'etude des Erreurs Progressives d'une Vis Micrometrique, et Sur le Calibrage des Thermometres (Note on the Cali- bration of the Subdivisions of a Scale, on the Study of Pro- gressive Errors of a Micrometer, and on the Calibration of Thermometers), O. J. BROCH. Travaux et Memoires du BIPM v5 1886 p 1-82. Development of the method of Hansen for the calibration of a single scale. Computation forms. Applications to calibration of line standards, micrometer screws, and thermometers. Weinstein Handbuch der Physikalischen Maasbestimmung v2 1888 p 274-82. Method of Hansen for single scales and method of Thiesen for a double calibration. On the Determination of Errors of Graduation Without Cumulative Errors and the Application of the Method to the Scales of the Cape Heliometer, D. GILL. Monthly no- tices of the Royal Astron Soc v49 1889 p 105-18. ( See also the errata on p 241 of the same volume.) A method is outlined of calibrating two scales simultaneously. This method is essentially that of Lorentzen. No general for- mulas are given and no computation system outlined. It is to be noted that Gill considered all intervals to be cali- brated with the same weight, whereas, as Jacoby pointed out, weight factors given by Lorentzen must be used. ♦Traits Pratique de la Thermometrie de Precision (Trea- tise on the Practice of Precision Thermometry), C. E. GUILLAUME. Gauthier-Villars et Fils, Imprimeurs- Libraires 1889 336 p 4 plates 45 figs refs. Methods of cali- bration of thermometer scales with illustrative examples are given on p 43-99 : Gay-Lussac's method ; Neumann- Thiesen method ; complete least squares method. The Cumulative Errors of a Graduated Scale, W. A. ROG- ERS. Proc. ASME vl5 1893 p 127-46. The method of Broch and the method of summing the corrections found for the unit lengths are each discussed and illustrated. Rather undue emphasis is placed on the possibilities of simple summing the corrections found for the individual intervals : Mr. Rogers was an experienced and careful ob- server ; repetition of length measurements to a certain pre- cision is no proof of their accuracy to that degree. ♦liber die Untersuchung der Scalen eines Heliometers I (Regarding the Investigation of the Scales of a Heliom- eter), G. LORENTZEN. Astron Nachr vl31 n3134 1893 p 217-38. This is a method of double calibration which differs only slightly from a least squares solution. IJber die Untersuchung der Scalen eines Heliometers II (Regarding the Investigation of the Scales of a Heliom- eter), G. LORENTZEN. Astron Nachr vl35 n3236 1S94 p 353-66. This is an application of the method of double calibration described by the same author in a previous paper to the calibration of two heliometer scales, each a decimeter in length. Note on the Division Errors of a Standard Scale, H. JA- COBY. Astron Nachr vl37 n3285 1895 p 357-60. Jacoby points out the advance made by Lorentzen over Hansen and also the practical identity of Lorentzen's method with that used and described by D. Gill. The fact that Lorent- zen gives a weight factor for the several intervals is em- phasized. Jacoby suggests repeating the observations on the first and last comparisons of the two scales in the usual order of measurement four times. The final results would then be more uniformly weighed. The possibility of com- puting the number of times to repeat each separate ob- servation in order to produce a weight of unity for all points is suggested by Jacoby as of some possible theoreti- cal importance. On the Determination of the Division Errors of a Straight Scale, H. JACOBY. Am J Sci vl51 May 1896 p 333-42. Gill's method, an improvement on Hansen's and Lorent- zen's formula, are both explained and discussed. A mod- ification of Gill's method, by the author, follows, whereby accuracy within 0.00002 inch is obtained. A method of calibration of two scales in which the various observa- tions are repeated such number of times as to secure a unit weight for the final result for the correction to each interval. An application to the calibration of screws is included, whereby the nonperiodic errors of a screw are determined without assumption of any law of error. Uber die Ermittelung der inneren Theilungsfehler zweier Masstabe nach der Methode des Durchschiebens (Regard- ing the Investigation of the Inner Division Errors of Two Scales by the Method of Translation), DZIOBEK. Wiss Abh der Kaisarlichen Normal-Aichungs-Kommission v4 1903 p 1-56. A least squares solution for a double calibra- tion with comparisons with the method of Thiesen ; numer- ical examples. Uber die gleichseitige Bestimmung der Theilungsfehler zweier Maszstabe durch die Methode des Durchschiebens (Regarding the Congruent Determination of the Division Errors of Two Scales by the Method of Translation), A. LEMAN. Wiss Abh der Kaisarlichen Normal-Aichungs- Kommission v6 1906 p 1-75. A method of double calibra- tion. ♦Standardization of Divided Scales, C. E. GUILLAUME. Ann des Poids et Mesures, vl3 1907 p 1-54. There are three factors in a complete determination: (1) The for- mula of thermal expansion ; (2) the total length : (3) the calibration of the divisions, i.e., the differences in the dis- tances between successive divisions. The theory is fully investigated and certain examples are given. The author considers that the third factor above need not introduce a greater error than 0.1/* throughout the meter scale, but uncertainties in temperature and in the expansion formula bring up the error to 0.2/* or 0.3/i. Both a method of single and one of double calibration are given, each with ex- amples. Note sur le Calcul des Etalonnages de Grandeurs en Pro- gression Arithmetrique (Note on the Calculation of the Calibration of Size by Arithmetical Progression), A. PERARD. Trav Mem du BIPM vl6 1917 p 1-77. A method of single calibration and a method of double calibration. The method given in this circular is a variation of the method of single calibration described by Perard. Calibration of a Divided Scale. NBS Cir n329 May 13 1927 15 p 1 fig. Method used at NBS for calibrating equal subintervals of length on a line standard ; apparatus, ob- serving procedure, and mathematical reduction of data. Bibliography. Calibrations of Line Standards of Length of National Bu- reau of Standards, L. V. JUDSOX. B. L. PAGE. J Res NBS vl3 n6 Dec 1934 p 757-72. Results of intercompar- 121 ison of total lengths of meter and of decimeter bars, and results of calibrations of subintervals of several of them are given. Instrument Scale Distribution and Its Effect on Observa- tional Errors, R. 6. JEWELL. Instrum v8 n3 Mar 1935 p 58-60, 79. Certain electric indicating instruments have uniformly divided scales while others have scales which are open over one portion and constricted over another portion ; purpose of paper is to show what factors affect distribution and to determine what effect distribution has upon observational errors. Bibliography. The New Graduated Prototype of the International Bu- reau of Weights and Measures for the Subdivisions of the Metre, H. MOREAU, N. CABRERA. Rev Opt (Theor In- strum) v23 Oct-Dec 1944 p 255-60 in French. The difficul- ties originally encountered in working with Pt-Ir (poor polish, difficulty in marking, etc.) meant that some of the older prototypes were not entirely satisfactory. One of these (T4) has now been renovated, markings removed, surface planed and repolished, and regraduated. Two in- dependent examinations have now been made of this new prototype and it is found that the error for any gradua- tion rarely exceeds a micron. The length is given as 1 m — 1.14/1 at 0°C. Adjustable Scale for Measuring Instruments, W. KOCH. J Sci Instrum v22 n5 May 1945 p 94-5. Method described for constructing and using scale which compensates fairly well for calibration errors ; principle involves use of three fixed points ; appropriate scale reading is determined by intersection of movable line with arc passing through each point on scale ; line is adjusted by reference to fixed points. Choix et Determination d'un Vernier, A. LABORDE, C. TURLAN. Techn Mod v38 n9-10 May 1-15 1946 p 106-11. Study of theory of vernier, its intervals and method of observation ; circular verniers ; charts and tables presented. Manufacturer's Viewpoint on Instrument Calibration, H. BERRING. ISA J vl n4 Apr 1954 p 32-4; Steel Proc- essing v40 nl Jan 1954 p 33-7, 51. Problems relating to correct positioning of pointer on calibrated scale, from viewpoint of manufacturer responsible for original dial calibration ; extent to which manufacturer's equipment, required for calibration of large numbers of instruments, may differ from that employed by testing laboratories and industrial instrument departments ; mechanics of calibra- tion ; scale division and layout. Photoelectric Microscope for Measurement of Linear Scales, J. S. CLARK, A. H. COOK. J Sci Instrum v33 n9 Sept 1956 p 341-7. Apparatus for accurate measure- ment of scales of high precision ; real image of gradua- tion line, formed by microscope objective, is caused to oscillate across fixed slit in front of photocell ; phase sensitive rectifier determines when mean position or line image coincides with center line of slit ; short scales were measured directly in wavelengths with standard deviation of about 0.1/i. Automatic Measurement of Small Deviations in Periodic Structures, H. T. CLOSSON, W. E. DANIELSON, R. J. NIELSEN. Rev Sci Instrum v29 nlO Oct 1958 p 855-9. Special optical, mechanical, and electronic techniques have been combined in a new instrument, the microdeviometer — originally developed for measuring and recording the pitch uniformity of helices in travelling wave tubes — in which a beam of light and two optical gratings are used to obtain a very accurate scale of distance. The location, with re- spect to this distance scale, of the salient periodic fea- tures in the structure being measured is established through the interception of a second light beam by the structure. Electronic circuitry automatically stores and processes the position information and feeds the processed information, in the form of deviations from the corre- sponding ideal structure, to a pen recorder. A measur- ing accuracy of ±1/4 has been consistently obtained, and measurements which formerly required nearly 2 man-days are accomplished in less than 10 min. Wiederholbarkeit und Richtigkeit der Messwerte beim Zusammenwirken von Optischen Ablesegeraten und Stri- chteilungen (Repeatability and Accuracy of Measured Values with Coordinate Action of Optical Reading Ap- paratus and graduations)', K. RANTSCH, Optics in Metrol- ogy, P. MOLLET. Pergamon Press 1960 p 50-6. Proposes the proportion of the scale value to the average error of the individual measurement as the reading quality characteristic, for which a simple formula is indicated. Calibration of Line Standards of Length and Measuring Tapes at the National Bureau of Standards, L. V. JUD- SON. NBS Monogr 15 1960 p 11. See 4.1 for abstract. General Theory of Verniers ; Verniers for Nonuniform Scales, P. M. PEPPER. Ohio State Univ— Eng Experi- ment Station — Bui v30 n2 Mar 1961 55 p. Novel means of applying verniers to nonuniform scales : mathematical principles on which vernier depends are treated ; rudi- mentary error theory for verniers ; and approximate methods for construction of generalized verniers ; concept of acceptability for approximate verniers is defined and employed in treating several examples of generalized verniers. Selection of the Number of Check Points on an Instru- ment Scale, A. S. NEMIROVSKII, V. A. VOLKONSKII. Meas Techns 1961 nl Sept 1961 p 6-13 1 fig 3 refs. Trans- lated from Izmer Tekh 1961 nl p 5-10 Jan 1961. Article describes the selection of an optimum number of check points on an instrument scale. This solution could be applied to developing or improving methods of checking a wide range of instruments. Calibration of Linear Scales by Method of Hansen-Perard, E. G. THWAITE, R. T. LESLIE. Austral J Phys vl6 nl Mar 1963 p 82-107. See 4.1 for abstract. 4.3. Calibration of Tapes Measuring a Steel Tape, W. GRIBBEN. Am Mach Mar 19 1896. A good illustrated description of a job quite out of the usual run of machine shop work. tjber eine Anreihevorrichtung fur Genaure Messungen mit dem Stahlbande (Details of a Series of Precise Measure- ments with Steel Tapes). Zeit Oesterreichische Ing und Architektonische Verein Feb 12 1897. An account of a series of experimental measurements to determine the probable error and limit of precision of steel tape measure- ments. Gives useful practical details. Steel Measuring-Tape Apparatus, A. E. BURTON, J. F. HAYFORD. Eng Record v45 Jan 25 1902 p 80-1. Outline is given of the development of this instrument at M.I.T. since 1888 and of tests to which it was submitted by the US Coast Survey. The Bureau of Standards and Its Relation to the United States Coast and Geodetic Survey, S. W. STRATTON. Re- printed by the Government Printing Office from the "Cen- tennial Celebration of the United States Coast and Geo- detic Survey" Apr 5-6 1916 18 p 11 figs. This is largely a review of F. R. Hassler's work in procuring instruments for a coast survey and in providing and comparing physi- cal standards. The Measurement of Tapes and Wires at the Reichsan- stalt, P. A. THOMAS. Zeit InstrumKde v39 Nov 1919 p 321-32. A description of the 30 m. measuring track used for the most accurate measurement of invar and other tapes and wires. A description is given of the sledge 122 carrying the travelling microscope and of the procedure involved in a complete test of length. Standardization of Measures of Length at the Laboratory of the Dominion Land Surveys. Bui 44, Dept of the In- terior, Canada, Topographical Surveys Branch 1921 33 p 32 figs. Description of equipment for calibrating tapes. Effect of Concentrated Loads on the Length of Measuring- Tapes, L. V. JUDSON. Sci Papers NBS v21 nS-534 Apr 15 1926 p 3S5-93. Formulas are given for computing the change in length of a tape when concentrated loads such as thermometers are added to the tape. Experimental data confirming the formulas are given. Testing of Measuring Tapes at the Bureau of Standards, L. V. JUDSON. NBS Cir n328 Mar 1927. Description of steel tape and invar geodetic tape calibration at NBS. Nomographic Chart for Steel Tapes, C. D. SHEPARD. Civ Eng v2 July 1932 p 440-2 4 figs. Elimination of cor- rections to tape measurements made possible by determina- tion of tension of accuracy. The 24 m interference comparator of the Potsdam Geodetic Institute, F. MUHLIG. Deutsch Akad Wiss Berlin. Veroff Geodat Inst Potsdam n2 50 p 1949 in German. An instrument for standardizing invar tapes for geodetic base measurements in terms of the red Cd line. The distance between mirrors 12.5 cm apart is compared with the dis- tance between the mirrors of a Fabry-Perot etalon by es- tablishing interference between white-light beams which have undergone one reflection at the 12.5 cm mirrors and two reflections at the etalon. A wedge is inserted into the combined beams to produce white-light fringes and the difference between the longer interval and twice the shorter interval is equal to the thickness of the wedge at the point where the white-light fringes occur. Similarly the 12.5 cm interval is compared with aim interval, that with a 6 m interval and the latter with the 24 m interval. The length of the etalon and the thickness of the wedge are obtained in terms of the red Cd line. The apparatus is arranged so that for convenience in field work the compar- isons between the different stages can be made simultane- ously, and with two observers the etalon can also be standardized at the same time. The influence of optical aberrations is discussed, the use of the instrument is de- scribed and some measurements are reported. 50-Metre Mural Comparator at N.P.L., J. S. CLARK. Engr. vl89 n4908 Feb 17 1950 p 201-3, Feb 24 p 228-30. Method used at National Physical laboratory to standardize pre- cision tapes and wires used by geodetic surveyors and for other measurements of length ; micrometer microscopes and other equipment are attached to brick wall 164 ft long, whole forming comparator of sufficient short term stability for comparisons of necessary accuracy ; descrip- tion of improved equipment and technique supplements ar- ticle in "Glazebrook's Dictionary of Applied Physics", Vol. 3, 1923 ; illustrations. Standardisation of Steel Surveying Tapes, J. S. CLARK, L. O. C. JOHNSON. Empire Survey Rev vll n81 1951 p 118-28 4 figs 7 refs. Surveying tapes of steel are much more satisfactory mechanically than those of invar, and are less subject to secular changes of length, but the mag- nitude of their coefficient of thermal expansion demands a closer knowledge of their temperature than can be obtained with ordinary thermometers suspended near the tapes. The measurement of steel tapes in terms of their electrical resistance has therefore been investigated. The history of this work is traced. The use of resistance methods has proved satisfactory in the field, and under Laboratory con- ditions at the NPL the accuracy of 1 part in 2 millions in the measurement of the lengths of 24-metre and 100-foot tapes of steel is attained. Such steel tapes appear to have remained stable on the average within about 2 parts in a million in 25 years. A New Method for Determining Linear Thermal Expan- sion of Invar Geodetic Surveying Tapes, P. HIDNERT, R. K. KIRBY. J Res NBS (RP-2407), v50 n4 Apr 1953 p 179-85. An electrical method for measurement of linear thermal expansion is described. A direct current is passed through the tape for heating. Observations of changes in length and electrical resistance are taken at different constant temperatures of the tape. Temperature of the tape is determined from its different resistances and the temperature coefficient of resistance. This method has several advantages over the old method of measuring the change in length of the tape at different ambient tempera- tures of the laboratory. Neues Priifungsverfahren fur die Eichung von Messban- dern (New Testing Method for the Calibration of Tapes), C. HOFFROGGE. Special reprint from the Amtsblatt n 4/56 of PTB, Deutscher Eich-Verlag, Berlin W 30 1955 p 320-1 2 figs. Meteranschluss von Invardrahten fur Basismessungen (Meter Reference of Invar Wires for Base Line Measure- ments), C. HOFFROGGE, H. RUMMERT. Veroff entli- chung der Deutschen Geodatischen Kommission, ser B n71 1958 11 p 7 figs 6 refs. A part of 1958 was spent by the PTB in the calibration against the prototype meter of the invar wires used in the measurement of the 8-km baseline in the Ebersberger Forest near Munich. The arrange- ments and measuring methods applied are described and the possible sources of error are quantitatively investi- gated. Berechnung der Messlange bei f rei durch hangenden Band- massen (Calculation of Length of Freely Suspended Tapes), M. GARY. Zeit fur Vermessungswesen v84 n6 1959 p 188. Discusses calibration of tapes. Universal Device for the Inspection of Direct-Reading Gages, M. A. ADADUROVA. Meas Techns 1959 nl Mar 1960 p 7 1 fig. Translated from Iznier Tekh nl Jan 1959 p 6. Describes a comparator having a 1 meter base with which every meter division of measuring devices of any length are compared with it in turn. In checking a tape measure its free front end is connected to the lead tape of the right-hand reel, passed over the guide rollers and, together with its case, placed onto the left-hand reel. Thus placed, the divisions of the tape being inspected are oppo- site the divisions edge of the master tape. The error of each meter is determined after placing the first gradua- tion of the tape being inspected against the corresponding mark of the master tape, by reading the error on the other end. Calibration of Line Standards of Length and Measuring Tapes at the National Bureau of Standards, L. V. JUD- SON. NBS Monogr 15 May 20, 1960. Description of tape calibration methods at NBS. Appendix on the use of steel tapes including Young's Modulus of Elasticity, corrections for sag, and tension of accuracy. 4.4. Measurirg Microscopes and Line Comparators See also Subsection 1.2.3 Measuring Objects in the Microscope, F. E. IVES. J Frank- lin Inst vl54 July 1902 p 73-6. The image of an illumi- nated scale is projected in the plane of the object by means of the substage condenser. In the author's arrangement a Welsbach light, with ground-glass chimney and hood, illuminates a jeweller's saw set up, on a block of wood, at a suitable distance from the condenser. The distance between two teeth was equivalent to 0.02 mm on the stage micrometer. 123 A Microscope for Measuring Screw Threads. Eng v76 Nov 13 1903 p 660 9 figs ; Am Mach v27-l Jan 21 1904 p 78-9 7 figs; Machy (N.Y.) v24 Feb 1918 p 494-5 4 figs. The instrument was made by the Cambridge Scientific In- strument Co. for the Small Screw Gage Committee of the British Association by whom it was placed in the custody of the National Physical Laboratory. Figures show dif- ferent views of the instrument and the arrangement of cross wires and various adjustments. Comparator, A. J. COX. Zeit InstrumKde v22 Nov 15 1907 p 229-31. Bureau of Science, Manila, Philippines. A solid base carries two vertical guide bars rigidly con- nected at the top by a cross piece, from the middle of which two scales to be compared are hung. The suspensions for both are provided with an adjusting screw, so that the scale zeros can be set together. The bottom of each scale is secured to the base by a suitable clip. The reading microscope (magnification=60 diams. ) has horizontal traverse on the edge of the plate, capable of adjustment, which is carried on a slide having vertical motion on the guide bars. With the aid of a scale in the eyepiece of the microscope, readings can easily be obtained correct to 0.01 mm. For greater accuracy the most costly method of the German Imperial Commission of Standards is recom- mended. See also Deutsche Mech Ztg 1907 p 230-1 and Phil J Sci v2 Manila 1907 p 139-43. The Transversal Comparator, A. BLASCHKE. Zeit InstrumKde v27 Dec 1907 p 361-9. Communication from the Phys Tech Reiehsanstalt. Improvements in the com- parator, including details as to thermostats. liber einige Neueinrichtungen fur Langen- und Kriestei- lungen mit Mikroskop-Ablesung (New Length-measuring Instrument), C. PULFRICH. Zeit Instrumkde v27 Dec 1907 p 369-73. Communication from the Optical Work- shops of C. Zeiss. The instrument is called the stereo- comparator. Rough readings are taken by the eye alone to 0.1 mm on a metal scale. Fine readings are taken on a glass scale to .01 mm. A series of mirrors is used to send the light onto the scale and then horizontally to the eye. The principle is also applied to the measurement of angles. The Microscope in the Tool Room, F. A. STANLEY. Am Mach v30 Dec 12 1907 p 887-92 and 916. An illustrated article showing how a great variety of operations in con- nection with tool work may be facilitated by the use of the microscope. A comprehensive article. The Microscope in the Manufacturing Plant, F. A. STAN- LEY. Am Mach v31 Jan 16 1908 p 77-8. Illustrates and describes some of the advantages of the microscope in connection with manufacturing processes. Includes the description of a microscope having two micrometers at right angles to each other mounted in the base of the instrument and actuating the work-supporting table. Registration Micrometer for Spectra, O. LOHSE. Zeit InstrumKde v30 June 1910 p 169-73. Description of a new measuring micrometer for spectra, with a series of registration keys for recording the readings directly as observed. Der grosse Komparator der Kaiserlichen Normal-Ei- chungs-Kommission (Large Line Comparator of K. N. E. Komm), W. ROSTERS. Zeit InstrumKde v33 Aug 1913 p 233-47 9 figs. Describes a new comparator for the finest length measurements and for comparison of meter bars. Describes the room in which it is installed ; the system of interchange of the standards ; the pier and microscope ; the rail, turntable, and carriage ; the troughs of the one- meter comparator and its length-standard supporting table ; special features of the one-meter comparator ; and the troughs of the four-meter comparator. Micrometer Microscopes, A. W. GRAY. NBS Sci Paper 215 Bui 10 1914 p 375-90. Discusses some errors affecting measuring microscopes, methods of applying corrections to a group of micrometers and of determining the correc- tions of micrometer microscopes. Measuring Templets and Screw Threads with a Micro- scopic Measuring Machine. Machy (N.Y.) v24 May 11*18 p 791-3 5 figs; Am Mach v53 July 22 1920 p 187; Eng Prod v2 Jan 13 1921 p 4-44 12 figs. Construction and ad- justment of Alfred Herbert design of measuring micro- scope and application for, testing accuracy of templets or contour gages and screw threads. The machine has a table capable of 12-in. longitudinal movement by accurate amounts by insertion and removal of hardened steel meas- uring rods between flat contact pieces. The table carries a pair of centers, one of which can be adjusted crosswise to enable accurate alignment of work. A microscope fitted with two crosshairs, one rotating with the outside tube and the other rotating with the eyepiece, is mounted on a compound slide controlled by micrometer screws. The outer tube of the microscope has a dial reading to half de- grees and the eyepiece has a vernier reading to one min- ute. A light projector is fixed to the machine and will project parallel rays of light past the work. Use of Microscopes in the Gage Section, Bureau of Stand- ards, R. L. RANKIN. Am Mach v51 Sept 18 1919 p 581-2. Discusses use of microscope in linear measurements on gages, etc. Note on a Handy Form of Measuring Microscope, T. F. CONNOLLY. Opt Soc Trans v22 nl920-21 p 194-8. The instrument comprises a microscope system of relatively low power ; a double-image prism traverses the object- space, and is controlled by the rotation of a milled band operating a spiral slot. Exit pupil discs of telescopes or other optical instruments and Brinell impressions can be measured by a single contact setting of the edges of the duplicated discs. The range is from 1 to 6 mm. and the accuracy with fixed focus ±0.02 mm. The reading scale is divided to 0.1 mm. No vernier is used. A New Ocular Micrometer, H. KELLNER. J Opt Soc Am v7 Oct 1923 p 889-91 4 figs. Describes micrometer em- ploying sliding measuring wedge in place of micrometer screw. Presents the advantages but not the defects of both the micrometer screw and the glass scale. A glass scale is adjusted by a sliding wedge and readings then taken to three places of decimals. On the Limit of Accuracy in Optical Measurement, A. A. MICHELSON. J Opt Soc Am and Rev Sci Instrum v8 321-8 Feb 1924. The limits of accuracy obtainable in observations with the telescope, microscope, interferom- eter, and spectroscope are discussed. Societe Genevoise Combined Measuring and Drilling Ma- chine. Am Mach v66 June 30 1924 p 1112. Adapted for measuring in polar coordinates. Has circular table per- mitting angular measurements, table lead screw of 4 in. range, and a microscope. Zeiss Thread-measuring Instruments. Am Mach v62 May 28 1925 p 861-2 5 figs. A toolmakers' microscope is shown in fig. 5. Work may be mounted on V-blocks or centers that are placed on a compound table provided with a swivel movement. For inspecting thread profiles the in- strument is provided with an accurate optical templet, containing the profiles of standard threads, as shown at C, fig. 13, which is located at the upper portion of the magnifying lens and turned by hand until the desired profile is brought into view. Microscopic Measuring Machine, C. M. GOOTSCHAU. Machy (N.Y.) v31 June 1925 p 791-2 3 figs. A binocular measuring microscope for inspecting and measuring the faces on type and embossing punches and for determining their position relative to bodies and shanks. One micro- 124 scope is focused on a scale and the other on the work, the images being blended when seen through the binoculars. Principles and Advantages of Optical Methods for Meas- uring Machine Parts, H. F. KURTZ. Mech Eng v47 nrid- Nov 1925 p 987-92 16 figs. Fig. 4 shows an erecting tool- makers' microscope, that is, one giving the image the same aspect and motion as that of the object. The cross- slide stage is actuated by micrometers reading to 0.0001 in. Fig. 5 shows a special screw-measuring stage, and Fig. 6 a goniometer eyepiece for the tool-makers' micro- scope. A New Measuring Micrometer, J. H. DOWELL. Opt Con- vention Proc. Part II p 991-8 : Disc. 998-9 1926. A new micrometer measuring up to 6 in. is described, and the theoretical considerations controlling its design are dis- cussed. The main features are a carriage with geometric bearings, which can be released from the nut to line up the specimen, an enclosed screw and slide, and a micro- scope of geometric design adapted to take a wide range of objectives. Societe Genevoise Measuring Microscope. Am Mach v64 Jan 28 1926 p 177-8. Measuring microscope suitable for the measurement of small machine parts, fibers, mesh of textiles, pitch and diameters of small screws. Performs both angular and linear measurements. The microscope is mounted in a slide, the ways of which are part of the rotating table. The angular position of the table is read by means of a graduated circle and vernier. The slide is moved by means of a micrometer. Ein UniversaLmessniikroskop (Universal Measuring Micro- scope), A. STEINLE. Maschinenbau v5 May 20 1926 p 445-9 16 figs. Discusses optical measurement of threads, and progress attained in increased precision with projec- tion method. Bausch and Lomb Toolmakers' Microscope. Am Mach v65 Oct 14 1926 p 652-3 2 figs. Microscope having base with micrometer adjustment, illuminator attachment, lead-measuring attachment, protractor eyepiece, etc. Zeiss Universal Measuring Microscope. Am Mach v66 May 26 1927 p 913-4. Has wider range than toolmakers' microscope and is designed to measure pitch diameter of screw threads, using knife edges. Societe Genevoise Two-Coordinate Measuring Machine. Am Mach v69 Nov 1 1928 p 706-7. Also Machy (N.Y.) Nov 1928. The object to be measured is placed on a table which moves in one direction on V and flat ways under the action of a precision micrometer screw which causes motion of the table through 16 in. The microscope is car- ried on a slide by which it is moved across the table by a similar micrometer screw through a range of 4 in. Has a variety of useful features. Zeiss Improved lx3-in. Toolmakers' Microscope. Am Mach v73 Nov 20 1930 p 832-3 2 figs. This model retains the features of previous designs, such as : the dial templet ; smooth table movement guided by balls; a free swiveling table top, and a quick-acting micrometer crank. The gen- eral design has been made more massive and sturdy, and longitudinal movement of table of 3 in. permits the use of gage blocks. The cradle for the centers and V-blocks can be clamped to the table. The box-type column can be swiveled for bringing the microscope tube and illumina- tion jointly into angular position for projecting the helix angle of a thread. Measurement of pitch diameter to within the limits of 0.0002 in. can be made. Specifications : Cross travel of table, 1 in. ; longitudinal travel of table, 3 in. ; magnification, 30 times ; range of micrometers, 1 in. ; graduation of micrometers, 0.0001 in. ; reading of angles on universal ocular, 1 min. ; reading of angles on dial templet, 10 min. A special projection attachment, for converting the Zeiss toolmaker's microscope into a pro- jector is available, making observation visible to both eyes from an image on the screen. Societe Genevoise Micrometer Microscope. Am Mach v75 July 30 1931 p 221-2. Model 281 -D may be used for check- ing the profiles of small gears or screw threads. The micrometer screw is fitted and lapped into the bronze nut, while the thrust bearing of the screw is a sapphire ground optically flat to eliminate periodic error. Micrometer- drum divisions permit estimates of a tenth of a division, or 0.000005 in. To obtain the complete reading it is merely necessary to set down successively the numbers indicated on the turn counter and the micrometer head. The eye- piece can be placed over the center of the desired field to reduce the distortion of the image. Total magnification is 41.5, 63 or 96 times. Optical Measuring Machine. Eng vl33 Mar 4 1932 p 294. Machine patented by R. Douglas, installed in Orthological Institute, London ; measures small wire and like, to ac- curacy of 0.00005 in. ; method of measurement ; though originally designed for measurement of very fine filaments or of very small holes, same method is applicable to ordi- nary workshop measurements. Measuring Microscope for Rubber Specimens, R. E. LOF- TON. Indus and Eng Chem (Analytical Ed) v4 Oct 15 1932 p 439-40. Microscope provided with six-times mi- crometer eyepiece and objectives of 32 and 48 mm focal length i,s suitable for measuring cross-sectional dimensions of rubber test specimens ; width of specimens is usually greater than that of die with which they were cut ; thick- ness of soft compounds as determined by microscope is greater than that indicated by gage of plunger type. Improved Toolmakers' Microscope. Engr vl66 n4320 Oct 28 1938 p 477-8 ; Eng vl46 n3799 Nov 4 1938 p 547. Illus- trated description of Zeiss microscope for measurement of gages, templets, form tools, screw threads, gears, and similar parts. "Home-made" Toolmakers' Microscope, E. W. PENNING- TON, Am Mach v84 nl3 June 26 1940 p 460-1. Illustrated description of conversion job done on contour projector which widened its usefulness without sacrificing any of its original functions. Direct-Reading Measuring Microscope, J. E. SEARS, JR., A. TURNER. J Sci Instrum v43 nl7 Feb 1941. The arti- cle describes a travelling microscope designed for meas- uring by direct readings Debye-Scherrer X-ray powder photographs. With this instrument measurements are made by direct reference to a glass scale which can be traversed, together with the photographic film, beneath a low-power microscope in which the scale and film can be viewed together. A fixed vernier also of glass, is viewed at the same time and readings may be made to 0.01 mm. The scale and film are traversed by hand, enabling rapid movements to be made throughout the length of the film. A fine traverse is provided for adjusting the film image to the cross wire in the microscope. Measuring Microscope, G. H. WAGNER, G. C. MAILEY, W. G. EVERSOLE. Indus and Eng Chem (Analytical Ed) vl3 n9 Sept 15 1941 p 658-9. Technique for measuring vertical distances up to several centimeters with precision of 0.00005 cm ; illustrated description of microscope which has range of 16 cm and can be read to 0.00005S cm ; dif- ficulties that were encountered and solved in construct- ing and calibrating instrument to this precision. Taylor, Taylor and Hobson Toolmakers' Microscope. Machy (London) v61 nl558 Aug 20 1942 p 217: Automo- bile Engr v32 n480 Nov 1942 p 497-8. Illustrated descrip- tion of microscope for use in toolroom and standards room, mainly intended for examination and measurement of screw threads, thread cutting tools and grinding wheels and for measurement of lengths and angles on small com- ponents, form tools, and gages. 125 Cooke Toolroom Microscope. Machy (London) v61 nl559 Aug 27 1942 p 235-7. Illustrated description of micro- scope developed by Cooke, Troughton and Simms, intended to serve as comprehensive measuring instrument in both factory and laboratory. The Toolmaker Microscope as Optical Comparator, F. KOENIG. Screw Mach Eng June 1944 p 40-3 5 figs. Deals primarily with the adaptability of the toolmaker microscope as a comparator. Optical Locating System Takes Guesswork Out of Posi- tioning, G. C. BECKER. Am Mach v90 nl Jan 3 1946 p 83-6. Developed for graduating curved gunsight elevating bars, optical indexing fixtures use 40X toolmakers microscope and specially engraved master scale; air clamps assure uniform pressure, permit operator to check setting with microscope while applying pressure, and al- low quick release of work ; construction, operating details, performance and working results ; modifications of fixture discussed in which same principle is applied to other close tolerance machine work. The Measurement with the Microscope of Inaccessible Di- mensions of Macroscopic Bodies, G. SCHENDELL. Arehiv fuer Tech Messen nl78 (Ref. V1121-8) Nov 1950 p T120 in German. Two arrangements are described. They are suitable for measurements of, for example, elec- trode dimensions or spacings which are inaccessible due to enclosure in glass envelopes or are at high potentials. Parasitic Vertical Movement of a Symmetrical System of Guided Rods, J. E. PLAINEVAUX. Nuovo Cimento vll June 1954 p 626-38 in French. A brief historical review of mechanical arrangements for the rectilinear guidance of elastic rods is followed by an approximate theoretical treatment of a particular compensation system which is used in microscope travelling stages. The treatment is based on the principle of the superposition of small de- formations. Das Mikroskop, A. METZ. Arehiv fuer Tech Messen n223 Aug 1954 p 185-8. Microscope for length measurement and contour control ; ocular micrometer ; measuring micro- scope with tube displacement ; applications. Semi-Automatic Recorder for Filar Micrometer Eyepiece and Its Application to Track Measurement, B. STILLER, F. I. LOUCKES. JR. Nuovo Cimento (Ser. 10) v4 n3 Sept 1956 p 642-7. A differential transformer has been mounted on a filar micrometer eyepiece and has been coupled to a recording circuit, to make possible automatic recording of the hairline positions. The apparatus greatly reduces the time required to make measurements with a filar eyepiece; e.g., as when measuring the multiple Cou- lomb scattering of tracks in nuclear emulsions. A Photoelectric Microscope for the Measurement of Linear Scales, J. S. CLARK, A. H. COOK. J Sci Instrum v33 n9 Sept 1956 p 341-7. A description is given of a photo- electric microscope which is suitable for the accurate measurement of linear scales of high precision. A real image of a graduation line, formed by means of an ordi- nary microscope objective, is caused to oscillate across a fixed slit in front of a photoelectric cell. A phase-sensitive rectifier determines when the mean position of the line image coincides with the center line of the slit. When this is so, the d.c. output of the rectifier is zero and for small displacements of the mean position of the line gage, the d.c. output — which is measured on a microammeter — is proportional to the displacement. The standard devia- tion of a single setting of the microscope is about 0.03/t and by associating the microscope with an interferometer, short linear scales have been measured directly in wave- lengths with a standard deviation of about 0.1/*. It is thought that, with a properly designed interferometer to measure the displacement of a scale with respect to a fixed photoelectric microscope a standard deviation of 0.05//. would be achieved. Measurement of the Diameter of Opaque Cylinder by Scan- ning Microscopy, J. A. DOBROWOLSKI, W. GODFREY, P. N. SLATER, W. WEINSTEIN. J Opt Soc Am v47 n2 Feb 1957 p 186-90. Experiments have been carried out to determine the systematic errors in the measurement of the diameters of opaque cylinders by scanning microscopy. It was found that for cylinders of diameter near the optical resolution limit, the scanning microscope gives too large a size estimate. The variation of the error with aberra- tions and numerical aperture of the scanning objective, and with the wavelength and state of polarization of the light were determined. Optimum conditions for size de- termination are suggested. Modifications to a Travelling Microscope Used for Meas- uring X-ray Powder Photographs, W. E. ARMSTRONG, R. J. DAVIS. J Sci Instrum v35 n2 Feb 1958 p 59-61. The cross-hairs in the microscope eyepiece were removed and the reference mark was obtained from a light spot thrown on the photograph from a projector clamped to the barrel of the microscope. Cross-hairs seen in silhouette tend to obscure faint lines on the photograph and prevent their measurement. The light spot eliminates this effect, allows change of magnification for measuring different lines without moving the reference mark, eliminates paral- lax and allows the use of a binocular eyepiece. These features reduce eyestrain while measuring a photograph, and improve the accuracy of measurement of faint or dif- fuse lines. The photograph is illuminated by a short fluorescent tube, the light of which is cooler and "harder" in quality than that of filament lamps. Means are de- scribed of adjusting the light intensity of the tube over a wide range. Microscope Mechanical Object Stage for the Study of the Tracks of Charged Particles in Photographic Emulsions or Other Objects in Transparent Media, H. SLATIS. Rev Sci Instrum v29 nil Nov 1958 p 968-70. In addition to the usual arrangements for measurements of the x and y coordinates for nuclear tracks in photographic emulsions, the stage is rotatable about the optical axis of the micro- scope as well as about an axis perpendicular to the optical axis. The angles of rotation can be read off scales. Through these arrangements and by the use of an eye- piece micrometer the orientation and the length of nuclear tracks can be measured directly. La Dispersion de Lecture dans les Microscopes Micro- metriques, J. PETTAVEL. Optics in Metrology, P. MOL- LET. Pergamon Press 1960 p 63-72 12 figs 2 refs. Dis- cusses measuring accuracy of micrometer microscopes having projection screens. The reading dispersion is the sole factor affected by the design of the micrometer. Comparison of dispersion curves for different types. The reading dispersion is less on projection screens than in microscope eyepieces provided that the surface is devoid of granulation. Length Measurement at the Optical Resolution Limit by Scanning Microscopy, W. T. WELFORD. Optics in Metrol- ogy, P. MOLLET. Pergamon Press 1960 p 85-91 4 figs 6 refs. The image of an edge object in a scanning micro- scope with full-cone illumination is calculated, and it is shown that the half-intensity point does not occur at the position of the geometric image, resulting in a systematic error in determination of the position of the edge. A Precision Microscope for the Measurement of Small Dimensions, V. E. KOSTIN. Meas Techns 1959 n6 June 1960 p 412-3 1 fig. Translated from Izmer Tekh n6 June 1959 p 18. The measurement of dimensions with the preci- sion measuring microscope is performed by absolute and comparative methods. The first method is used with the ocular micrometer, and in the second, the measurements 126 are performed by comparison with a length standard placed between supports. A Semi-Automatic Analyser for Bubble Chamber Photo- graphs, O. R. FRISCH, A. J. OXLEY. Nuclear Instrum and Methods (Int) v9 nl Oct 1960 p 92-6. Photographs of nuclear particle tracks can be accumulated rapidly with fast-cycling bubble chambers. This article describes a machine for measuring the photographs quickly so that the subsequent computation can be done with an elec- tronic computer. The films are projected onto a ground glass screen bearing a reference mark, and moved by hand through a pantograph to bring interesting points onto the mark. The pantograph carries a plate with a fine square lattice of dots, and four photocells serve to digitize its X and Y coordinates. The two stereoscopic images of a point can be merged by moving one of the projection lenses ; this motion also is digitized photoelectrically. After setting each point, the measured data are punched on tape, to be fed later to an electronic computer. The design, operation, and performance of the machine are described in some detail, together with the principles of measurement and some proposed improvements. A New Micrometer Microscope, R. BARER. Nature (Lon- don) vl88 Oct 29 1960 p 398-9. Measurement of the size of particles in a microscope against an eyepiece scale is tedious and often inaccurate. A new system is described in which two images are seen, sheared by a known amount. Particles whose diameter equals the shear will just touch, those smaller will appear as two distinct objects, while layer particles will overlap. An attachment to a standard microscope is described. This allows the shear to be con- trolled in amount and direction, so allowing the meas- urement of irregular shaped objects. Photoelectric Microscopes for Comparing Graduated Linear Measures. L. K. KAYAK, S. I. TOROPIN. Meas Techns 1960 n2 Nov 1960 p 90-2 2 figs 3 refs. Translated from Izmer Tekh n2 Feb 1960. The developed experi- mental photoelectric microscope, applied to a four meter comparator, is suitable not only for sighting graduations, but also for direct measurement of length differences read off a comparator by the objective method. Measurement of Object-Micrometer Type Scales, N. A. KLIENTOV. Meas Techns 1960 n2 Nov 1960 p 93-4 1 fig. Translated from Izmer Tekh n2 Feb 1960. A special- ized instrument for measuring object-micrometer type scales has now been installed in a production shop. By means of this instrument rapid and efficient measurements of object-micrometers are made according to the specifica- tion of GO ST 7513-55. Checking MPB-2 Measuring Microscopes, F. P. VOLOSE- YICH. Meas Techns 1960 n2 Nov 1960 p 95-6. Translated from Izmer Tekh n2 Feb 1960. Describes a modified hori- zontal comparator IZA-2 for checking the readings of measuring microscopes MPB-2 used with hardness testers TSh. Modernized Horizontal Comparator, E. I. FINKEL'- SHTEIN. Meas Techns 1961 nl Sept 1961 p 16-20 4 figs 2 refs. Translated from Izmer Tekh 1961 nl p 12^1 Jan 1961. Describes an improved comparator for testing ref- erence linear scales. Method for Determining Comparator Screw Errors with Precision, J. M. BENNETT. J Opt Soc Am v51 nlO p 1133-8 Oct 1961. A method is described for determining with precision the relative cumulative error and the periodic error of a comparator screw. Measured curves of these errors shown for two comparators. The method also gives the relative lengths of the intervals on the scales used in the measurements. The SIP Type CLP-10 Photoelectric Longitudinal Com- parator, A. W. ASTROP. Machy (London) v99 Oct 25 1961 p 944-62 19 figs. Details of new length-measuring and comparing equipment. The basic principle as proposed by M. Volet ; features of the mechanical design ; the travers- ing carriage ; traversing the carriage ; drive to the carriage and microscopes ; the photoelectric microscope ; measure- ment and comparison without interferometry ; the inter- f erometry equipment ; using the Fabry-Perot etalon ; special permises. A Photoelectric Setting Device for a Measuring Micro- scope, H. GOLLNOVV. Monthly Notices Roy Astron Soc ( GB ) vl23 no 1962 p 391-7. A photoelectric setting device for the measurement of emission and absorption lines is de- scribed. Its special advantages for the case of ill-defined and asymmetrical stellar lines is discussed. The probable error for one setting is well under half a micron and is independent of line definition; systematic errors between different observers are practically eliminated. Setting Accuracy of Graduation Lines, W. LOTMAR. Microtecnic vl6 n2 Apr 1962 p 55-60. Comparative in- vestigations concerning setting accuracy of graduation lines between 2 straddling reference lines have shown that method of image formation has no manifest influence on standard deviation, providing comparable optical equip- ment is used. A Device for Accurate Linear Measurements of Chart Traces and Graphs, M. D. ROGERS. J Sci Instrum v39 n6 June 1962 p 317 1 fig. Measures to within 0.002 in. the position of x-ray diffraction peaks obtained on a chart recorder. A Cathetometer with Automatic Levelling, J. GIELES- SEN, K. STEINER. Zeit Angew Phys (Germany) vl4 nl2 Dec 1962 p 715-7 in German. An optical device elimi- nates the need for levelling the cathetometer telescope each time it is displaced. Microscope for Measuring Small Diameter Holes and Their Concentricity, S. L. GONDIK. Meas Techns 1962 n8 Feb 1963 p 648-9 2 figs. Translated from Izmer Tekh n8 Aug 1962 p 23-4. See abstract in subsection 7.4. Test Measurements in Comparators and Tolerances for Such Instruments. B. P. HALLERT. Photogrammetric Eng v29 n2 Mar 1963 p 301-14. Comparator tests are as- sumed made with aid of measurements of grid coordinates of high and known geometrical quality ; tolerances of regu- lar errors, residuals and standard errors of unit weight are determined according to confidence limits from statistics : practical examples ; certain regular errors of grid coordi- nates can be distinguished from errors of comparator : tests of some different glass scales are shown. Magneto-Optic Positioning, R. J. MELTZER. IEEE Trans Ind Electronics vIE-10 May 1963 p 46-56 27 figs. The system described permits production of accurate scales and grids, with a precision better than one /x in, by form- ing an image of the line with polarized light whose angle of polarization varies with the position of the line. A combination of position sensitive polarization of Faraday modulation produces a signal whos« phase depends on the sense and whose amplitude depends on the amount of dis- placement of the line image from the optic axis. Sensi- tivities of one microampere per microinch displacement can be achieved with unit magnification. Cathetometer KM-8, F. M. DANILEVICH, Y. A. NI- KITIN. Measurement Techniques (English translation of Izmeritel'naya Teknika) n7 July 1963 p 544-6. Cathe- tometer described is intended for measuring vertical seg- ments up to 500 mm in length, at distance of 280-1S10 mm from protective glass of telescope (with lens attachments) and in range of 1810 to infinity (without attachments) : as compared to its Western counterparts, instrument is claimed to have higher precision in measuring vertical linear segments, smaller error in its reading device, and 127 , higher efficiency and ease in operation, since image of object, millimeters scales, and level bubbles are seen si- multaneously in eye piece field of vision. Measure to Millionths-in Seconds, C. STEAD. Am Mach/ Metalworking Mfg vl07 nl9 Sept 16 1963 p 109-11. Carl Zeiss Universal Measuring Microscope employed by Taft- Peirce Manufacturing Co, Woonsocket, RI measures all kinds of contour gages, threads of any shape, cutting tools, templets, chasing tools, and similar parts ; with attachment it can measure eccentricity and helix angle on threads, worms, gear shaper cutters, and gear and thread hobs ; direct readings can be made to 50 mil- lionths of in. and 1 min of arc ; measuring time cut 85%. Development and Applications of Photo-Electrie Micro- scopes, A. MOTTU, J. PETTAVEL. Proc Mach Tool De- sign and Res, Pergamon Press 1964 p 455-71 18 figs. Prin- ciple of photo-electric microscope is discussed, together with applications in calibrating divided scales, determin- ing the position of a movable member of a machine or in- strument, and positioning manually or automatically a movable member of a machine or instrument. An Improved Temperature-Controlled Bath for the Com- parison of Line Standards, E. G. THWAITE. Microtec- nic vl8 nl Fe"b 1964 p 2-7 7 figs 3 refs. The interrelation- ship of uncertainty of temperature, material of standards, and inaccuracy of linear measurement is discussed to- gether with the special requirements of a temperature- control system to allow temperature to be measured to the accuracy required in very precisely comparing reference line standards. A description is given of a temperature- controlled bath, having a stability of ±0.003 °C at 20 °C for periods of 15 minutes, developed for use on a 1-meter line standards comparator. Photo-Electric Microscope for Precise Setting on Scale Lines, J. L. GOLDBERG. H. J. RITTER, Microtecnic vl8 n2, 3 Apr 1964 p 54-67, June p 117-24. Description of pho- toelectric miscroscope designed for use in transferring from optical wavelength standards to mechanical linear standards ; instrument provides indicator to permit im- personal settings to be made on line standard consistent to 0.01 n as compared with 0.2 fi for visual microscope ; de- viations of up to plus or minus 0.2 (i from set position can be measured ; lineal magnification of displacement is 350.000 times ; electronic system uses semiconductor cir- cuits which meet all requirements of stability for instru- ment of this type. Measurement of Microscope Magnification, D. H. FREE- MAN. App Optics v3 n9 Sept 1964 p 1005-8. Procedure of calibrating ruled scale and of measuring magnification of visible light microscope is described ; measurement tech- niques include use of movable hairline micrometer, image- splitting ocular, photoelectric scanning of photomicro- graphic plates, and photoelectric scanning of image plane ; empirical treatment of magnification measurements, in- cluding effects of optical distortion, is employed, so that residual errors are assigned to imperfections in measuring screw plus random contributions. Classification of Photoelectric Microscopes, A. M. DUBI- NOVSKII. Meas Techns n3 Oct 1964 p 205-8 8 refs. Translated from Izmer Tekh n3 p 13-5 Mar 1964. Photo- electric microscopes can be divided by the principle of their conversion of the measured quantity into an elec- trical signal into three groups, of amplitude, pulse-posi- tion, and modulated types. Each type has a characteristic functional circuit from which it is easy to determine the relationship between their measurement error and their circuit component parameters. Pulsed photoelectric mi- croscopes are superior to others in their quality char- acteristics, such as stability of readings, range, etc. The amplitude and modulated photoelectric microscopes are mainly used as null detectors, whereas it is possible by means of pulsed photoelectric microscopes to measure the position of graduation lines, as well as distances between them. An analysis made by means of the information theory has shown that it is possible to evaluate the prop- erties of photoelectric devices by means of information characteristics, such as the flow of useful information and the capacity of the reading unit. These character- istics are suitable for finding such parameters of micro- scopes as precision and speed of operation. Addendum to Section 4 4.1. Line Standards, General Untersuchungen und Maasregeln zur Herstellung der Ein- heit des preussischen Langenmaases (Experiments and Measurement Control for the Production of the Prussian Length Standard), F. W. BESSEL, Berlin 1839 148 p. On the Measurement of the Base Lines at Holton, Indiana and at St. Albans, W. Va., 1891-2, A. T. MOSMAN, R. S. WOODWARD, O. H. TITTMANN. Appendix 8, Report for 1892, U.S. Coast and Geodetic Survey, Government Printing Office 1893 p 329-503. Contents : Description of iced bar base apparatus and its application to the measure- ment of base lines ; length of iced bar Br? ; measurements made with iced bar apparatus ; the metallic tape base apparatus ; measurements of bases made with the tape apparatus ; method of computing correction for flexure of 5-meter bar Bi 7 ; and mathematical theory of metallic tapes, including changes in length due to variable parameters. (Continued on p. 173) 128 Section 5. Dimensional Measuring Instrument Design Features CONTENTS Page 5.1. Measuring instruments, design principles 129 5.2. Amplification 131 5.2.1. General 131 5.2.2. Electrical 132 5.2.3. Mechanical 138 5.2.4. Optical 139 5.2.5. Pneumatic 141 5.3. Dials and pointers 143 5.4. Optical features 143 5.5. Pivots 146 5.6. Slides, stands, and tables 146 5.7. Springs and suspensions 148 Addendum to Section 5 151 5.1. Measuring Instruments, Design Principles The Parallel Motion of Sarrut and Some Allied Mecha- nisms, G. T. BENNETT. London, Edinburgh and Dublin Phil Mag v9 June 1905 p 803-10. A link mechanism for exact parallel motion is described. See also Dunkerley's Mechanics, page 386. Design and Construction of Scientific Instruments, R. S. WHIPPLE. Opt Soc Trans v22 1920-21 p 35-52; Eng vlll May 27 1921 p 659-62. A general resume of the principles underlying the design of scientific instruments. The Mechanical Design of Scientific Instruments, A. F. C. POLLARD, J Roy Soc Arts v70 Sept 29, Oct 6 and 13 1922 p 769-80, 783-94, and 797-808 43 figs ; Eng vll3 June 9 16 23 and 30 1922 p 729-30 763-64 794 and 828-9 24 figs. Consideration in design of qualitative and quantitative instruments used in many branches of physical, engineer- ing and chemical sciences. Abstract of three Cantor Lec- tures delivered before Royal Soc of Arts. Notes Upon the Mechanical Design of Some Instruments Shown at the Exhibition of the Physical and Optical Societies, 1928, A. F. C. POLLARD. J Sci Instrum vo Mar 1928 p 88-92 5 figs. Ross kinematograph projector ; Maltese cross movement ; W. Ottway and Co. screw meas- uring machine ; Laby X-ray spectograph ; goniometer fit- ting of Muller's X-ray goniometer spectrograph. Konstruktionsgrundlagen der feinmeehanischen Technik (Principles of Instrument and Apparatus Design), W. KNIEHAHN. VDI Zeit v72 n49 Dec 8 1928 p 1773-5 34 figs. Discussion of standard structural elements, joints, bearings, gearing, etc., of mechanical, electric, optical, and acoustic apparatus. The Geometric Design of Scientific Instruments, J. A. TOMKINS. Instrum Wld vl Dec 1928 p 229-31. Con- siders degrees of freedom and gives examples showing the result of the imposition of successive constraints on a rigid body, each constraint being imposed by causing one point of the body to touch a fixed surface. Examples of geometrical slides and geometrical clamps. Lists authorities. Notes on Design of Measuring Instruments, F. H. ROLT. Ch. 14 of Gauges and Fine Measurements, Vol. II. Mac- millan and Co. Ltd, 1929. Discusses geometric location, geometric slides, the principle of alinement, form and flexure of measuring machine beds, the thrust of microme- ter screws, the use of flexible steel strips, micrometer screws, and fine adjustments. Grundlagen und Geraete Technischer Laengenmessungen, G. BERNDT. 2d ed. Berlin, Julius Springer 1929 374 p illus diagrs tables. Survey of scientific principles of measurement and instruments for practical use ; evolu- tion of usual standards is described, and methods by which shop and control standards of length are made and cali- brated are discussed ; application of various types of gages and other measuring instruments ; physiological errors in measurement and reference of meter to wavelength of light are discussed in appendixes. Eng. Soc. Library, N.Y. H. SCHULZ was coauthor of 1st ed 1921. Zwei Messtechnische Grundsaetze und ihre Befolgung (Two Fundamental Rules of Measuring Techniques and Their Observation), G. BERNDT. Werkstattstechnik v24 Sept 1 1930 p 461-7 22 figs and Sept 15 1930 p 495-8 10 figs. Sept 1 : Example of comparators shows that to avoid errors of first order, object and not measuring in- strument should be moved ; it is further made apparent that for longitudinal comparator standard and object must be located on same axis (Abbe's principle) ; observa- tion of these rules in principal measuring instruments and methods is investigated. Sept. 15 : Technical meas- uring methods and instruments based on principle of transversal comparator. Works of Messrs. Cambridge Instrument Co., Ltd., Eng vl32 n3416 July 3 1931 p 1-5 21 figs partly on p 16 and supp plate. In design of instruments, geometric principle, of which late Darwin was perhaps greatest exponent, is largely employed ; examples of effective application of geo- metric principle of instrument designs ; layout and equip- ment of works ; research ; work organization. Zeiss Optical Cam Checking Device. Am Mach v75 Sept 3 1931 p 397. The outfit consists of a scraped sur- face plate with two parallel T-slots, an optical dividing head and tailstock and a measuring microscope. The camshaft is taken between centers, and the angular set- ting secured from the optical dividing head. The reading 129 may be taken directly to one minute of arc. Rise and fall of the cam for each angular setting is secured by means of the measuring microscope. The reading is obtained directly from a scale. Distance between centers can be up to 60 in. Daempfung von Messgeraeten (Damping of measuring in- struments), W. HOFMANN. Archiv fuer Tech Messen vl Mar 1932 p T38-9, and Apr p T54 ; Veroeffentlichungen aus dem Gebiete der Nachrichtentechnik 2 n2 1982 p 103-6. Mar : Fundamentals, theory and determining values ; theoretical mathematical analysis and curves. April : Calculation of air damping devices for measuring instru- ments. Bibliography. Luftdaempfungen fuer Messgeraete (Air damping of measuring instruments), F. EICHLER. Archiv fuer Tech Messen vl Apr 1932 p T55. Application and de- sign of air damping devices for measuring instruments. Some Industrial Applications of Metrology, M. F. TUR- RETTINI. Machy (London) v50 nl299 Sept 2 1937 p 692-5. Fundamental conditions that must govern design of precision instrument or machine, in order to ensure best chances of success ; example given of causes of error which may arise in operating screw cutting lathe. Before Bcole Nationale Besancon. Measuring and Gauging Contacts for Modern Production, F. HORNER. Can Machy v48 nl2 Dec 1937 p 192-5, 202 and 220. Production methods demand great accuracy which can only be obtained by suitable measuring devices equipped with surface of contacts of special design, some of which are briefly described ; solid and adjustable gages ; micrometer calipers ; internal micrometers ; screw gaging and measuring ; contacts for indicating. Design Factors Controlling Dynamic Performance of In- struments. C. S. DRAPER, G. P. BENTLEY. ASME Paper n30 mtg Dec 4-8 1939 9 p. Generalized treatment of in- struments which have single movable index, controlled by magnitude- of single actuating quantity ; such instru- ments act as system with 1° of freedom ; properties can be specified in terms of range, scale sensitivity calibration and environmental error and uncertainty ; definitions and use of each of these quantities discussed. Bibliography. Use, Care and Maintenance of Laboratory Instruments, H. N. HAYWARD. J Eng Education v30 n5 Jan 1940 p 506-10. If accuracy is to be maintained and known, fre- quent checking of test instruments with reliable working standards is essential ; if possible, correct type of instru- ment should be used in every application ; cause of errors in instruments ; calibration and checking of instruments. Instruments for Measuring Dimensions, O. W. BOSTON. Metal Progr v48 n4 Oct 1945 p 991-6. Linear dimension measuring instruments and gages discussed in relation to design, principles and applications as quality control tools. General review, O. W. Boston ; Rules, Micrometers and Calipers, H. D. Hiatt; Comparators, W. H. Baker. Geometrical Measurement, C. H. H. FRANKLIN. Eng Inspection vll n2 summer 1946 p 9-23. In principles set forth engineering production is considered mainly as art of controlled production of geometrical forms in agreed relation to standard units of size and shape ; standards of length measurement ; accuracy and limits ; systems of geo- metrical measurement ; complex measurements ; apparatus characteristics ; geometrical construction of measuring appliances ; sources of error in geometrical methods ; use of interferometer. Before Instn Eng Inspection. Precis of a discussion on "Practical considerations in in- strument design" — London, 1948. J Sci Instrum Phys Ind v25, Apr 1948, p 122^. New Optical Precision Measuring Instruments for the Workshop, A. METZ. Trans Instrum Meas Conf Stock- holm 1949 p 182-5 1950 in German. A brief illustrated de- scription of new Leitz instruments. These include an instrument for the control of sizes of workpieces, a co- ordinate drilling machine with a precision measuring ocular, a telescope with a magnification of 32 and a range of 1-50 metres, and the "Perflektometer," an instrument for the measurement of end gap and other gauges. Laboratory Instruments, Their Design and Application, A. ELLIOTT, J. H. DICKSON. Chemical Publ Co, New York, 1953 414 p. Principles of good design necessary for construction for instruments in laboratory workshop ; sep- arate chapters discuss properties, treatment, and use of various materials ; methods of construction to meet special requirements ; Kinematic design of instruments ; optical instruments and glass ; use of photography in research. Eng Soc Library, N.Y. Discussion on Kinematic Design Applied to Instruments. Soc Instrum Technol Trans v6 n2 June 1954 p 66-82. Views of various participants on advantages of instru- ment design based on kinematic principles ; such practice is of value in improvisation of research apparatus to be put together without specially good workmanship, con- struction of apparatus which is precise in function with- out imposing close dimensional limits, and design of equip- ment for metrology applications ; particular instrument designs. Instrument Linkages, W. O. DAVIS. Soc Instrum Technol Trans v7 nl Mar 1955 p 1-9. Design of linkages which have to operate accurately in indicating or com- puting instrument mechanisms under conditions of vibra- tion and abnormal acceleration ; return springs and counterpoises ; relationship of number of kinds of calibra- tion adjustment to number of null error points obtainable in calibration curves ; examples of linkages for providing linear, square-law, and log-law approximations in trans- lation-to-rotation mechanism. Some Principles of Measurement and Control, J. F. COALES. J Sci Instrum v33 nl2 Dec 1956 p 457-64. Two classes of measurement are those which only have to be observed and recorded and those which are used to control ; limitations from which all measuring instru- ments suffer, e.g. they all disturb physical system on which measurements are being made and they all have inertia and damping to some degree, also no measuring instrument is completely stable; these limitations are dis- cussed ; simple theory of linear control systems is developed. New Comparator for Measuring Pitch Errors of Fir-Tree Root Serrations in Gas Turbine Discs, L. W. NICKOLS. Machy (London) vl9 nil Nov 1957 p 450-4. Comparator described is complementary to instrument reported in Engineering Index 1955 p 202 ; new comparator rapidly measures pitch errors to desired accuracy by comparison with composite slip gage standard, with errors recorded on chart ; design and principle of operation ; measuring head and turret ; workholder and indexing mechanism ; setting comparator ; interpretation of chart record. Aperture Corrective Systems, J. OTTERMAN. IRE Trans Instrum vI-8 nl Mar 1959 p 8-19. Corrective networks for improving performance of certain instru- mentation systems ; desired correction serves to offset averaging effect common to such sensing devices as deflec- tion plates of oscilloscope, scanning beam of television camera, networks particularly useful when aperture small enough to provide essentially flat response up to desired frequency is not technically feasible. Mesure et Instrument de Mesure (Measurement and Meas- uring Instruments), J. IDRAC, 4th ed. Dunod, Paris 1960 130 125 p. Basic principles of measurement ; areas of measure- ment and sensitivity ; accuracy ; velocity ; statistical distributions. La Mesure dans FAutomatisme, l'Automatisation des Me- sures (Measurement in automatization, and automatiza- tion of measurements), U. ZELBSTEIN. Genie Chim v83 nl Jan 1960 p 1-14. Automatization of measurement is essential when manual observation and control is im- possible (for example, at high speeds) or when standard arrangements have reached limit of their possibilities. Universal Mechanical Assembly for Laboratory Purposes, Particularly for Optical and Semi-Automatic Measure- ments. J. BAKOS, Z. ERDOKURI, K. KANTOR Magyar Tudomanyos Akad Kozponti Fiz Kutato Intezetenek Kozlemenyei (Hungary), v9 n3 p 171-80 1961 in Hun- garian. Describes a versatile mechanical unit and driv- ing mechanism both easily assembled from universal ele- ments. The driving mechanism can be remote controlled. The two assemblies are suitable either for individual or for joint use. The various elements are provided with connections to optical and precision mechanical tools, and in this way their usefulness may be considerably extended. Logarithmische Verstaerker mit VDR-Widerstaenden (Logarithmic amplifiers with voltage dependent resistor resistances), R. ROEHLER, H. P. POPP. Zeit In- strumKde v70 nl Jan 1962 p 15-16. It is found that certain ceramic resistances have logarithmic characteris- tic within wide range which is made use of in construc- tion of logarithmic amplifier ; deviation of amplifier- characteristic from logarithmic scale is maximum of 2% within 3.5 decades ; amplifier is used for direct indication of emulsion densities, but its range of application is much larger. Grundbegriffe der Messtechnik (Fundamentals of Measur- ing Practice). DIN 1319 15p Jan 1962. German standard available in both German and English from ASA, price $2.50. Covers basic principles governing the use of meas- uring instruments and fundamentals of errors arising in measuring practice. Applies to measuring instruments in which an index associated with the instrument is set, or sets itself, to a position on a scale belonging to the instrument. Kontakteinrichtungen fuer empfindliche Zeigermessge- raete (Contact devices for sensitive indicating instru- ments), K. H. ZEITZ. Archiv Tech Messen n313 315 Feb 1962 p 33-6, Apr p 87-90. Principles of operation and design of devices for wide range of instruments used for chemical processes, industrial temperature measure- ment, etc., 23 refs. Non-Contact Dimensional Measurements by Optical and Electronic Techniques, C. D. BRYANT. IRE Trans on Indus Electronics vIE-9 nl May 1962 p 1-6. Accurate dimensional measurements of. products during processing are major requirement in many industries ; because of high heat radiation, rapid motion, or other factors non- contact measurement system is desirable ; systems which have been developed using combination of closed circuit television and special optical techniques together with special purpose computers and associated readout devices. Some Uses of Elasticity in Instrument Design, R. V. JONES, J Sci Instrum v39 n5 May 1962 p 193-203. Dis- cussion of anti-distortion instrument mountings, elastic- movements for rotation and translation, movement magni- fying and reducing devices, elastic averaging schemes. simple harmonic force and constant force systems, elastic energy stores, and slow relaxation device for transmit- ting rapid displacements only. 45 refs. Graticules and Fine Scales : Their Production and Appli- cation in Modern Measuring Systems, E. BOVEY. J Sci Instrum (GB) v39 n8 Aug 1962 p 405-13. After a histori- cal survey an account is given of a wide range of proc- esses employed for graticule manufacture. Optical, photographic and mechanical requirements together with their respective limitations are discussed. Finally, some special high-quality graticules and scales employed in modern measuring systems are described. Classification of Automatic Measuring Instruments, V. M. SHLYANDIN. Meas. Techns 1962 n6 Dec 1962 p 456-7. Translated from Izmer Tekh n6 p 9-11 June 1962. Devel- ops the definition that an automatic measuring instrument is a device which evaluates objectively the measured quantity by balancing it automatically with a compen- sating quantity, and which uses for this purpose an auxiliary power source. 5.2. Amplification 5.2.1. General Measurement of Small Displacements, A. RIGHI. N Cimento v6 1897 p 349-52 in Italian. The author describes a simple method of measuring small displacements, such as the motion of a point on an expanding bar. It consists essentially of a short lever supported at two close points on the same side of its centre of gravity by two very fine stretched fibres, one of which runs in an upward direction, and the other downward. The directions of the fibres will intersect on the vertical through the centre of gravity of the lever. The lower end of the lower fibre is fixed, and the upper end of the upper one is attached to the moving point. When the point moves upward or downward, the lever is tilted, and the angle of tilt is measured by a tele- scope, or lamp, and scale. In the actual instrument the suspension is bifilar; a thread of three cocoon-fibres is formed into a rectangle, the two upper corners of which are fastened to a rod connected with the moving point, and the two lower corners to a similar rod connected with the fixed point. The thread passes between two jaws at each end of a crosspiece attached horizontally at right angles to the lever. By this means errors due to torsion of the fibre are avoided ; and by using short fibres changes in length due to humidity of the air do not cause any ap- preciable error. The author has succeeded in magnifying a small motion twenty thousand fold by this apparatus. Empfindlichkeit von Instrumenten, G. KEINATH. Archiv Tech Messen vl Feb 1932 p T22. Sensitivity of measuring instruments ; rules outlined are applicable pri- marily to electric instruments and also to great extent to other types ; definitions ; value of high sensitivity ; sensi- tivity of various types ; current, voltage and energy sensi- tivity ; numerical data. Bibliography. Recent Progress in Making of Precision Instruments. A. J. PHILPOT. J Roy Soc Arts v96 n4764 Mar 12 1948 p 213-22 ( discusssion ) 222-1: Mech Wld v 123 n3187 Feb 13 1948 p 193-4; Metal Industry v72 nS Feb 20 194S p 151-2 ; Machy Market n2474, 2475, Apr 16 1948 p 195-6. Apr 23 p 205. Discussion of means by which increased accuracy of instruments is obtained : examples of optical and surveying instruments accuracy of which has been increased by magnification ; magnification by conversion applied to conversion of small temperature changes into large pressure changes ; data on recently developed instru- ment in which small changes in linear dimensions are converted into changes of frequency ; discussion of magni- fication by electronics. 131 Primary Detectors for Measurements, E. E. LTNOH, A. J. CORSON. Elee Eng v67 n9 Sept 1948 p 849-59. Basic elements of any measurement system may be classified into three functional groups known as primary detectors, intermediate means, and end devices ; by classifying pri- mary detectors for both electrical and non-electrical quan- tities, convenient selection of suitable detector may be made when quantity to be measured together with range over which it will vary is known. Paper 48-104 before Am Inst Elec Engrs. Is There a Science of Instrumentation?, E. U. CONDON. Sci vllO n2858 Oct 7 1949 p 339-42. Rules governing classification of instruments ; characteristics of trans- ducer ; transforming and amplifying elements of instru- ment ; present demands for instrumentation improvement are essentially higher sensitivity and faster response. Theory of Mechanical, Electrical, Electronics and Air Gaging. W. F. ALLER. ASME Paper n52— A-89 for meet- ing Nov 30-Dec 5 1952 16 p. Characteristics of mechani- cal, electrical, electronic and air gages that have made possible separation of inch into smaller and smaller divi- sions : descriptions of dial indicator, mechanical compara- tor, reed gage mechanism, electric transducers, gaging circuits, limit type gage head, flow type gage, Venturi type gage, back pressure gage and differential gaging circuit. Sensitivity of a Vibrating Reed Null Indicator, L. .1. SOMERVAILLE. J Sci Instrum v31 nl2 Dec 1954 p 439- 40. A simple vibrating reed null detector is described. The sensitivity of the instrument has been studied by two methods. In each case consecutive readings were ob- tained within ±2X10"" in. Mechanic-Electric Transducer, K. S. LION. Rev Sci Instrum v27 n4 p 225-5 Apr 1956. Description of a transducer system which permits the conversion of me- chanical displacements into electrical signals. The sys- tem is based upon a high-frequency discharge in a gas under reduced pressure. Different modifications permit the detection of either very small movements (<1 mm) or large movements (several cm), or small changes of capacitance (fraction of a micro-microfarad). A Mechanical-Electric Transducer of Simple Design, M. MANZOTTI. J Sci Instrum v33 n8 Aug 1956 p 314- 15. A probe electrode plunged into a current field experi- ences a potential which is a function of its position in the field ; when it is moved, the variation of potential is also a function of the displacement. This principle makes possible the design of mechanical-electrical transducers of simple construction and easy assemblage. An application to pressure recording is here described. The sensitivity (5 cm of water per full deflection) and speed of response (no distortion for variation of pressure up to 220 cm of water per second) can, if necessary, be easily improved. Six Transducers for Precision Position Measurement, J. O. MORIN. Control Eng v7 n5 May 1960 p 107-12. Review of high precision transducers, with measurement capabili- ties up to one part in quarter million, includes pin-and- pawl mechanism, magnetic bench-mark system, resolver- type transducers, electrostatic transducers, and diffraction gratings. A Recording Extensometer. A. D. MARTYNOV. Meas Techns 1959 n3 May 1960 p 163-4 1 fig. Translated from Izmer Tekh n3 Mar 1959 p 7. Discusses inclusion of elec- trical recorder into amplifying devices. Screening Micrometer — New Principle for Measuring Small Movements. B. E. NOLTINGK. Brit Communica- tions & Electronics v7 n6 June 1960 p 430-5. Limitations of conventional resistive, capacitive, inductance, and photoelectric pickups for measuring small movements are reviewed; new type of transducer is described in which coupling between coils is varied by screen moving be- tween them ; sensitivity of device is such that movements of 1/i and less can be readily measured. Hydraulic Method of Measuring Length, V. G. SHTEIN. Meas Techns 1959 nl2 Sept 1960 p 934-8 3 figs. Trans- lated from Izmer Tekh nl2 Dec 1959 p 10. The instru- ment described proves the possibility of using the hydrau- lic method for linear measurements and the production of commercial instruments operating on this principle and capable of wide application in different devices, in- cluding those used in various methods of automatic control. Electromechanical Transducer for Small Displacements and Forces, G. S. BERLIN. Pribory i Tekh Eksper (USSR) 1961 n5 p 152-7 Sept-Oct in Russian. The design, characteristics, and parameters of an electro- mechanical transducer (mechanotron) for small displace- ments and forces, and of a simple, highly sensitive mechanotron micrometer and dynamometer with a potentiometer recorder are described. [Eng. translation in : Instrum exper Tech (USA) n5 Sept-Oct 1961 p 973-7 ; publ. April 1962.] Investigating the Kinematic Error in a Hydraulic Com- parator, V. V. MATVEEV. Meas Techns 1961 nlO Mar 1962 p 784-8 4 figs 6 refs. Translated from Izmer Tekh nlO p 11-4 Oct 1961. The kinematic error in hydraulic comparators plays an important part in. determining the final judgment on the advisability of using the hydraulic method and on selecting a suitable arrangement for the instrument. In order to eliminate the kinetic error and raise factor, and hence raise the sensitivity of the instru- ment, it is necessary to use hydraulic comparators which provide a constant pressure on the diaphragm due to the liquid head independently of the displacement of the instrument's measuring rod. Barium Titanate Ceramics for Fine-Movement Control, J. V. RAMSAY, E. G. V. MUGRIDGE. J Sci Instrum v39 nl2 Dec 1962 p 636-9. Barium titanate transducers are described for use in automatic control of Fabry-Perot interferometer, to achieve parallel displacements of plate to accuracy required in interferometry. High Precision Linear Electro-Mechanical Transducers, F. BROUWER. Int Production Eng Research Conference Proc Sept 9-12 1963 p 592-600. Published by ASME. Various types of transducers for linear positioning and measuring problems in machine tool and gages are ana- lyzed, including mechanical linkages and leadscrews, rack and pinion drives, diffraction graftings, digital scales, linear inductosyn. Steward-Warner linear position trans- ducer etc. of which only digital scale gives absolute ma- chine position directly ; final choice of system for particular application depends to large extent on indi- vidual factors determined by environment in which meas- uring systems shall be used, and on magnitude of allowable errors. Extensometer Calibrator, G. E. RICKWOOD, Canada, Nat Research Council-Mech Eng Report MH-102 Aug 1963 p 3 plates. Arrangement suitable for producing and measur- ing linear extensions of order of 1 /tin. over range of plus or minus 0.0035 in. is described ; provision is made for referring measurements to gage blocks ; originally de- signed to permit calibrating vibrating wire strain gages, it is readily adaptable to calibrating other types of exten- someters and strain gages by addition of suitable mounting blocks. 5.2.2. Electrical An Electric Micrometer, P. E. SHAW. Proc Phys Soc London vl7 Mar 23 1900 p 431-59 16 figs ; Phil Mag v50 Dec 1900 p 536-62 6 figs ; Abstract, Electrician v44 Apr 6 132 1900 p 854-5. Describes a method, said to be reliable, of measuring small distances by electric contact. Electric Contacts, H. ROHMANN. Phys Zeit v21 Aug 15 1920 p 417-23. A torsion arrangement is described by means of which displacements of the order of lfi/i could be determined. With this apparatus the variations of current, due to closer approach of the electrodes of a contact, could be followed. The "contact distance" for different materials was of the order of magnitude of 1-50/ifi. The results made it possible to produce an efficient metal microphone and a reliable coherer. A Method of Measuring the Periodic Error of a Mecha- nism, G. A. TOMLINSON. J Sci Instrum v6 n5 May 1929 p 152^3 3 figs ; Mech Eng v51 nl2 Dec 1929 p 955. Sim- ple apparatus devised in the Metrology Department of National Physical Laboratory for determining periodic error in motion transmitted by kinematic pair ; consists of two similar electromagnetic markers connected in series so as to produce series of simultaneous kicks on smoked- plate records attached to two components of kinematic pair ; mechanism is allowed to move at very slow rate. The Electric Gage, A. V. MERSHON, J. W. MATTHEWS, B. C. WAITE, JR. Gen Elec Rev v32 nl2 Dec 1929 p 674- 5 3 figs ; West Machy Wld v21 nl Jan 1930 p 10 30 3 figs. Instrument is independent of human sense of touch; simple and rapid to manipulate ; amplification factor is 10.000 ; electric gage has been developed to meet need for accurate gaging device that has but minimum of moving parts and that wiil permit routine gaging operations to be conducted with great rapidity. Electric Precision Gage of Great Accuracy. Machy (N.Y.) v36 n6 Feb 1930 p 435-6 3 figs. Description of electric gage designed to meet demand for accurate gaging device that has minimum of moving parts and that will permit routine gaging operations to be conducted with greater rapidity : with amplification factor of 10,000, this gage, independent of human touch, makes possible meas- urements to 0.00005 in., gage may be used for both inside and outside measuring. General Electric Magnifying Electric Gage. Am Mach v74 Feb 19 1931 p 340. An electric gage that measures one one hundred thousandth of an inch, and then magni- fies that dimension 10.000 times, has been developed. This type of gage is suitable for almost any kind of meas- urement with certain changes in set-up. The gage con- sists essentially of a contact point supported to move through a limited distance in the direction of measure- ment, say 0.0005 in. This movement causes a pointer to travel 5 in. over a scale of an indicating instrument. The diamond contact point is fitted in the gage spindle, which is made to suit the work. Piezo-Electric Gage and Amplifier, R. A. WEBSTER. J Franklin Inst v211 n5 May 1931 p 607-16 7 figs. Pressure gage using cartridge of pure bakelite : within this was placed pile of 21 quartz crystals, each 0.69 in. sq. by 0.053 in. thick, being separated by platinum electrodes : screwed brass ends held them in cartridge which was then sealed with beeswax : gage has given good service, and although few of crystals cracked, no loss in sensitivity has been noticed. Grid Glow Micrometer, R. W. CARSON. Am Mach v75 nil Sept 10 1931 p 407 2 figs. Operating principles and hook-up of instrument using vacuum tube to avoid errors resulting from contact pressure. New Electric xYrrangement for the Measurement of Small Displacements, S. REISCH. Zeit fiir Hochfrequenztech- nik v38 Sept 1931 p 101-11. A brief description is given of various electric micrometer arrangements, with a full bibliography. The various arrangements are criticized, and then a new type of capacitative displacement meas- uring apparatus is described which is based on the poten- tial distribution across condensers arranged in series. The theoretical capacity sensitivity is 2.5 X10" 8 . Precision Measurements of Mechanical Dimensions by Electrical Measuring Devices, A. V. MERSHON. Gen Elec Rev v35 Mar 1932 p 139-14. Electric gages for measuring diameters ; combination electric gages for mak- ing two or more measurements at same time; electric- sizing control used to automatically machine parts to given dimension ; electric matching control used to ma- chine parts to existing masters ; strain gage used to meas- ure change in length of structural member, etc. Korkeajaksointerferenssiin Perustuva Rekisteroeivae Mitrometri, P. E. KUOKKANEN, A. BAECKSTROEM. Teknillinen Aikakauslehti nl2 Dec 1934 p 388-95. High frequency interference recording micrometer invented by authors for measuring and recording diameter variations of thin wires used for manufacturing of glow lamps ; variation of 0.0001 mm in wire diameter will cause deflec- tion of 1 or 3 mm respectively on recording paper of in- struments. (Brief abstract in English p 395.) Elektrisches Ultra-Mikrometer zur Messung des Waer- meausdehnungskoeffizienten keramischer stoffe (Electric micrometer for measuring coefficients of thermal expan- sion of various ceramic materials), A. HEINZ, H. KOTTAS. Sprechsall v68 n4 and 5 Jan 24 1935 p 49-51 and Jan 31 p 65-7. Details of procedure ; illustrations. Galvanomagnetic Measurement of Small Displacements, S. REISCH. Akad Wiss Wien Ber vl45 2a 9-10 1936 p 725-52. The method depends on the variation of the resistance of Bi with the magnetic field in which it is placed. To obtain a high sensitivity and good tempera- ture compensation four Bi resistance coils, connected so as to form a Wheatstone bridge, move in the gaps of two permanent magnets. In order that correction may be applied for the temperature of the whole network, this forms the arm of another bridge enabling the total resist- ance to be measured. Theoretical considerations lead to the calculation of a calibration curve and give informa- tion concerning the constancy of the zero, and the limit of sensitivity. Two practical designs are given, to- gether with their experimentally-determined sensitivities. These, expressed as fractional changes of resistance for 1 mm of movement, were 1.6 X10" 2 . Measuring Millionths of an Inch, R. W. CARSON. Elec J v33 n2 Feb 1936 p 106. After several years of experi- mental work, entirely new method of measuring spring deflections was developed, using electronic micrometer : device used electronic means of indicating point of con- tact between hand micrometer and test specimen in form of small cantilever beam. Electric Gage, C. M. HATHAWAY, E. S. LEE. Mech Eng v59 n9 and 12 Sept 1937 p 653-8 and (discussion) Dec 1937 p 963. Mechanical measurements involving displacements as small as 0.00001 in. and even 0.000001 in. can be made with electric gage described ; displacements being measured can be amplified 10,000 or 100,000 times on indicator without introducing frictional effects ; four methods of electric gaging, capacitance, bridge, saturation, and eddy current, are described. Bibliography. Before Am Soc Mech Engrs. Elektrische Messung kleinter Laengenunterschiede (Elec- tric measurement of small differences in length ) . E. FROBOESE K. SCHOENBACHER. Archiv fuer Elektro- technik v33 n5 May 12 1939 p 341-6. Fundamental opera- tion of electric measuring gage discussed : special reference made to sources of error and their correction : examples of practical application. Convenient Electrical Micrometer and Its Use in Mechani- cal Measurements, R. GUNN. ASME Advance Paper n34 133 meeting Dec 4-8 1939 4 p. Simple micrometer of mechani- cal and electrical stability developed ; electric current out- put from micrometer is accurately proportional to impressed mechanical displacement ; zero drift, hysteresis, temperature, and pressure variations reduced to less than 1% ; special circuits described which permit indication of sums, difference, ratios, or products of mechanical displacements and are useful in mechanical measurements. Note on Electromagnetic Induction Micrometers, Includ- ing Novel Circuit, Incorporating Metal Rectifier, R. J. COX. J Sci Instrum v 19 n8 Aug 1942 p 117-20. Con- venient method of measuring displacements of order of few thousandths of inch is one which utilizes changes in inductance of iron cored coil produced by changes in lengths of airgaps in its magnetic circuit ; methods of indicating these changes in inductance are discussed ; new circuit is described which incorporates metal rectifiers and microammeter or galvanometer as indicator. Electric Gauges, H. P. KUEHNI. Gen Elec Rev v45 p 533-6 Sept 1942. The gage is an a.c. bridge circuit in which one or more impedance branches are acted upon by the quantity to be measured. The calibrated amount of brdige unbalance is indicated on an instrument which may be remotely installed at any convenient location. Detecting Small Mechanical Movements, J. C. FROMMER. Electronics vl6 p 104-5 July 1943. A valve circuit for detecting movements of 10" 6 in. is described. These move- ments are converted into capacitance changes of the order of O.Olftu F. Variations in oscillator and cable charac- teristics are nullified by the insertion of a displacement unit between the oscillator and amplifier. The amplifier has been used successfully for measuring blood-pressure curves. Elektrische Verfahren zur Messung kleiner Laengen ( Electrical methods of measuring small lengths ) , W. REDEPENNING. Archiv Tech Messen nl50 Dec 1943 p T145 (2 p) (J112-4). Illutrated description of electric methods at measuring short linear dimensions with aid of induction or contact instruments ; both types described and illustrated. Measurement of Displacement and Strain by Capacitv Methods, B. C. CARTER, J. F. SHANNON, J. R. FOR- SHAW, Engr vl77 n4602 Mar 24 1944 p 237-8. Account of some developments for which authors and colleagues at Royal Aircraft Establishment have been responsible ; authors have found it advisable to employ electronic equipment that is adaptable to any class of pick-up, e.g., resistance, electromagnetic, capacity, or induction, with associated pre-circuits. Abstract from Symposium before Instn Mech Engrs. Electric Gaging Methods for Strain, Movement, Pressure and Vibration, H. C. ROBERTS. Instrum vl7 n4, 5, 6, 7, 8, 9, 10, 11, 12, Apr 1944 p 192-6, Mav p 260-5, 284, 286, 288, June p 334-9, July p 398-403, 414, 416, 418, 420, 422, 424, Aug p 475, 484, 486, 488, 490, Sept p 534-4, 544, 546, 548, 550, 552, 554, Oct p 603-5, 626, 628, Nov p 668- 70, 684, 686, 688, Dec p 742-4, 755. Apr-May : Principles of operation ; auxiliary circuits and recording devices ; operating techniques ; gaging methods based on varia- tions of capacitance; sensitivity, stability, and accuracy discussed. June-Aug : Gaging methods based on varia- tion of inductance. Sept-Dec : Gaging methods based on variation of resistance. A Ohange-of-Capaeitance Method for the Measurement of Mechanical Displacements, E. BRADSHAW. J Sci Instrum v22 June 1944 p 112-4 2 figs 2 refs. Method is suitable for the measurement of static or alternating dis- placements. The circuit includes two radio-frequency oscillators feeding a mixer valve. Variation in the fre- quency of one of the oscillators, and therefore in the frequency of the mixer output, is effected by the changing capacitance. A frequency-amplitude converter circuit produces a direct voltage which is proportional to the change of capacitance. Use of Radio-Frequency Apparatus in Inspection, J. COR- NELIUS. Machy ( London ) v66 nl699 May 3 1945 p 473-6. Details of construction and operation of apparatus which measures such mixture variations as one thousandth part of millionth of inch ; comprising measuring and indicating units, physical units in inspection are translated into electrical units which are amplified by external power on indicator; electronic arrangement and radio circuit em- ployed are explained, and economics and advantages of its application discussed. The Use of Frequency Modulation in a Sensitive Microme- ter, G. M. FOLEY. Am Phys Soc Proc June 1945. Abstr. in Phys Rev v68 p 101 Aug 1 and 15 1945. To measure the unimpeded displacement of an object, one plate of a small air capacitor is attached to the object. The other plate is fixed close to the moving plate, and the capacitor is used to tune a r.f. oscillator. The change in frequency resulting from motion of the object is converted into pro- portional d.c. voltage by a receiver similar to a radio receiver. Voltages of ±300 V are obtained from small displacements, and a magnification of the motion 10*-10 5 times can be obtained, permitting detection of displace- ment of 10~ 6 in. The apparatus is robust and stable and requires no electrical connection with the object. Two such micrometers were placed at rt. angles to measure the rotation of a precision lathe spindle in its bearings, the outputs of the two micrometers being applied to two axes of a c.r.o. A similar micrometer was used as a high-speed recording dilatometer to follow the allotropic transforma- tion of steel on heating and cooling. Electric Gaging Methods, H. C. ROBERTS. Instrum vl8 n9, 10, 12, Sept 1945 p 616-7, 624, 626, 628, 630, 632, 634, 636, Oct p 685-9, 706. 708. Dec p 882-9, 912-4, 916-8. 920. Sept : Calibrating devices. Oct : Calibration check- ing circuits and oscillographs. Nov : Power supplies. See earlier parts of series listed above. Capacitance Micrometer, R. W. DAYTON, G. M. FOLEY. Electronics vl9 n9 Sept 1946 p 106-11. Variations in oscillator frequency caused by minute movements of capacitive circuit element are converted to output voltage changes in electronic gage ; using principle which has been successfully used for dilatometer, monometer, roughness gage and hardness testing apparatus ; device uses limiting amplifier to free instrument from errors which might be caused by amplitude variations ; design details. Electronic Gaging, P. H. HUNTER. Electronic Indus vo n9 Sept 1946 p 68-71. New standards of accuracy and speed in dimensional inspection made possible by preci- sion electronic instruments, is exemplified by two mi- crometer developments ; Carson Electronic micrometer employs screw of high lead accuracy with electronic cir- cuit facilitating interpolations to 25 microinches or less ; Wilmotte "Visi-Limit" micrometer features sensitivity not dependent on size of material being measured, and accuracy of ±0.0002 in. Indicateur de Contact Electrostatique a Battements (Electrostatic oscillating contact indicator), P. FAY- OLLE. Rev Gen de Elec v56 n3 Mar 1947 p 124-8. Appli- cation to comparator for ultra-micrometric recording: illustrated description of screw comparator combined with electric contact indicator, claimed to give very accurate results. Les Ultra-Micrometres Electrostatiques (Electrostatic ultra micrometers), A. PARNET. Machines et Metaux v31 n343 Mar 1947 p 107-9. Principle of apparatus and comparison of two different solutions ; illustrated descrip- tion of 150-inm and 250-mm comparator and micrometer Used for internal measurements. 134 A Variable Capacitor for Measurements of Pressure and Mechanical Displacement ; A Theoretical Analysis and Its Experimental Evaluation, J. O. LILY, V. LEGALLAIS, and R. CHERRY, J App Phys vl8 n7 July 1947 p 613-28. A variable capacitor is described for measuring small dis- placements, small volume changes, and pressure differ- ences. The capacitor consists of a deflectable diaphragm and a fixed electrode. The diaphragm is metallic, plane- parallel, clamped at the edges, and at earth potential ; the electrode, at an a.c. potential, has a plane surface parallel to the undeflected plate across an air gap. For use in displacement measurements, the diaphragm's center is deflected by a point contact from a mechanical link to the observed system, or by a uniform pressure load from a fluid link to the system. The plate deflection results in a change in the air gap, and thus generates a capacitance signal, which is measured by electrical methods. The theory of the device is analyzed and sensitivity and alinearity factors are derived. Cathode-Ray Recording Micrometer and Force Gauge, J. EWLES. C. CURRY. J Sci Instrum v24 nlO Oct 1947 p 261-5. Features of device using oscillograph with mov- ing coil system to record and measure rapidly varying movements of order of 3 mm to accuracy of 0.0025 mm ; by attaching moving coil to specially designed force gage of natural period of about %ooo sec, device has been applied to record and measure rapidly varying forces and prelimi- nary study of rapid shear. Electronic Gauges, J. SCHWARTZ. Microtecnic v2 n5, 6 Oct 1948 p 199-206, Dec p 267-74, v3 nl Jan-Feb 1949 p 10-8. Systems for transformation of mechanical dimen- sions into voltages such as piezoelectric gaging heads for measurements of pressure, resistance extensometers for measurements of strains and stresses ; study of types of gaging heads suitable as sensitive part of electronic com- parators; gaging heads utilizing variations of capacity or of selfinductance can be adapted for accurate measure- ments of lengths. Mesure et Amplification de Faibles Deplaeements par Modulation de Frequence (Measurement and amplifica- tion of small displacements by frequency modulation ) , P. BRICOUT, M. BOISVERT. Rev Gen de l'Elee v58 nlO Oct 1949 p 402-^. Use of manometric capsule as variable gap in capacitor in tuned circuit; frequency modulation resulting from pressure changes are determined using Bradley discriminator and output is read on calibrated milliameter; equipment is suitable for manometer, vibrometer, or seismograph. Electronic Developments in Instrumentation, D. ED- MUNDSON. Soc Instrum Techn Trans vl n5 Dec 1949 p 8-17 (discussion) 18-9. Use of amplifiers for indicat- ing instruments applied to measurement of physical quan- tities; consideration of a-c amplifier in instrument form, a-c bridge detector, negative feedback amplifier, d-c am- plifiers, chopper amplifier, self balancing potentiometers and photoelectric amplifiers; questions of reliability and maintenance. Measurement and Amplification of Minute Displacements by Frequency Modulation, P. A. BRICOUT, M. BOIS- VERT. Rev Sci Instrum v21 p 98-9 Jan 1950 2 figs. All functions are performed using only two tubes, an oscillator and a discriminator. Describes apparatus and discusses principle, characteristics, and applications of same. Kleinstwegmessung mit induktivem Geber (Measurement of Very Small Movements by Means of an Inductive Pickup), F. STEJSKAL. Electrotech Zeit v71 no Mar 1 1950 p 115-6 6 figs 5 refs in German. Mechanical vibra- tions, as they occur in the testing of vehicles or station- ary machines are converted by means of small pickup coils into a compensation circuit in electrical voltage fluctuations and shown on a loop oscillator. The pickup elements and circuits are described. Differential Transformer as Applied to Measurement of Substantially Straight Line Motion, W. D. MacGEORGE. Instrum v23 n6 June 1950 p 610-^1. Methods for deter- mining displacement of bellows or diaphragm, motion of float, tip travel of Bourdon tube and tilt of weigh beam; discussion of basic design of differential transformers and circuits which permit their application to measurement of instrumentation variables such as pressure, flow, force, etc. ; schematic diagrams. A Micro-Inch Micrometer of One-tenth Inch Range, E. B. BAKER. Rev Sci Instrum v22 p 373-5 June 1951. Many instruments exist which will magnify small displacements to almost any degree desired but always at the expense of range. The micrometer screw is a notable exception, but does not give an electrical output nor will it measure distance directly and continuously without extra equip- ment. The present device combines a lever, a micrometer screw, a sensing element and a servometer to achieve this purpose. Improvements in Null Indicator Electromagnetic Gauges, E. B. BROWN. J Sci Instrum v28 p 272-4 Sept 1951. The conditions for elimination of errors due to mains fluc- tuations are discussed, and an improved form of null setter is described, which in itself is a useful piece of laboratory equipment since it may be used as an a.c. potentiometer, having a small and nearly constant phase defect less than 1 / 2 °- The null setter was originally designed by the au- thor for use as a counterbalance for a diaphragm oper- ated moving coil gauge, but in this paper its application is shown to an a.c. mains operated gauge for remote indication with magnification of small angular deflections. Inductance-type Transducer and its Applications, J. YAMAGUCHI, Y. SAKURAI. Tech. Rept Osaka Univ vl p 201-12 Oct 1951. The "variable-gap" inductance- type transducer is used as the pick-up in measurement of length, pressure and mechanical vibration. In this paper fundamental considerations and practical applications of this transducer are described. The sensitivity of source which is applied to the transducer and the acting current of inductance coil, and the adequate values of these are shown in the case of a micrometer. Next, in the meas- urement of dynamic pressure or acceleration the relation between these mechanical quantities and gap length is discussed theoretically. As practical applications the ultra-micrometer, pressure recorder and acceleration meter are described. By the ultra-micrometer the diame- ter of a steel ball can be measured with sensitivity Vzon- The pressure recorder is applied to the measurement of dynamic pressure between pantograph and trolley wire and as an acceleration meter for vehicles. These instru- ments are stable, use light transducers of small size and robust construction, and are suitable for telemetering. They are thus suitable for field testing. Micrometer Dilatometer, E. J. VANDERMAN. Rev Sci Instrum v22 Oct 1951 p 757-60. The construction, cali- bration, and use of a dilatometer that is ideally suited for use with radioactive materials is described. Expansion measurements are made electrically with a linear variable transformer. Electronic Ultramicrometer. W. ALEXANDER. Elec- tronic Eng v 23 n286 Dec 1951 p 479-80. Micrometer uti- lizing single octode tube and particularly adapted to measuring small changes of length ; circuit makes use of change of anode voltage when resonant frequencies of two grid oscillator circuits are separated progressively from common value ; change of length measured is ap- plied to capacitor plates in one grid circuit. Electronic Measuring Instrument for Small Displace- ments, L. A. GONCHARSKII. Elekt richest vo 1952 n6 p 62-5 in Russian. The theory of the input diode of a thermionic measuring instrument for small mechanical displacements using a moving electrode is presented. A 135 771-846 0—66 method for determining the current and voltage sensitivi- ties of the instrument is found. It is seen that a diode with flat parallel electrodes is the most sensitive input element for such purposes, as far as current sensitivity is concerned, whereas the possibilities for improving voltage sensitivity are rather limited. Die Electronic ini Dienste der Messtechnik (Electronics in the Service of Measurement Technique), F. TURRET- TINI. Ind Organisation v21 n6 1952 p 166-72. Electronic Device for Measuring Small Transient Dis- placements, J. J. TROTT. J Sci Instrum v29 n7 July 1952 p 212^4. Micrometer device for measuring displacements down to 10 micro in., being suitable whenever it is possible for equipment to be mounted on stable support ; use for measuring relative and absolute movements of concrete road slabs under wheel loads of vehicles; device is based upon variation of output of h-f oscillator due to movement of metal disk near tuning coil. A Linear Transducer for the Electrical Measurement of Displacement, M. J. TUCKER. Electronic Eng v24 Sept 1952 p 420-2. This device depends upon the change in coupling between two coils with linear displacement. The primary is wound round the centre limb of a stack of Permalloy gate stampings. It extends almost halfway up this limb and above it is located the movable secondary coil. This latter coil is connected through a bridge recti- fier to a d.c. indicating instrument. Over the linear oper- ating range, corresponding to a displacement of approx. 1 cm, the output current varies from 1.3 to 2.7 mA. Ac- cordingly, sensitivity can be improved by backing off some of this current, and two circuits intended for this purpose are shown. The circuit as used has to work off a 250c/s supply, but the advantages of a high frequency, e.g. 2 kc/s, are pointed out. Over the 1 cm range, linearity within the accuracy of measurement, approx. 0.005 cm, is achieved. Electronic Dimensional Gaging, C. W. WILLIAMS. ASME Paper n52 A-98 for meeting Nov 30-Dec 5 1952 12 p. Features of gaging devices where displacement of measur- ing tip which engages piece to be measured is magnified by vacuum tube or amplifier to permit user to read dis- placement on scale, or to furnish impulse to control auto- matic gaging and handling equipment, use of recorders driven by amplifier where permanent records are useful. Electronic Circuitry for Instruments and Equipment, M. H. ARONSON. Instrum Pub Co, Pittsburgh, 1953 310 p. Nonmathematical presentation of basic circuits and funda- mental techniques with examples and application covering broad scope ; resistance, capacitance, inductance and sig- nal shaping, vacuum tube and gas tube fundamentals, amplification, rectification, and oscillation circuits dealt with. Eng Soc Library, N.Y. Comparateur Electromecanique (Electromechanical Com- parator) , J. HUETZ. Techn Mod v45 n2 Feb 1953 p 47-50. Principles and characteristics; apparatus described has characteristics of strain gage, such as high degree of sta- bility and fidelity. The Photodianode, G. DELOFFRE E. PIERRE, J. ROIG. CR Acad Sci [Paris] v237 pl507-9 Dec 9 1953 in French. The use of the two anodes in a vacuum photo- tube with suitable geometry enables the relative anode currents to be used as a measurement of the displacement of a light spot on the cathode. The tube is of use for the precision measurement of small displacements or rotations. Direct Reading Instrument for Measurement of Small Displacements, W. C. CORNER, G. H. HUNT. J Sci Instrum v31 nl2 Dec 1954 p 445-7. Arrangement whereby differential condenser forms part of a-c bridge network ; displacement of central plate causes proportional off bal- ance voltage; small displacements can be measured to accuracy of 10" 7 cm ; applicability to measurement of mag- netostriction of small crystals of nickel, maximum change in length being 85 X 10"° cm. A Simple Circuit for Use With Condenser Strain Gauges, D. M. MAURICE. J Sci Instrum v31 nl2 Dec 1954 p 442—4. A one-valve circuit operating at 200 Mc/s is de- scribed which gives a stable output proportional to the strain and sufficient to d,rive directly a low-impedance recording milliammeter. It may be used with a wide range of recording capacitance down to 3pF. The con- necting cable to the recording condenser acts as a trans- mission line and may be long without affecting seriously the working of the circuit. Electronic Indicators of Mechanical Quantities, L. A. GONCHARSKII. Uspekhi fiz Nauk v55 nl 1955 p 81-100 17 refs in Russian. A survey, including material on the electronic micrometer, vibrometer, dynamometers, manometers. History of Electrical Devices for Measuring Strains and Small Movements, B. E. NOLTINGK. J Sci Instrum v32 n5 May 1955 p 157-8. The development of apparatus for measuring strains and small movements by transduction into electrical signals is traced over the past hundred years. Instruments depending on resistive, capacitive, inductive, piezoelectric, acoustic and photoelectric systems are considered, and the chief contributors to the introduc- tion of different techniques are enumerated. Electronics : New Answer to Shop Gaging Problems, D. M. GASKILL. Am Mach v99 n25 Nov 21 1955 p 134-6. De- sign and functioning of electronic gaging system ; gages can be made sufficiently sensitive to measure deviations in dimensions as small as 0.000010 in., 0.000001 in., or even 0.0000005 in. ; other applications ; examples of checking dimensions on lapped hydraulic motor pistons, high pre- cision gears and armature shafts. Apports de l'Electronique a la Metrologie (Contributions of Electronics to Metrology), J. AVRIL. Soc. Francaise des Mecaniciens Bui v6 n20 1956 p 22-^. Different meth- ods enabling physical quantities to be transformed into electrical variables, irrespective of nse made of them ; examples. A Magneto-Resistance Displacement Gauge, I. M. ROSS, E. W. SAKER. Nature (London) vl78 Nov 24 1956 p 1196. The displacement to be measured causes a small strip of InSb to change its position relative to a permanent magnet the poles of which are shaped to give a strong field gradient in the direction of movement. The mean field over the crystal and hence its resistance are then a function of position. In practice two crystals rigidly connected are used to overcome temperature errors. Instrument Transducers, J. THOMSON. J Sci Instrum v34 n6 June 1957 p 217-21. After dividing the problems of instrumentation into two categories (1) the determina- tion of what is to be measured, and (2) the investigation of how to make the measurements, the importance of en- ergy transformations to problems in the second category is established. The attempt is made to define the forms of energy in a manner suitable for instrument research and a chart is presented showing important physical and chemical phenomena as transformations between these forms of energy. Particular attention is paid to those transducers which provide an electric signal. In con- clusion, recent developments of transducers are consid- ered from the point of view of instrumentation and the significance of solid state science is underlined. Use of Piezoresistive Materials in the Measurement of Displacement, Force, and Torque, W. P. MASON, R. N. THURSTON. J Acoust Soc Am v29 nlO Oct 1957 p 1096- 136 _± . 101. The use of piezoresistive materials as strain gauges and in the measurement of displacement, force and torque is discussed generally. A torsional transducer, which was constructed from w-type Ge, is described, and the experi- mentally obtained voltage-torque characteristic is given. Der heutige Stand der Entwicklung elektrischer Messge- raete fuer mechanische nnd waermetechnische Grossen ( Present status in development of electric instruments for measuring mechanical and thermotechnical values), G. BECK. Werkstattsteehnik und Maschinenbau v48 n3 Mar 1958 p 169-78. Survey of indicating, amplifying and recording instruments. A Sensitive Micrometer for Measuring Small Displace- ments, J. NORBURY, D. SHEWRING. J Sci Instrum v35 n6 June 1958 p 217-20. A variable parallel-plate ca- pacitor associated with an oscillating circuit forms the basis of an apparatus which can measure displacements of the order of 200A. The apparatus is so designed as to combine robustness with sensitivity, ease of calibration and reproducibility. The use of a diode pump integrator circuit makes the sensitivity independent of the gain of the a.c. amplifier. The capacitor is of simple construction and standard electronic components are used throughout. The Measurement of Small Displacements by Electrical Screening. B. E. NOLTINGK. Inst of Phys Stress Anal- ysis Group Conf, Delft, 1959. A conducting screen inter- posed between two coils affects their electrical coupling. It is shown how the dependence of this effect at the exact position of the screen can be made the basis of a trans- ducer converting mechanical displacements to electrical scale. Such a system needs only a small element attached to the moving part to be measured ; it is insensitive to movements in directions other than those studied ; and it can allow an indefinite travel of the moving element. A small instrument is described, used on this principle, which has a linear range of 10 mm and a stability of a fraction of a micron, allowing displacements to be observed on any scale between millimetres and hundreds of Angstrom units. Inductance Bridge for Sensitive Displacement Measure- ments Over Long Periods, D. MURRAY. J Sci Instrum v36 n7 July 1959 p 312-15. An application of linear dif- ferential transformers in an ac. bridge that provides reproducible displacement measurements over long pe- riods, extends the linear response while retaining high sensitivity, and can be readily adapted for automatic re- cording of displacement. Modern Measuring Instruments — Electric and Electronic Gages, F. W. WITZKE. ASTME Tech. Papers 60 book 1 paper n245. Electronic gage heads now provide extreme precision and accuracy for standards laboratory use. Performance specifications are listed. Application of Electronics to Industrial Metrology, J. QUENTIN. Microtecnic vl4 n3 June 1960 p 125-35. Roles of electronics in solving metrological problems are re- viewed ; applications to high and low resolution instru- ments, equipment for remote measurements, and for auto- matic control based on small dimensional variations are discussed. Application of Continuous Secondary Electron Multipli- cation for Amplifying Small Currents, P. K. OSHCHEP- KOV, B. N. SKVORTSOV, B. A. OSANOV, I. V. SIPRI- KOV. Instruments & Experimental Techns (English translation of Pribory i Tekhnika Eksperimenta ) n4 July- Aug 1960 p 611-14. Electron multiplier developed at Metallurgical Inst of Acad of Sciences, USSR, operates on principle of continuous secondary electron amplification without central focusing electrode ; approximate calcula- tion of multiplying system ; production technology and composition of one of versions of emitter material. Novel Displacement Detector and its Application in a Recording Thermobalance, J. C. VAN DER BREEGGEN, H. J. WOUTERLOOD. J. Sci Instrum v37 n8 Aug 1960 p 297-300. A transducer has been developed to detect changes in position of a balance beam. Its operation is based upon a differential capacitor. Variations in capaci- tance are made to produce directly a d.c. voltage corre- sponding in sign to the sense of deflection of the balance beam. The construction of the transducer is described, and its application in automatic apparatus for thermo- gravimetric analysis is illustrated by results obtained on the dehydration of copper sulphate and the decomposition of quinoline phosphomolybdate. The sensitivity of the instrument can be varied in nine steps to give full-scale deflections from 10 to 500 mg. An accuracy of about 1.5 mg or 0.75% of full scale was obtained for the 200 mg range. Unicom Measuring System, S. RIGBY. Automatic Con- trol vl3 n6 Dec 1960 p 31-8. Mechanical inspection sys- tem developed by Adage, Inc., which employs linear vari- able differential transformers as input transducers to sense contours, and electronic system for processing trans- ducer outputs and producing printed inspection reports; basic resolution of automatic gaging system of various types of components, is 0.001 in. Sensitive Output Indicator for Differential Transformer Displacement Determinations, D. WOBSCHALL. Rev Sci Instrum (USA) v32 nl Jan 1961 p 71-3. A transistor- ized circuit particularly designed as an output indicator for linear variable differential transformers for the meas- urements of small displacements is discussed. Resolution of the unit is about 0.05/u ; the linearity is about %%. Refining Measurements by Capacitance Techniques. F. K. HARRIS, R. D. CUTKOSKY. ISA J v8 n2 Feb 1961 p 63- 6 8 figs 1 ref. Through recent advances in the art of capacitance measurement, capacitance may be determined solely by a length, and vice versa. Accordingly capac- itance bridges will be useful for measurement of mechan- ical displacement, film thickness, and dielectric constant, both as a spot check and as a continuously recording quality control technique. Design and Construction of Device for Recording Small Displacements, P. R. JAMES. Mag Concrete Res vl3 n37 Mar 1961 p 37-9. Design and construction of electrome- chanical device for remote, continuous recording of dis- placements of order of one mm in concrete structures ; elec- tronic potentiometer recorder is used in conjunction with bridge circuit of four resistance strain gages, variation in out-of-balance potential being used as measure of displace- ment ; instrument developed to measure movement of sec- tions of concrete road on either side of expansion joint. Method for Adjusting Nominal Inductance of Transducers. B. E. KOSTICH. Meas Techns 1962 n3 Sept 1962 p 187 1 fig 2 refs. Translated from Izmer Tekh n3 p 9 Mar 1962. Describes a method for a smooth adjustment of the trans- ducer's inductance by varying the reluctance of a hollow core by means of displacing inside it a screw of a high permeability. Compensated Electrical Instrument for Remote Measure- ments of Displacements. M. I. BELYI. Meas Techns 1962 n8 Feb 1963 p 641-2 1 fig 2 refs. Translated from Izmer Tekh n8 p 17-9 Aug 1962. The author has developed an electrical instrument which uses a method of compensat- ing two emfs for measuring large displacements with an error not exceeding 10/*. This instrument can be used as a transducer in devices for automatic control of displace- ments, especially of carriages and tables of metal-working machines. Computation of an Inductive Transducer with an Adjust- able Short-Circuited Turn, V. YA. EDUSH, M. A. NA- BIEV. Meas Techns 1962 n8 Feb 1963 p 684-90 3 figs 2 13^ refs. Translated from Izmer Tekh n8 p 50-3 Aug 1962. An inductive transducer of linear displacements whose sensing element consists of a moving short-circuited turn. Displacements Transducer with Electrical Recording, V. V. NIKIFOROV. Meas Techns 1962 n9 Apr 1963 p 733-4 1 fig. Translated from Izmer Tekh n9 p 17-8 Sept 1962. A transducer on the basis of a clock type indicator, pro- vided with an electric-spark paper recorder for registering displacement of tenths or hundredths of a mm. New Electrical Contact Head Type GK-3, F. M. DANILE- VICH, V. A. NIKITIN. Meas Techns 1963 nl Aug 1963 p 19-21 2 figs. Translated from Izmer Tekh nl p 14-6 Jan 1963. Describes an improved electric contact head used as an attachment to measuring or gaging devices for measuring 1 to 13.5 mm diameter holes either directly or by a differential method. A Automatic Recording Differential Dilatometer, J. BAR- FORD. J Sci Instrum GB v40 n9 Sept 1963 p 444-5. The apparatus is suitable for the study of the kinetics of phase transformations and precipitation processes in the solid state. Relative length changes between a specimen and a control are measured by means of a variable inductance transducer. The differential system works to better than 1%, over temperature ranges of up to 1000°G Indicating Instrument for Measuring Very Small Dis- placements, K. I. ZABLONSKII, V. I. NASSAL'. Meas Techns 1963 n5 Nov 1963 p 381 1 fig. Translated from Izmer Tekh n5 p 13-4 May 1963. Describes a resistance wire transducer by which it is possible to record displace- ments of the order of 0.1,u by means of ordinary amplify- ing equipment. Application of Induction Transducers for Measuring Dis- placements at High Temperatures, M. I. KORSUNSKII, A. S. LAGUNOV, L. P. BAIVEL. Meas Techns 1963 n8 Feb 1964 p 651-4 5 figs. Translated from Izmer Tekh n8 p 16-9 Aug 1963. The transducer can be used as a basis for designing an instrument for automatic checking and control of the starting and operating of powerful steam turbines. The temperature-compensated transducer can also be used for remote contactless measurements of clear- ances in other machines which operate at high tempera- tures. The method of temperature compensation can be used for induction transducer measurements of other quantities. There exists the possibility of increasing the temperature operating range of the transducer. However, for this purpose it may be necessary to use magnetic ma- terials with higher Curie points, for instance, cobalt. 5.2.3. Mechanical See also Subsection 3.6.4 The Minimeter for Fine Measuring, F. C. PERKINS. Can Machy v20 Nov 21 1918 p 592-93 5 figs. Principle and forms of Hirth apparatus for measuring threads, balls, cylindrical parts and grooves, also for inside measuring of various diameters. The Determinateness of the Hysteresis of Indicating In- struments, F. J. SCHLINK. J Washington Acad Sci v9 Jan 19 1919 p 38-45 2 figs. Hysteresis determinations of non-integrating mechanical measuring instruments require no unusual care, and are fully reproducible. The Concept of Resilience with Respect to Indicating In- struments, F. J. SCHLINK. J Franklin Inst vl87 Feb 1919 p 147-69 2 figs. Deals particularly with instruments of index-and-scale and value-controlling types of class of non-integrating instruments, as distinguished from inte- grating instruments and those used for comparison pur- poses strictly. Die Genauigkeit mehrfacher Fiihlhebel (The Accuracy of Multiple Lever Gages), G. BERNDT. Werkstattstechnik vl5 June 15 1921 p 347-50 2 figs. Comparison of accuracy of single and multiple levers. States that, when possible, instead of using several levers with smaller gear ratios, it is better to use a double or single lever with gear ten times as great. A Study of Commercial Dial Micrometers for Measuring the Thickness of Paper,- P. L. HOUSTON, D. R. MIL- LER. Tech Papers NBS n226 Dec 29 1922 p 125-52. The mechanisms were studied to determine the effect of the various designs on the contact pressure, the variation in contact pressure, and the accuracy and variance of the instruments. Specifications are given for a standard instrument. Das Reibungsfreie Minimeter ( Frictionless Minimeter), N. PFLEIDERER. Zeit fur Feinmech v32 Feb 20 1924 p 38-9. Description of Hirth minimeter, with a sectional view showing the construction. New Societe Genevoise micro-indicator. Machy (London) v36 Apr 3 1930 p 19-20 2 figs. Embodies rocking plate and knife edges to give max amplification of 500. Spindle travel is approx. 0.03 in. Precision Measuring Instrument. Eng vl31 n3404 Apr .10 1931 p 500 2 figs. At Leipzig Fair, Fortuna-Werke Spe- zialmaschinen-fabrik A-G., of Stuttgart-Cannstadt, exhib- ited number of examples of their precision measuring instruments, many of which embody Hirth minimeter ; interesting application of minimeter is shown in combina- tion instrument for testing distance between gudgeon-pin hole and piston head or pistons of internal-combustion engines, as well as whether axes of this hole and of piston are truly at right angles. Recent Developments in Design of Precision Measuring Instruments, M. A. ROBBIN. Mech Wld v91 Feb 5 1932 p 123-5. Operating principles and accuracy of Hirth- Minimeter, Krupp's Mikrotast gage, Zeiss optimeter and Werner's Microlux indicator. Mechanische Fuehlhebel, G. BERNDT. Archiv fuer Tech Messen vl May 1932 p T71 (2 p.). Operation of lever mechanisms of precision gages with data on accuracy and use of German and Swiss makes. Fuehlhebelmessgeraete ( Contact Lever Measuring Instru- ment), ALBRECHT. Werkzeugmaschine v40 nl2 June 1936 p 299-304. Application of contact lever to various types of movements for mechanical, optical and electric measuring instruments. Mechanical Amplification of Small Displacements, A. F. C. POLLARD. J Sci Instrum vl5 n2 Feb 1938 p 37-55. De- scribes a number of the more satisfactory methods of amplifying small displacements and of accurately reducing large movements to small and corresponding displace- ments. The mechanisms described and discussed include levers, combined with optical means of increasing their sensitivity, the rolling cylinder of small diameter, gear trains of various types, the differential screw mechanisms, mechanisms depending on the bending, twisting or sagging of flexible elements, hydraulic and liquid indicating de- vices, including spirit levels, and a pneumatic micrometer. The paper concludes with a discussion of the natural limit to the sensitivity of all measuring instruments, and a short Bibliography. Die Messeigenschaften der Messuhr und ihre Berueek- sichtigung in der Werkstatt (Characteristics of clock dial micrometers and consideration of their use in work shops) , E. BARZ. Werkstattstechnik und Werksleiter v32 nl2 June 15 1938 p 287-9 and 291-5. Study of measuring errors and underlying fundamentals of standards for this type of micrometer. 138 Draft Standard Specification for Dial Gauges. Machy (London) v54 nl400 Aug 10 1939 p 594-5. Specification prepared under authority of Mechanical Industry Com- mittee of British Standards Institution, in response to request received from Institution of Production Engi- neers ; main purpose is to set up standard of accuracy for commoner types of dial gages now in use. Dial-Gauge Research, G. SCHLESINGER. Eng vl38 n 3859 Dec 29 1939 p 725-7. Review of report on dial gage and its use issued by Institution of Production Engineers, giving account of researches carried out at Loughborough College ; examples of employment of instrument in accept- ance tests for machine tools illustrated. British Standard Specification for Dial Gauges for Linear Measurements (Excluding Back Plunger Type). Brit Stand Instn BS Specification n907 1940 19 p. Specifica- tion applies to gages having axis of plunger movement parallel to plane of dial ; with dial diameters of 1% in. to 2 in. and having ranges of movements of plunger up to y 2 in. or 12 mm and measuring by steps of 0.001 in., 0.0005 in. and 0.01 mm. Levers of Constant Ratio, R. S. CLAY. J Sci Instrum vl7 n3 Mar 1940 p 49-55. Theoretical discussion of simple lever, bent lever, and lever with connecting link ; applica- tions of levers of constant ratio. A Fine Mechanical Adjustment of Variable Sensitivity, D. S. PERFECT. J Sci Instrum v21 p 123-4 July 1944. It was desired to adjust to a specific setting the tilt of a mirror to an accuracy of the order of 0.1 in. or better. A spring was encastered at one end and also constrained on one side near this end by an adjustable fixed ball. Near this ball a second ball presses against the other side of the spring, and is given minute displacement when the spring is flexed by a screw controlling the free end. The dis- placement can be used to give linear or angular adjust- ment to a suitably constrained body linked to the second ball. Adjustment of the longitudinal separation of the two balls controls the minification factor. A Mechanical Arrangement for Measuring Small Changes in Length, G. LEIBFRIED. Zeit Phys vl27 n5 p 580-7 1950 in German. An apparatus for measuring length changes such as are observed when plastic deformation begins in a single crystal is described. The linear move- ment is taken up by two fine wires rolling between plane surfaces, and the angular movement of the wires is re- corded optically. A magnification of 3X10 5 is achieved, and an accuracy of about 10 A is claimed. Some results for single Al crystals are discussed. New Johansson Measuring Instruments. Machv (Lon- don) v83 n2144 Dec 18 1953 p 1217-9. Feature of Mikro- kator comparator, designed by Swedish Co., is that fric- tionless drive to pointer is provided by twisted metal strip ; two designs of surface finish indicators developed which also employ twisted metal strips for operating pointers : Deltameter air operated automatic sizing unit which is available with measuring heads of various designs. Ultra-Sensitive Mechanical Comparator. Eng vl77 n4588 Jan 1 1954 p 23. Comparator with magnification of 200,- 000 is production model from range of "Mikrakators" made by C. E. Johansson, Ltd ; special Mikrakators made with range of plus or minus 0.00002 in. and graduations for each 0.000001 in. Bin Neues Verfahren zur Messung kleiner Laengenaen- derungen (New method for measuring small changes in length), D. KUHLMANN-WILSDORF. Zeit fuer Angew Phys v6 n4 Apr 1954 p 171-4. Differential method of measuring length by means of horizontal roller having two sections of different radii; movable bands attached to length being measured are fastened to perimeter of each roller section; rotation of roller is determined by mirror arrangement ; apparatus construction and applications are included. Basic Principles of Link and Lever Adjustment, N. A. ANDERSON. ISA J v3 nl Jan 1956 p 10-12. Calibra- tion steps for link and lever recorder or indicator which has pen or pointer connected to element or other power source by 4-bar linkage; adjustments for zero, multiplica- tion and angularity ; first covers angle between pen and pen lever ; second, ratio of total pen or pointer motion to total element motion ; last, unequal rates of pen or pointer travel for equal increments of rotation. CE J Mikrokator. Machy ( London ) v92 n2366-67 Mar 21 1958 p 658-66, Mar 28 p 713-6. Mikrokator produced by Aktiebolaget C. E. Johansson, Eskilstuna, Sweden is shock resistant, dial type measuring instrument capable of high amplification, which incorporates thin twisted metal strip design ; its application to diameter, load and surface finish measurement ; operations in production of Mikrokator methods employed in assembling amplifying mechanisms. Adjusting Device Incorporating an Ultrafine Movement, H. M. KING, J. B. WEIR. J Sci Instrum (GB) v39 nl p 31 Jan 1962. The primary screw thread is on the out- side of a shaped hollow bar with a necked extension in which two slots are cut. A lapped contact button is at the end. The secondary screw is inside the bar and has a tapered extension. When this is pushed into the neck the outer bar expands and contracts. A maximum shrinkage of 0.0006 in. is obtained and a one-hundredth turn of the secondary screw gives a movement of two millionths of an inch. New Instruments for Linear Measurements, G. B. KAINER, N. N. MARKOV, V. YA. EIDINOV. Meas Techns 1962 n3 Sept 1962 p 184-7 5 figs. Translated from Izmer Tekh n.3 p 6-8 Mar 1962. Describes several types of mechanical indicators including an optical spring head ; spring head having a bronze tape twisted helically from the middle ; two gear and lever indicators ; a head having moving electric contacts ; waviness instrument for check- ing gears ; and an indicating hole gage. 5.2.4. Optical Photographic Registration of Sounds, D. C. MILLER. Phys Rev v28 n2 Feb 1909 p 151 ; Sci v29 p 471 1909 ; Eng v94 p 550 1912. A small steel cylinder, 1 mm in diameter, is arranged to receive angular motion, with a minimum of reaction effects, which is proportional to the displacement of a sensitive diaphragm. A minute mirror, with its plane parallel to the axis of the cylinder, reflects light to a spe- cial camera, and at a distance of 30 cm gives waves 15 cm wide which show great detail. See also The Science of Musical Sounds, D. C. Miller, Macmillan Co. N.Y. 1916. The Phonodeik p 78-88. The National Physical Laboratory — Optical Lever Com- parator. Eng vllO July 9 1920 p 56-8. Apparatus for measuring thermal expansion by tilt of a glass or quartz disc. Optical Strain Gages and Extensometers, L. B. TUCKER- MAN, NBS. Proc ASTM v23 pt II 1923 p 602-10, 10 figs 7 refs. Describes three optical lever observing and four mirror systems. A Sensitive Optical Lever Method for Measuring the Thermal Expansion of Small Specimens, J. GUILD. J Sci Instrum vl Apr 1924 p 198-204 3 figs. Method employed is comparative one in which two specimens of suitable form stand close together on flat reflecting surface and support second reflecting surface approximately parallel to first ; inclination between two surfaces is measured by auto-collimating telescope system. Optical lever system 139 employed, magnification 390, corresponding to measure- ment of change in length of approximately X/20 for green light. Molecular Measurements by Optical Lever, W. N. BOND. Nature vl22 Aug 4 1928 p 169-70. Optical lever giving very large magnification to test the accuracy with which a steel-to-steel contact will return after separation, and whether the thickness of a mica sheet can be detected as varying in multiples of the "molecular" length. Prelim- inary results are given. Molecular Length Measurement by an Optical Lever, W. N. BOND. Phil Mag v7 June 1929 p 1163-82. Used in a series of penetration experiments on mica and steel. A periodicity is shown, viz, 10X10" 8 for mica, and 6.8 Xl0" 8 for steel which agree with the lengths of the unit cells of mica and of cementite as determined by X-rays. Optische Fuehlhebel (Optical Contact Levers), G. BERNDT. Archiv Tech Messen v2 July 1932 p T100 (2 p.). Optical systems by which limitations in length of mechanical feelers are extended by application of friction- less ray of light ; details of Zeiss optometer, Sears feeler, Mikrolux, Optotest and interference feeler. Bibliography. Der Lichstrahl als Zeiger in Technischen Messgeraeten (Light beam as pointer in technical measuring equip- ment), K. H. SIEKER. Zeit fuer Fernmeldetechnik vl3 Dec 15 1932 p 186-90. Application of pointer is shown in series of examples ; selection of examples made from practical standpoint and no critical analysis is given. Bibliography. Geometry of Optical Indicators, K. J. DE JUHASZ. J Franklin Inst v229 nl Jan 1940 p 53-80. Article describes term "optical indicator," embracing all kinds of instru- ments in which one or more optical levers are incorporated classification of optical indicators; optical lever; kine- matic considerations ; optical levers with one degree of freedom of rotation ; application of theorem to particular cases ; effect of deviations from assumed conditions ; non- spherical screens ; convergent light beams ; mirror support. A Multiple-Reflection Optical Lever, H. O. HOADLEY. Rev Sci Instrum v20 Jan 1949 p 30-41. A detailed descrip- tion is given of an optical lever which secures increased sensitivity by means of multiple reflections from a single small mirror. It is of particular use where space is lim- ited, or where the mirror must have minimum size and mass. Its limitations are an inherent restriction of the measurable range, and a comparatively rapid loss of light with increasing number of reflections. A model system was constructed, which demonstrates that no special difficulty is met with in making an optical lever according to these principles up to 7 reflections. Tests made with the fifth-order reflection proved the model to be quite satisfactory. An Apparatus for Measuring Small Changes in Linear Dimensions, D. G. R. BONNELL, A. WATSON. J Sci Instrum v27 Jan 1950 p 10-12. During the study of the effect of freezing on certain building materials, it became necessary to develop an apparatus to measure small linear changes in two dimensions. In the apparatus described, movement of the specimen is magnified by the change in the angle of reflection of a beam of light incident on a system of rotating mirrors. A device is incorporated to translate horizontal movements of the specimen into ver- tical movements on the extensometer. Some Points in the Design of Optical Levers and Amplifi- ers, R. V. JONES. Proc Phys Soc London B v64 June 1951 p 469-82. The design of optical levers with photoelectric amplifiers is examined and sources of instability are traced. Convection currents causing refraction variations are found in some circumstances to affect the light bal- ance in the optical lever ; they may be minimized by prop- erly designed shrouds around the optical path. The better known causes of instability are discussed, and the appro- priate remedies are described. The discussion is extended to the stability of galvanometers. The design of an op- tical lever and amplifier is given which can detect a change of 10" 9 radian in a mirror 5 mm in diameter with an indi- cation time of 1 sec and with a long-term drift of the order of 10~ 8 radian/hour. Deflection Multiplier for Reflecting Galvanometers, T. M. DAUPHINEE. Rev Sci Instrum v26 n9 Sept 1955 p 873-5. A very simple multiple reflection system is described by which the effective sensitivity of a reflecting galvanometer can be increased by a factor of five or more without in- creasing the mirror-to-scale distance. The full width of the galvanometer mirror is used for each reflection, so that with a good quality mirror there is little reduction in the sharpness of the hairline image and only moderate reduc- tion in the brightness of the spot. Use of a 2 m path dis- tance and four or five reflections makes it possible to ex- tend the useful sensitivity of a sensitive galvanometer close to the limit set by Brownian movement. The princi- ple of this amplifying system can be applied directly to most forms of optical lever. On a Light-Pointer Arrangement for Null Instruments, H. HAAS. Optik vl5 n2-3 Feb-Mar 1958 p. 135-7 in Ger- man. The use of a porro-prism permits the light beam re- flected from a mirror to be split into two beams which deflect in opposite directions for a mirror rotation. Thus the null position is shown as the only position for which there is a single beam. Recording Optical Lever, R. V. JONES, J. C. S. RICHARDS. J Sci Instrum v36 n2 Feb 1959 p 90-4. A small optical lever is described which can detect a change of 10" 10 rad in orientation of a 2 mm 2 mirror, with a re- sponse time of about 0.25 sec. A differential cadmium selenide photocell is used with a standard optical grid technique to detect the displacement of the reflected light beam from a 4V, 3.2W lamp. Transistors are used to sta- bilize the lamp current and to amplify the signals for a pen recorder. "Noise" arising from convection currents in the light beam and from the photocells appears not to exceed greatly the photon fluctuations in the light beam. Records illustrate the performance of the lever and ampli- fier in detecting changes in dimension of a crystal of a few times 10" )0 cm and changes in refractive index of a gas by a few times 10"". The system has also been applied to an infrared detector using the linear expansion of a metallic strip, where the limit for a 5 x 0.2 mm strip is about 10" 11 W for a 1 c/s bandwidth. For this purpose the signal can be differentiated with respect to time, and velocities of down to 30^/annum can be observed. It appears that a displacement of 10" 12 cm could be detected. Some Developments and Applications of the Optical Lever, R. V. JONES. J Sci Instrum (GB) v38 n2 Feb 1961 p 37- 45 22 refs. The history of the optical lever is briefly re- viewed from its invention by Peggendorf in 1826 to the recognition by Ising in 1926 of Brownian fluctuations of a galvanometer in the records obtained by Moll and Burger in 1925 with their thermoelectric relay. The design of optical levers and amplifiers by the author and his collab- orators is outlined ; these give sensitivities of the lO -30 ra- dian for a mirror 2.00 mm x 2.0 mm, and an observation bandwidth of 10 c/s. The effects of convection currents and photon fluctuations are indicated. The applications of optical levers to a range of measurements, including Brownian fluctuations, radiation pressure, linear expan- sion and infra-red detection are described. Optical and photoelectric systems similar to those developed for the optical lever can be used for alignment measurement ; ap- plications include refractometry for refractive index changes of order 10"°, and a test of the constancy of the velocity of light in a transverse magnetic field. 140 An Optical Lever Gauge for Local Thickness Measure- ments on Fragile Crystal Plates, W. E. SPEAR, A. R. ADAMS. G. A. HENDERSON. J Sci Instrum (GB) v40 n6 June 1963 p 332. The design and use of a simple and inexpensive gauge is described which is suitable for thick- ness probing on fragile crystal platelets between 1(V and ■500n thick. It employs a miniature optical lever which gives an optical magnification of 10 3 , and the local crystal thickness can be determined to within 0.5/1. Ultraoptimeter IKP-2, V. A. NIKITIN, E. P. SMIRNOVA. Meas Techns 1963 n6 Nov 1963 p 461-3 2 figs. Translated from Izmer Tekh n6 p 6-8 June 1963. A new model of an ultroptimeter IKP-2 was developed in 1961 by the Lenin- grad association of optical-mechanical plants. The instru- ment is intended for contact measurements of external linear dimensions, and uses a relative method by compar- ing the measured article with block gauges, jigs, or sample components. The instrument's optical system is based on the autocollimation principle in combination with repeated reflections. 5.2.5. Pneumatic High-Precision Measurement of Lengths and Thicknesses, M. MENNESSON. CR Acad Sci vl94 Apr 25 1932 p 1459-61. The method consists essentially of a measure- ment of change of pressure in air when flowing through an orifice whose section is a function of the length or thickness to be measured. A supply of air at constant pressure, regulated to within 1 mm of water, flows through a calibrated orifice into a vessel and thence through a second orifice whose size has to be found. The object whose dimensions are required is placed on a movable base whose distance from the second orifice is known. The air pressure between the two orifices is a function of their sectional areas and is measured by a water manometer. The sensitivity can be varied by a suitable choice of the orifice diameters and the initial air pressure. Groupe "Meeanique de Precision et Metrologie." Me- chanique v21 n271 Mar-Apr 1937 p 69-83 ; English review in Engr vl64, n4254 July 23 1937 p 106. Symposium before Societe Francaise des Mecanieiens, as follows : Metrological Instrument of French Make, DUMANOIS ; Pneumatic Amplification, L. WATTEBOT; Application of Solex Micrometer in Industrial Metrology, J. OUTIN ; Application for Measuring Strength of Materials, H. DE LEIRIS ; Application in Study of Metals Cutting, R. BEN- SIMON ; Application in Measurement of Surface Condi- tions, P. NICOLAU. Die praktische Verwendung des Solex-Messverfahrans (Practical application of Solex measuring method), O. XIEBERDING. Werkstattstechnik und Werksleiter v36 n23/24 Dec 1942 p 498-504. Air is used as measuring medium ; testing of small nozzle openings and bores ; early form of Solex plug gage; testing of calipers and external diameters : multiple test apparatus ; testing of pistons. Solution of Instrumentation Problems by Pneumatic Null Balance Method, C. B. MOORE. Instrum vl8 n9 Sept 1945 p 598-603. Principal characteristics of pneumatic null balance method ; description and summary of design factors including nozzle characteristics, effective area of flexible member, and materials of construction ; typical examples of utilization of pneumatic null balance principle in solving instrumentation problems; automatic control. (Reprint with additions available from Moore Products Co.) Nozzle Flow Characteristics in Pneumatic Force-Balance Circuits, D. B. KIRK. Moore Products Co. Outline of an illustrated lecture before Industrial Instruments and Regulators Div., ASME. Pneumatic Gauges, H. NIEPEL. Mech Wld vll9 n3098 May 17 1946 p 545-50. Principles and applications for measuring instruments. Translated from German journal Feinmechanik und Praezision v50 1946 p 255-60. Pneumatic Length Measurement Principles, E. GOTHEL. Archiv fur Tech Messen Issue 152 (Ref. V1121-6) T3 July 1947 in German. The "Solex" pneumatic method of length measurement, invented by Marcel Menneson, gives an accurate indication of small length differences by using gas flow. Constant-pressure compressed air flows through an orifice into a closed chamber and through a second orifice, where it impinges on a surface at distance d. The pressure in the closed chamber then ozd. The incoming air pressure is kept constant by an air-bubble overflow and the chamber pressure is measured by a water ma- mometer. The theoretical air flow relations are deduced. Owing to moisture and orifice-bore roughness these rela- tions are very approximate, and the instrument must be empirically calibrated. Air Jets . . . Their Characteristics for Gaging Devices, R. S. ELBERTY. Mach Design v20 nl Jan 1948 p 111-4. Discussion of air jets used for ultrasensitive gages ; char- acteristics of air jet gaging devices are revealed in tests relating to pressure drop across air jet, sensitivity of pres- sure type air gage, sensitivity of air jet, and zone of greater sensitivity of pressure type air gage; data on pressure regulators and air gage circuits. Evolution de la Metrologie Pneumatique (Evolution of pneumatic measuring apparatus), R. YRIBARREN. Ma- chines et Metaux, v32 n356 Apr 1948 p 123-7. Principles ; self control and quality control ; pneumatic control of micrometers, internal cylindrical gages, "Solex" pneumatic vernier, and vertical scale; illustrations. A New Pneumatic Method for Measuring Small Variations in Length and Some Applications of It. C. G. HARD. IVA, Stockholm, v20 n3 1949 p 107-19 in English. After a brief survey of other pneumatic measuring methods the principle and theory of the Delta system are described. The device consists of two measuring chambers fed with air at constant pressure through an intermediate chamber, the air passing from the intermediate to the measuring chambers and then out into the atmosphere through valves, all mounted on the same spindle, and designed for greatest sensitivity. The relation between the ratio of the chamber to the applied constant pressure, and the spindle position, is shown to be approximately linear. The merits of the system are listed. The Delta meter, a commercial form of instrument, utilizing the Delta sys- tem, and generally used as a comparator, is fully illus- trated and described. Les Lois de la Metrologie Pneumatique (Laws Governing Pneumatic Metrology), R. MOLLE. Rev. Gen de Meca- nique v 34 nl3 Jan 1950 p 26-30. Laws governing pneu- matic metrology and their application to development of new apparatus in laboratories of Faculte Polytechnique de Mons ; principle of Solex apparatus and various other types of pneumatic gages described and illustrated. Versatile Pneumatic Instrument Based on Critical Flow, W. A. WILDHACK. Rev Sci Instrum v21 nl Jan 1950 p 25-30. Principles of instrument for measurement and control of pressure, temperature, flow, humidity, gas com- position, or mechanical displacement : in simplest form, critical flow is maintained through two nozzles in series : variation in flow through first nozzle, occurring with changes of pressure, temperature, etc.. are reflected as change in absolute pressure at entrance to second nozzle. Pneumatic Comparator of High Sensitivity, M. GRA- NEEK, J. C. EVANS. Machy (London) v79 n2016 July 5 1951 p 33-6 ; see also Engr vl92 n49Sl July 13 1951 p 62- 4; Eng vl72 n4470 Sept 28 1951 p 414-5. Comparator, having good speed of response, consists essentially of hol- 141 low double piston which is air tight sliding fit inside cylinder of % in. bore ; calculation of force exerted on surface under measurement; example of use of compara- tor for fine measurement. Maximum Sensitivity in Pneumatic Gauging, N. R. WYNN, N. STOLOW. Letters in J Sci Instrum, v32 n4 p 55 Apr 1955. The first author points out with reference to the paper by the second that the condition for max. sensitivity when a null-point method is used in pneumatic gaging is obtained when H cff = 1 /2H. The second author argues, however, that this is correct for one application of the gauging method but not for the practical operation of his apparatus. Application of Pneumatic Gauging to High Precision Linear Measurement, J. C. EVANS, I. G. MORGAN. J Sci Instrum v33 nlO Oct 1956 p 388-90. Pneumatic system employed in precise measurement of variation in thickness, in each of three principal directions, of nearly perfect cube recently used at National Physical Laboratory ; theoretical basis of method, and details of experimental arrange- ments; advantages of pneumatic gaging techniques for linear measurement. Schlag- und Fluchtungsmessung mit Luftmessgeraten (Twist and alinement measurement with air measuring instruments), O. NIEBERDING. Zeit fur Maschinenbau und Fertigung v90 n3 p 181-3 1957 13 figs 1 ref. Cites 5 advantages of pneumatic measuring apparatus for twist and alignment measurement. Discusses deviation from perpendicularity to axis of the end faces of bores and shafts, alignment of coaxial holes, and alignment of parallel bores. Pneumatische Gerate Zum Messen von Achsabstanden (Pneumatic Instruments for Measurement of Eccentrici- ties), O. NIEBERDING. Werkstattstechnik und Ma- schinenbau v47 nil 1957. Pneumatic Gauging Technique in Its Application to Di- mensional Measurement, J. C. EVANS. Inst Prod Engrs J v36 n2 Feb 1957 p 110-20, 140 ; see also Inspection Engr v21 n3-4 May-June 1957 p 50-54, July-Aug p 79-86. Work described was carried out as part of research pro- gram at National Physical Laboratory dealing only with type of gaging in which displacement or change of size is determined by measuring change of pressure which it is made to produce ; theoretical and practical considera- tions ; calibration and performance ; applications. Eigenschaften pneumatischer Feinmessgerate (Properties of pneumatic precision measuring instruments), O. NIEBERDING. Industrie-Anzeiger n20 Mar 8 1957 3p 11 figs. The problem of establishing finest dimensional dif- ferences with the necessary reliability is better solved with pneumatic measuring equipment than with usual and known means. The article discusses the manner of op- eration of fine pneumatic measuring equipment, air pres- sure requirements, contactless measurement, influence of surface roughness sensitivity against dirty surfaces, ad- vantages of the pneumatic caliper, advantages of the jet in yielding numerical values, distance transmission of meas- urement values, measuring units yielding average values, pneumatic means for amplification, damping. Dynamic Air Gaging Reduces Cycle Time in Precision Measurement, A. H. JOYCE, K. E. RUGG. Gen Motors Eng J v5 n4 Oct-Nov-Dec 1958 p 29-32. In study of dynamic gaging characteristics, analog computer was used to simulate dynamic air gaging; mathematical relation- ship between pressure, time, restrictor size, jet size, circuit volume, and distance established ; diagrams of electronic circuitry and air gaging circuit ; example. Kennzeiehnende Eigenschaften pneumatischer Messgerate (Characteristic Properties of Pneumatic Measuring Equip- ment ) , R. CARL. Four FoKoMa Oct 1959 p B81 Miinchen. In the scope of the investigations of measuring equipment and controls organized by Prof. Eisele this report is a compendium of the extensive theoretical and practical results. Contents : Introduction and systematik ; the feeler ; transducer and indicator ; experimental investiga- tions, conclusions, bibliography. Bauarten und Eigenschaften pneumatischer Messgerate (Types and Properties of Pneumatic Measuring Equip- ment), O. NIEBERDING. Four FoKoMa Oct 1959 Miinchen. p B77 ; Masehinenma'rkt v66 nl9 Mar 4 1960 4 p 10 figs. The author characterizes the types and properties of pneumatic measuring equipment, elaborates the com- mon characteristics, and characterizes the individual peculiarities in their advantages and disadvantages. Electrification of a Pneumatic Micrometer with a Liquid Manometer, B. D. KOSTROV, S. P. IUDIN. Meas Techns 1958 n5 Feb 1960 p 509. Translated from Izmer Tekh n5 Sept-Oct 1958 p 10. The authors have electrified a manometric pneumatic micrometer which used a 1.5% solution of sodium bicarbonate. Owing to the minute currents used and a polarity of connection in which the reducing agent, hydrogen, is produced on the small sur- faces of conductors, the harmful electrolytic action was eliminated. Pneumatic Gauges for In-Pile Measurements, J. PEFHANY. Nuclear Eng (GB) v6 p 77-9 Feb 1961. A description is given for the development of a pneumatic gauge for in-pile measurements of very small movements. Work done suggests that accurate results can be expected at temperatures in excess of 400 °C. Pressure Stabilizers for Pneumatic Instruments Used in Linear Measurements, A. P. KUROCHKIN, F. V. TSI- DULKO. Meas Techns 1961 n8 Feb 1962 p 604-7 3 figs. Translated from Izmer Tekh n8 p 4-7 Aug 1961. The spe- cial work carried out by the Interchangeability Bureau in establishing the relation between the operating pressure error, and hence, the error of measurement, has made it possible to specify the requirements for various measuring systems with respect to pressure stabilizer accuracy. Knowing the actual accuracy characteristics of stabilizers, it has been made possible to specify their ranges. Pneumatic Self-Balancing Systems, A. P. KUROCHKIN, I. YU. OKUN'. Meas Techns 1963 nl Aug 1963 p 14-5 1 fig 3 refs. Translated from Izmer Tekh nl p 10-1 Jan 1963. Describes development of a bridge schematic, namely a self-adjusting balanced pnevimatic bridge, which was successfully utilized in an automatic machine for selecting balls by the differences in the ball bearing races. Errors in Pneumatic Linear-Measurement Systems, A. P. KUROCHKIN, E. L. NOSKIN, F. V. TSIDULKO. Meas Techns 1963 n2 Aug 1963 p 108-11. Translated from Izmer Tekh n2 p 14-6 Feb 1963. The error of a pneu- matic measuring system produced by the instability of the operating pressure H is one of the components of the system's total error. The degree and nature of the effect produced by this error on the readings of the system de- pends on the type of the latter, its parameters, design, etc. The error is conveniently represented as a ratio of the absolute error to the corresponding measurement range expressed in linear or pressure units, provided the measur- ing range does not exceed the linear portion of the characteristic. Les Capteurs Pneumatiques (Pneumatic Pickups), C. RE- NET. Automatisme v8 n9 Sept 1963 p 305-10. Basic structure of measuring instruments using pneumatic servomechanisms is reviewed ; operation of various types of pressure-sensitive elements and pneumatic pickups is 142 described ; relative merits and shortcomings are com- pared. Precision of Pneumatic Instruments for Linear Measure- ments, A. TA. ROSTOVYKH. Meas Techns 1963 n5 Nov 1963 p 376-9 2 figs 4 refs. Translated from Izmer Tekh n5 p 10-2 May 1963. Analyzes and evaluates the factors which affect the precision of measurements made by the "solex" instrument based on a pneumatic method for measuring dimensions, and examines the problem of elim- inating the causes which lower this precision. Principles of Pneumatic Gauging, J. C. EVANS, I. G. MORGAN. NPL Notes on App Sci n34 1964 32 figs 19 refs. Discusses scope of pneumatic method, range of linear measurement, pneumatic sensitivity, overall magni- fication, basis for design, practical considerations, and pneumatic equipment developed at NPL. 5.3. Dials and Pointers See also Subsection 3.6.4 A Set of Proposed Standard Numerals for the Scales of Measuring Instruments, A. P. TROTTER. Inst Elec Engrs J Feb 1 1916. Col. A. Strange's designs and pro- posed changes in interests of simplicity. Pointers of Low Inertia for Measuring Instruments, R. MIELICH. Zeit fur techn Phys vl7 nl 1936 p 27-31. It is shown experimentally that glass is superior to alumi- num as a material for constructing low-inertia pointers for measuring instruments. This is mainly because glass can be drawn down into the form of tubes with extremely thin walls, and a suitable method of performing this op- eration is described. Rigidity in the pointers can be maintained by combining together tubes of different thick- nesses ; at the same time, low moments of inertia are achieved. Designing Instrument Dials for Quick, Accurate Reading, W. F. GRETHER. Machine Design v20 n6 June 1948 p 150-2 208-9. Review of psychological findings which underlie first steps toward design of aircraft or other instruments for maximum ease and accuracy in reading. Based on paper before Soc. Automotive Engrs. Machine Dials and Scales, W. R. GARNER, J. W. GEB- HARD. Machine Design v21 n8 Aug 1949 p 98-105. De- sign of dials to insure quick, accurate reading; dial uses can be classed into three groups ; check, directional, and quantitative readings; factors affecting reading precision and speed of reading as related to dial numbering and markings, kind of pointer, dial grouping, etc. ; other design data. Bibliography. Indicators and Controls, A. CHAPANIS. Machine De- sign v27 n4 Apr 1955 p 212-4. Designing for maximum readability and efficiency. From "Some Applications of Experimental Psychology to Machine Design" in Office of Naval Research, Research Reviews. June 1954. Tensator Spring as Force Transmission System in Instru- mentation, C. PERNETTA. Machy (London) v91 n2344 Oct 18 1957 p 927-31. Results of preliminary survey of possible applications of Tensator constant force spring as force/transmission element in field of instrumentation; dial gage incorporating Tensator springs; use of spring for avoiding hysteresis effects ; Tensator employed in con- junction with metal band ; suggested design for direct reading gage and caliper gage. On a Light-Pointer Arrangement for Null Instruments, H. HAAS. Optik vl5 n2-3 p 135-7 Feb-Mar 1958 in Ger- man. The use of a porro-prism permits the light beam reflected from a mirror to be split into two beams which deflect in opposite directions for a mirror rotation. Thus the null position is shown as the only position for which there is a single beam. Design of Visual Indicators, J. SPENCER. Eng Matls & Design v4 n9-10 Sept 1961 p 572-6, Oct p 672-5. Sept : Design characteristics of indicator dials and scales for general industrial purposes requiring accuracy of plus or minus 1% of maximum scale values ; examples of good and poor design. Oct : Design of qualitative and repre- sentative indicators. Quality and Quantity of Information, K. F. H. MUR- RELL. Soc Instrum Technol Trans vl5 n2 June 1963 p 96-9. Progress review of instrumental displays and design of their use in Great Britain ; it is concluded, from instruments still being manufactured, that not enough thought is yet being given to suitability of instrument to needs of operator. Mechanische Schwingungen erschuetterter Messwerke in Spannbandlagerung. (Mechanical vibrations of taut- suspension instrument movements subjected to shock). F. WEIDENHAMMER. Frequenz vl7 n8 Aug 1963 p 302- 11. Motional equations for low-amplitude vibrations about finite, electrically established deflection of pointer ; 6 degrees of freedom are considered ; equations show that compliance with certain decoupling condition generally yields maximum possible mechanical stabilization of movement ; otherwise, pointer extremity will perform am- plified forced vibrations in plane of indication ; such vi- brations are approximately calculated for almost-satisfied decouping condition. Recommendations for Design of Scales and Indexes. Brit Standards Instn— Brit Stand 1449 pt 1 1964 44 p. Recommendations in this part are intended to be gener- ally applicable to quantitative instruments of bold presentation and designed for rapid reading, intended to be read to resolution of about 1 to 2% of scale range and are particularly concerned with relating scale dimensions to maximum reading distance ; they are only applicable to single scale instruments having dials with full circle, part circle or straight scales as defined. 5.4. Optical Features Optische Hilfsmittel an Messgeraten (Optical Aids to Measuring Apparatus), W. BLOCK. Bebrieb v4 n9 Feb 11 1922 p 285-9 6 figs 2 refs. The object is not to form experiments regarding optical methods of measurement but to form about their convenient application a few con- siderations regarding optical auxiliaries to measuring equipment of each kind and to completely exploit and increase their measuring accuracy. Quelques Points Particuliers de Metrologie (The Setting of Microscope Cross Wires), A. PERARD. Rev Opt v2 Dec 1923 p 506-11. On the Limit of Accuracy in Optical Measurement. A. A. MICHELSON. J Opt Soc Am and Rev Sci Instrum v8 Feb 1924 p 321-8. The limits of accuracy obtainable in observations with the telescope, microscope, interferom- eter, and spectroscope are discussed. Optical Measurement in the Workshop (Optische Messver- fahren in der Werkstatt), C. von HOFE. Praktischer 143 Maschine-Konstrukteur v58 Mar 10, June 16, July 14, and Aug 11 1925 p 187-89, 382-84, 446-^8, and 507-11 14 figs. Discusses methods of optical measuring, especially those used in optical shops, covering spectrometers, measuring thickness and radii. Bibliography. Principles and Advantages of Optical Methods for Meas- uring Machine Parts, H. F. KURTZ. Mech Eng v47 Mid-Nov 1925 p 987-92 16 figs ; Machy v63 Dee 3 1925 p 894 for abstract. Outlines four classes of optical instru- ments namely, interference apparatus, imaging systems, optical scale reading, and optical levers; and describes measuring instruments already designed for machine- measuring purposes. Measurement of Fiber Diameters by Diffraction Method, H. J. McNICHOLAS, H. J. CURTIS. Rev Sci Instrum v2 n5 May 1931 p 263-86 6 figs. New construction of Young's instrument (eriometer) ; critical study of accu- racy and adaptability of instrument in averaging of wide range of diameters as distributed in group of fibers ; sources of error and limitations of method. A Mirror Comparator for Production Inspection, O. P. VAN STEEWEN. Am Mach v75 Sept 10 1931 p 417-8 4 figs. Unit works with combined optical and mechanical magnification. Quantitative Thermo-electric Magnifier for Optical Point- ers, J. H. JEFFREE. London. Edinburgh and Dublin Phil Mag and J Sci vl4 Sept 1932 p 366-72. Simple device for magnifying deflections of optical pointers, giv- ing large magnification which is independent of fluctua- tions in illumination intensity. Neue Erfahrungen mit dem Ultra-Optimeter (Recent ex- perience with ultra-optimeters), C. BUETTNER. Werk- stattstechnik und Werksleiter v29 n4 Feb 15 1935 p 65-6. Usefulness in measurements of high precision ultra-optim- eter made by C. Zeiss, in Jena. Durchmessermessgeraet. fuer lange Bohrungen (Diameter measuring equipment for long bores), Werkzeugmaschine v40 nl6 Aug 31 1936 p 394. Detailed description of equip- ment using optical methods of observation. Ueber eine einfache Anordnung zur parallaxefreien Able- sung von Zeigermessageraeten (New type of mirror ar- rangement free of parallax error in reading of scale indicating instruments), H. BUMAN, G. RITZOW. Zeit fuer Techn Phys vl9 n4 1938 p 97-8. Method of Dimensional Gaging with Photoelectric Cells, C. TUTTLE, W. BORNEMANN. Instrum vl2 n2 Feb 1939 p 67-70. Notes on procedure and equipment ; photo- electric photometry applied to gaging; optical magnifica- tion in photoelectric gage ; accuracy of method. Some Applications of Optics to Engineering, M. H. TAY- LOR. Inst Production Engrs J v20 nil Nov 1941 p 439-65 (discussion) 466-70. Types of measurement to which optics can be usefully applied ; notes on optical measure- ment to which optics can be usefully applied ; notes on optical measurement of lengths, angles, and irregular con- tours ; screw thread projection ; measurement of some irregular shapes which cannot be projected by conven- tional means. Uber die optischen Grundlagen der teehnischen Feinmess- geraete (Optical principles of technical precision measur- ing apparatus), K. RAENTSCH. Werkstatt und Betrieb v74 nil 12 Nov 1941 p 295-9, Dec p 315-22. Nature of light ; law of reflection and refraction ; survey of physio- logical optics : various optical instruments described ; single lens microscope and telescope ; protection devices ; multi-lens microscope and telescope ; photographs and diagrams. A Long Optical Path in a Restricted Space, H. R. DRATZ, J. E. MACK. J Opt Soc Am v32 p 457-64, Aug 1942. An instrument is described for attaining a long optical path by repeated traversal between a concave spherical mirror and a totally reflecting prism. Its properties are outlined and compared with those of other devices for similar purposes. The number of traversals is in principle un- limited but the angular spread of the final beam is less than that of the first traversal. The final image, which is almost free of aberration, is as large and almost as bright as the source. The optics of the instrument is considered in detail. The Measurement of Small Linear Motions by Optical Methods, R. W. G. HUNT. J Sci Instrum v23 p 119-21 June 1946. Two optical methods for measuring small linear motions have been used, and some results obtained thereby are reproduced. The first makes use of two microscope objectives and depends on lenticular magnifi- cation for high sensitivity ; the second uses a concave mirror and two prism systems, high sensitivity being ob- tained by means of prismatic magnification. Engineering Optics, K. J. HABELL, A. COS. Sir Isaac Pittman & Sons, London, 1948 411 p. illus diagrs charts tables, 35s. Critical survey of most important optical methods and instruments applicable to engineering prac- tice ; properties of ideal optical systems and actual systems discussed ; light and illumination, microscopes, telescopes, optical projection and profile microscopes considered. Eng Soc Library, N.Y. Die Optik in der Feinmesstechnik, K. RAENTSCH. Carl Hanser Verlag, Munich, Germany, 1949A.317 p illus diagrs charts tables. Book describes measuring instruments and their optical principles ; fundamentals of technical optics discussed ; various instruments for fine measurements considered. Bibliography. Eng Soc Library, N.Y. Optical Tools for Shop Precision, C. EMERSON. Am Mach v93 n25 Dec 15 1949 p 91-8. Optical flats and their applications ; optical projection discussed including light- ing and lenses, screens and charts, staging and surface projection ; shop microscopes and microscope attachments : collimation, optical systems for boring and grinding ma- chines, and small optical tools described. An Interference Micrometer for Diameter measurement of textile filaments in moisture-controlled atmospheres, P. DENTON. J. Sci Instrum v29 Feb 1952 p 55-7. An instrument is described for determining minute dimen- sional changes on a specimen enclosed in atmospheres of different but pre-determined moisture condition. Local- ized Fizeau fringes, formed by reflection from a pair of aluminized glass plates that correspond to the fixed and movable jaws of a normal micrometer, are used as sensi- tive fiducial indicators for the appropriate setting of a micrometer head. One edge of the movable plate is laid in contact with the specimen and the other rests on a lever, the longer arm of which lies in contact with the microm- eter head. This is adjusted until the fringe formation, which is viewed through the eyepiece of a Fizeau inter- ferometer, indicates parallelism of the aluminized surfaces in a direction set by the line joining the ends of the lever ; specimen thickness is then derived from the lever reduc- tion ratio. Air of standard moisture condition moves past the specimen in a glass cell which is fitted with a flat roof to transmit the light. The instrument applies a small known force on the specimen and is especially appli- cable to measurements on compressible bodies. Data on the variation in diameter of cellulose filament with mois- ture condition are presented to illustrate the performance of the instrument. A New Instrument for Measuring the Thickness of Glass Tube Walls, K. BERNOLAK. Exper Tech der Phys vl n2 1953 p 91-2 in German. A simple optical device is 144 described whereby the direct measurement of the thick- ness of glass tube walls may be made to an accuracy of 0.01 mm ; the latter depends on the regularity of the tube thickness. Ultrasonic Microscope, S. Y. SOKOLOV. Radio & Tele- vision News ( Radio- Electronic Eng) v49 n2 Feb 1953 p 8-9. How obtaining of very short ultrasonic waves of order of wavelength of visible light, has led to develop- ment of microscope with which it is possible to view object in magnified scale, image is seen directly on cathode ray tube screen ; calculations show that magnification ap- proaches order of tens of thousands of times ; design and operating details of various versions. Translated from Russian journal, Progress in Phys Sci v40 Jan 1950. Design of Graticules and Reference Marks, and Some Factors in Operation of Scientific Instruments, R. T. LES- LIE, L. D. ARMSTRONG. Austral J App Sci v6 n2 June 1955 p 167-82. Experimental study of factors affecting accuracy of combinations of graticules with reference marks, effects of line thickness, separation of fixed line pairs, angle between crossed transverse lines, width of light gap between central and outer elements, illumination, ambient temperature and other factors. A Large Optical Slit Mechanism Employing Spring Move- ments, R. V. JONES. J Sci Instrum v33 n5 May 1956 p 169-73. A spring layout is described for producing symmetrical movement in an optical slit 10 cm long, and capable of operating at any width between 5 and 1000/i. Such factors as the parallelism and separation of the jaws are made independent of gravity by suitable arrangement of spring strength and disposition of centres of gravity of the moving members. The jaw edges are optically worked to confine width variations along the slit to about ±0.15/* r.m.s., and the jaws can be set parallel by eye and hand to within about 0.3/x variation in the 10 cm length. Measurement of Small Displacements of a Plane Surface with a Semi- Virtual Slit Modulator, P. BARRET. J Phys Radium vl7 n6 June 1956 p 29 S in French. This method is suitable for measuring the displacement of a polished or plated surface. A metal plate, such as a razor blade, is mounted parallel to and about 0.01 mm away from the surface. Observation of the slit at grazing incidence shows a real and a virtual (reflected) edge. Variations in the magnitude of this "sem-virtual slit" are used to modulate a beam of light falling on a photocell for record- ing static or dynamic displacements of the surface. Optical Probe for Accurately Measuring Displacements of Reflecting Surface, K. W. T. ELLIOTT, D. C. WILSON. J Sci Instrum v34 n9 Sept 1957 p 349-52. Displacement of plane reflecting surface along its normal can be accu- rately measured by probe without making mechanical con- tact with it ; successive settings of probe relative to fixed surface indicate that standard deviation of single setting of probe is about 0.4/x(1.6X10~ 5 in.) when probe is used with calibrated line standard, displacements may be meas- ured with standard deviation of 0.7/*(2.8X10~ 5 in.). Precision Measurements on the Z-Axis of a Microscope, D. HEUGHEBAERT, J. HEUGHEBAERT. "Particle Photography" Conf, Montreal, 1958 in French. A con- siderable increase in the accuracy of measurements in the vertical plane is obtained if the relative distance between the objective and the eyepiece is made variable, the dis- tance between the objective and the plate remaining un- changed. A device based on this principle is described, its use and the attainable accuracy are illustrated for a number of cases. Considerations Regarding Possible Use of Some Optical Elements, N. BARANY. Periodica Polytechnica — Elec Eng v3 n3 1959 p 183-96. Review of known adjusting de- vices for optical and precision instruments with examples of unduly neglected control mechanisms ; mechanical con- structions in military instruments adaptable to civilian uses. A Recording Scanning Micrometer, V. R. REGEL', V. G. GOVORKOV. Pribory i Tekh Eksper (USSR) 1959 n4 p 133-6 July-Aug in Russian. This displacement microm- eter is based on the photoelectric measurement of a lumi- nous flux which passes through a system of two rasters moving with respect to each other. A laboratory model of the instrument permitted the measurement of displace- ments of up to 10 mm with an accuracy of 0.1/j.. [English translation in: Instrum Exper Tech (USA) n4 p 654-7 July-Aug 1959; publ. June I960.] Beriihrungloses Messen grosserer Aussen-und Innendurch- messer (Contactless Measurements of Large External and Internal Diameters), K. RAXTSCH, E. LEPPER. 4 FoKoMa Munich Oct 6-7 1959. Contactless measurement is an acute problem of the progressive finishing technique to the metrologist. This problem is solved electrically, pneumatically, and optically. The explanations of this paper are concerned only with optical contactless measure- ments, especially for external and internal diameters. Next the demands placed on new equipment are set forth for large measurements. An especially remarkable such measuring equipment is the flawless, contactless, indica- tion response of the cylinder surface. For this the field of surface indication is especially treated. Optical indica- tors of known and of newer kinds are systematically ar- ranged and closely elucidated. Two principal groups of indication responses are thus developed. These chief groups are further classified. Thereby the application possibilities of the single indicators may be recognized. From this knowledge conclusions are derived for practical application in metrology. The already obtained experi- mental information presents a prospect of future flawless measuring methods. An Image-Splitting Microscope for Accurate Measurement, J. DYSON. Nature (London) vl84 Nov 14 1959 p 1561. Dsecribes how, by fitting in the eyepiece a suitable image splitting device, the two images may be sheared across each other until edge-to-edge contact is obtained. By reversing the shear until edge-to-edge contact is again ob- tained, the diameter of the object may be measured. The technique is illustrated by application to blood corpuscles. Adjusting Your Point of View, J. R. SULLY. Eng Matls & Design v3 nl Jan 1960 p 13. Description and diagram of optical instrument developed to eliminate distortion often found when viewing small-scale models with naked eye; instrument can be used for models of various scales by adjusting distance between reflectors or prisms. Precise Measurement of Small Objects, J. DYSON. AIE Eng (formerly AEI Eng Rev) vl nl Jan 1961 p 13-17; Machy (London) v92 n2520 Mar 1 1961 p 503-8; Quality Engr v25 n2 Mar- Apr 1961 p 41-5. Optical principle of and apparatus associated with new method based on application to microscope of "image splitting principle" : method enables measurements to be made with precision about 10 times better than resolving power of microscope allows, and is particularly suitable for rapid and precise measurements of repetitive nature, such as are required in inspection department. Device for Adjusting Universal and Measuring Micro- scopes. N. K. KRASNOPEROV. Meas Techns 1961 nl Sept 1961 p 21-2 2 figs 1 ref. Translated from Izmer Tekh 1961 nl p 15-6 Jan 1961. A device was made for eliminat- ing the displacement of the optical axis of a type UIM-21 and BMI microscope tube with respect to the axis of rota- tion of the supporting column. 145 Development and Application of Fiber Optics Techniques to Precision Measuring Devices, Transducers and Auto- matic Transducers and Automatic Control Systems, E. D. GRIM. Electronic Components Conferenee-Proc 1962 p 137-10. Application of techniques using fine filament of glass of circular cross section and high index of refraction surrounded by thin jacket of lower index glass as basic element in design of transducers, distance and angle meas- uring devices, automatic position control systems, card and tape readers, light operated relays, function gener- ators, and other similar devices. Quality and Quantity of Information, K. F. H. MUR- RELL. Soc Instrum Technol Trans vl5 n2 June 1963 p 96-9. Progress review of instrumental displays and design of their use in Great Britain ; it is concluded, from instruments still being manufactured, that not enough thought is yet being given to suitability of instrument to needs of operator. Optimum Operating Conditions for Scanning Devices in Photoelectric Recording, M. G. MIKHAILOVA. Meas Techns 1963 nl Aug 1963 p 22-5 4 figs 6 refs. Translated from Izmer Tekh nl p 16-8 Jan 1963. Scanning photo- transducers are widely used in systems requiring precise focusing on a graduation. Scanned phototransducers with a small scanning amplitude can be used under the same conditions as similar transducers based on the meas- urement of the duration of adjacent pulses, since the parameters of the former do not depend in a zero measur- ing method on the amplitude of vibrations or the width of the graduation image. Modern Optics in Machine Tool Technique. Firm of Dr. Johannes Heidenhain, Traunreut. Mar 1964 46 p 36 figs. Discusses advantages of optical measuring methods, fun- damental terms in metrology, and principles of measuring system employing transverse step vernier chart. Pre- sents a survey of standard instruments. 5.5. Pivots Instruments Pivoting, C. E. FOSTER. Wld Power vl4 Aug 1930 p 116-9 6 figs. To grasp nature of problems which face manufacturer of electrical instruments, it is necessary to study conditions under which pivoting sys- tem works ; each modification or extension of existing standard specifications is in direction of greater sensitiv- ity, smaller forces, and higher accuracy. Important Points on Pivot Bearing Design, P. H. WHITE. Machy (N.Y.) v37 n6 Feb 1931 p 450 1 fig. Application and care of pivot and center bearing ; construction details. New Method of Pivoting on Instruments, A. J. LUSH. Instrum v4 n2 Feb 21 1931 p 106-8 4 figs. Position of pivots within their jeweled bearings is of vital impor- tance ; any other position taken up by movement than that in which it was calibrated will very obviously affect con- stancy of calibration. Die Drehzapfen-Aufstellung (Pivot Mounting), K. LUE- DEMANN. Zeit fuer InstrumKde v51 n9 Sept 1931 p 449-63 10 figs. Historical review ; test results on meas- urement of small-size pivots ; avoidance of centralizing error was so complete that remaining error could be dis- regarded ; results of various measurements given in tables. Bibliography. Friction of Pivots and Journals. Machy (London) v39 n995 Oct 29 1931 p 142-4 7 figs. Mathematical investiga- tion of conditions obtaining in flat, conical, truncated conical, hemispherical and Schiele pivots and journals. Static and Clinging Friction of Pivot Bearings, M. C. HUNTER. Proc Inst Meeh Engrs London vl51 n3 1944 p 274-84 ; Abstract in Eng vl57 p 117-20, Feb 11 and p 138-40, Feb. 18, 1944. Describes special apparatus used in the investigation carried out to determine the static fric- tion of various combinations of metals, including stainless steel and duralumin, under several conditions of dry and viscous lubrication. The paper gives data showing the rapid growth of the coefficient of friction during the first 24 hr at rest, and the subsequent increases over a period of 5 days. A series of long-term tests of 30, 60, and 90 days, on a selected number of specimens, provides a direct comparison from which the relative merits of the various combinations of materials is drawn. Evidence is provided suggesting advantages to be derived from the use of graph- ite as a preventive of clinging friction. Apparatus for Measuring Static Frictional Torques of Instrument Jewels, W. H. PEARSE. J Sci Instrum v25 nlO Oct 1948 p 344-6. Device which can be used to ob- tain measure of surface quality of synthetic sapphire "V" jewels and hence enable their performance as jewel bear- ings for precision indicating instruments to be expressed quantitatively ; pivoted element rests on jewel to be ex- amined and is deflected by air jet, flow of which is grad- ually reduced and element allowed to return to position of equilibrium ; results of tests given. Physical Basis of Mechanical Factors of Merit in Pivoted Measuring Instruments, L. MERZ. Archiv tech Messen Issue nl6 (Ref. J011-2) T3-T4 Jan 1950 in German. The Keinath mechanical factor of merit, given by F m =10 (torque for 90° defection) /(weight of moving system) 16 , is discussed. The view that this factor of merit is em- pirical is concluded to be unjustified, and that the index 1.5 has a real physical basis. Design and Manufacture of Jewels and Pivots for Instru- ments and Meters, G. F. TAGG, E. A. HOWELL. Soc Instrum Technol Trans. v3 n3 Sept 1951 p 124-33. Pivots and jewels employed in indicating instruments and meters are subject to considerable stress in normal usage, during transport, etc. ; theoretical considerations necessary in de- sign of bearings to give satisfactory performance under static and impact conditions; design nomograms for de- termining whether safe operating conditions prevail. Gas Bearings in Precision Instruments, G. B. SPEEN. Electromechanical Components & Systems Design v8 n4 Apr 1964 p 40-3. Use of gas bearings in instruments, such as gyroscopes, accelerometers, gimbal bearings of inertial platforms, space simulators, and test tables, is dis- cussed, along with methods of avoiding their improper application. 5.6. Slides, Stands, and Tables Micrometer Leveling Table. J. H. DOWELL. J Sci Instrum v9 July 1932 p 234-6. Levelling table designed to give precise adjustment in three directions. Particularly valuable for interferometers. The construction is robust and its geometrical design ensures that wear is taken up autohiatieally. Standard Dimensions of Bail-Bearing Slide Races and De- rived Kinematic Constraints, A. F. C. POLLARD. J Sci Instrum vll n6 June 1934 p 173-83. Construction and di- mensions for ball-bearing slide races suitable for slides with single degree of freedom as well as for certain bear- ings of spherical contacting elements peculiar to kine- 146 matic design, are discussed ; table of dimensions for use of designers, in inches and millimetres included. Precision 60° V-Block, A. N. APPLEBY. Machy (Lon- don) v66 nl706 June 21 1945 p 675. Author presents sev- eral additional uses for V-block applications ; providing block is made with 60° included angle and distance from apex formed by angular sides to base of block is known, precision measurements can be obtained by aid of height gage, clock indicator or any two point measuring instru- ment ; exemplary application is denned. Ball Bearing Slides, C. JOBST. ASME Advance Paper n47 A-42 for meeting Dec 1-5 1947 6 p 2 supp sheets. Ex- amples of progress made in reducing friction in sliding movements of machinery to minimum with addition of pre- loading of slide mechanism so that higher operating speeds, greater precision of product and longer life at lower cost are possible ; preloading produces high stability in slide because operating loads merely modify total load, either increasing or decreasing it, in contrast with con- ventional slides in which live load changes from no load to full load. Stander mit Tisch fiir Messgerate ( Stand with Table for Measuring Instruments). DIN 2223 Oct 1949 1 p, avail- able from ASA. Gives post diameters and lengths of sup- port arms for various ranges. Surface Plates, Sizes, Dimensions, and Requirements. DIN 876 June 1950 2 p, German Standard available from ASA. Cast iron surface plates, design and bearing area requirements. The Sliding Surface, G. I. FINGH. Proc Phys Soc London B v63 p 465-83 July also ibid A v63 Aug 1950 p 785-803. The 34th Guthrie Lecture delivered to the Physical So- ciety. A review of the existing state of knowledge of what actually takes place when one solid surface slides over another, with or without intervening lubricant, a critical survey of past and current ideas, and an account of the author's own work and that of his school on the subject : Particular attention is paid to the role of the oxide layer on the surfaces and to the lubricant as a carrier of oxidant to the high temperature regions of solid-to-solid contact. Nine Types of Ball Slides for Linear Motion. Prod Ehg v21 n9 Sept 1950 p 128-9. Diagrams show construction details of antifriction devices used for precision, straight line motion. Three-dimensional Surface-table. Machy (London) v78 n2000 Mar 15 1951 p 438-9. Surface table developed by Fairey Aviation Co., Ltd. of Hayes Middlesex, permits measurement in three dimensions ; guide rails attached to two adjacent edges of table serve as means of supporting vertical members ; great accuracy of table noted ; details of equipment and its use. Get More From Your Surface Plates, J. HYLER. Iron Age vl73 n5 Feb 4 1954 p 156-8. Requirements of cast iron and granite surface plates employed for inspection and checking operations; selection and use of surface plate ; their value for gaging, checking, and especially for layout work on small lots of parts where tooling is not economically practical. Wear of Cast Iron Machine Tool Slides, Shears and Guide- ways, H. T. ANGUS, D. MARLES, M. H. HILLMAN. Brit Cast Iron Res Assn J Res and Development v6 n3 Dec 1955 p 72-82, 4 plates, 3-page chart, Appendix 83-135. Survey of slides of 30 machine tools, still in operation at time of examination ; severity of wear indicated by grad- ings good, fair, poor and very bad; influence of micro- structure and phosphorus content on wear particularly considered ; case history of each examination, including operating details, analysis, hardness, etc. The Influence of Elastic Deformation Upon the Motion of a Ball Rolling Between Two Surfaces, K. L. JOHNSON. Proc Inst Mech Engrs (GB) vl73 n34 1959 p 795-810. When a ball rolls between two surfaces, in general, a tan- gential contact force and a relative angular velocity of spin are present at each point of contact. Both these actions give rise to tangential frictional tractions trans- mitted across the contact surface which are shown to result in a velocity of creep of the ball in a direction per- pendicular to the nominal rolling path. The magnitude of the creep velocity depends critically upon the magni- tudes of the tangential force and the velocity of spin. If these actions are small there is negligible slip between the contacting surfaces and the creep motion is predominantly a function of the elastic properties of the materials. At larger spin velocities slip extends over a greater propor- tion of the contact area and the creep is influenced by the frictional properties of the surfaces. Creep measurements were made over a wide range of conditions of rolling. The results are reduced to non-dimensional form, in terms of two parameters expressing the effect of tangential forces and spin respectively. The resistance to rolling was meas- ured and is shown to control the axis about which the ball rolls. The detailed mechanism of the rolling process is discussed. Cantilever Indicator Stand for Precision Inspection, D. C. K. .PEARCE, F. R. TOLMON. Machy (London) v95 n2452 Nov 11 1959 p 1002-4. New stand developed by National Physical Laboratory is very much simpler than previous designs and therefore less expensive to manu- facture ; very fine adjustment can be obtained by bending vertical column through medium of cantilever and fine screw ; data showing sensitivity of adjustment provided by indicator stand ; specially devised steel band clamp for holding indicator. Anti-Distortion Mountings for Instruments and Appara- tus, R. V. JONES. J Sci Instrum ( GB ) v38 nlO Oct 1961 p 408-9. Some principles for the mounting of instrument platforms are discussed. For many optical and mechan- ical instruments, the working platform may best be pro- tected from external mechanical distortion by supporting or suspending the platform by members, usually three, whose stiffness is much less than that of the platform. At the same time, these members can be stiff enough to give a fairly rigid location. Some possible arrangements are outlined. The Design of Air Bearings and their Application to Measuring Instruments and Machine Tools, H. L. WUNSCH, NPL. Int J Mach Tool Design and Res vl n3 Nov 1961 p 198-212 14 figs 6 refs. Contents: Introduc- tion ; general principles ; design data for flat air bearings operating under steady load conditions ; same under alter- nating load conditions; application of pressurized air bearings for machine tool slideways, automatic lead screw measuring bench, pneumatic roundness measuring instru- ment, etc. Method for Slideway Error-Compensation on Measuring Instruments and Machine Tools, C. HOFFROGGE. Micro- tecnic vl5 n6 Dec 1961 p 247-50. Slideway errors may be compensated with respect to guided element by using simple lever system arranged between that element and .slideways, system of levers being controlled by means of compensation guidebar or rail ; this makes it possible to reduce angular errors of graduated scale carrying table of longitudinal comparator 4.50 m in length from 3.5 to 0.3 sec of arc. Amelioration des Surfaces Planes de Glissement et Par- ticulierement des Glissieres de Machines Outils par Differ- ents Procedes. et Notamment, par Trempe Haute Fre- quence et par Sulfinusation (Improvement of plane sliding surfaces, and of machine tool slides in particular, by vari- ous processes, especially by HF hardening and by Sulfinuz 147 process), Y. DE VILLEMEUR. Rev Universelle des Mines vl8 nl Jan 1962 p 102-9. Selection of materials for slides and their hardening treatment considered. Raschet napravlyayuschikh kacheniya iiprichiny vykhoda ikh iz stroya, Z. M. LEVINA. Stanki i Instrum n6 June 1962 p 8-12; see also English translation in Machines & Tooling v33 n6 1962 p 10-15. Anti-friction slideway cal- culations and causes of failure; as result of experiments and analysis of influence of manufacturing errors on mag- nitude of pressure, engineering calculation method has been derived based on contact stresses ; calculations make it possible to determine optimum slideway dimensions and materials ; roller slideways can bear considerably greater loads than ball bearing slideways, their load bearing ca- pacity being approximately 10 times greater. How to Stop "Stick-Slip" on Ways, H. E. TIFFANY. Am Mach/Metalworking Mfg vl07 n4 Feb 18 1963 p 102-3. Difficulty of detecting and preventing stop-start motion of table as it slides along machine ways is noted ; why table sticks and slips as it slides along ways ; special lubri- cants can help to make it easier to start table ; how to select right lubricant. A Rotator to Study the Dimensions of Non-Circular Fila- ments, J. D. COLLINS. J Sci Instrum GB v40 n4 Apr 1963 p 198-9. An instrument is described which en- ables a fiber or filament to be rotated under a micro- scope so that the fiber profile diameter at any angle may be measured. In particular, for elliptically shaped fibers such as wool, the major and minor axes and the angles at which they occur may be observed. The instrument uses a dial gage, which measures in 6.0005 in. intervals up to 1 in., and this enables accurate longitudinal move- ments of the fiber to be made. By the use of an adjust- able stop accurate movements may be made along the whole length of fibers up to six inches long. Cross- sectional area variations and ellipticity along the whole fiber length can thus be measured. Further, the mecha- nism enables the fibers to be extended by a known amount so that dimensional changes may be studied. The in- strument was designed to be used with a projection micro- scope specially made for wool fiber diameter measure- ments. Universal Measuring Block, R. D. PURVIS. Machy (Lond) nl03 n2662 Nov 20 1963 p 1154-7. Equipment de- scribed, meeting requirements of accuracy and also those of full utilization of instrument, consists basically of block of close grained cast iron which has accurately machined central vees and locating pads on base, sides and ends ; these pads allow block to be set in any of 5 positions while maintaining squareness, parallelism and symmetry with central vees to high degree of accuracy ; applica- tions indicated; equipment was found to be extremely useful for toolroom and experimental machine shop applications. 5.7. Springs and Suspensions Reed Gages Guarantee Close Tolerance Under Shop Con- ditions, C. F. DREYER. Factory and Indus Mgmt v80 n4 Oct 1930 p 722-4 10 figs. Improvement in indicator gage which will permit its use in control of product toler- ances defined in ten-thousandths of inch ; limitations of fixed gages and of usual forms of indicators ; construction of fixed gages and of improved indicator gage ; advantages shown in number of successful applications. Flexure Pivots to Replace Knife Edges and Ball Bearings, F. S. EASTMAN. Univ Wash Eng Experiment Station— Bui n86 Nov 1935 47 p. Derivation of equations for simple flexure pivot without fixed center of rotation, flexure pivots with fixed centers of rotation, self-compensating flexure pivot ; miscellaneous uses for flexure-pivot. Equations. Instrument Springs, J. W. ROCKEFELLER, JR. Wire and Wire Prod vll Nov 1936 p 631-9. Considerations important in design and manufacture discussed, together with relative merits of extension under axial load, me- chanical hysteresis, creep under load, temperature effect on modulus of elasticity ; Elinvar and related nickel- chromium steels, and approved methods of manufacture. Bibliography. Measuring Elastic Drift, R. W. CARSON. ASTM Pre- print nl07 meeting June 28-July 2 1937 10 p. Recording electronic micrometer, sensitive to deviations as small as millionth of inch, developed to measure deflections of spring members of precision instruments without disturb- ing load deflection ; test strip specimens and actual elastic elements used in instruments. Bibliography. Ueber die elastische Naehwirkung (Theory of Elastic After action), SCHOLETZER. Zeit fuer InstrumKde v57 n9 Sept 1937 p 371-78. Theory of elastic after-action of instrument spring; mathematical and graphical analysis. Utilizing Flat Spring in Accurate Mechanisms, A. M. WAHL. Machine Design vll nil Nov 1939 p 40-2. In- dicative of versatility of flat springs are some unusual applications to two recently designed extensometers ; both utilize flat strips of spring steel to serve dual purpose of guides to obtain straight line motion and as means of exerting definite pressure on contact points. Federgelenke im Messgeraetebau (Spring Suspensions in Measuring Instruments), H. STABE. VDI Zeit v83 n45 Nov 11 1939 p 1189-96. Most important of numerous sus- pension systems discussed and illustrated ; necessity for elimination of f rictional defects pointed out. Instrument Springs Control Performance, P. MacGAHAN. Elec Mfg v34 n4 Oct 1944 p 99-102, 174, 176. Compared to springs in other mechanisms or even in watches, springs used in instruments may be very weak ; their strength is measured in "mili-metergrams" of force required to pro- duce certain angular deflection ; measuring strength of springs ; proper mounting of springs. Bandaufhaengung fuer den beweglichen Teil bei Messge- raeten (Suspensions for moving parts of measuring instru- ments), J. BUBERT. Archiv fuer Tech Messen nl52 Oct 1947 p T29 2 p. Considerations concerning bearing fric- tion ; fiber suspensions in electric and other measuring devices ; simple and fixed suspensions. Aufhaengebaender (Suspensions), J. BUBERT. Archiv fuer Tech Messen nl52 Oct 1947 p T30 (4 p). Suspension fiber materials ; applicability in galvanometers and like devices, of phosphor bronze, silver, gold and copper as well as silk or quartz fibers and steel wires ; torsional and other characteristics of fibers as related to cross sectional shape. Theorv of Symmetrical Crossed Flexure Pivots, W. H. WITTRICK. Austral J Sci Res Ser A vl n2 June 1948 p 121-34 1 supp plate. Use of pivots in scientific instru- ments in place of knife edge bearings ; general theory of symmetrical crossed flexure pivots under any combination of vertical and horizontal loads is given ; theory used to derive set of curves presenting all information necessary for design of such pivots. Parallel and rectilinear spring movements, R. V. JONES. J Sci Instrum v28 Feb 1951 p 38-41. Discusses the design 148 of instrument movement in which the moving member is held by two equal and parallel leaf springs ; the member can be moved parallel to itself by pushing it normally to the springs. In a constructed specimen the parallelism was maintained to within ±3.5 sec of arc over 6 mm of travel by a simple method of balancing the springs. Ar- rangements are described for combining two or more spring systems to develop a rectilinear movement. Per- formances are quoted for three constructions, the best of which held a straight line within about ±0.25/i over 5 mm of travel, and ±lju over 10 mm. In some applications spring movements are superior to kinematic slides. Suspension Strip, P. CHRISTOPH. Arch fur Tech Messen Issue nl82 (Ref J013-5) Mar 1951 p T34 in Ger- man. Suspensions for comparatively heavy weights (e.g. gyros, torsion balances, torsional pendulums for clocks) are considered. Formulae are given for: (1) torsion moment for given dimensions of suspension, suspended weight, torsion angle, and constants of suspension mate- rial; (2) width/thickness ratio of suspension to give minimum torsion moment for given cross-sectional area ; (3) ratio of torsion moments of round wire and rectangu- lar suspension of optimum width/thickness ratio, of same cross-sectional area and material; (4) time of swing as function of weight and amplitude. Instrument Springs and Spring Instruments, J. W. ROCKEFELLER, JR. Wire and Wire Prod v26 n9 Sept 1951 p 764-5, 802-7. Properties required in springs to make them suitable for precision instruments ; principle of spring as measurement of force; attitude of Weights and Measures departments toward tolerances; Elinvar wire ; instrument spring ; improvement in scale springs : three charts showing errors in otherwise perfect 3-revolu- tion circular dial in scale, and effects of these errors. Design Characteristics of Cross-Spring Pivots, L. W. NICKOLS, H. L. WUNSCH. Eug vl72 n4472 Oct 12 1951 p 473-6 ; Engr vl92 n4994 Oct 12 1951 p 458-61 ; Machy (London) v 79 n2030 Oct 11 1951 p 645-51. Investigation to provide information of use to designers wishing to in- corporate cross spring pivots in their instruments; sizes were kept within range usually employed for this purpose ; work relates to type of cross spring pivot most commonly used, in which cross strips intersect at 90° at midpoint of their functional lengths to 90° symmetrical cross spring pivot ; illustrations, graphs. Alignment by Suspension on Elastic Strip, J. E. C. PLAINEVAUX. Note in Nuovo Cimento vlO Oct 1953 p 1451-60 in French. After a brief review of systems used for the near rectilinear alignment of a suspended part on elastic strips, a method is described for calculating these suspensions where the strips operate in flexure along the whole of their length. The method takes account of the large deformation of the strip and enables the parasitic movement perpendicular to the principal movement to be determined. A New Method for the Measurement of Small Changes in Length, D. KUHLMANN-WILSDORF. Z Augew Phys v6 n 4 1954 p 17L-1 in German. The instrument described consists of a horizontal roller which is divided into two parts of different radii and which is supported by two ver- tical bands. The upper band is fastened at one end to the part of smaller radius and the lower band to the other part. The other ends of the bands are fastened to the two points between which the changes in length are to be measured. The rotation of the roller is measured by means of a mirror attached to the roller. Details of suit- able properties and materials for the bands, the types of measurement and of the practical application, range of use and sensitivity of the instrument are given. Flexure Devices, P. J. GEARY. Brit Sci Instrum Res Assn 1954 44 p. Literature survey and bibliography. Dis- cusses means of : supporting movable members, control influencing scale shape, indicating recording, and influenc- ing sensitivity. Angle-Spring Hinges, R. V. JONES. J Sci Instrum v32 n9 Sept 1955 p 336-8. Features of hinges whose design is based on each of twisting L-section cantilever beam about its corner edge ; simplest form is easier to make and is more compact than cross strip hinge ; limitations of angle spring are described and various designs of simply com- pensated hinges indicated ; such hinges can be useful com- ponents in instrument design, being free from friction and backlash. Application of Spring Strips to Instrument Design. Notes Appl. Sci NPL nl5 1956 25 p 22 figs 4 refs. This booklet provides designers with information about some of the various applications for providing pivoting and parallel motion, conversion of linear to angular motion. The uses of buckling and twisting strips are described, and indi- cating mechanisms based on them. Miscellaneous uses include support of counterweights, protection of precision scales, biasing springs, and locking a carriage to a slide. Methods of attachment of spring strips are also described. Zur Berechnung von Torsionsbaendern und Torsions- sponnbaendern im Feingeraetebau, (Calculation of torsion suspension bars and prestressed torsion bars in precision apparatus), S. HILDEBRAND. Dresden. Tech Hoch- schule-Wiss Zeit v6 n4 1956-7 p 749-56. Calculation for rectangular cross sections according to L. Bubert-A. Foeppl formulas, and C. Weber method ; comparison of these methods. Some Parasitic Deflections in Parallel Spring Move- ments, R. V. JONES, I. R. YOUNG. J Sci Instrum v33 nl Jan 1956 p 11-15. Some parasitic departures from parallel and rectilinear movement in simple and compound assem- blies are analyzed. The following factors are considered : accuracy of construction, geometrical proportion, spring variations, spring distortion, platform bending, clamp dis- tortion, and gravity effects. It is shown that the "ideal" height at which to drive a parallel spring element is at half the spring height, and it is concluded that while spring tolerances are surprisingly "easy" care must be taken with the platforms and clamps if the highest per- formances are to be achieved. In compound movements, the possibility of "slaving" the intermediate platform, sug- gested by Plainevaux has been tested in practice with good results. Fundamental Behavior of Sensitive Springs, R. TOMAS- CHEK. J Sci Instrum v33 n2 Feb 1956 p 78-81. It is shown that by extending a flat spiral spring by a force acting at one of its ends perpendicular or at an angle to its original winding plane, shapes of a special form, called serpent springs, can be obtained. Though capable of sup- porting relatively heavy loads, these springs respond under certain conditions to small changes in the loads by con- siderable lengthening and twisting. The conditions for obtaining such springs of high sensitivity and their funda- mental behavior are described. Pitching Movement of an Elementary Suspension on Elas- tic Strips, J. E. PLAINEVAUX. Nuovo Cimento serlO v4 n5 Nov 1956 p 1133-11 in French. A horizontal plate mounted on two identical vertical elastic strips, rigidly fixed to its ends and clamped vertically at their lower extremities, tilts whenever it is moved laterally, through a small angle of the second order in the horizontal dis- placement, unless the loading of the plate is symmetrical. If such pitching is to be reduced to a minimiun, there is an optimum position for the line of action of the horizontal displacing force, which is approximately midway between the plate and the fixed ends of the strips. But the appli- cation of the force in the plane of the plate may be 149 preferable, for this makes the system less sensitive to vibrations and involves only a third-order error in the orientation of the plate. Elastic Aftereffect in Bronze Suspensions of Electrical Measuring Instruments, A. A. TIMOFEEVA. Meas Techns 1958 n3 May-June 1958 p 342-6 6 figs. Translated from Izmer Tekh n3 Nov 1959 p 73. Investigation estab- lishing certain regularities in behavior of suspensions, which provide possibility of determining stresses arising in them and expected deviation from their return to zero, with error permissible in preliminary instrument calcula- tions. Statics and Dynamics of a Helical Spring, R. GEBALLE. Am J Phys v26 no May 1958 p 287-90. The theory of the extension and twisting of a helical spring was given in a recent paper by Krebs and Weidlich. This theory is re- viewed and its applicability as an experiment in advanced mechanics is described. From measurements of extension and twisting under static load, and also from simple observation of the coupled oscillations of these degrees of freedom, it is possible to calculate Poisson's ratio and the shear modulus. The two independent procedures give consistent results. The experiment provides an excellent demonstration of the geometry and elastic deformation of a helix, its static equilibrium and its coupled oscillations. Improved Magnetic Suspension System, C. G. McIL- WRAITH, J. B. BREAZEALE, E. N. DACUS. Rev Sci Instrum v29 nil Nov 1958 p 1029-33. Magnetic suspen- sion apparatus which supports ferromagnetic object free from contact with its surroundings and which is capable of maintaining this support for any attitude or orientation in space of apparatus as whole; applications as friction- less bearing and as force balance in various instruments, such as accelerometer, analog double integrator, differen- tial pressure detector, long period pendulum, and fluid density instruments. Torsion Devices, P. J. GEARY. J Electronics and Control v5 n5 Nov 1958 p 483-96. Elastic connections are being used increasingly in measuring instruments for suspend- ing or guiding moving parts which have to travel back and forth through limited distances or angles ; two types of torsion devices are described ; torsion suspensions and torsion hinges ; suitable types of material indicated and problems in mechanical construction discussed. Dynamik der Spannbandlagerung (Dynamics of strap suspension systems), E. SAMAL. Archiv fuer Tech Messen n277 Feb 1959 p 31-4. Analysis showing advan- tages of such system for protection of measuring instru- ments against shock damage during transportation as well as other undesirable effects of shock and vibration during operation. A Gauge for the Precision Measurement of the Thick- ness of Germanium and Silicon Wafers, D. BAKER. Proc Inst Elec Engrs Paper 2891E [Int Conv on Transistors and Associated Semiconductor Devices], publ. May 1959 3 p. Some of the difficulties associated with the precision measurement of the thickness of thin germanium and sili- con wafers, together with several possible methods of measurement, are briefly discussed. A gauge which em- ploys the optical-lever principle is described in which frac- tional restraint of the moving parts is reduced to that of a knife edge alone, thus ensuring good repeatibility of reading with probe pressures of less than 3 g. The gauge covers the range 0.270 micron with an overall accuracy of ±0.5 micron. Taut-Band Suspensions for 250-Degree Instruments, V. S. THOMANDER, R. C. MACINDOE. AIEE Trans v 79 pt 1 (Communication and Electronics) n44 Sept 1959 p 379-83 (discussion) 383-1. New design of instrument suspension containing moving element suspended by two metal bands under tension which replace conventional spiral springs, jewels, and pivot bearings, design is free from bearing friction, thus eliminating major causes of trouble experienced particularly with electrical measur- ing instruments. Paper 59-159. Torsion Devices, P. J. GEARY. Brit Sci Instrum Res Assn Survey of Instrument Parts n3 1960 142 p. Review of available information on, design, construction and func- tioning of torsion devices as working parts of measuring instruments ; torsion suspensions ; suspension ligaments ; bifllar and trifllar suspensions ; coiled torsion suspensions ; torsion hinges; torsional magnifying devices, 207 refs. Magnetic Suspension for Low Temperature Studies, A. D. SHVETS, V. B. KASHIRIN. Instrum & Exper Techn (English translation of Pribory i Tekhnika Experiments) n6 Nov-Dec 1961 p 1180-2 ; Cryogenics v2 n5 Sept 1962 p 276-8. Arrangement for connecting apparatus for studies both at normal and at low temperatures, to ferro- magnetic part of suspension ; portion at helium tempera- tures is electromagnet coil, control and ferromagnetic core to which vessel with liquid helium is fixed ; whole system is brought into rotation by external rotating mag- netic field ; such apparatus has been used for measuring moment of inertia of rotating liquid helium ; circuit and apparatus diagrams. Taut-Band Suspension Instruments, G. STOLAR, C. B. STEGNER. Instrum & Control Systems v35 n2 Feb 1962 p 134-5. Advantages obtained in using taut band sus- pension, instead of pivot type suspensions, including elimination of friction in movement; suspensions devel- oped by Weston Instruments Div. Daystrom, Inc. espe- cially for a-c and d-c indicating instruments. Instruments without Pivots. Eng vl93 n5005 Mar 23 1962 p 388. Dispensing entirely with jewels, pivots and control springs, instruments are being manufactured by Crompton Parkinson Ltd, in which movement is suspended on ribbon of heat treated beryllium cooper held taut by tension springs mounted on bushes fitted to supporting brackets on movement frame; ribbon may be only 0.005 in. wide by 0.0005 in. thick, with latter held to within 0.00001 in. ; suspension is for ammeters, voltmeters, fre- quency and speed indicators, etc. Why Taut-Band Suspension, J. MEILI. ISA J v9 n4 Apr 1962 p 44-7. Advantages of taut-band suspension, use of which has been made economically feasible by mod- ern manufacturing techniques; eventually, taut-band sus- pension will replace pivotnand-jewel movements in electric instruments. Some Uses of Elasticity in Instrument Design, R. V. JONES. J Sci Instrum (GB) v39 n5 p 193-203 May 1962. The paper presents the text of a discourse delivered at the 1962 Exhibition of The Institute of Physics and The Physical Society, which reviews anti-distortion instru- ment mountings, elastic movements for rotation and trans- lation, movement magnifying and reducing devices, elastic averaging schemes, simple harmonic force and constant force systems, elastic energy stores, and a slow relaxation device for transmitting rapid displacements only. Accuracy of Parallelogram Spring Suspensions, A. S. VALEDINSKII. Meas Techn 1962 n4 Sept 1962 p 284-5 3 figs 1 ref. Translated from Izmer Tekh n4 p 13-4 Apr 1962. Determines the error in displacement in the direc- tion of the indicator tip movement which is placed at an angle /3. Construction and Performance of Various Flexure Hinges, D. M. MARSH. J Sci Instrum v39 nlO Oct 1962 P 493-7. Simple and yet precise clamp for strip hinges which facilitates construction of flexure hinges of fairly 150 general application; merits of single strip hinge, which becomes especially simple to construct by method pro- posed; it is shown that for limited rotations it is often superior in performance to cross strip hinge. Considerations in the Application of Flexural Pivots, H. TROEGER. Automatic Control vl7 n4 Nov 1962 p 41. Sensitivity, accuracy and repeatability are limited primar- ily by pivot friction and backlash where pivoted members are used to transfer or algebraically operate upon forces or displacements. Since many instruments, controls, and measuring devices employ pivoted members the reduction of pivot friction and backlash is consequential to the re- duction of their contributed error. Spannband- and Spitzenlagerung (Strap and point sus- pension), S. GOETZE. Assn Suisse des Electriciens Bui v53 n25 Dec 29 1962 p 1268-73. Relative merits of two types of suspensions for measuring instruments are dis- cussed ; taking into account accuracy, robustness and other characteristics of intruments involved. Guides with Flat Springs for Forward Displacements, YA. M. TSEITLIN. Meas Techns 1963 n9 Feb 1964 p 732-6 2 figs 11 refs. Translated from Izmer Tekh n9 p 11-5 Sept 1963. Deals with widely-known spring guides of the par- allelogram type for forward displacements, and certain characteristics to be considered in design to prevent over- loading and premature failures. Addendum to Section 5 5.2.2. Electrical Amplification The Ultra-Micrometer ; an Application of the Thermionic Valve to the Measurement of very small Distances, R. WHIDDINGTON. Phil Mag 6ser v40 n289 Nov 1920 P634-9 2 figs ; v46 n274 Oct 1923 p607-8, with A. HARE, co-author; v49 n289 Jan 1925 pll3-21 3 figs with F. A. LONG, co-author. If a circuit consisting of a parallel plate condenser and inductance be maintained in oscilla- tion by means of a thermionic valve, a small change in the distance apart of the plates produces a change in the frequency of oscillations which can be accurately deter- mined by methods described. It is shown that changes as small as one two-hundred millionth of an inch can be easily detected. Sensitive Valve Method for the Measurement of Capacity : Applications, J. J. DOWLING. Roy Soc Dublin. Proc vl6 Dec 1920 pl75-84, Mar 1921 pl85-8 ; Eng vll2 Sept 9 1921 p395 ; Phil Mag v46 July 1923 p 81-100, Nature vlll June 2 1923 p 742-3. Describes arrangement of the appa- ratus and its application as an ultramicrometer for meas- uring minute movements, inasmuch as the capacity of a condenser varies with the separation of the plates. Electrical Apparatus for Measuring Small Motions, H. A. THOMAS. Engr vl35 Feb 9 1923 pl38-40; J Sci Instrum vl 1924 p22-6 7 figs. Apparatus consists of a high- frequency oscillator and an inductance coil arranged in close proximity to the metallic body whose motion is to be measured. It is applicable to the analyzing of the transient conditions existing in all types of engineering structures when subjected to live loads. The principle has been applied successfully to the operation and main- tenance of a standard pendulum, without any contacts being required to operate the mechanism for inserting energy into the stroke. The "Ultramicrometer," a New Instrument for Measuring very small Displacement or Motion, and Its Various Appli- cations, J. OBATA. World Eng Congress, Tokyo, 1929 v r 5 p79-84 12 figs refs. Distributed by Kogakkai, Maru- nouchi, Tokyo, 1931. The detailed construction together with various applications were published previously, else- where. The present paper contains the results of further applications, namely : The recording of earth movements ; direct recording of accelerations ; an electrical indicator for high speed internal combustion engines ; precise recording of sounds, pressure variations, and various mechanical vibrations. Capacitive Displacement Transducers, A. V. FEDOTOV. Meas Techns n7 Feb 1965 p 571-5 2 figs. Translated from Izmer Tekh n7 p 15-6 July 1964. The necessity of extend- ing the range of capacitive displacement transducers has led to the theoretical and experimental investigation of certain systems of these transducers. A capacitive trans- ducer with a range of 200/j. and a scale factor of 1/i was produced. It is stable in operation and insensitive to external interference. Addendum to Section 3 (continued from page 116) 3.5. Measuring Machines and Bench Micrometers Thickness Gauge with an Antenna Transducer for Non- conducting Materials, B. M. SHLYAPOSHNIKOV, E. M. KON'KOVA. Meas Techns n7 Feb 1965 p 578-81 1 fig 3 refs. Translated from Izmer Tekh n7 p 18-20 July 1964. A device has been designed and built for measuring the thickness of glass plastics and similar nonconducting materials by means of a metal backing. It is provided with direct reading in units of length and can be used at any distance from the edge of the tested sample, with- out destroying it and without first determining its physico- chemical properties. Extensive testing has shown that the design is satisfactory and it is convenient to use. Its electrical circuit is simple, and the number of control devices is small. 151 771-846 O— 66 Section 6. Angle Measurement CONTENTS Page 6.1. Angle measurements, general 153 6.2. Alinement, straightness, and autocollimators 157 6.3. Angle gage blocks and polygons 162 6.4. Calibration of graduated circles, dividing heads, and protractors 164 6.5. Angle measurement by interferometry 167 6.6. Sine bars, plates, and fixtures 169 6.7. Spirit levels 170 6.8. Tapers 172 Addendum to Section 6 173 6.1. Angle Measurements, General See also subsections 10.1.3 and 10.5. The Telescope-Mirror-Scale Method, Adjustments and Tests, S. W. HOLMAN. John Wiley & Sons, N.Y. (re- printed from The Technology Quarterly), Sept 1898 39 p 11 figs 3 refs. This presentation is designed for putting the method of measuring small angles into direct service. It discusses the several sources of error. It describes the various adjustments and tests in the sequence in which they should ordinarily be made and gives a numerical measure of the closeness with which each must be carried out to secure a specified precision in the result. Some re- marks on the selection of instruments are appended. Solid Angles, L. WEBER. Zeit fur InstrumKde v28 May 1908 p 129-36. Describes at length two new methods of measuring solid angles. In the first method, which is adapted to measuring areas on the surface of a sphere, use is made of the pantograph to obtain (1) the projection of a given area on some fixed plane and (2) the projection of the central section parallel to this plane. From a com- parison of these two the area on the sphere can be deter- mined. In the latter part of the paper a modified form of Moritz apparatus is described. Setting Angles for Milling Angular Cutters and Taper Reamers, W. A. KNIGHT. Machy vl5 Nov 1908 p 161-8. Mathematical development of subject with numerous tables. Bibliography. The Measurement of Angles and the Rectilinear Scale of Constant Sensibility (La Mesure des Angles et L'echelle Rectiligne de Sensibilite Constante), M. DUGIT. Techn Mod vl2 n9 Sept 1920 p 353-61 14 figs. Advantages and disadvantages of rectilinear scale as compared with circular scale. Construction of spiral protractors. The Measurement of Angles in Radians (Le Mesure des Angles en Radians ) , J. MAITRE. Genie Civ v78 n2003 Jan 1 1921 p 10-2 1 fig. Utilization of radians for measuring angles by means of straight lines. Winkelmessung (Angle Measurement), F. GOPEL Chap- ter 3 of Handbueh der Physik, Verlag Julius Springer, Berlin v2 1926 p 91-111 20 figs refs. Discusses the division of the circle, and instruments and set-ups for angle measurement. Determination of Angles by the Use of Microscopic Areas, A. ARNULF. CR Acad Sci vl89 July 22 1929 p 152-3. The object of the device is to determine to an accuracy of 1' the direction of the normal to a polished surface of small radius of curvature (e.g., 0.001 mm 2 ). A luminous point situated laterally is by means of an unsilvered plate of glass placed at an angle of 45° in the optical axis of a microscope, reflected through the object glass on to the polished surface under examination, and thence back to the eye. The variations in the resultant illumination reaching the eye according as the tangent plane to the surface at the point of incidence of the pencil of light is, or is not, accurately perpendicular to the optical axis of the microscope, enable the direction of the normal to be accurately determined. Accuracy in Angle Gaging, J. A. POTTER. Am Mach v72 June 26 1930 p 1024—5 8 figs. Procedure for proper meas- urement of angles, simple, double and compound. Testing Safety Razor Blades, R. W. WOODWARD. Iron Age vl31 June 22 1933 p 981-3 22 figs. Measurement of cutting angle, testing edge with photoelectric cell, Wood- ward sharpness tester. Winkelverwandler und Winkeluhren (Angle Converters and Meters), H. MAURER. Zeit fur InstrumKde v55 Nov 1935 p 448-50 2 figs 4 refs. Disadvantages of various sys- tems of angular measurement, e.g., in terms of radians, degrees, minutes, seconds, etc., are briefly referred to, the application of such systems in military and naval science being, inter alia, referred to. The advantages of a system in which 2w radians is divided into 6000 units are pointed out. The term "set" (derived from sechs and tausend) is suggested for the new unit. Devices for interconversion of the various scales are described and their use exem- plified. Simple High-Sensitivity Method for Optical Measurement of Very Small Angles, A. PERRIER. Helvetica Physica Acta v9 n5 1936 p 332-4 in French. Details are given of a method of measuring small angles in which the move- ment of a real image of a fixed object, formed by a concave mirror attached to the moving system, is measured with a micrometer eyepiece. Messen von Winkeln mit Messcheiben und Lehrdornen (measurement of angles with disks and plug gages). Werkstatt und Betrieb v70 n% Feb 1937 p 33. Outline of practice for measurements of angles by aid of disks and cylindrical calipers ; practical examples given. 153 Alignment Projectors and the Precision Measurement of Angles, C. DEVE. L'Optique (Rev Opt Theor Instrum) v20 1941 p 115-48. Discusses the limitations of telescopes for the measurement of small angles, then proceeds to analyse the advantages, and estimate the precision, of alignment projectors. Two types of work are discussed, the measurement of angles subtended by distant objects and the use of goniometric work in laboratories and work- shops. Details are given of the instrument suited to each type of work and the various methods of use and applica- tions are considered. These include the manufacture of precision prisms, measurement of small angles between two reflecting faces, the variation of the refractive index of the atmosphere, etc. Measuring and Inspection Instruments. Eng vl56 n4053 Sept 17 1943 p 227. Brief illustrated description of three instruments demonstrated by E. H. Jones (Machine Tools), Ltd, London, namely. Sigma taper measuring ma- chine manufactured by Sigma Instrument Co : Brisdon inspection table made by F. Brauer ; and universal sine table made by Papworth, Ltd. Projection Angle "Dekkor." Eng vl57 n4093 June 23 1944 p 487-8. Illustrated description of improved precision optical instrument for checking angular relationship be- tween plane surfaces, manufactured by Adam Hilger, Ltd : scales are visible on screen on to which they are projected by optical system. Notes on the Use of Circular Dividing Apparatus for Angular and Linear Measurement, G. P. BARNARD, NPL, His Majesty's Stationery Office July 1945 81 p 55 figs. Contents : Introduction ; main apparatus required ; divid- ing heads ; universal measuring block ; accessory ap- paratus ; introduction to measurement ; preparation for gauge inspection ; measurement of selected examples. Ap- pendixes, note on location of center of small circular arc ; note on pitch radius measurements ; rotation involving translation, sources of error ; intersection dimensions and gauging triangles ; principle of minimum rotation ; prop- agation of accidental error. Calibration of a Set of Master Wedges, D. H. RANK. J Opt Soc Am v36 Feb 1946 p 116-9. Calibration of a Set of Master Wedges, D. H. RANK. J Opt Soc Am v36 n2 Feb 1946 p 116-9 2 figs. Discusses two methods: (1) telescope and scale and (2) multiple beam method. The latter permits determinations to better than 0.25". Describes experimental procedures and discusses quality of surfaces, measurement of index of refraction, errors, and comparison of wedges with the Twyman Interferometer. Standards of Length and Angle for Precision Engineering. H. BARRELL, NPL. Trans. Instrum and Meas Conf. Stockholm, 1947 p 182-90 7 figs. Discusses practical standards of length, measurement of longer distances, practical standards of angle. Precision Method of Checking "Compound Angles, J. AHEARN. Machy (NY) v53 n5 Jan 1947 p 178-81. Method involves use of angle block for supporting work piece on sine plate which is elevated to bring compound angle face into horizontal position ; steel ball is placed in pocket formed by faces of included angle of angle block and supporting end plate : largest size ball will give most accurate measurements. A New Theodolite Goniometer. I. R. RAO, and S. V. S. RAO, J Sci Industr Res v6 Dec 1047 p 485-7. The gen- eral features, adjustment and method of use, of a universal type of goniometer for measurement of the angles be- tween crystal surfaces is described. The instrument con- sists of a 6 in diameter horizontal and 5 in diameter vertical scale, both divided in half degrees, together with verniers and magnifiers enabling readings to one minute ; a crystal-holder attached to the centre of the horizontal telescope, with total light from the crystal surface. The telescope has a combination objective so that it can also be used as a low power microscope. A photograph of the assembled instrument is given. Applications of the Hilger Angle Dekkor, B. P. HARROLD Machy (London) v72 nl848, 1850 Mar 25 and Apr 8 1948 p 391-7, 458-60 27 figs. An instrument intended for meas- uring and comparing angles. The standard instrument gives readings through an eyepiece to 1' and by estimation to 6". The large instrument reads directly to 30" and by estimation to 3". Comprises a telescope, base, and tele- scope arm. Numerous accessories and their applications are described. Alignment Testing, K. J. HUME, Eng. Inspection vl3 n4 Winter 1949 p 163-73. Methods in accurate establishment and checking of large dimensions and measurement of deviations from straight line or plane ; use of instruments and autocollimators ; applicability to testing of machine tools, jigs and fixtures. Electro-optical Measurement of Angles by a Photometric Method, H. BENDER. Optik v8 n5 1951 p 206-23 in Ger- man. A detailed description of the apparatus necessary for surveying operations using i.r. lignt for its greater penetrating properties. The light is detected by a photo- cell, and the visual alignment of a telescope is replaced by an adjustment similar to a photometric setting. An accuracy of 4" of arc is claimed under favourable con- ditions. Grundlagn der Technischen Winkelmessungen (Funda- mentals of angular measurement in industry), K. RAENTSCH, Carl Hanser Verlag. Munich. Germany, 1952. 110 p illus, diagrs, tables, graphs. Publication deals with most useful methods, procedures, and fields of application ; describes and discusses German and foreign instruments for both direct and indirect measurement and layout of angles in machine shop work. Eng Soc Library, N.Y. A New Mirror Multiplier, B. M. LEVIN. Zh Tekh Fiz v22 nl 1952 p 105-10 in Russian. A method is described per- mitting of raising and varying the sensitivity of auto- collimation readings and photo-recording arrangements ; this is accomplished through the corresponding selection of angles with the known multiplier having two mirrors. On the Elimination of Some Errors of Angular Measure- ment, E. TERRANA. Atti dell' Accademia Nazionale dei Lincei Randiconti della Olasse di Scienze Fisiche, Mate- matiche e Naturali. vl2 Mar 1952 p 290-3 in Italian. Messgeraete fuer 90° Stahlwinkel (Measuring instruments for 90° tool angles), G. BERNDT, K. SCHMIDT. Dres- den—Tech Hoehschul lie tested. Examination of Very Flat Surfaces for Interferometry, M. DUFFIEUX. Rev Opt vll Apr 1932 p 159-66. The surfaces to be tested are resilvered with a layer which is semi-transparent and then examined in pairs with the help of a specially constructed interferometer. The me- thodical displacement of the interferometer allows the tracing of the fringes and thus the thickness of the air gap. Accidents of relief amounting to 3 m/t can be detected. The errors introduced by the silvering can be avoided or disclosed. The individual topography of the two surfaces can be found by graphical methods. Determination of Defects in Flatness of Surfaces, A. BIOT. Ann Soc Sci de Bruxelles v52 June 8 1932 p 54-8. A comparison of two surfaces is made by selecting two points along a line for each surface. With these surfaces facing each other and using an interference method with transmitted monochromatic light, the distance apart of successive fringes is found. This process can be contin- ued across the surface. A precision of X/200 can be readily obtained. The process can be used to determine the three principal radii of curvature of a body. Testing Planeness of Surface by Haidinger's Rings, O. SCHONROCK. Zeit fur InstrumKde v 59 Jan 1939 p 31- 40. The author develops the theory of an interferometer method for determining the deviation from planeness of the surface of a glass plate without reference to a plane liquid surface. Method for Measurement of Flatness of Polished Surfaces, C. TUTTLE, R. CARTWRIGHT. J Opt Soc Am v30 n8 Aug 1940 p 348-50. Optical method providing for rapid inspection of extended surfaces described ; two beams of parallel light are reflected by sample through cylindrical lens to form astigmatic image of source; if this image is single line, surface is flat within accuracy of instrument ; inspection device for testing glass to be used for photo- graphic purposes now in service. Optical Flats. Aircraft Prod v3 n27 Jan 1941 p 34-5. With optical flats it is possible to gage surface inaccu- racies which are too small to be checked by micrometer ; use of optical flats is based on fact that if glass or quartz plate is put into close contact with surface of another plate, series of color fringes or bands will be visible and these will indicate inaccuracies of surface being checked. Generating Flat Surfaces, E. V. WAIT. Eng vl52 n3957 Nov 14 1941 p 381-3. Particular interest centers around Whitworth's three-plate method, because no machine made tools or instruments are necessary, and because plates of highest degree of accuracy can be generated ; speaking generally, engineers are under mistaken impression that this process is much simpler in operation than it actually is ; this has been due to deficiency in published literature, which it is purpose of this article to make good. An Interferometer for Controlling Large Mechanical De- tails, V. P. LINNIK, OR Acad Sci URSS v35 nl p 16-9 1942. Describes an interferometer for the examination of long surfaces of linear nature (plane, cylindrical) for departures from rectilinearity. As compared with a pre- vious arrangement described by the author in the same journal (32, 3, 1941), the present scheme is free from the drawbacks associated with aberrations due to superficial irregularities. As an example, the interference pattern obtained from a plate of mirror-glass 400 mm. long is reproduced. Checking Micrometers with Optical Flats. Machy (Lon- don) v60 nl541 Apr 23 1942 p 353. Method of checking anvils of screw micrometer for flatness and parallelism with assistance of optical flats ; sets of flats are made to nominal thicknesses of 1 in., 0.500, 0.5062, 0.5124 and 0.5186 in : working surfaces are flat to within 0.00001 in., and they are parallel to within 0.00002 in. Auto-Collimator Test for Flatness, W. A. TUPLIN. Machy (London) v61 nl577 Dec 31 1942 p 729-34. Method of checking surface flatness, using optical instrument to measure rise and fall of reflected ray from tilted mirror on auto-collimator. Instrument is used for checking straightness of long narrow surface, such as lathe bed and determination of departures from flatness of surface, such as large surface plate. On the Planenes of Interferometer Plates, E. K. RAS- MUSSEN. Danske Vidensk Selsk Mat -Fys Medd v23 n3 18 p 1945. Describes a method of applying interference fringes to measure the planeness of Fabry-Perot plates and discusses the accuracy of the method and the depend- ence of the resolving-power on the planeness. The use of a wedge between silvered plates is advocated for fine-struc- ture observations on intense lines, using Fizeau fringes. The Measurement of Finely Finished Surfaces by Optical Interference. C. J. TIMMS. Sci Instrum v22 p 245-6 Dec 1945. Plane-Parallel Glass Indicators and Technical Interform- eters, J. G. VOGL. Tekn Tidskr v76 June 29 1946 p 657- (!4 in Swedish. The principle of measurement of surface irregularities with interference by means of a plane-paral- lel glass plate is explained in detail and the contour map- ping of the surface is described. Usual interferometers, in- cluding the Twyman-Michelson instrument, are described and various applications are explained, with illustrations. Additional Interference Fringes Produced by Scattering and Reflexion, V. D. HOPPER. Nature London vl58 July 20 1946 p 101. A double system of interference fringes, produced by a combination of multiple reflection and scat- tering similar to that suggested by Bauchwitz and Schoen- berg was observed with an arrangement of aluminized and semi-aluminized optical flats with scattering scratches which is described. Interference Fringes Produced by Scattering and Reflec- tion. V. D. HOPPER. Proc Roy Soc Vict v58 Pts I-II 1947 p 69-80. When a partly polished optical flat was placed face downwards on a standard flat, and illuminated by a small bright white-light source, the pattern cor- responding to the colours of thick plates was observed encompassing the image of the source. When the top sur- face of the standard flat was aluminized. the pattern was much more intense. A new phenomenon occurred when the pair of plates was illuminated by light from a Hg lamp which passed through a narrow slit, the single pat- tern giving place to two separate patterns, whose intersec- tions gave the locus of the pattern observed with white light. When the scattering surface was made semi-reflect- ing, the double set of patterns became sharper, one set 176 being localized in the plane of the scattering surface, the other in planes corresponding to the position of the Newton ring pattern formed by multiple reflections. Various ex- periments are described for studying these patterns. It is concluded that all three systems of fringes are produced by multiple reflections between the two reflecting surfaces, the assumption of Stokes that the colours of thick plates could only be produced by light passing and repassing the same particle being unnecessary. It is considered that the pattern corresponding to the colours of thick plates is pro- duced by the summation of the intensities of the light from a pair of separate patterns of the simpler Newton ring type, one set being produced by light scattered by the top surface and then suffering multiple reflections between the surface before reaching the observer, the other set being produced by light from the source suffering multiple re- flections between the plates, and finally being scattered by the scattering centres. Testing of Flatness by Beam Comparator Method, R. MARRINER, W. O. JENNINGS. Engr v 184 n4778 Aug 22 1947 p 164-5. Method described was devised at Na- tional Physical Laboratory and used for testing quickly and with reasonable accuracy large batches of surface plates of same size ; it is particularly convenient for test- ing flatness of surfaces during manufacture ; principle is that of comparing by means of sensitive dial indicator straightness of succession of generators in surface under test with that of known reference straightedge. A Liquid Surface Interferometer, H. BARRELL, R. MAR- RINER, NPL. Brit Sci News v2 1948 p 130 ; Nature n4118 Oct 2 1948 p 52a. Describes a Fizeau type of liquid surface interferometer used at NPL. Liquid Surface Interferometry, H. BARRELL, R. MAR- RINER, NPL. Letter in Nature vl62 Oct 2 1948 p 529-30. The surface of liquid paraffin has been used to provide a reference plane up to 25 cm dia. For this dia. the earth's curvature produces a difference in height of only 12 A, while liquid paraffin has less capillary curvature than water, which has been used previously. Testing of Polished or Fine Ground Surfaces for Flatness, A. J. ELLIOTT. Sci Instrum Phys Ind v26 Jan 1949 p 24. The testing of nearly flat surfaces by the astigmatism pro- duced in a light beam reflected from the surface is dis- cussed. The use of the test for ground surfaces is de- scribed, and attention is drawn to its use in the working of soft materials such as rock salt. Test of an Optical Flat by the Fabry Perot Etalon, T. SAKURAI, K. SHISHIDO. Sci Rep Res Inst Tohuko Univ Ser A vl May 1949 p 83-6. An application of Fabry's fringe method for the examination of optical flats. The flats are mounted as a Fabry-Perot, fringe or- der being changed by altering gas pressure between the flats. The accuracy of l/50th of a light wave is claimed. Zur Messung der Ebenheit von reflektierenden Flaechen mittels Interferenzen gleicher Dicke (Measurement of flat- ness of reflecting surfaces using interferences of equal thickness), R. LANDWEHR. Optik vo n6 Sept 1949 p 354-64. Consideration of deviation of uniform and non- uniform spherical surfaces from flatness; formulas and nomograms for determining curvatures. Improving the Quality and the Testing of Optical Flats, E. EINSPORN. Optik v7 n3 1950 p 147-68 in German. A discussion of the evaluation of slight curvature of opti- cal flats by means of Fizeau fringes. The method is shown to be comparable to that using Haidinger fringes. A dis- cussion is included on the effect of combining slightly curved flats. Interferometer for Testing Measuring Gauges, Eng vl70 n4417 Sept 22 1950 p 243-5. Instrument being manufac- tured by Coventry Gauge and Tool Co. under name of Matrix Interferometer; by means of instrument, devia- tions from flatness of order of one millionth of inch on highly finished surface may be seen by aid of interference fringes which they produce. See also discussion, by H. BARREL and J. PUTTOCK, in n4426 Nov. 24, p. 412. Contour Mapping of Optical Surfaces with Light Waves, Glass Indus v32 n8 Aug 1951 p 409-11. Vacuum light interferometer developed by J. B. Saunders of National Bureau of Standards makes contour maps by photograph- ing interference patterns formed when light waves are reflected from precise optical surfaces of specimen and standard reference of known shape ; adding additional lines between half wavelength lines reduced spacing to 6 ten-millionths of inch. Precise Topography of Optical Surfaces, J. B. SAUN- DERS, J Res NBS v47 n3 Sept 1951 (RP2239) p 148-55. Unit of length usually used in measuring optical surface features, by interference of light, is one half wavelength of monochromatic light that is used ; method is described in which unit of length is much smaller fraction of wave- length ; topographic maps of optical surfaces are made in which contour interval is less than l/30th wave length. Determination of Planeness and Bending of Optical Flats, W. B. EMERSON, NBS. J Res NBS v49 Oct 1952 p 241-7. The true contours, undistorted by gravitational bending, were determined for four 10% in. diameter standard opti- cal flats of fused quartz. The bending deflections of these flats were determined by a method based upon the differ- ential bending with thickness of the flats. Bending deflec- tion curves of a flat supported at three points equidistant from the center of the flat and equidistant from each other were obtained. The locus of the bending deflections at the center of a flat, similarly supported but with supports at different distances from the center, approximates a straight line. This paper describes the method used to ob- tain the true contours and the bending deflection curves of the flats, and compares the bending values so determined with theoretically derived values. Collimator and How To Use It, R. F. MITCHELL. Am Mach v96 n23 Nov 10 1952 p 161-4. Goniometer-Colli- mator for use in shop operations ; collet and lathe tool angles easily checked ; bedway flatness can be measured to 0.00007 in. ; applications illustrated. The Science of Precision Measurement. The DoAll Co. 1953. Chapter 6 covers applications of optical flats. Why Don't We Standardize Surface Plate Specs? R. J. RAHN. Am Mach v97 June 8 1953 p 169. Suggests a form of specification. A Micro-Reference Flat for Multiple Beam Interferometry. S. TOLANSKY, M. OMAR. Note in J Sci Instrum v30 Sept 1953 p 337-8. For high definition multiple beam interference fringes, the optical flat must approach very closely to the object. A micro-flat is described enabling close approach to selected regions of an object, such as a crystal, in which there are areas differing considerably in surface level. This flat consists of the polished tip of a small truncated cone. The cone tip (i.e. the flat) has a diameter of 1 mm or less. The mounting and method of adjustment are described. The technique is illustrated by use with diamond and silicon carbide crystal surfaces. The Metrology of Surface Plates, J. C. MOODY. Sandia Corp., Oct 1953. Discusses application of the autocolli- mator. See also : Tool Engr Feb 1958 and Dec 195S. Testing of Large Optical Surfaces With Small Test Plates. J. B. SAUNDERS, NBS. J Res NBS v53 nl July 1954 (RP2514) p 29-34. With increased use of massive optical parts, there is need for practical method of testing large 177 optical surface with small standards, available in average optical shop ; simplified formulas are used to apply statis- tical method for obtaining increased precision; practical example illustrating procedure for testing surfaces as- sumed to have revolution symmetry. "New Look" in Surface Plates, A. P. DIEFFENBACH. Machine & Tool Blue Book v49 n9 Sept 1954 p 196-8. New forms of surface plates described and illustrated; long surface plate made up of three individual plates is used to check straightness on airplane wing struts ; advantages of round type surface plate ; Surface Floor Tee-Rail. It Takes Three-Point Specification to Insure Surface Plate Flatness, R. J. RAHN. Tooling & Prod v20 n7 Oct 1954 p 123-5, 140. Details of specification for black granite surface plates produced by Rahn Granite Surface Plate Co., Dayton, Ohio ; errors will be not over 100% of unit being used. Precision Measuring Tools. Catalog and Handb n36 Ap- pendix G Optical Flat Specifications and Data. The Van Keuren Co., Waterfrown 72, Mass. 1955. Discusses testing of flatness, using an optical flat; testing of flat ring sur- faces ; and presents tentative optical flat specifications. Surface Plates Compared by Physical Tests, R. MER- RIAM. Tool Engr v35 n2 Aug 1955 p 99-100. Strength characteristics, compressibility and absorption, and ther- mal properties of granite and black granite plates ; com- parison with cast iron plates. How to Calibrate Surface Plates in Plant, J. C. MOODY. Tool Engr v35 n4 Oct 1955 p 85-91. Method used in metrology laboratory at Sandia Corp, Albuquerque, NM is application and extension of procedures developed by K. J. Hume and involves no new principles ; details of autocollimator employed ; directions for converting auto- collimator readings into linear displacement in hundred- thousandths of inch are given, accompanied by work sheets for calibrating 48 x 78 in. surface plate. Control and Interferometric Measurement of Plate Flat- ness. P. D. CARMAN. J Opt Soc Am v45 nl2 p 1009-10 Dec 1955. For two flatness requirements involved in the testing of air survey cameras special techniques have been devised. Photographic plates used for camera calibra- tion should be flat to one or two microns. To achieve this the x /4-in. plate glass supporting the emulsion is bent flat and held flat during exposure. Flatness is determined in an interferometer using infrared light. Camera register glass flatness is also checked interferometrically. Since counts of over 100 fringes are required, two monochro- matic light sources are used, chosen to produce regular arrangements of black and coloured fringes which permit counting by groups. Untersuchungen fiber die Eignung eines Fliissigkeitsspie- gels als Ebenheitsnormal (Investigation on the Use of a Liquid Surface Mirror for a Flat Plane of Reference), R. BtJNNAGEL. Zeit Angew Phys v8 n7 1956 p 342-50 in German. Experiments are reported using paraffin, silicone oil and castor oil on mercury. Distortions pro- duced on the liquid surface both by static charging and by temperature variations are studied. With a disc of 24 cm diameter at 4 cm from the edge the radius of curva- ture is 2X10' km. The influence of earth curvature is not established. The observed curvature is the same for the three liquids studied. Static charges can persist for sev- eral days and are formed even by the pouring of the oil on the mercury. To avoid this the oil used should have a conductivity of at least 10" u ohm: 1 cm" 1 . With castor oil, a temperature difference of 0.01 °C at the ends of a 11 cm disk does not produce a detectable effect. The Showing of the Degree of Planeness of a High Polish by Means of Surface Topography, R. SEGELETZ. Optik vl3 n2 1956 p 59-63 in German. A description of the best method for revealing clearly the topography of a large "flat" as derived from interference fringe patterns. The method of computing the complexities of the topog- raphy in terms of contour lines 0.01/4 apart is discussed. These contour lines are derived from ordinary fringe patterns. Einfaches Verfahren zur topographischen Darstellung einer Optischen Planflache ( Simple Method for the Topo- graphic Representation of an Optically Plane Surface). R. BUNNAGEL. Zeit Angew Phys v8 Feb 27 1956 p 447. Method is based on the evaluation of a unique photo- graph of Fizeau interference. ( Partial translation avail- able). Intercomparison of Optical Flats, S. W. HUGO. Mech Wld vl3S n3444 Apr 1956 p 150-2. Comparison of three flats, not supplied as set ; flats comprise circular one, 2% in. diam by 7/16 in. thick and two rectangular ones, 2 in. by 1% in. by % in. thick ; deduction from results leads to establishment of test routine ; several flats were intercom- pared but three described were selected as demonstration set in view of their particular contour. Production of a Mercury Mirror which is Insensitive to Shocks and its Application as a Flatness Standard, R. BUNNAGEL. Optica Acta v3 n2 June 1956 p 81^ in Ger- man. A mercury mirror which is insensitive to vibration consists of a layer of mercury about 0.2 mm thick. The formation of such a thin layer is achieved by using a vessel of a metal which readily forms an amalgam. By silvering the inner surface of the metal vessel the mirror is made durable, and the formation of a skin on the mer- cury surface is prevented. The flatness of the mercury mirror has been tested by two different interferometric methods, and its suitability as a standard flat established. Multiple beam interferometry may be used to increase the accuracy of the testing for flatness. As every liquid mirror flows when its position is slowly changed, a firm mounting is necessary. A Simple Technique for the Topographical Evaluation of an Optical Flat, R. BUNNAGEL. Zeit Angew Phys v8 n9 Sept 1956 p 447-50 in German. A mercury surface is used as reference mirror. A geometrical method of deriv- ing the topography of a nearly plane surface from the Fizeau fringe pattern is described. The limits of error are discussed. Cheeking Flatness of Plane Surfaces with Straight-Edges. C. MINAIRE. Machy (London) v91 n2335 Aug 16 1957 p 357-62. Wedge blocks for checking flatness, checking flatness of surface plate ; topography of surface plate ; ob- taining true plane surface with minimum removal of material. Interferometric Testing of the Planeness of Long Beds. K. KUHNE. "Optics of all Wavelengths" Meeting, Jena, 1958 p 362-8 in German. The testing of beds of some meters in length for precision machinery is described. An interferometric set up is used which employs Fizeau double slits and an autocollimation device. Constructional and operational details are given. As an example the testing of aim long test-bed is illustrated. Can You Prove Flatness of Your Flat Surface Plates? Here's How, E. W. PENNINGTON. Tooling & Prod v24 n2 May 1958 p 69-70, 72 74, 76. Planekator method devised by R. J. Rahn of Rahn Granite Surface Plate Co. for cali- brating out-of planeness of surface plate is simple, ac- curate, and fast working ; master geometrical reference plane which is "suspended in air" above surface plate can be established or located ; procedures described. Zur Steigerung der Genauigkeit mikrointerferometrischer Untersuchungen und zur einer Interferenz-Sphaerometrie ( Improvement of accuracy of micro-interferometric exami- 178 nations and problem of interf erence-spherometry ) , R. LANDWEHR. Zeit InstrumKde v 66 n7 July 1958 p 134- 8. Corrections to be considered in precise miero-inter- feronietric work to determine form of objects, where dou- ble beam interference with conventional micro-interfer- ometers is used ; possibility of more accurate interference- spherometry. 17 refs. Checking Flatness with Straightedges, C. MINAIRE. Machy (N.Y.) v64 nl2 Aug 1958 p 99-102. Set of three special blocks used to check flatness instead of making up various gage block combinations, which requires more time; checking flatness of surface plate; obtaining true plane surface with minimum removal of material. Applications of the Interference Strioscope to Metrology, M. PHILBERT. Rev Opt v37 nl2 Dec 1958 p 598-608 in French. A simple apparatus is described, using inter- ference between two beams formed by binefringence. Its application in wind tunnel work is given in detail and some results are shown. Other uses are the testing of the fig- ure of optical surfaces and the detection of veins in opti- cal materials. Interferometer for Large Surfaces, J. B. SAUNDERS, F. L. GROSS. J Res NBS v62 n4 Apr 1959 (RP2943) p 137-9. Instrument described which permits testing of large areas, such as layout plates, obtains extension to large areas by causing collimated beam of light to reflect from specimen at large angle of incidence ; resultant fringe pattern is contour map of surface relative to arbitrarily chosen plane and contour interval is function of wave- length and angle of incidence. Instruments for Measuring Surface Irregularities and Alignments. Machy (London) v94 n2421 Apr 8 1959 p 775-6. Description of straight line interferometer capable of measuring profiles of surfaces up to 15 in. long with accuracy of 15 microin. ; instrument has been applied, for example, for checking straight edges and precision sur- faces of such parts as sealing rings for axial flow com- pressors. Indicating Surface Flatness with Electronics,, P. E. CAR- BONE, Tool Engr v43 nl July 1959 p 57-8. To fulfill need for fast checking method, electronic straightedge was developed to measure flatness within 0.000025 in. over 120 in. A Method of Testing Optical Flatness of Pre-polished Glass Surfaces, A. S. HAMEED, S. HARIHARAN. J Sci Industr Res vl8A n7 July 1959 p 311-3. A method for the quantitative estimation of the form of an optical sur- face, just before polishing, is described. The optical layer with suitable modifications is used for the purpose, so that departures from a standard form, say an optical flat, can be evaluated in terms of wavelengths of light. This data will be helpful in correcting surfaces even in the pre-polish- ing stages. The time spent in effecting the corrections at this stage will be very much less than the time taken in the figuring stages, after polishing. The results obtained were verified by interference methods. How to Calibrate Small Surface Plates, R. J. RAHN. Tool Engr v43 n3 Sept 1959 p 111-3. Dimensional variations as small as five millionths of inch can be measured with auto-collimator if instrument is used correctly ; calibration with auto-collimator on plate and off plate ; readings taken are shown and curves obtained illustrated. Herstellung und Verwendung eines gegen Ershiitteriingen unempfindlichen Quecksilberspiegels als Ebenheits normal (Production and Application of a Mercury Mirror Insen- sitive to Vibration as a Planeness Standard), R. BUN- NAGEL, PTB. Optics in Metrology. P. MOLLET. Per- gamon Press 1960 p 172-8 2 figs 8 refs. Mirror consists of a layer of mercury about 0.2 mm thick. Thin layer achieved by using a metal vessel which readily forms an amalgam. The mirror is made durable by silvering the inner surface of the metal vessel, and the formation of a skin on the mercury surface is prevented. Flatness has been tested by two different interferometric methods, and suitability of the mirror as a standard flat estab- lished. As every liquid mirror flows when its position is slowly changed, a firm mounting is necessary. Check Surface Plate Flatness by Applying Geometry of Sphere, R. J. RA HN. Tooling and Prod v26 no Aug 1960 p 41-4. Unusual approach to surface plate flatness based on premise that plane is actually sphere with infinite radius, and segment, of sphere, having radius much less than infinity, would make very good surface plate ; mathe- matical calibration of spherical surface; inspection of surface plate with ordinary tool inspection. Fehlermogliehkeiten beim Messen Zylindrischer Teile mit Kugeligen Messflachen ( Possibility of Errors in the Meas- urement of Cvlindrical Parts with Spherical Measuring Surfaces), O. NIEBERDING, S. TROST. Zeit fur Prak- tische Metallbearbeitung v55 1961 p 163. Testing the Straightness of Lines and the Flatness of Surfaces, A. C. S. VAN HEEL and J. D. DE VEER. Optical Instrum Conf London 1961 p 383-405. By mak- ing use of conventional optical parts, alignment and the flatness of surfaces can be tested to within a few tenths of a second of arc by making use of spherical aberration and diffraction. The range in some cases is several hun- dreds of meters, and the brightness of the diffraction pat- tern is high enough for observation in daylight. Only flat and spherical surfaces are needed. The most simple form to test alignment is a sphere with a cap of the same material of very good homogeneity. A concave spherical mirror and a flat mirror were used in combination, in order to obviate the stringent requirement of homogeneity of the glass. Though the sphere with cap can be used also to test the flatness of surfaces, other means are more efficient. In the first place one spherical mirror with one minute light source (of white light) suffices to test the flatness up to distances of 20 meters with a precision below one second of arc. By combining a concave and a convex spherical mirror, precision can be lowered to a few tenths of a second of arc, while the observation distance is en- larged. The working of the mirrors is based on the form- ing of (colorless) "rainbows," a fact that is perhaps not well known. The diffraction pattern associated with these rainbows (Airy's fringes) makes it possible to attain the mentioned precision. Much time was given to testing the straightness of the line produced by the apparatus by in- dependent means, a difficult process seldom applied by other workers. Analysis in Use of Optical Flats, S. W. HUGO. Mech Wld vlll n3498 Jan 1961 p 6-10. Discussion of geometri- cal analysis of possible errors arising in lapping of gage surfaces and their comparison with reference standard by methods of comparative interferometry ; methods are equally applicable to checking of slip gages and notes on checking of secondary gages are appended ; illustrated with diagrams and calculations. Investigation of Surface Deformation, L. GRUNBERG, D. SCOTT, K. H. R. WRIGHT. Brit J App Phys vl2 n4 Apr 1961 p 134-40. Methods used in National Engineering Laboratory for studying surface deformation ; enhanced photoelectric emission is studied with open-ended Geiger Mueller counters or electron multipliers ; oxide films are studied by electron microscopy and changes in chemical reactivity by radioactive tracers ; surface topography, im- portant factor in lubrication and wear research, is studied with aid of interferometry, phase contrast and electron microscopy. Optical Flats. Federal Specification GG-O-635 May 31 1960, Amendment 1 May 10 1961 6 p. Available from 179 General Services Administration Region 3, Federal Supply Service, Printed Materials Supply Division, General Serv- ices Regional Office Bldg., Washington, D.C., 20407. 5 where the functions CI and SI denote the integral cosine and integral sine respectively. The values of these func- tions can readily be obtained from Jahnke-Emde tables and hence curves of any required length and curvature variation can quickly be drawn, using the relations 0=L/R, #=L CI

. Such curves have been in use for a considerable time and have proved extremely useful. Neuer Profilmesstand (New type of profile measuring equipment), A. METZ. Werkstattstechnik und Werks- leiter v33 nl6 Aug 15 1939 p 400-1. For measurement and testing of thread cutting tools and similar equipment. Improved Spherometer, J. L. HOUGHTON. J Sci In- strum vl8 n8 Aug 1941 p 167-8. Spherometer is described which is fitted with device for indicating point of contact ; plunger passes up center of screw and on contacting sur- face to be measured, rises relatively to screw ; upper part of plunger carries small glass disk which, when it rises, touches convex glass surface fixed to screw and so pro- duces Newton's rings ; spherometer can be used for meas- uring finely ground or opaque surfaces. Radius-of-Curvature Measurements, H. C. SCHEPLER, Am J Phys vl2 Apr 1944 p 107-8. Method uses a point source of light, a card having a hole in it, a collimating lens, and a steel scale. Profile Gages (Measurement). Ordnance Inspection Handb ORD-M608-5 1 July 1945 p 899.0-899.18. Various methods of checking radii and profiles are described. Measurement of Radius of Curvature of Concave Spheres, D. H. RANK, J Opt Soc Am v36 Feb 1946 p 108-10. In the method of measuring the radius of curvature of a sphere with an autocollimating microscope it is claimed that the substitution of an Abbe for a Gauss eyepiece leads to an improvement in ease of manipulation and accuracy. Abbe eyepieces manufactured by Gaertner are described and their method of use detailed. The sensitivity of the method is also discussed. The Measurement of the Radii of Curvature of Convex Spherical Surfaces by Autocollimation, B. JUREK, F. KAUTSKY, Rev Opt (Theor Instrum) v27 June 1948 p 369-70. in French. The difficulties encountered in the pre- cision measurement of the radius of curvature, r, using objectives of small size and small numerical aperture, due to the high values attained by a in the formula r=(D'- -a 2 ) 1 / 2 and the slow change in quality of the returned image with displacement of the moving part of the instru- 190 ment used, are discussed, and the errors they introduce examined experimentally. It is concluded that a should be made as small as possible, and the errors introduced by its non-zero value controlled by a modification of the microscope. Remarks on Precision of Optical Spherometer, B. JUREK. Microtecnic v2 n5 Oct 1948 p 215-21. Description of in- strument ; experimental determination of error limits with consideration of diffraction, spherical aberration, eye accommodation and reading error. Measurement of Radii or Large Diameters, C. MINAIRE. Machy (London) v94 n2414 Feb 18 1949 p 380-2. Methods of determining radii described for cases where difficulties may arise owing to lack of sensitivity, or expansions of micrometers or other instruments employed, and in instan- ces where it is necessary to check radii of arcs on work surfaces, which extend over less than 180°. The Determination of Radii of Curvature by Mechanical Methods of Measurement and a Comparison of Their Ac- curacies, H. JENSEN. Optik v6 n5 1950 p 261-72 in Ger- man. A brief illustrated review of the various mechan- ical instruments, including templates, test curves and spherometers. Accuracy of Spherometer Measurements, H. SCHULTZ. Optik v9 n4 1952 p 164-6 in German. For a ring type spherometer head, the radius of the ring cannot be taken as constant when the highest accuracy is required. The apparent radius has been found to vary in a linear fashion with the radius of the surface being measured. A correc- tion chart for the spherometer head can be drawn. Accuracy of Spherometer Measurements, E. HEINE- MANN. Optik v9 nil 1952 p 525-6 in German. The re- sults of Schultz are confirmed and re-arranged to give a more convenient practical formula for the correction to the radius measured with a spherometer. The Effective Radius of Curvature of Knife Edges, G. F. HODSMAN, F. A. CHAPPELL. J Sci Instrum v29 Oct 1952 p 330-2. Knife edges used as bearings in fine chem- ical balances exhibit a finite radius of curvature. This radius affects the precision of the instrument and its mag- nitude is of interest to the balance designer. A technique is described for the measurement of this "effective" radius. Some results are given for brass and agate knife edges, values in the range 1-3 /i being obtained in the latter case. The Measurement of the Radius of Curvature of Test Glasses with the Ring Spherometer, J. PICHT. Optik vlO n9 1953 p 423-5 in German. When measuring the radius of curvature of a pair of test glasses known to have the same curvature, by interference, it is usual to substi- tute the arithmetic mean values of the sagitta and the ring radius in the spherometer equation. It is shown that a geometric mean value of the inner and outer ring radius should be used and that the value of the correction form is then very small. The Measurement of the Vertex Radius of Curvature of Parabolic Surfaces with a Moffitt Traversing Spherometer, J. PICHT. Optik vlO nil 1953 p 557-63 in German. The spherometer measures the position of a central probe held in contact with the parabolic surface. The probe ends in a small sphere and the relationship between the probe position and the zone radius is derived in terms of the parameters of the parabola and the probe radius. On a Method of Measuring the Radii of Curvature of Spherical Surfaces by Comparison, A. BIOT. Atti Fon- derie Ronchi, v8 Mar-Apr 1953 p 114-17 in French. By means of the Newton rings appearing between two spheri- cal surfaces in contact it is possible to find the difference AR between the two radii of curvature. With an ordinary microscope, provided with a micrometric eyepiece, the radii of any two rings can be measured, using nearly mono- chromatic radiation (wavelength \). If n'—n is the difference between the orders of interference of the two rings considered, then AR= \(n'—n)R 2 r' 2 -r> The Production and Inspection of Aerofoil Models, R. S. MARRINER, NPL. Machy (London) v83 Aug 14 1953 p 327-9. Describes process of machining delta wing type where the section progressively diminishes from root to tip. Inspection was by means of SIP universal measur- ing machine type MU214B. The Accuracy of Spherometer Measurements, S. MOHO- ROVlClC. Optik vll nil 1954 p 493-5 in German. Pre- vious methods of using spherometer measurements have required the approximate value of the radius of curvature to be used in a small correcting term. A re-arrangement of the equation is suggested which requires only measured values and the spherometer constants to be inserted to obtain an accurate value of the radius of curvature. The Measurement of Radius of Curvature of Proof Glasses with the Spherometer, H. JENSEN. Optik v 11 nil 1954 496-8 in German. The suggestion that the geometric mean of the internal and external radii of the spherometer ring should be inserted in the spherometer equation is criti- cized. It is said that either the arithmetic mean radius or the mean square radius gives smaller errors than the geometric mean radius. The Measurement of Radius of Curvature of Proof Glasses with the Ring Spherometer. II, J. PICHT. Optik vll nil 1954 p 499-504 in German. An extension of an exam- ination of the criticism by Jensen. The residuals arising from various methods of using the spherometer ring radii are calculated. Measurement of Radii, K. W. B. SHARP. Machy (Lon- don) v84 n2146 Jan 1 1954 p 15-20. Various methods for determining radius of circular arc on component ; appa- ratus for measuring radii of plate gages; measurement with surface plate and rollers; depth micrometer for ob- taining arc height ; methods using optical instruments ; coordinate method; equations given and degree of ac- curacy attainable with each method indicated. A Precision Spherometer, J. W. GATES, K. J. HABELL, S. P. MIDDLETON. J Sci Instrum v31 Feb 1954 p 60-3. The instrument described has been developed from the de- sign of Guild ; it is suitable for the accurate measurement of the curvature of transparent lenses and test plates, and particular attention has been given to protecting the sur- faces measured from risk of damage. A brief comparison with other spherometers is made, and, in conclusion, at- tention is drawn to the convenience of specifying optical surfaces by their curvatures, rather than by radius of curvature. A Note on the Design of the Spherometer, H. S. C. CHEN. Am J Phys v22 Sept 1954 p 374-5. A discussion is made of the errors involved in the use of a spherometer, and it is shown that the accuracy is limited by the accuracy with which the radius of the base circle is measured. A sug- gested change in design is given, which promises to mean easier manufacture and higher accuracy. A Note on the Accuracy of Measurement of Radius of Curvature of Proof Glasses with a Ring Spherometer, V. BLUMOVA, J. HRDLICKA. Optik vl3 n3 1956 p 122-7 in German. Previous papers have discussed the best approximation to the ring radius to be used in calculation of results of spherometer measurements. An exact equa- tion is derived and this is shown to give most accurate results if the mean square value is used to obtain the first approximation to the radius of the proof glass. 191 The Accuracy of Optical Measurement of Radius of Cur- vature, K. ROSENHAUER. Optik vl3 nl 1956 p 5-6 in German. Mechanical measurements of radius of curva- ture of proof plates have am accuracy of about lxlO- 4 of the radius. An optical method is described which depends upon bringing two reflected images to coincidence, and is said to have an accuracy of ±1 fi or lxl0~ 5 of the radius of 100 mm. Correction Tables for the Measurement of the Radius of Curvature of Proof Glasses with the Ring Spherometer, Z. CZERSKI. Optik vl3 n8 p 369-74 1956 in German. Numerical tables to assist in the rapid calculation for the cases considered by Jensen and Sehulz are presented. New Instrument for Measuring Camber on Large Rolls, P. W. HARRISON. Machy (London) v89 n2287 Sept 14 1956 p 642-6 ; Engr v202 n5250 Sept 7 1956 p 327-9. In- strument designed at National Physical Laboratory to measure camber of top surface on very large rolls such as those employed in paper making industry ; instrument makes use of Young's interference fringe patterns to pro- vide optical datum plane to which surface contour can be referred ; design details ; method of use ; performance of apparatus. Precision Measurement of Small Radii of Curvature, R. N. WILSON. J Sci Instruni v33 nl2 Dec 1956 p 487-8. Conditions for accurate measurement of small radii of curvature by microscope methods ; relevant formulas ; reference to work of J. Guild inasmuch as recent require- ments for precision measurement of radii of order of 5 mm have led to reassessment of techniques available ; ap- plicability in optical industry. Praezisionsmessungen mit Ringsphaerometern, K. ROSENHAUER. Optik vl4 n7-8 July-Aug 1957 p 328- 34. Precision measurement with ring spherometers ; dis- cussion of differences between mechanical and optical calibration of ring radius of spherometer ; it is possible to make precise measurements of radius of curvature pro- vided that effective radius of ring is calibrated optically. Method for Measuring Plane Curves by Series of Straight Lines, K. MIYAZAKI. Japan Soc Mech Engrs Trans v24 nl38 Feb 1958 p 93-8. Theory and experimental results for testing plane curves given as profile curves of templets, etc. based on principle of curves as series of straight lines ; relative errors of curves compared with standard curves by use of simple instrument. (In Japanese). Bestimmung des Kruemmungshalbmessers von Kugel (flaeche) n mittels Sphaerometers (Determination of curve diameter of spherical surface by means of spherome- ter), G. BERNDT. Dresden. Tech Hochschule Wiss Zeit v8 n4 1958-59 p 801-28, n5 p 1001-11, v9 nl 1959-60 p 77- 92. Critical study of method and instrument ; estimate of errors involved ; determination of curve diameter by direct measurement ; method for determining curvature by means of difference measurement. Measuring to Millionths with Standard Equipment, L. KICKMAN, M. HOSKINS. Tool Engr v42 n3 Mar 1959 p 117-19. Conventional electronic gaging components and fixtures can be used for measuring spherical and circular parts to six figure accuracy ; setup at Eli Whitney Memo- rial Laboratory, Sheffield Corp, Dayton, Ohio for measur- ing template having arc of approximately 100° with 4 in. radius is described ; instrumentation consists of two Ac- cutron amplifiers and Electrojeet cartridge or pickup unit. An Optical Device for the Measurement of the Radius of Curvature, A. I. OMEL'CHENKO, A. V. MOKHOV. Meas Techn 1958 nl Aug 1959 p 20-1 1 fig 2 refs. Trans- lated from Izmer Tekh nl Jan-Feb 1958 p 18. The paper describes the construction and principle of a new and original optical instrument based on the optical section principle and designed for the control of objects whose surface radius of curvature is small. The Measurement of Geometrical, Dimensional, and Posi- tional Errors of Technical Bodies by Means of the E-sys- tem, H. VON WEINGRABER, PTB. Microtechnic vl9 n4 Aug 1960 p 173-180 12 figs. Starts by considering the geometrically perfect form of a technical body to provide a unified spacial reference system for all errors of form and position. Defines form error, dimensional error, and positional error. Investigation of Method for Measurement of Convex Sur- faces, Z. REZNIK. Machy (London) v97 n2499 Oct 5 1960 p 786-8. In connection with need for measuring radii of large circular segments, instrument was made which comprised two balls carried by light rigid frame with dial gage located centrally between them ; data presented which enabled instrument to be correctly de- signd and dimensioned ; examples show procedure to be followed ; method described could also be used to check gages already in stock to determine their suitability for particular measuring applications. Kinetic Circuits of Devices for Continuous Testing of Components, N. M. KARELIN. Meas Techns 1962 n3 Sept 1962 p 181-4 5 figs 3 refs. Translated from Izmer Tekh n3 p 4-6 Mar 1962. The article deals with kine- matic schemes which can be used in designing testing devices for measuring component profiles described by curves which are widely used in production. Such curves include the ellipse, parabola, hyperbola, synoid and in particular cases limaeon and cardioid. Profiles whose components are described by the above curves include elliptical wheels ; elliptical webs of crank-shafts ; parabolic templets in secondary instruments for linearizing quad- ratic relationships, for instance, between the flow and pressure difference ; parabolic profiles, for instance, those of control gauges used in the optical industry ; cardioid cams in automatic machines, etc. Investigation and measurement of the Cutting Edges of Razor Blades, E. V. LORENTS. Meas Techns 1962 n6 Dec 1962 p 464-5 1 fig. Translated from Izmer Tekh n6 p 15-6 June 1962. The author used a method based on the utilization of diffracted rays by illuminating the cutting edge from one side. Primenenie metoda vytertykh lunok i ottiskov k izuch- eniyu iznashivaniya, V. P. MITROVICH, M. K. FOMI- CHEVA. Zavodskaya Laboratoriya v29 n2 1963 p 217- 18 ; see also English translation in Indus Laboratory v29 n2 Feb 1963 p 202-4. Use of scuffed-pit and replica methods in investigation of wear; method used in in- vestigation of wear to lead-screws of precision metal- cutting machine tools combine scuffed-pit and replica techniques and is suggested for measuring small wear, and profile of worn surfaces. Metrology for Ground Cams and Shapes, C. J. GREEN. Machy (NY) v69 n6 Feb 1963 p 83-93, 129. Three typical optical cam-contour reading devices which permit making extremely accurate and consistent readings ; types of tap- pets and their relative accuracy ; checking cam contours in toolroom : quality check and control ; contour, angular- ity and timing checks ; cam ramp design and how to measure base diameters ; new far superior cam contour composed of Infinite series of instantaneous radii of curvatures. Measurement of Small Radii of Curvature, I. M. PASTU- KHOV. Meas Techns 1962 n8 Feb 1963 p 652-3 2 figs. Translated from Izmer Tekh n8 p 26-7 Aug 1962. De- scribes contact indicating gage for checking radii of curvature between 0.03 and 2 mm. Computer Corrects Gaging Bias, J. R. GILSON. Tool & Mfg Engr v50 n3 Mar 1963 p 61-5. Studies made of 192 contour measuring systems at Livermore Laboratory, Sandia Corp, to determine what problems must be solved to increase gaging accuracy, data bias resulting from mis- placing part in coordinate reference frame of gage; math- ematical repositioning; application of computer analysis to gaging data permits increased inspection accuracy while reducing dependence on operator skill ; it eliminates need for nonfunctional datums previously used to ease fixturing problems ; other advantages. Effect of a Surface Shape Error on the Precision of Meas- uring a Circular Profile Radius, D. I. KOLPAKOV, V. V. M ATVEEV. Meas Techns 1963 n3 Sept 1963 p 192-4 2 figs. Translated from Izmer Tekh n3 p 10-1 Mar 1963. A me- thod for evaluating a radius by the chord and the height of segment cannot be recommended for testing ball bear- ing races because the radius evaluation error may be more than 8 times greater than the geometrical shape error which produced it. Kinematic Effects of Cam Profile Errors, M. D. ROGERS. R. R. SCHAFFER. ASME — Paper 63-WA-269 for meet- ing Nov 17-22 1963 8 p. Numerical analysis of profile errors has been developed : computer program conducts analysis of regularly spaced polar coordinate specifica- tions of cam profile; errors introduced in rounding off theoretical curves in incremental cutting are shown to correlate with accelerations determined from experi- mentally measured cam profile. Measuring the Critical Profile of Barrel Bearing Rollers with Microinch Sensitivity, F. FARAGO. Gen Motors Eng J vll nl 1964 p 17-23 14 figs. 1 ref. Describes a pro- cess for measuring the form of accurate surface elements of barrel bearing roller components by tracing a single surface element in rigorously controlled relation to other significant dimensions of the part. Two methods for Determining Minimum Radius of Curva- ture of Disk Cams, N. E. REID. ASME— Paper 64- MECH-20 for meeting Oct 19-21 1964 7 p. Analytical method of determination of minimum curvature radius of cycloidal disk cam without use of computer is given for case of flat-faced follower ; numerical values of minimum radius are obtained and tabulated for various values of parameters involved ; method is not suitable for cycloidal and harmonic disk cams when used with radial roller followers ; instead, solutions are obtained by using com- puter to solve equations and then tabulating minimum values. Recent Developments in Cam Profile Measurement and Evaluation, J. H. NOURSE. SAE— Paper 964A for meet- ing Jan 11—15 1965 47 p. New techniques are presented for cam profile measurement and evaluation based upon recently derived analytical methods and electronic com- puter programs ; new methods include mathematical re- finement of profile raw lift data and obtain following advantages, namely, accuracy, repeatability, evaluation and efficiency ; new acceptance criteria for cam profile quality control, and direction for further development of cam profile measurement and evaluation methods and techniques are suggested. 8.2. Contour Measurement by Optical Projection The Projecting Lantern, J. B. TAYLOR. Ilium Eng Soc Trans v 11 May 1 1916 p 414-35 12 figs. The early part of the paper summarizes the fundamental principles of optical projection, and also describes the means by which solid objects may be projected. L. C. Porter discussed the conditions in which electric glow lamps may be used for projection. Deals mostly with projection of slides. Note on Setting Up and Using the Gauge Projection Lantern. NPL. Jan 20 1917. Projection Method of Testing Screw Threads, F. D. JONES. Machy (NY.) v24 Apr 1918 p 735-8 8 figs. Arrangement and use of projection apparatus as applied to inspection of thread gages for munitions manufacture. Methods used in the New York Lab of the British Ministry of Munitions. Optical Projection Apparatus for Testing Gages. Engr. vl25 Apr 19 1918 p 346-7 3 figs ; Sci Am Supp v85 June 15 1918 p 380-1 3 figs. Details of British Horizontal projec- tion apparatus and the requirements and use. Extracted from "Notes on Screw Gages" by the staff of the National Physical Laboratory, Nov 1917. Projection Lantern for Thread Measurement, H. L. VAN KEUREN, E. C. GRIESS. Am Mach v49 nl8 Oct 31 1918 p 805-11 11 figs. The measurement of screw threads presents more kinds of difficulties than almost any other machine part. The apparatus here described has been developed at the Bureau of Standards and is proving very satisfactory, and in common with all developments of the bureau it is free to be used by anyone. The apparatus is easily handled and is well worth careful consideration. Optical Projection for Screw-Thread Inspection, J. HART- NESS. Mech Eng v41 Feb 1919 p 127-35 10 figs; Iron Age vl03 Feb 6 1919 p 357-8 2 figs. Analysis of screw- thread elements essential to strength and dependability; description of method for their accurate inspection. Optical Projection Applied to Inspection, H. S. BEAN. Inspector vl Sept 15 1919 p 25-30 7 figs. Description of apparatus developed and used by Bureau of Standards. Some Optical Aids for the Engineer, A. C. BANFIELD. Machy (London) vl4 Sept 18 1919 p 737-40 10 figs. De- scription of Wilson projection comparator. Operator avoids distortion by special twin optical system of such a nature that respective optical centers are adjustable to diameter of screw under test. See also p 613 650 705. Optical Aids for the Engineer, R. J. WHIBLEY. Machy ( London) vl5 Jan 8 1920 p 451-9 18 figs. Optical methods that have been developed at National Physical Laboratory, Teddington, England, for aiding inspection work in metrology department. Vertical Gauge Projecting Apparatus, National Physical Laboratory . Eng vl09 Feb 27 1920 p 273-6 14 figs. Stand- ard type designed in National Physical Laboratory, England, Nov 1917. Improved Type of Optical Projection Apparatus, L. A. FISCHER. Am Mach v53 Dec 16 1920 p 1158; Sci Am vl24 p 94 1921. Description and illustration of horizontal projection lantern developed by the Bureau of Standards. Increasing the Scope of Projection Apparatus, L. E. KING. Machy (NY) v 27 Jan 1921 p 463-4 3 figs. De- scribes improvement of gage holder for measuring dis- tances on thin flat work ; also a chart for measuring center distances. New Lantern for Screw Testing. Sci Am vl24 Jan 29 1921 p 94. Description of Bureau of Standards horizontal type projection lantern, which incorporates the protractor for measuring the thread angle of screws as a component part of the lantern. Mesure de l'Usure ou de la Deformation d'une Piece (Measurement of the Wear or Deformation of a Mechan- 193 ical Piece), P. BEURET. Rev Metallurgie vl8 Mar 1921 p 157-60 7 figs. Photographic projection of gears, screws, etc. Use of Optical Instruments in Machine Work. Am Mach v56 May 11 1922 p 697-701 19 figs. Describes the use of the microscope and projector in checking the shapes of formed tools and their products. See also Contour Measuring Projector by the Bausch and Lomb Optical Co. Inspecting by Optical Projecting. Machy (N.Y.) v28 Aug 1922 p 984-8 6 figs. Description of methods, with par- ticular data on screw and gear inspection. Bausch and Lomb contour measuring projector which can be used to measure thread gages, but is furnished with a univer- sal screw holder and adjustable thread chart which per- mits its use as a projection comparator for inspecting screws in quantity. New Projector Measures Wide Range of Precision Parts. Automotive Indus v49 Aug 23 1923 p 364-7 9 figs. De- scribes contour measuring projector, an instrument de- veloped by Bausch and Lomb Optical Co., for visual in- spection of screw threads, forms of gear and cutter teeth, and other parts ; accuracy of 0.0001 in. can be attained ; separate attachments make photographs. A New Projection Microscope. Eng vl37 June 27 1924 p 728. Description of Vicker's projection microscope in which the image is projected upon one of two ground glass screens, and on the other screen a microscopic trans- parency of a standard specimen is projected so that it may be readily compared with the object under examination. Optical Method for Testing Wire Mesh, D. P. MUIR- HEAD. Am Mach v62 May 14 1925 p 785. Optical pro- jection apparatus for determining number of meshes per inch. Measurement by Optical Projection, G. A. TOMLINSON. Optical Convention Proc Part I 1926 (3d London), p 311-26. The paper commences with a brief history of the development of the method of projection at the N.P.L. leading on to a description of the two types of apparatus, horizontal and vertical of N.P.L. design now widely used. A series of examples are then given, illustrating the wide range of the utility of the apparatus. Other projection apparatus of British manufacture is described, including the Wilson screw thread projector and the Beck projec- tion microscope for fine wire measurement. In conclu- sion the theory of the formation of the image is con- sidered briefly. Some Applications of Optical Projection to Engineering Practice, C. F. SMITH. Machy (London) v27 Jan 7 1926 p 473-5 6 figs. Describes instruments manufactured by scientific instrument makers, Adam Hilger, Ltd. Zeiss Measuring Machine. Machy (London) v27 Mar 18 1926 p 815-6 5 figs. Details of design ; principle of optical system. A Screw Projector, C. F. SMITH. Machy (London) v29 Oct 28 1926 p 103 3 figs. Instrument designed by writer to deal with screws of diameters varying from 2 to 10 inches in lengths between centers up to 16.5 inches of parallel or taper form ; illuminating system is arranged so that light may be directed along helix and lamphouse is pivoted about center approximately coincident with second nodal point of lens. Profile Measuring by Projection. Automobile Engr v20 Mar 1930 p 108-9 6 figs. Contour measuring projectors consist of highly perfected optical system and suitable mechanical parts to protect and support system, to hold work in position, and to provide necessary adjustment and means for making measurements ; work is illuminated by single-filament 108-watt Mazda lamp, in conjunction with transformer on alternating current. Projection Testing Apparatus, C. F. SMITH. Machy (London) v37 n954 Jan 22 1931 p 547-8 6 figs. Projector made for Coventry Gauge and Tool Company, by A. Hilger, Ltd. as applied to projection of contours of anvils used in Wickman screw gages. Vickers Contour-Projection Appartus. Eng vl39 n3609 Mar 15 1935 p 280-1. Apparatus made by Cooke, Trough- ton and Siinms intended for accurate gaging of screw threads, irregular templets and parts, cams, etc, and con- sists of optical system which projects magnified image of part to be gaged on to horizontal translucent screen, on which measurements can be made by scale or in other ways. Die Projektion in der Messtechnik (Projection in meas- uring technique), P. NICHTERLAIN. Werkstattstech- nik und Werksleiter v31 n23 Dec 1 1937 p 534-9. Optical and mechanical principles governing correct measure- ment ; influence of optical methods on accuracy and ef- ficiency ; ideal objects, such as templets, and sheet metal parts. Optical Projection, H. F. KURTZ, Mech Eng v60 n6 June 1938 p 469-73. Possibilities and limitations of most modern optical projection apparatus in industry con- sidered ; optical systems for use in projection ; results of projection test ; optical projection as means of compara- sion ; contour projector used as measuring device, Before Am Soc Mech Engrs. Jewel Inspection Microscope, F. E. J. OCKENDEN. J Sci Instrum n7 July 1939 p 228-30. Microscope incorpora- ting objective with built-in illuminator anl illuminating system described ; use of this device greatly facilitates measurement of radii of polished spherical surfaces by optical means, particularly when of order of 0.1 mm or less. Die mikroskopische Abbildung von Zylindern und Gewinden (The Microscopic Imaging of Cylinders and Threads ) , N. GUENTHER. Zeit InstrumtKde v59 n8 Aug 1939 p 315-21. The object of this paper is to derive those illumination apertures by which the geometrical data for cylinders and screw threads may be obtained within the limits afforded by the microscope. The mathematical treat- ment deals with the physiological shading limits, the shade limits of geometrical optics, the most favorable stops, and the determination of flank diameters and angles of threads. From a large number of measurements with different apertures, interpolation and error formulas have been derived. Measurement by Projection. Aircraft Prod v3 n33 June 1941 p 262-3. Description of Dekkor microprojector for measuring and checking machined parts. Dekkor Universal Measuring Projector. Eng vl51 n3934 June 6 1941 p 446-7. Principle embodied in instrument is that of making all linear measurements with aid of slip gages and micrometers, combined errors of which do not exceed 0.0001 in ; angular measurements are made by protractor having very high order of accuracy ; no draw- ing is required. Measurement by Projection. Automobile Engr v31 n412 July 1941 p219-20. Instrument and method suitable for large contours illustrated and described. Optical Sections. Aircraft Prod v4 n48 Oct 1942 p 610-11. Principles and applications of Taylor-Hobson section projector by means of which it is possible to take optical 194 sections in any plane through all types of gears, splines, and similar objects. Ueber ein interferentielles Verfahren zur Bestimmung der Formfehler an Bohrungen und Innenkegeln (Inter- ferential method for determination of form defects in drilled holes and internal cones), K. HOLECEK. Werk- stattstechnik und Werksleiter v36 n23/24 Dec 1942 p 481-86. Definition given of form tolerance and error; method described for determination of total form error for cylindrical and tapered holes, by comparing specimen with optically produced nominal form. Hilger Large Toolmaker's Projector. Machy (London) v62 nl591 Apr 8 1943 p 381-3. Illustrated description of projector which retains all mechanical advantages of toolmaker's microscope, and embodies stage of entirely new design capable of carrying work of considerable size and weight ; entire stage can be rotated over small angle enabling lining up to be quickly and accurately carried out. Optical Problems in Design of Comparator, F. J. ACTON. Machine Design vl5 nlO Oct 1943 p 81-4. Illustration, drawing and description of Postman optical comparator capable of handling parts of size formerly considered outside of range of optical inspection apparatus ; develop- ment of increased object-to-lens distance for greater opti- cal and mechanical capacity and increased illumination ; flatness problem solved by use of thick mirrors. Inspecting Turbosupercharger Blades — By Optical Pro- jection Comparator, E. C. POLIDOR. Iron Age vl59 n3 Jan 16 1947 p 40-4; Machy (NY) v53 n5 Jan 1947 p 185-8. Past and accurate method of inspecting blade and bucket profiles, using newly developed Pant-O- Jector ; operating principle is based on use of simple pantograph X and Y : Motion, tracing path of scribing end of pantograph on projection instrument at known magni- fication ; using beam of light to trace profile on special comparator chart indicates form of blade and also locates it in relation to center of gravity. New Machine Speeds Turbine Blade Contour Measure- ment, W. A. LLOYD. Iron Age vl62 n6 Aug 5 1948 p 76-8. Features of measuring machine employing com- bination of optics, light beams and photography, to meas- ure and dimensionally record contours and angular twists of mixed flow and axial flow compressor and gas and steam turbine blades ; machine will mechanically meas- ure to ±0.00025 in. across width of blade in increments of either 0.0125, 0.025 or 0.050 in. at speed of approxi- mately 0.375 in. per min ; setup and operations detailed. Societe Genevoise Contour Projector for Turbine Blades. Machy (London) v74 nl907 May 12 1949 p 637-9; Air- craft Prod vll nl29 July 1949 p 234-6. Description of type AP-14 profile projector developed by Societe Gene- voise d'Instruments de Physique, Geneva ; design incor- porates same optical system as firms AP-6 projector ; on new projector entire blade contour at any selected section is shown on screen at one time ; photographs, sketches. Precision Measurement of Rockwell Hardness Diamond Penetrators, F. R. TOLMON, J. G. WOOD, NPL. Eng vl72 n4460 July 20 1951 p 89-90. Photographs taken on Linnik interference microscope gave clear general impres- sion of shape and surface of tip of penetrator over re- stricted distance corresponding to axial depth 0.002 in. from apex of penetrator; photomicrographs. Inspection by Optical Projection Methods, E. C. POLI- DOR. Tool Engr v27 n2,3 Aug 1951 p 43-6, Sept p 52-4. Recent developments in contour measuring projectors ; arrangement of optical elements indicated ; requirements of projector used for inspection ; laying out of chart by drafting board technique and by scribing machine meth- ods; new types of chart lines facilitate accuracy and bring about other improvements; advantages of this inspection method ; planning for typical part ; importance of size and dimensions of parts ; illustrations. Evaluation of Small Radii of Curvature Using the Light- Profile Microscope, S. TOLANSKY, M. OMAR. Letter in Nature (London) vl70 Nov 1 1952 p 758-9. The light- profile microscope is applied to the measurement of the radius of curvature of a small metal sphere, calibration being performed by means of Newton's rings with a 0.6 mm sphere. Accuracy of \ ( U is attainable. The Optical Projection of the Profile of an Article at a Given Cross-Section, F. G. MORTON, V. E. GOUGH. J Sci Instrum. v30 Aug 1953 p 277-80. Two types of pro- jector are described which permit the continuous observa- tion of the sectional shape of a rod-like or thread-like object, of substantially constant cross-sectional shape, as the object is passed through the projector. The article may be of any length and may be flexible or rigid. The projection of sectional shape may be accomplished by two distinct methods. The first employs the projection of light scattered from the surface of an illuminated peri- pheral band of the object. In the second method the object is placed co-axial with a projection lens which receives scattered light from all points on the surface of the object under examination. The lens selects a thin section of the object and projects the peripheral shape of this section on to a screen. The application of these projectors to the continuous gauging of the outside dimen- sions of rubber tubing is described. Two Precision Projectors. Engr vl96 n5091 Aug 21 1953 p 252. Measuring projectors made by Hilger and Watts ; universal instrument performs normal comparison of projected image with template, and makes precise meas- urements in two mutually perpendicular directions over distances greater than area projected on screen ; lathe projector can do most of work required from normal projector ; profile of work, magnified to suitable degree, is clearly shown on screen together with cutting edge of tool. Inspection of Prismatic Bodies by means of an Optical Section and Application of this Method to Turbine Blades, J. TURRETTINI. Eng Dimensional Metrology, Proc of Symposium at NPL Oct 1953. Her Majesty's Stationery Office. Describes method of controlling optically inter- mediate sections of prismatic bodies. Variants of a New Spherometer Method, B. JUREK. Letter in Czech J Phys v4 Feb 1954 p 97 in German. Two alternative layouts of a double prism attachement, allowing the accurate measurement of radii of curvature l»v autocollimation, are described. Photometry of Microscope with Special Reference to Pro- jection, G. E. J. OCKENDEN. J Sci Instrum v 31 n9 Sept 1954 p 309-13. Transmission losses in microscope optical systems and their effect on brightness of both visual field and projected images estimated ; it is shown that production of large, well illuminated, projected images by means of microscope is subject to limitations for which only solution is provision of illuminants having higher intrinsic brilliance than any at present available. Blade-Profile Inspection. Aircraft Prod vl6 n9 Sept 1954 p 373-5. Comparator, based upon optical principles, and built by Taylor and Hobson, Leicester, for inspection of turbine blade profiles ; instrument is designed to project profiles of either shrouded or unshrouded blades upon ground glass screen, at magnification of X 10. Some Usual and Unusual Tool Room Measurements with Contour Projector, A. R. FULTZ. Tooling & Prod v20 7, 8, 9 Oct 1954 p 72-3, Nov p 61-3, Dec p 65-8 134. Measur- ing screw machine circular form tool on contour projec- tor; solution for overcoming phenomenon known as "wall 195 effect" which is found wnen fiat surface lies along line of light projection; inspection by contour projection of single point turning tool for side rake angle ; method for examin- ing punch and die indicated. An Optical Show-casting Miscroscope, S. TOLANSKY. Lab Prac v3 nlO Oct 1954 p 405-9. The heights of small objects can be measured from long shadows cast by illu- minating at a grazing incidence less than 5°. It is essen- tial that the objects should rest on a specially prepared surface which scatters light up into the microscope. The technique is described in detail and is used with shadow magnifications up to X2500. The technique is extended to include features on crystal surfaces by producing the appropriate scattering surface in situ on the crystal. Ex- amples from diamond, quartz and zinc crystals are illus- trated. In addition to measuring surface structural fea- tures, local enhanced contrast of topographical features results. Anisotropic Projector, R. B. LEIGHTON. Rev Sei In- strum v27 n2 Feb 1956 p 79-82. Optical projector having different magnificatons, 5X and 50X, in two rectangular directions ; although designed principally for rapid meas- urement of cloud chamber track curvatures, it has been applied to various situations in which plane-to-plane imaging at constant magnification is desired ; simple plano-convex cylindrical lenses are used as image forming elements. Measurement of a Profile in Coherent Light, J. C. VIENOT. Rev Opt v35 nlO Oct 1956 p 517-25 in French. The measurement of the diameter of a small object, such as a thread, is difficult with incoherent light because of the out of focus images of the third dimension. The diam- eter can be measured more precisely from the diffraction fringes formed with coherent light. Conditions are ob- tained for best definition and most accurate measurement. Sample results are quoted. Precision Measurement of Small Radii of Curvature, R. N. WILSON. J Sci Instrum v33. nl2 Dec 1956 p 487-8. The conditions for the accurate measurement of small radii of curvature by microscope methods are discussed and the relevant formulae stated. On the Improvement of the Precision of Microinter- ferometry. Investigations Concerninng Interference Spherometry, R. LANDWEHR. Zeit InstrumKde v66 n7 Aug 1958 p 134-8 in German. A geometrical analytical examination concerning the calculation of corrections in exact two-beam interferometry. The displacements aris- ing both from the small angle of inclination between the surfaces and also from the finite angles of the incident cone of light are computed. Tables of corrections are given for numerical apertures up to 0.65. The applicaton of these computations to the possibility of accurate inter- ference spherometry is discussed. Microinterference as an Aid to Testing the Shape of Aspherical Surfaces, R. LANDWEHR. Ann Phys (Leip- zig) Folge7 v4 nl-5 1959 p 154-66 in German. The testing of the strongly curved aspherical surfaces of rotation now so widely used can be carried out with a microinterference method. Measurements made over small regions permit an analysis of the whole. The theory of the method is developed in detail and the equations of the interference curves are derived. Interference curves are given for a paraboloid viewed in various zones and special cases are numerically evaluated. It is shown that the interfero- metric results are in agreement with spherometer measurements. Precision Measurement. Aircraft Prod v24 nl Jan 1962 p 18-20. Trioptic-maehine built by Soe Genevoise Instrum Phys, Geneva, Switzerland, for measurement in 3 axes; direct readings can be made to 0.0005 in. (0.001 mm) and estimated to % of direct readings, accessories include feelermicroscope, goniometric microscope and illu- minating-table ; readings of carriage and inspection-head movement are displayed on projection screens ; for longi- tudinal and transverse movement there are 2 dial indica- tors reading to 0.05 in. (or to 1 mm) ; accuracies for .** ordinate movements shown. New Comparator Gages-Photos on Glass, E. C. POL1- DOR. Am Mach/Metalworking Mfg vl06 nl5 July 23 1962 p 79. With special photographic process, glass charf gages are produced at Automation Gages that, inserted in optical comparators, give extreme accuracies needed to inspect jet engine blades ; more permanent than plastic charts, new chart gages are also cheaper and easier fc» prepare than conventional etched glass gages. High-Magnification Optical Projector, W. G. RIDGE. J. E. FURSE, P. W. HARRISON. Machy (London) vlO.1 n2593 July 25 1962 p 181-4. Reference made to prototype high magnification projector of horizontal type, described in article by F. R Tolmon, J. G. Wood ; projector was now redesigned ; with aid of accurately flat mirrors, optical path has been folded so that projector appears in rigid compact form ; observer can take readings and ad- just position of object while sitting in front of screen ; optical system described ; 2 special attachments of fine wire were made for projector. Accuracy in Measuring the Dimensions of Components bv the Shadow Projection Method, V. P. KORONKE- VICH, L. YA. GUSTYR'. Meas Techn 1962 n5 Nov. 1962 p 362-5 7 figs. Translated from Izmer Tekh n5 p. 5-9 May 1962. Article shows that, providing the illuminator is correctly adjusted, the accuracy of the shadow-projec- tion method is higher than that of the blade method. Advanced Optics Solve Quality-Control Problems. Machy (NY) v70 n7 Mar 1964 p 132-3. Timken Roller Bearing Co, having one of finest tool and gage laboratories in coun- try, uses universal measuring microscope called UMM, manufactured by Zeiss in West Germany ; its basic func- tion is measurement of irregular profiles, angles, radii and threads ; typical application is in measuring threaded components; one instrument can check all thread dimen- sions; it is also used in maintaining accuracy in master gages ; various applications of UMM, pertaining to manu- facture of precision bearings, are given. Ein Objective fur Profilprojektion (An Objective for Pro- file Projection), L. CANZEK. Optik (Germany) v21 nl2 Dec 1964 p 672-5 4 figs 1 ref in German. An objective for profile projection (magnification X50 and object — image distance about 1000mm) is described. Methods of cor- rection are given and the state of correction is discussed. 8.3. Measurement of Involute Contours All references under this heading are given in subsection 10.2.1. Addendum to Section 8 8.1. Measurement of Radius or Profile by Mechanical Methods Measurement of Macrodeviations in External Surfaces of Cylindrical Components. T. S. LOPOVOK. Meas Techns 1962 n8 Feb 1963 p 649-51 3 figs 1 ref. Translated from Izmer Tekh n8, p 24—6, August 1962. Microprofilo- grams of external surfaces are distorted because of errors in the center holes of measured components. The technol- ogy of producing better center holes was studied. 196 Section 9. Measurement of Screw Threads CONTENTS Page 9.1. General 197 9.2. Lead measurements.; 202 9.3. Wire and ball measurements of screw threads and other helicoidal features 205 9.4. Tables for ball, pin, or wire measurements 212 Addendum to Section 9 212 9.1. General A Microscope for Measuring Screw Threads. Am Mach v27 ptl n3 Jan 21 1904 p 78 7 figs. Illustrations show the microscope, the arrangement of the cross wires, and vari- ous adjustments. Instrument made by the Cambridge Scientific Inst. Co. for the Small Screw Gage Committee of the British Association, by whom it was placed in the custody of the National Physical Laboratory. A Device for Measuring Screw Threads, M. E. ANDER- SON. Am Mach v32 Oct 14 1909 p 665-8 11 figs. Il- lustrates and describes roller calipers which can be con- veniently adjusted to suit any angle of helix and to measure accurately threads of any lead. System evolved to meet the needs of the S. S. White Dental Mfg. Co. 12 or 15 years ago. Instruction a L'Usage des Etablissements Constructeurs pour la Reception des Vis et Ecrous au Filetage (Instruc- tion on the Usage of the Etablissements Constructeurs for the Receipt of Threaded Screws and Nuts), S. I. Ministere de la Guerre, Artillerie, Dec 23 1913. Includes a description of a comparator for checking pitch diameter of screw threads, which embodies V-shaped anvils for contact with thread. Also includes description of a lead tester. New Measuring Instruments and Measuring Methods in Automobile Manufacture. Horseless Age Aug 12 1914. Deals with the measurement of. screws and gears. How to Measure Screw Threads. Greenfield Tap and Die Corporation Bui nl Jan 1917 p 1-15. Gives methods of measuring screw threads. Gaging and Inspecting Threads, D. T. HAMILTON. Machy v23 n6 Feb 1917 p 477-86 Front 15 figs ( half-tones sections etc. ) tables ni-ix ; the same, ii. Machy v23 n7 Mar 1917 p 581-6, 7,000 words Figs 16-34 (half-tones, sections, etc.). Table i. British standard Whitworth threads.— Tolerances for bolts.— ii. British standard Whitworth screw threads, iii. Allowances to com- pensate for errors in pitch of British standard Whit- worth screw-threads, iv. Tolerances on included angle of screw threads. (The Engineering Standards Com- mittee), v. Tolerances on pitch diameters of U.S. Standard screws, taps and gages (loose fit tolerances), vi. Tolerances of pitch diameters of U.S. Standard screws (taps and gages close fit tolerances), vii. Propositions for Briggs standard reference pipe ring gages (Cadillac Motor Car Co.). viii. Propositions for Briggs standard reference pipe plug gages (Cad- illac Motor Co.). ix. Dimensions of ball points used in measuring screw threads. Part 2 consists of a general survey of devices for testing lead of taps and screws. Subjects taken up : simple device for testing lead of screw threads ; Well's indicator for testing lead of screws and taps ; indicating comparator for testing lead ; Wolfe dial indicator for testing lead of taps ; testing included angle of thread ; limit working and inspection thread gages ; limit, snap and plug gages for thread work ; limit snap gages for testing lead and pitch diameter ; indicating gage for inspecting lead and pitch diameter ; inspecting die chasers ; microscope for measuring screw thread gages ; projection method for measuring screw threads. Screw Thread Measurement, A. BROOKER. Eng vl03 n 2666 Feb 2 1917 p 113-6 ; n2667 Feb 9 1917 p 139-41 ; 2668 Feb 18 p 165-6. Figs 1-28 (half-tones diagrs section etc.) formulas. Contents : Section I. Introduction. — Section II. Definitions, p 113. — Section III. Methods of measure- ment. 1. Measurement of elements by microscope mi- crometer, p 114-6. 2. Diametrical measurements by floating micrometer, p 139. 3. Optical projection appara- tus. 4. Measurement of pitch by mechanical means, p 165. (Section iv. Concluding remarks, p 165-6. This paper was read before the Liverpool Engineering Society. Deals with the Whitworth standard system, and with the methods of measurement. See also Cambridge Scientific Instrument Co., title no. 79. First installment. Gives En- gineering Standards Committee definitions of configura- tion of screw and threads (effective diameter, core diameter, etc.) Author describes measurements of ele- ments by microscope micrometer method. In the second installment are described measurements of core diameter and effective diameter by floating micrometers. This is a method which makes possible taking measurements on the lathe during screw cutting operation, and also serves to check optical methods. The optical projection appara- tus method of testing form at root and crest of thread described, with suggestions as to use of photography. Third installment, describes new method for micrometric measurement applicable to male and female screws with addition of special optical device to indicate when thread of rotating screw has reached exactly same phase as at preceding measurement. Discusses importance of close measurement. Includes comparative illustrations. Table showing constants of 10 screw thread systems. The Microscope for Inspecting Screws, F. R. WIL- LIAMS. Am Mach v46 nl7 Apr 26 1917 p 736 350 words 1 half-tone illus. The microscope and the fixtures used in adapting it for testing threads. Author treats on accu- rate checking of hobs, taps, thread chasers, forming cutters and a number of other tools with cutting edges. ... He also refers to the chapter on "The use of the compound microscope in the toolroom" in the work under the title : Accurate tool work, by Goodrich and Stanley. 197 The Inspection of Screw Gages for Munitions of War, H. J. BINGHAM-POWELL. Am Mach v47 n25 Dec 20 1917 p 1065-73 incl figs 1-5 (half-tones). Contents: The measurement of the pitch. Devices for measuring pitch. — Pitch from thread to thread. — Leveling operations. Ring screw gages. Plug screw gages. The thread-micrometer principle. One wire better. Tolerance allowed. Illus- trations : 1. National Physical Laboratory projection machine. 2. Bingham Powell pitch machine. 3. Appar- atus for taking true casts or ring screw gages. 4. National Physical Laboratory screw measuring machine. 5. At- tachment placed in Pratt & Whitney measuring machine. Aim of author is to assist screw-gage manufacturers in their work of making gages for munitions of war, which have to be accurate within very low tolerances. Measurement of Internal Threads, W. S. ROWELL, Machy v24 n5 Jan 1918 p 429 incl 2 figs formulas. Recommends the use of an inside micrometer with ball points to assist in making and gaging internal threads. Precision Screw Measuring Machine. Machy (London) v24 Feb 1918 p 494-5 4 figs. Describes precision screw measuring machine made by the Cambridge Scientific Inst. Co. Ltd. for the Small Screw-Gage Committee of the British Association. For measuring major diameter, pitch diameter, lead, and angle of commercially produced screw threads and taps. The Measurement of Thread gages, H. L. VAN KEUREN, Chief of Gage Section, NBS. ASME J v40 nil Nov 1918 p 913-8 Trans ASME v40 1918 p 827^19. Contents : Meas- urement of plug thread gages, pitch, form and angle of thread, core diameter, full diameter, effective diameter. Choice of wires, standardization of wires, computation of effective diameter, precautions in making three-wire measurements. Test of ring thread gages : Measurement of pitch or lead, angle, thread farm, full diameter, core diameter, and effective diameter. A Machine for Measuring Screws, P. E. SHAW. Eng vl07 Jan 24 1919 p 104-8 16 figs. Methods described depend upon a simple point contact in all cases. The machine used deals with the diameters and the pitch and is of a simple type, easy to use. Mechanism consists of a beam rotating about its center, one end bearing by a special pin on the thread surface, the other end bearing by another pin on an optical lever. Beam has two motions, a rota- tion and a sliding action parallel with the axis of the screw being measured. Especially adapted to measuring ring gages. The Precision Measurement of Thread Gages. Can Machy v21 Jan 30 1919 p 113-5 4 figs. Commercial equipment manufactured by Arthur Knapp Eng Corp after models developed by Bur. of Standards. Automative Indus v39 p 1008-10. A New Screw-Measuring Machine, P. E. SHAW. Eng vl08 Dec 19 1919 p 816-7 4 figs. Suggested simplification of machine described in Eng Jan 24 1912 p 104. Principle employed is to measure profile of imaginary axial section of screw whether plug or ring. Messen und Priifen von Gewinden (Measuring and Verify- ing of Screw Threads), F. MEYER. Betrieb v2 Feb 1920 p 136-9 9 figs. Discusses measurement of pitch dia- meter, lead, and thread angle by means of a screw thread measuring microscope in which knife edges to contact the thread surfaces are used. Screw Thread Measuring Instruments. Eng Prod vl June 1920 p 221-5 13 figs. Machines designed by Metro- logy Department of National Physical Laboratory, Eng- land. Measuring Templets and Screw Threads with a Micro- scopic Measuring Machine. Am Mach v53 July 22 1920 p 187 ; Eng Prod v2 Jan 13 1921 p 40-4 12 figs. ; Machy (NY) v24 May 1918 p 791-3 5 figs. Construction and ad- justment of Alfred Herbert design of measuring machine and application for testing accuracy of templets or contour gages and screw threads. Zwei Apparate zur Messung von Gewinden and Lehren (Two Apparatus for the Measurement of Threads and Gages), F. GOPEL. Werkstattstechnik vl4 Nov 1 1920 p 559-63 14 figs. Description of a measuring machine with spirit-level indicator for determination of pitch of thread ; and an anglemeter for chasing tools based on principle of goniometer. The Bath Internal Thread Micrometer. Am Mach v54 n25 June 23 1921 p 1102; Machy (N.Y.) v27 July 1921 p 1070. An internal micrometer having sliding-wedge-op- erated threaded measuring jaws available with any num- ber of threads per inch in sizes from 1 to 5 inches in diameter. Die Messung des Flankendurchmessers (The Measurement of the Pitch Diameter), G. BERNDT. Betrieb v4 n3 Nov 12 1921 p 70-81 26 figs ; nlO Feb 18 1922 p 333-8 7 figs German. Nov 12 : Critical considerations regarding errors occurring in the measurement of flank diameter by different methods (thread micrometers, special microm- eters) wire methods and optical measurement. Applica- tion of the results to the allowable error in the measure- ment of pitch. Feb 18 : in the comparison of thread gages with standard gages by means of thread microm- eters, in measurement with a micrometer having ball con- tacts. Error of an inaccurate adjustment or positioning of the thread axis in the vertical plane in the measure- ment of flank diameter or pitch. It is absolutely neces- sary to measure on 2 oppositely leaning flanks and to take the mean. Gewinde-Messkomparator (Screw-Thread Measuring Com- parator), C. BUTTNER. Betrieb v4 Feb 11 1922 p 289-93 11 figs. Describes construction and function of a new Zeiss optical screw-thread measuring machine for maxi- mum accuracy, with which all thread dimensions can be determined. Sine Bar Fixture for Accurately Checking Thread Angles, Machy (NY) v28 May 1922 p 722. A sine J bar fixture attachment for a bench lathe comprising a pivoted plate carrying at one end a contact point accurately ground to the basic thread angle and at the other end a plug or button, which, with the plate pivot, comprises the sine bar, screws for adjusting the angular position of the plate, and a fixed block opposite the plug on the plate which serves as a reference point for taking micrometer meas- urements over the block and button. The fixture is first set to a master groove cut on a cylinder by aligning the contact point with the conical sides of the groove, and a micrometer reading over the block and button is taken. The master is then replaced by the work to be checked, and from differences between measurements taken when the sides of the contact point are aligned, first with one side of the thread and then with the other, the error in thread angle is determined. Work at the National Physical Laboratory. Machy ( Lon- don) v20 Aug 3 1922 p 558-61 7 figs. Internal effective diameter measurement of screw threads. Thread Measuring Devices, B. M. W. HANSON. Machy (N.Y.) v29 Aug 1923 p 946-8 4 figs. Describes different devices with special reference to lead-measuring machine. Inspection of Taper Thread Gages. NBS Letter Cir nl3 Oct 20 1923 27 p 15 figs. Describes methods of measuring taper screw thread gages, with seven tables of wire sizes, constants and other data. Uber Fortschritte in der optischen Gewindemessung (Re- garding Progress in the Optical Measurements of Screw 198 Threads), O. EPPENSTEIN. Zeit Feinmechanik v32 June 5 1924 p 115-7 6 figs. Communicated from Zeiss works in Jena. Discusses measurement of pitch diameter, using knife edges. Zeiss Thread-Measuring Instruments. Am Mach v62 May 28 1925 p 861-2 5 figs. Describes several thread-measuring devices, including screw-thread micrometer caliper, thread-profile gage, optical thread caliper and toolmaker's microscope. Herstellung der Gewindelehren (Manufacture of Screw Thread Gages), E. KREIS. Technik und Betrieb v2 n8 Aug 1925 p 253-62 22 figs 7 refs (In German). Describes measuring methods. For highest accuracy of measure- ment of thread elements of thread gages, author advocates use of optical means such as the Zeiss universal measur- ing microscope with contacting knife edges. Discusses inadequacies of wire measurements. The Measurement of Screw Threads. Mech Wld v81 Feb 11 Mar 4, 25 May 6 and June 24 1927 p 103-4, 159, 211, 320-321 and 446-447 18 figs. Coarser and finer tests; causes of inaccuracy ; temperature changes. Mar. 4 : Origination of screws : evolution of thread sections. Mar. 25 : Pitch errors ; effective diameter. May 6 : Adjustment of external gages, snap type of thread gage ; snap limit gage. June 24 : Microscopic methods of determining errors in screw threads. Devices for Thread Measurements — Methods and Equip- ment for Accurately Gauging Tap Threads, A. L. VALEN- TINE. Machy (London) v31 Dec 29 1927 and Jan 14 1928 p 417-21 and 476-8 14 figs. Dec. 29 : Accurate measuring devices suitable in quantity production plant ; Hanson de- vice measures to 0.000025 in. ; Wickman machine measures all dimensions of tap and other external and internal dimensions on plain, threaded, and tapered work ; measur- ing pitch diameter with wires and micrometers ; measuring root diameters with micrometers. Jan. 14 : Four gages for resharpened taps ; Wickman go and not-go gages ; device for measuring odd-fluted tools in process of manu- facture ; standard micrometer head, specially designed anvils and wires used ; formulas for taps with five flutes and Whitworth form of thread ; and international forms of threads ; formulas for three-fluted taps ; errors in meas- uring pitch diameter with wires ; device for measuring outside and pitch diameters of taper taps. The Measurement of Taper-Screw Thread Gauges, J. E. BATY. Machy (London) v32 Aug 16 1928 p 617-21 13 figs. Methods of inspecting outside, effective, and core dia- meters of taper screw plug gages, which are applicable to British Standard pipe, Briggs, American Petroleum Institute or any other standard thread and taper ; meas- uring fixture described and formulas for each computation given. Ein neues Verfahren zum Messen von Innengewinden (New Method for Measuring Internal Threads), A. HAERTEL. Zeit InstrumKde v49 n6 June 1929 p 301-1 4 figs. Principles of F. D. Jones, Machy v24 1918 p 35, have been improved by equipment described, which allows positive casting of small inside threading to be taken out undistorted in two parts. Machine for Measuring Up to One Hundred Thousandths of an Inch. West Mach Wld v20 n9 Sept 1929 p 329-30 4 figs. Description of Zeiss universal optical measuring machine for measuring dimensions of screw thread, in- cluding correct pitch diameter, and for checking, laying out, or spotting of all kinds of jigs, templets, and forming tools, measurements being made up to 0.00001 in. ; com- parison made with mechanical methods of measuring pitch diameter. Die Priifung konischer Normalgewinde (Testin* of Coni- cal Standard Threads), F. GOPEL. Werkstattstechnik v23 Oct 15 1929 p 586-90 7 figs. Communication from German Governmental Phys Inst; new equipment for measuring conical pipe-threading gages and results ob- tained with this ; testing of threads was carried out on basis of pipe specifications of American Petroleum Insti- tute and directions of U.S. Bureau of Standards. The Measurement of Internal Threads by Means of Casts, G. BERNDT. Mech Wld v86 n2234 Oct 25 1929 p 395. Method devised for measuring internal threads by means of casting ; some form of material used by which diameter, pitch, and angle of thread can be measured, and tools for making correspondingly correct external threads can be designed. From Werkzeug, p 157-63. Gewinde-Priifmethoden (Screw-Thread Testing Methods), H. PAMPEL, A. SOMMER. Automobiltechnische Zeit v32 n30 Oct 31 1929 p 689-93 13 figs. In connection with recently conducted investigations of thread tolerances, authors present detailed description of measuring and testing methods and equipment. Methods of Measuring Odd-Fluted Taps. Am Mach v71 n23 Dec 5 1929 Supp No 17 p 945 8 figs. Five methods of measuring type taps are described. Condensed from Nat. Screw Thread Commission Bulletin No 143 Oct 22 1929. Verbessertes Gewindemessgeraet (Improved Screw- Thread Measuring Equipment), F. GOEPEL. Zeit In- strumKde v50 Jan 1930 p 33^12 10 figs partly on supp plate. Measuring equipment described in Zeit Feinme- chanik und Praezision 1924 has been improved ; equip- ment and its applications are described. Ein neues Verfahren zur Messung von Innengewinden (New Method for Measuring Internal Threads), G. BERNDT, E. BOCK. Zeit InstrumKde v50 n6, 7 June 1930 p 375-84, and July p 407-16 7 figs. Principles of measuring methods based on use of balls and prisms and Universal measuring microscope, developed by University of Dresden and Zeiss Co., mathematical analysis of accu- racy and errors ; tables give instrument correction for Whitworth and metric thread. Flankenmessungen an Schnecken und Trapezegewinden (Measurement of Pitch Diameter of Worms and Trape- zoidal Threads), A. RICKENMANN. Maschinenbau/Be- trieb vlO nl9 Oct 1 1931 p 619-20 4 figs. Describes a spe- cial micrometer having three conical contacts for measur- ing worm and trapezoidal threads. Discusses measuring errors. Die Pruefung Konischer Innengewinde, (The Testing of Internal Taper Threads), A. WERNER, G. BOCHMANN, R. LEHMANN. Zeit InstrumKde vl Jan 1932 p 14-9. Methods and equipment for measuring internal dimensions of ring gages for taper threads developed by Physika- lische-Technische Reichsanstalt, according to specifications of American Petroleum Institute. Die Messung des Flankendurchmessers dreinutiger Gewindebohrer (The Measurement of Pitch Diameter of Three-Fluted Taps, G. BERNDT. Zeit InstrumKde v52 July 1932 p 307-19, and Aug p 353-64; Sept p 408-16. Mathematical analysis of accuracy of methods of meas- uring diameter of taps with three flutes, including use of wires, cones, cylinders, prisms, etc. ; experimental veri- fication. Fortschritts und Forschungen auf dem Gebiete des technischen Messwesens (Progress and Research in Field of Technical Measuring Methods). G. BERNDT. Maschi- nenbau vl2 n5 Mar 2 1933 pll8-21. With particu- lar regard to equipment for measuring screw threads and gears. Bibliography. 199 771-846 O — 66- -14 Das Messen von Saegegewinden (Measurements of But- tress Screw Threads), W. KNEDEL. Werkstattstechnik und Werksleiter v29 n3 Feb 1 1935 p 50-2. Outline of measuring methods with data on calculation of face diam- eter and of gage wire. Optical Inspection of Screw and Worm Profiles, C. F. SMITH. Machy (London) v46 nll79 May 16 1935 p 185- 9. Limitations of optical thread inspection ; method of determining whether interference is present ; optical sys- tem providing compensation for varying helix angle ; Matrix projector. Untersuchungen von Gewinde-Rachenlehren ( Study of Screw-Thread Micrometer Calipers), H. SCHORSCH. Wertstattstechnik und Werksleiter v29 n21 Nov 1 1935 p 419-21. New method recommended for adjustment of calipers in which natural weight is changed by additional weight. Also published separately as a book. Gewindemessungen (Screw Thread Measurements), G. BERNDT. VDI Zeit v80 n48 Nov 28 1936 p 1455-60. Outline of various methods and equipment at present available for measurement of screw threads. Bibliog- raphy. Measuring Plating on Screw Threads, E. C. ERICKSON. Bell Lab Rec vl5 n6 Feb 1937 p 187-9 ; Wire & Wire Prod vl2 n3 Mar 1937 p 144-5. In absence of any standard gag- ing apparatus which could be used to make determina- tions accurate for ascertaining thickness of coatings on finished screw threads, optical contour projector was de- vised to determine such measurement ; apparatus and methods used, with special reference to screws used in telephone apparatus. The Measurement of Pipe Threads, B. B. WESCOTT, Am. Petroleum Inst June 3 1937. A critical discussion of the various instruments available for the purpose and sug- gestions regarding a proposed standard measuring practice. Machine for Measuring Plug Screw Gauges in Quantities, F. H. ROLT, A. TURNER. Machy (London) v52 nl352 Sept 8 1938 p 701-2. Illustrated description of machine for measuring diameters of batches of gages of same no- minal size ; machine closely resembles floating micrometer type of screw measuring machine ; only difference is in fittings of upper measuring carriage ; in present machine these units are replaced by adjustable anvil and measur- ing indicator. Begriffsbestimmungen in der Gewindemesskunde (De- finitions in the Science of Thread Measurement), G. DIETTRICH, Maschinenbau vl8 nll/12 June 1939 p 289-93. Measurement of screw threads ; geometric re- lations explained and universal rules generally applicable in measuring practice given. Genaue Innengewindemessung durch ausschraubbare Gewindeabguesse, L. TSCHIRF. Werkstattstechnik und Werksleiter v33 nl9 Oct 1 1939 p 467-9 ; Pratique des In- dustries Mechaniques v23 n4 Jan 1941 p 89-91. Accurate measurement of internal screw threads by molds which can be unscrewed ; descriptions and principles of system. X-Ray Measurement of Internal Screw Threads, R. C. WOODS, E. K. HIGHT. Aero Digest v38 n5 May 1941 p 199-200. Methods used at Bell Aircraft Laboratories for measurement of internal screw threads ; radiographic procedure as routinely applied is illustrated. Optical Projector for Measuring Tapered and Square Threaded Screws, J. W. DRINKWATER. Machy (Lon- don) v62 nl590 Apr 1 1943 p 353-4/ When measuring ef- fective diameter of tapered screw plug gage, it is essen- tial to relate measurements to position of thread along taper; optical projector described is used in conjunction with thread form layout, to find start of thread on tapered screws. Measurement of Large Ring Screw Gauges, J. W. DRINK- WATER. Machy (London) v64 nl638, 1647 Mar 2 1944 p 238^0 and (discussion) May 4 p 49-56. Illus- trated description of omtimeter (E. H. Jones, Ltd.) which is optical comparator arranged for measurement in horizontal plane ; principle of measurement is to com- pare ring under examination with assembly of Matrix slip gages and pair of adapters arranged to simulate perfect ring gage. Measurement of Screw Thread Gages. Ordnance Inspec- tion Handb on Gages, ORD-M608-5-See 800 Sept 1944 p 110-11. Inspection Gage Sub-Office, Office of Chief of Ordnance, U.S. Army. Describes measurement of thread plug, ring, and snap gages. Simplified Inspection of Thread Gages F. W. BOECKEL. Tool Engr vl4 nil June 1945 p 29. Illustrated descrip- tion of simple fixture, in combination with three wire method, which provides easy checking of pitch diameters of pipe thread gages ; method provides accurate means of analyzing many perplexing problems associated with pipe thread inspection. Two Screw Thread Measuring Devices. Eng vl81 n4703 Mar 1 1946 p 208. Brief illustrated description of simple means of measuring effective diameter of screw thread, introduced by Thos. Firth and John Brown ; first is by means of ascertaining points on flanks of thread vee where width is half of pitch ; second effective diameter meas- uring instrument is comparator arranged for use by setting with standard thread. See also Machy (London) v68 nl757, p 756-7, June 13, 1946. Internal-Thread Comparator. Eng vl62 n4201 July 19 1946 p 55. Illustrated description of instrument de- veloped by Machine Shop Equipment, Ltd, for rapid and precise measurement of effective diameter of internal screw threads ; it consists of beam, on which slide pair of heads carrying brackets furnished with projecting ball tips, and dial indicator. Measurement of Straight - Flanked Helicoids, J. W. DRINKWATER. Machy (London) v69 nl762, 1764, 1767, July 18 1946 p 77-82, Aug 1 p 139^3, Aug 22 p 235^0. Methods of mathematical treatment for determining re- lations existing between radius and rake of measuring cylinder, thread form, effective diameter and helix angle ; effect of helix angle from zero to 90°, including straight splines ; thread angle in axial, normal and transverse sec- tions considered for screw threads, taps, hobs, spiral broaches and gears. On the Influence of Periodic Screw-Error on the Density Distribution in Spectroheliograms, V. VON KEUSSLER, Zeit Astrophys v24 n3-4 p 233-9 1948 in German. Even small periodic errors of the order of 0.002 mm prove very disturbing. A new device for testing measuring-spindles is described. Gauging of Precision Screw Threads, A. C. PRULIERE. Microtechnic v2 n2, 3, 5, 6, Apr 1948 p. 71-8, June p 115-22, Oct p 222-8, Dec p 234-40. Description of dif- ferent methods such as Zeiss measuring prism method, optical-mechanical and mechanical method ; illustrated description of measuring apparatus. Comparator-Chart Inspection of Tapered Pipe- Thread Gages, K. A. CLARK. Machy (NY) v54 nl2 Aug 1948 p 165-7. Inspection practice at Lockheed Aircraft Corp., in use of comparator charts to check pitch diameter, gaging notch diameter, taper, angles, and forms of pipe thread production gages ; charts are designed to provide all contours and check points necessary for inspection of 200 each of National pipe thread standard pitches, as outlined in Army-Navy Specification An-GGG-P-363. Ein stufenloses Schaltgetriebe hoher Genauigkeit (A Stepless Switchgear of High Accuracy), A. BUDNICK. Werkstattstechnik und Maschinenbau v39 n2 1949 p 45-8. High precision apparatus with stepless switchgear for measuring cylindrical milling cutters and spiral shaped objects ; indicator motion in measuring slide by precision spindle screw and frictional transmission ; indicator is set up at angle by set of permanent and varying gears with holes on rim ; measurement errors do not exceed 4X10" 5 in. ; photographs, table. Gauging and Measuring Screw Threads. NPL Notes Appl Sci nl 1951 109 p 7 supp plates. General definitions and symbols; gaging of parallel screw threads; errors of screw threads ; control of accuracy of pitch ; hardness of screw gages ; measurements of parallel screw plug and ring gages ; inspection of parallel screw ring gages with check plugs ; testing of screw caliper gages ; optical projection apparatus; gaging of taper screw threads; measurement of taper screw plug and ring gages. (See also 1958 edition.) Interferometric Calibration of Precision Screws and Con- trol of Ruling Engines, G. R. HARRISON, J. E. ARCHER. J Opt Soc Am v41 Aug 1951 p 495-503. A new device is described with which screws of any length can be calibrated rapidly for both periodic and cumula- tive errors in terms of interference fringes. It can also be used to plot correction cams to remove fixed errors of translation or rotation, and to monitor the operation of an engine while ruling diffraction grating or scales, cor- recting by automatic feedback differences between the actual carriage position and its proper position as shown by an optical interference field. The "Commensurator" (i.e. for over-coming the incommensurability of the wave- length of the light used for calibration and the lead of a screw) consists principally of a screw drive system, eight-figure dials, and a generator, geared together in ratios that can be controlled to one part in 10 8 . Fringes produced by a Michelson interferometer are changed photoelectrical^ to a wave train that measures transla- tion to within 0.1/i in. A second wave train of almost identical average frequency is produced by the Commen- surator generator to measure screw rotation, and the two trains are continuously compared by means of a phase- sensitive amplifier and motor to within 1/100 cycle or fringe. Corrections for changes in barometric pressure or in temperature can be introduced during operation. Transient as well as fixed errors of run and period can be automatically compensated for. If the fringe system is lost, it can be re-established from the Commensurator record, so that controlled ruling of gratings wider than any available coherent fringe-field appears possible. Die optische Messung von Aussengewinden (Optical Measurement of External Threads), G. BERNDT, K. H. KUEBLER, Dresden. Tech Hochschule Wiss Zeit v2 n2 1952-53 p 199-213, n3 p 467-78, n6 p989-1000. Part 1 : Measurements of threads with symmetrical profile. Part 2 : Threads with asymmetrical profile. Part 3 : Measure- ment of identical threads. Screw Gauge Measurement Gives Continuous Record, P. W. HARRISON. Mach Feb 14 1953 p 250. An electric measuring head replaces the indicator of the floating micrometer-diameter measuring machine designed by the National Physical Laboratory. It thus shows variations in effective diameter to be continuously recorded. Methods and Instruments for Thread Gauge Inspection, C. A. LE BOURHIS (Laboratoire Central de l'Armement, France). Proc of Symposium on Eng Dimensional Metro- logy, H. M. Stationery Office, vl Paper 5 Oct 21-24 1953 p 81. Describes some methods and instruments which have proved efficient in daily practice. Methods and Equipment of the Physikalisch-Technische Bundesanstalt for the Inspection of (A.P.I) Taper Thread Gauges, K. BURGER, M. GARY. Proc of Sym- posium on Eng Dimensional Metrology, H. M. Stationery Office, vl Paper 6 Oct 21-24 1953 p 97. Discusses meas- urement of pitch cone diameter, lead, taper of ring gages, and thread angle, 14 refs. Effect of Differences Between U.S. and British Practices in Measuring Screw Gauges for Unified Threads, L. W. NICKOLS. Machy (London) v90 n2315 Mar 29 1957 p 723-5. American and British methods of measuring ef- fective diameters of screw plug gages and setting plugs ; effective diameter measurements made at single specified position on each of five screw plug gages having unified threads in order to determine experimentally effect of differences between two methods. The Effectiveness of Various Contacting Elements Used for Gaging and Measuring Pitch Diameter, S. G. JOHN- SON. Johnson Gage Co. Bui n400 May 15 1957. Con- trasts cone and-vee method against three-wire method of measuring pitch diameter. Thread Gage Measurement, G. H. STIMSON. Automatic Machining Mar 1958 p 31. Points out some of the con- ditions which contribute to inaccurate results, and the measures which must be taken to avoid them. Screw Thread Flank Tester, O. ENDO, N. HOSHINA, Y. YOKOYAMA, M. SAWABE, S. SUKIGARA. Rept Cen- tral Inspection Inst of Weights and Measures, Japan, v9 n4 rept 24 1960, vlO n3 rept 27 1961 in Japanese. A new screw thread flank tester is developed in order to determine the flank profile and the half-angle of the thread. The tester consists of bed, sine-table, column, carriage, electronic micrometer and pen-recorder. The measuring method is as follows. A screw threaded gauge to be examined is set on the sine-table which can be inclined by the nominal half-angle of the thread by using the angle gauge block. Then the generator of the upper flank of the thread which lies in the vertical plane containing the line of the greatest slope of the sine-table is to (become parallel to the direction of the displacement of the carriage carrying the detector. The stylus of the detector is brought into contact with the upper flank and the carriage is driven horizontally by the feed motor. The deviation of the profile of the flank from that of ideal one is detected by the differential transformer. The recorded profile of the flank has the vertical magni- fication of 3200 and the horizontal magnification of 50.0. The error of the half-angle of the thread may be deter- mined by the ratio of the deviation from the horizontal line to the horizontal displacement of the stylus. The measuring error of the half-angle of the thread due to the fact that the line of the direction of the stylus dis- placement does not literally intersect the center line of the gauge is estimated. The measuring accuracy of the flank profile being able to be kept within ±0.3/*, the half- angle of the thread can be measured with an accuracy within ±2.0' in the case of the ring of the diameter 50 to 600 mm or the plug 50 to 140 mm. Lastly there are given some illustrations on several flank profiles which are recorded by the tester of some screw thread gauges. In the measurement of the half-angle of the thread carried out by a screw thread flank tester developed at the NRLM, it is unavoidable that the line representing the direction of the stylus displacement can not literally be made to intersect with the axis of the screw thread and, therefore, an unnegligible error produces, especially when the diameter of the screw thread is small. A proce- dure for correcting the above mentioned error is found out by treating this measuring method mathematically, and yet this correction is able to be given by a convenient nomogram. 201 Microscope for Measuring Internal Threads, A. I. OMEL'CHENKO. Meas Techn 1959 n8 July 1960 p 584-6 4 figs. Translated from Izmer Tekh n8 Aug 1959 p 7. The described microscope for measuring internal threads provides better measurements than other methods of the three basic internal thread elements with a nominal diameter of 18 mm and over. The instrument is based on the double microscope of Academician V. P. Linnik. Note on Measurement of Rake Angle and Relief Angle of Taps and Dies, K. EDENSOR. Machy (London) v97 n2507 Nov 30 1960 p 1237-9. Measurement requires set- ting of graticule cross line so that it is tangential to circle, method described provides means for positive loca- tion of tangent. Further Report on the Effect of Differences between U.S. and Britsh Practice in the Measurement of Screw Gauges for Unified Threads, P. W. HARRISON. Machine Shop v22 n4 Apr 1961 p 207. Measuring the Profile Angle of Internal Conical Threads, A. A. KHAIROV. Meas Techns 1961 n7 Dec 1961 p 521-4. Translated from Izmer Tekh n7 July 1961 p 6-7. De- scribes an electrical contact instrument for measuring half the profile angle of internal threads with a pitch of 6 and 6.35 mm. With an appropriate change in the dimen- sion of the electrical contact head it is possible to measure profiles of threads with a pitch of 5 mm. Measurement of a Large-Size Internal Buttress Thread Mean Diameter, N. V. SERGEEV. Meas Techns 1963 n2 Aug 1963 p 100 1 fig. Translated from Izmer Tekh n2 Feb 1962 p 8. Describes a micrometer hole gage for meas- uring a buttress thread 600 mm in diameter. Interference Method for Measuring Thread Elements, V. P. KORONKEVICH, L. YA. GUSTYR', A. N. RAZUVAEV. Meas Techns 1963 n2 Aug 1963 p 100-7 5 figs. 8 refs. Translated from Izmer Tekh n2 Feb 1963 p 8-14. If the distance between the first fringe and the edge of the shadow contour is evaluated, it becomes possible for this fringe to be used as a setting line instead of the gradua- tion of a measuring knife-edge. The application of inter- ference fringes for measuring the mean thread diameter and the dimensions of components which have a curvature along the optical axis is beset with certain difficulties which, in the first place, consist of the effect of microscope focusing on the distance to the first interference fringe and of the effect of the light-beam aperture on the inter- ference pattern. This article aims at elucidating the effect of these factors. Technique for Galibraton of Large Thread Gages, H. E. BROUSSEAU. ASTME Tech Paper 590 1964 14 p 6 figs 1 ref. Annular shaped thread gages remain mounted on the arbor as processed in manufacture. The arbor center holes locate the axis of the gage, permitting measurement of lead and helical variation. Gages over 8 in. in diameter are inspected on a modified optical comparator. Special holding fixtures and underside projection are used. Combined Micrometer and Sensitive Indicator Unit, W. F. ATKINS. Quality Engr v28 n4 July-Aug 1964 p 118-9. Combined micrometer and fiducial indicator unit capable of measuring to accuracy of about 0.25 r m is described ; unit is intended for incorporation in measuring machine of type used to measure screw plug gages of sizes above about 12 in. diam ; it enables operator to watch movement of indicator pointer and micrometer simultaneously ; unit described is equally suitable for measuring diameter of sizes down to about 4 in. Combined Micrometer and Sensitive Indicator Unit, W. F. ATKINS. Machy (Lond) vl05 n2697 July 22 1964 p 271-2. To overcome difficulty when measuring work pieces of large diameter, design was produced at National Physi- cal Laboratory in which micrometer and fiducial indicator are combined in single unit that can be mounted on ma- chine ; external and sectional views of unit are described ; unit was fitted to diameter measuring machine used at NPL for checking API screw plug gages. 9.2. Lead Measurements Note on an Instrument for Measuring Screw Threads, H. J. C, Standards Dep, Board of Trade, Westminster, Oct 1 1901. A design of a measuring instrument, the Vis- ometer, for measuring the angle and pitch of a screw thread. Determining the Errors in Screws, R. A. BRUCE. Am Mach v27 Apr 7 1904 p 454-5 5 figs. Miscroscope and. scale arrangement for determining lead errors of lead screws, with a micrometer for measuring the magnitudes of the errors, a contact point being inserted in the thread space, and a cross hair of the miscroscope being set on the scale divisions. Measuring the Pitch of Nuts. GB NPL Rep 1906 p 43. A carriage actuated by an accurate guide screw can slide along a bed A, and on the carriage is a second slide B making an angle 62y 2 c with the slide A. On slide B is a pivoted lever arrangement. The nut is set up with its axis parallel to slide A, and the arrangement is such that when the lever point on slide B is brought into con- tact with the side of the thread any movement of the point in the direction of the slide B causes no displacement of the lever, the angle being 55°. This acts as an indicator of contact between the point and the side of the thread, and by means of the guide screw the pitch may be measured. Testing the Lead of Taps and Screws, E. OBERG. Machy (NY) vl4 Jan 1908 p 317-8, 4 figs. Describes testing the lead by gages and comparators for the lead of taps and screws. Testing the Lead Screw of a Lathe, E. R. CONNERS. Am Mach v31 Nov 19 1908 p 751. Uses micrometer to measure motion of carriage. Testing Pitch of Micrometer Screws, H. L. WHITTE- MORE. Am Mach v34 Mar 9 1911 p 437-8 3 figs. Optical lever device for testing uniformity of pitch and diameter. Calibration of New Screw-Measuring Machine, A. J. LEE, H. B. STEELE. Astron J v30 May 5 1917 p 128-9. De- scription of tests of a new measuring machine designed by F. Schlesinger and made by Gaertner of Chicago. The screw is 18 mm. in diameter and has 249 threads of 1 mm. pitch. The periodic error was found to have a max. value of 0.00013 mm., which is negligible in all work with stellar images. The progressive errors were determined for every cm. of the screw, with a temperature range, during the measurement, of 1.3° C. They are small and negligible for the work in view. Screw Thread-Lead-Testing Machine, West & Dodge Co., Am Mach v48 May 30 1918 p 931-2. Machy (NY) June 1918 p 949-50. To test the lead of threads the contact point is placed in position in one of the threads and the micrometer spindle adjusted so that the dial indicator points to zero. The point is then moved along a number of threads and micrometer readings taken. Drunken threads are detected by turning the gage partway around and again measuring. The dial indicator is not used for obtaining the actual measurements, but only to show the correct amount of pressure to apply on the micrometer spindle. The large graduated wheel gives readings to 202 0.0001 in. if desired and a solid plug can be used in place of the indicator spindle and Johansson blocks used between contact points on the base. Sheffield Thread-Lead Testing Machine for Screw Gages. Am Mach v49 n4 July 25 1918 p 180 incl 1 half-tone. Description of a testing machine for the lead of screw- thread gages. The machine has been placed on the market by the Sheffield Machine and Tool Co., Springfield, O. Coats Lead Testing Machine. Machy (N.Y.) v24 Aug 1918 p 1150 2 figs. A lead measuring machine in which a fluid gage is used as indicator and measurements of lead are made by means of precision gage blocks. Thread-Lead Testing Device. Arrow Tool Co., Am Mach v50 Mar 13 1919 p 517-8. To use the device the gage to be tested is placed on the centers and tightened. One of the gaging points is then brought into contact with the gage, observation being made against a piece of white paper or other reflecting material laid on the base. After this adjustment is made the slide is clamped, and the measuring spindle of the micrometer head, which has been brought to some predetermined reading is brought into contact with the raised hub, and slide is then clamped. The micrometer spindle is then turned back, the first gaging point is withdrawn and the second one advanced to contact with the thread. The gage under test must not be allowed to rotate on the centers. If any error exists it must be met moving the slide along the slideway until the second gaging point is in contact. When this is done the variation from true lead is measured directly plus or minus with the micrometer. Checking the Accuracy of Lead Screws. Machy (N.Y.) v28 July 22 1922 p 903-4 3 figs. Lead screws are checked by determining the distance that the nut moves for a given rotation of the screw. Measurements are made by means of a micrometer and end standards, using P. & W. measur- ing machine. The Mechanical Measurement of Pitch, H. T. WRIGHT. Machy (London) v23 Nov 22 1923 p 236-9 8 figs. Method of recording and analysis of test results ; describes pitch- measuring machines. John-Sons Screw Thread Lead Tester and Comparator. Am Mach v61 July 10 1924 p 79. Made in two sizes, No. to y 2 " and %" to 1%". The cradle of the screw is com- posed of annular gaging elements which are free to rotate on their holding stud and, with the exception of one fixed roll, can also move laterally to adapt themselves to the lead variations of the screws to be measured. A wedge- shaped plunger which runs in a groove in the "indicator roll" is elevated against the spindle of the indicator, when the screw is placed in the cradle, and provides the means by which the lead errors are recorded on the indicator. The indicator is set to zero by masters. Steigungsprufer fur Leitspindeln (Pitch Testers for Lead Screws), H. WILDE. Zeit fur Feinmech und Prazision Dec 15 1926 p 265-8 6 figs. Describes Zeiss optical instru- ment and gives examples of measurements. Screw Thread Pitch Measuring Machine. Machy (N.Y.) v33 May 1927 p 710-1 2 figs. Am Mach v66 May 5 1927 p 752-3, 2 figs. Apparatus brought out by Societe Gene- voise d'Instruments de Physique, Geneva, Switzerland, embodying a micrometer having a range of 4 in. and a knife-edge multiplying lever system sensitive to 0.00001 in. as the indicator. Machine is adapted to the measurement of both internal and external threads. It will hold plug gages up to 6 in. in diameter and 8 in. in length, and has a travel of its micrometer screw of 4 in. Michigan Spiral Gear Lead Checking Fixture. Am Mach v75 Sept 3 1931 p 395. This spiral-lead checking fixture will handle spiral gears up to 16 in. in diameter and with any lead of 10 in. or over, either right or left-hand. The gear is mounted on a stub arbor or between centers up to 12 in. in length. The fixture is of the sine bar type. Mounted on top and towards the sides of the gear carriage are two lapped surfaces which drive the work spindle by contacting two friction rolls. These rolls cause the spindle to rotate in timed relation with the movement of the carriage on which the indicator is mounted. National-Cleveland Helical-Gear Checking Device. Am Mach v75 Nov 26 1931 p 830. This device is shown at- tached to the Model "B" gear checking machine, and may also be attached to the Model "C" machine. In addition, it is furnished as a bench type, or mounted upon a pedestal stand. The helical gear is mounted upon a stub shaft carried by a slide, which is moved so that the teeth of the gear engage the teeth of the rack. The reading of the angle thus established is taken direct from the large drum. The device will check right or left hand helical gears. When mounted on a pedestal the device may be placed in the production line to permit 100 per cent inspection, "Detroit" Lead Testing Instrument. Am Mach v75 Dec 17 1931 p 939-40. Measurement is made by means of a spiral micrometer and microscope, supported on a carriage and focussed on an optical scale. The carriage is fitted with a spring-loaded plunger, carrying at its extremity a remov- able ball point, which engages two adjacent threads of the piece. This plunger mechanically locates the carriage. Maximum error does not exceed a total of 0.00018 in. for the 8-in. length. Develops Machine for Testing Lead of Helical Gears. Iron Age vl33 nl3 Mar 29 1934 p 35; Machy (N.Y.) v41 n3 Nov 1934 p 150-1 ; Automobile Engr v24 n319 May 1934 p 187. Details of machine introduced by Lees-Bradner Co., Cleveland, Ohio, which accurately measures helix angles or lead of helical gears, and also calibrates machine settings. New Helical Lead Checking Machine. Machy (N.Y.) v41 Nov 1934 p 150 2 p 3 illus. Details of machine introduced by Illinois Tool Works, Chicago, 111. for determining the accuracy of helices. New Helical Lead Checking Machine. Machy (London) v46 nll95 Sept 5 1935 p 690-1. Machine, marketed by Illinois Tool Works, Chicago, for determining accuracy of helixes, has capacity for gears up to 12 in. in diam and will take work up to 15 in. between centers : checks helix angles from to 90°. Measurement of Drunkenness of Screw Threads, F. H. ROLT, A. TURNER. Machy (London) v52 nl345 July 21 1938 p 489-91. Method devised by authors, which can be applied to testing of machine tool ; based on fact that if screw has true helix, then threads or grooves on one side of it are always exactly midway between those on opposite side in same axial plane ; machine for testing screw threads for drunkenness illustrated and described. Messen des Zahnschraegewinkels an Stirnraedern mit Schraegverzahung (Measurement of Helix Angle and Pitch of Teeth on Helical Gears). F. LAESSKER. VDI Zeit v83 n5 Feb 4 1939 p 133-5. Outline of measuring method and detailed description of testing equipment and its operation, characteristics, and results attainable. "Sine Line" Machine for Checking Spiral-Gear Leads. Machy (N.Y.) v48 March 1942 p 162 1 illus. Machine of the adjustable sinebar type, is designed to check right- and left-hand spiral gear leads with spiral angles from 0° to 90°. Method of Screw Pitch Measurement, J. W. DRINK- WATER, Machy (London) v60 nl541, 1542 Apr 23 1942 p 341-5 and Apr 30 p 372-3. Outline of necessary meas- urements to be checked in screw threads if accuracy is desired ; description of screw pitching machine ; details 203 of how machine can be used to determine certain defects in screw threads and machine tools. New Electromagnetic Method of Measuring Screw Thread Leads to Few Millionths of Inch, H. T. RIGHTS. Instrum vl7 n3 Mar 1944 p 134-5. Method has been embodied in instrument of comparator type, which can be read di- rectly to within 0.00001 in. and readings can be estimated to within 0.000001 in. ; method being electrical rather than mechanical, gaging point functions with pressure of only three ounces ; it has no time lag and is rapid in operation ; anyone experienced in checking thread lead can set up instrument quickly and operate it successfully. Fellows Introduces New Lead Measuring Instrument, A. JANSSON. Tool Engr vl7 n3 Oct 1946 p 53. Features and operation of new instrument developed by Fellows Gear Shaper Co; instrument incorporates arrangement whereby lead of helix is checked by continuous motion of measuring pointer in conjunction with desired rotation of work ; principle embodies two tangent bars and pins, both of which operate slides, one effecting traverse move- ment of member carrying measuring pointer and other, rotation of work. Autographic Me"thod of Checking Accuracy of Micro- meter Screws, F. H. ROLT. Machy (London) v78 nl993 Jan 25 1951 p 165-7; Engr vl91 n4957 Jan 26 1951 p 117-9. Conventional method necessitates recording of numerous readings ; new method of obtaining autographic records compares travel of micrometer spindle contin- uously with that of master screw, differences being re- corded as trace on moving strip of paper ; design and gen- eral arrangement of micrometer head testing apparatus ; illustrations. Measuring Gear Components, F. M. BUTRICK, JR. Tool Engr v26 n2 Feb 1951 p 44-5. Lengthy but simple method for measuring helix angle of helical, herringbone, or screw gear when regular gear checking machine is not available ; equipment required and steps to follow ; in- accuracies are small ; illustrations. Homemade Checker Bridges Gap, F. M. BUTRICK, JR. Steel vl33 n26 Dec 28 1953 p91. Lead comparator for helical gears fabricated in tool room is designed to serve until commercially made comparator arrives ; drawing shows how this simple device compares gear with master. Automatic Measurement of Small Deviations in Periodic Structures, H. T. CLOSSON, W. E. DANIELSON, R. J. NIELSEN. Rev. Sci Instrum v29 nlO Oct 1958 p 855-9. Description of accurate microdeviometer, originally de- veloped for measurement and recording of pitch uniformity of helices in traveling wave tubes ; instrument combines optical, mechanical, and electronic techniques ; electronic circuitry automatically stores and processes position in- formation and feeds processed information, in form of deviations from corresponding ideal structure, to pen recorder. At Last a "Drunkonieter" for Threads, W. M. STOCKER, JR. Am Mach vl02 n26 Dec 15 1958 p 87-9. "Drunken helix" being deviation of helix from theoretical or true helical path can now be measured by new electronic- thread comparator developed by Greenfield Tap and Die Division ; new instrument compares two points, separated by predetermined angle such as 90 or 180°, on single thread and measures deviation from true helix ; typical recorded patterns showing rejected, acceptable and mas- ter thread for 8-32 thread plug gages are presented. Contribution to Testing of Precision Lead Screws, J. SIMONET. Microtecnic vl3 nl Feb 1959 p 15-11; In- spection Engr v23 116 Nov-Dec 1959 p 134-9. Details of design, construction, and operation of special precision measuring instrument developed at Metrological Labora- tory, University of Liege for checking pitch of lead screws. Presents a critical study of a new lead measuring instru- ment and a statistical examination of results of measure- ments. Neues vereinfachtes Messverfahren fuer die Bestimmung des Steigungsfehlers innerhalb eines oder mehrerer Ge- windegaenge (New simplified measuring method for de- termination of errors in pitch within one or several screw threads), H. GIESLER. Werkstattstechnik v49 n4 Apr 1959 p 192-5. Review of existing methods ; new method described is more accurate, permits simpler handling and saves time. New Method of Measuring Pitch Errors of Screws to Very High Accuracy, L. W. NICKOLS. Machy (London) v96 n2480 May 25 1960 p 1171-6. r Method developed at National Physical Laboratory employs autocollimator technique to compare pitch of screw with end-standards of length ; apparatus was designed to measure pitch errors of V-threaded precision lead-screws, within certain limita- tions of size, and is also suitable for measuring pitch errors of reference screw plug standards used to calibrate pitch measuring machines ; apparatus and measuring procedure described ; effect of errors on accuracy of pitch measurement. New Method of Measuring Pitch Errors of Screws to Very High Accuracy, L. W. NICKOLS. Quality Engr v24 n4 July-Aug 1960 p 107-11. Method developed at National Physical Laboratory for measuring pitch errors of screws having vee-thread form to considerably higher accuracy than formerly ; method employs autocollimator technique to compare pitch of screw with end-standards of length ; results indicate that, provided no temperature variations occur, pitch may be measured in terms of measured sizes of end-standards to accuracy better than ±5 /x in. Controlling the Curvature of Thread Gauges, N. M. ZHURAVLEV. Meas Techns 1959 nl2 Sept 1960 p 940-3 6 figs. Translated from Izmer Tekh nl2 Dec 1959 p 14. Proposes a new instrument combining high productivity with great precision for measuring helix variation of screw thread gages. Checking of gages showed that such variation sometimes exceeded the pitch tolerance. Can be used for automatic thread testing in conjunction with electric induction or pneumatic recorders. Checking the Curvature of Thread Gauges, F. P. FROLOV. Meas Techns 1960 n7 Feb 1961 p 583-4 2 figs 1 ref. Translated from Izmer Tekh n7 p 24-5 July 1960. Describes instrument for checking helix variation at 180°. Method for Determining Comparator Screw Errors with Precision, J. M. BENNETT. J Opt. Soc Am v51 nlO Oct 1961 p 1133-8. Precise determination of relative cumu- lative error and periodic error of comparator screw ; measured curves for Mann comparator and Gaertner comparator ; method gives relative lengths of intervals on scales used. Mitsui Leadscrew Measuring Machine with Automatic Recording Equipment, R. E. GREEN. Machy (London) vlOO n2564 Jan 3 1962 p 37^1. Machine built by Japanese company will detect inaccuracies as small as plus or minus (2 plus or minus 3L/1000)/i, where L is length to be measured in millimeters ; for such measurements, temper- ature difference between workpiece and master leadscrew built into machine, must be less than 0.05 C : new measur- ing principle employed is based on use of 2 electrical meas- uring contacts, average of two readings being provided electronically ; errors due to distortion or eccentricity of screw are automatically canceled out. Teilungsmessungen an Verzahnungen in der Praxis (Pitch Measurements on Gear Teeth in Practice), H. A. KOOP. Werkstattstechnik v52 nl2 Dec 1962 p 646-52. Installa- tions and devices employed are described ; interpretation of measuring results with regard to various types of er- rors is explained. 204 Interferometric Device for the Calibration of the Microm- eter Screw of a Microscope, J. MONTILLA. Anales de la Real Sociedad Espafiole de Fisica y Quimica v59A nl-2 Jan-Feb 1963 p 19-20 in Spanish. The device is based on the relation between the displacement of interference fringes of Fizeau tvpe and the displacement of the micro- scope tube. An accuracy of X/200 or better is obtained. The Error in Measuring Periodic Faults in Guide Screw Pitches T. S. KIRILLOVA, E. A. SHILOVA. Meas Techns 1962 n7 Feb 1963 p 543-4. Translated from Izmer Tekh n7 July 1962 p 8-10. Compares accuracy of meas- urements obtained by the use of recorders with those obtained with universal microscopes. Podatnose statvczna ukladu "O-P-N" i jejwykorzystanie do korekcji bledow skoku przy obrobce srub pociagowych (Static Flexibility of Machine Tool-Workpiece-Tool Sys- tem and Its Use for Pitch Error Correction in Lead- Screw Machining. H. KALUZKA. Prezglad Mechan- iczny v22 n6 Mar 25 1963 p 163-6. Sources of pitch errors in machining high-precision lead screws are analyzed and error formula derived; simple method is suggested for eliminating pitch error by applying to workpiece axial force determined from expression derived and acting from back center towards chuck plate. Error in Measuring Pitch of Screw Propellers by Means of Goniometers, F. M. KATSMAN, S. V. YAKONOVSKII. Meas Techns 1962 nl2 July 1963 p 992-5 3 figs. Trans- lated from Izmer Tekh nl2 Dec 1962 p 8-11. Analyzes the precision with which it is possible to measure this element by means of goniometers, in view of the stringent tolerances specified in GOST (All-Union State Standard) 8054-59 for the local pitch of screw propellers which must not exceed ±2% for propellers of the higher and ±3.5% for those of the lower grade. Investigation and Trial Manufacture of Leadscrew Meas- uring Machine with Automatic Recording Equipment, A. YAMAMOTO, S. YAMATO, S. ISA, C. KAWAMURA, I. KUMAGAI. Bui Japan Soc Prec Eng vl nl Oct 1963 p 13-6 9 figs. Contents : Machine construction ; measur- ing principles ; specification ; examples of lead measure- ment ; conclusion. On a Screw Thread Lead Measuring Machine with Auto- matic Recording Equipment, A. YAMAMOTO, M. ICHIKAWA. Bui of the Tokyo Inst Technol n58 1964 p 37^7 11 figs 3 refs. A SIP model 4 type screw thread cutting lathe which had been used in a machine shop for many years, was repaired and adapted to serve as a screw thread lead measuring machine with automatic record- ing equipment. From this investigation the following results were obtained. (1) An electric micro-comparator with automatic recording equipment was made by utiliz- ing wire strain gauges, and it was ascertained that it had the satisfactory accuracy and linearity for the lead meas- uring machine. (2) Periodic error of measurement which was caused by the eccentric rotation of the lead screw was fully eliminated by using a suspension type lead nut instead of the original one. (3) The screw thread lead measuring machine could measure to an accuracy of ±l/i, within the measuring range of 100 mm, by giving a correction curve to the plate cam and repairing several parts of the machine. (4) Lead error of an internal thread could be measured without taking into account the influence of eccentric chucking. 9.3. Wire and Ball Measurements of Screw Threads Features and Other Helicoidal Note : Measurements described in this section relate to evaluation of thread groove diameter (or pitch diameter) of screw threads. As related to gearing where the pitch diameter is an exact theoretical value, not subject to any deviation from the ideal, such measurements are commonly designated as the measurement of tooth thickness or checking of backlash. See also subsection 10.2.4. Measuring External Screw Thread Diameters, W. CAN- TELO. Am Mach v26 n26 June 25 1903 p 904-6 7 figs 2 tables. Describes three wire method and wire method for Acme threads. Furnishes formulas and tables of constants applicable to measurements of standard threads by means of a micrometer caliper. Measuring External Thread Diameters, J. M. STABEL. Machy (N.Y. Eng Ed) v2 no Jan 1904 p 248-50 3 figs 3 tables. Describes method of thread measurement by means of wires and micrometers. Measuring External Screw-Thread Diameters. Am Mach v30 Mar 7 1907 p 356-7. The application of micrometers and wires in the measurement of USS, V, and Whitworth threads. Measuring Screw Thread Diameters, W. CANTELO. Machy (N.Y.) vl4 Sept 1907 p 33-4. Gives formulas for the limiting sizes of wires for 60°, 55°, and 29° threads. Notes on Screw Threads, H. H. JEFFCOTT, NPL. Proc Inst Mech Engrs Dec 1907 p 1067-1108 17 figs. ; Collected Researches NPL v5 1909 p 215-50 17 figs. Contain an account of some theoretical aspects of screw threads, partly from the stand-point of accuracy in the interpreta- tion of results of measurement. Equations of the surface of the screw thread were obtained in two different ways : One by a consideration of the method of generation and the other by the use of Fourier series. Approximate formulas for the measurement of effective diameter of a screw are derived on the basis that measurements are taken over cylinders, which being free, set themselves nearly along the rake of the thread. A similar case in which the cylinders are fixed perpendicular to the axial plane of measurement of the screw is also considered. The effect of small errors in the various elements of a screw on the interpretation of the results of measurement of effective diameter is exhibited as a formula. Com- piler's comment: JEFFCOTT's (approximate) Three- Wire Method has been internationally used for almost 60 years in the measurement of standard screw threads, particularly for single-start screws. Making Thread Gages, A. L. MONRAD. Machy (N.Y.) vl4 Feb 1908 p 387-90 10 figs. Illustrates thread grinding attachment for lathe, fixture for charging diamond lap, thread tool setting gage, lap for plug gages, simple dia- grams for determining wire sizes, lead tester, gage for testing angle of thread, holder for micrometer stop. Gives tables of wire diameters for measuring thread angle. Measuring Metric Screw Threads. Am Mach v33 pt2 Dec 1 1910 p 1028. Includes tables of constants for 205 measuring the pitch diameter of metric threads by the three-wire system. Wires for Measuring Threads, J. J. STEWART. Am Mach v36 May 23 1912 p 842. Illustrated discussion of use of wires. Measuring Screw Threads by Means of Micrometers. Machy (N.Y.) vl9 n5 Jan 1913 p 384, 1 fig 1 table. In- cludes a table of sizes of two types of micrometer ball points applicable to various threads per inch. One Wire System for Measuring Threads, I. BANWELL. Machy (N.Y.) v20 July 1914 p 978. Gives a formula for measuring pitch diameter with one wire. Notes on Screw Gages. NPL ( Teddington ) Feb 1916 28 p. Includes discussion of measurements of effective diameter and angle by cylinders of other than best diameters. Use of a reference groove and cylinder for effective and core diameter measurements. Measuring B and S or Acme 29 deg. Threads, K. FEN- NELL. Am Mach v45 Nov 16 1916 p 846. Gives formulas for any size of wire that will touch the sides and project above the top of the thread, not taking the lead angle into account. Master Whitworth Thread Gages, W. T. ILER, Jr. Machy (N.Y.) v24 Sept 1917 p 51-2. Formulas for meas- uring the pitch diameter and checking the flank angle by means of two wires. Measuring Screw Threads by the Three-Wire System. Machy ( London ) vll Nov 15 1917 p 181. Formulas proving that the effect of lead angle readings is negligible with standard threads. Errors in Measuring Thread Pitch Diameters With Wire, J. H. BILLINGS. Am Mach v47 n25 Dec 20 1917 p 1007-8 1 fig ; Mech Wld v63 May 3 1918 p 207. Discusses dis- crepancy in measurements of pitch diameter obtained by means of wires and by thread micrometers. Measurement of Internal Threads, W. S. ROWELL. Machy (N.Y.) v24 Jan 1918 p 429. Uses inside microm- eter with ball points. Gives formulas for computing pitch diameter from measurements. Error in Wire Method of Measuring Worm Threads, H. H. WRIGHT. Machy (N.Y.) v24 n5 Jan 1918 p 439-40 1 fig. Points out the necessity of taking the lead angle into account. Simple Method of Measuring Pitch Diameter of Screw Threads. Machy (London) vl2 May 2 1918 p 128. Sketch and formulas are given, using three wires and measuring from crest of thread to over wires. The Measurement of Internal Threads, W. RICHARDS. Machy (London) vl2 July 18 1918 p 425-7. Diagrams. Internal ball point micrometer, with calculations for its use, and table of diameters for ball points. Fortney Measuring Wires. Machy (N.Y.) v25 Nov 1918 p 269. Four styles of wires are shown designed for use with special machines for measuring pitch diameter. Thread Measuring Formulas, H. M. FUNNELL. Am Mach v49 nl9 Nov 7 1918 p 839 1 fig. States that when using the three-wire system of measuring threads the usual formulas given in various popular handbooks are correct only when the thread is standard. Gives formula based on "angle root diameter" for threads which depart from standard form. Use of Measuring Wires, H. L. VAN KEUREN. Auto- motive Industries v39 Dec 19 1918 p 1056. Choice and standardization of wires, Computations. Determining Error in Thread Angle by Three Wire Method. Machy (N.Y.) v25 Feb 1919 p 552. Measuring Acme Threads Without Special Wires, H. W. MILLER. Am Mach v50 May 15 1919 p 932. Gives formulas for wires or balls. Gewindemessen mit Drahten (Screw Thread Measure- ments with Wires), J. REINDL. Betrieb vl nl4 Aug 1919 p 361-5 11 figs. Discusses manufacture of wires, use for pitch diameter and thread angle measurements, and gives tables for Whitworth, International, and Lowenherz threads. Gaging Acme Threads Without Special Wires, H. A. PEARSON. Am Mach vol Nov 6 1919 p 830 1 fig ; Mech Wld v68 July 23 1920 p 60. Equations are given which, it is said, can be applied to any wire which may be available. Three-Wire Svstem for Measuring Standard Worm Threads, H. A. PEARSON. Machy (N.Y.) v26 Aug 1920 p 1131. Gives formulas and tabular data, when using wires of any suitable diameter. Discussion by T. A. Reilly, Machy (N.Y.) v27 Nov 1920 p 238. Screw Thread Measurement. Eng Prod vl Nov 1920 p 440-4 8 figs. Determination of effective diameters by three wire system. Measuring Screw Threads by the Three- Wire Method, V. E. AYRE, NBiS. Machy (N.Y.) v27 Nov 1921 p 281. Gives formulas. Die Optische Messung des Flankendurchmessers von Ge- winden (Optical Measurement of Flank Diameter of Threads), O. EPPENSTEIN. Priizision n22 1922 4 p 8 figs 2 refs. Describes measurement of pitch diameter using a projector and contacting the thread by means of knife edges. Measuring Thread Plug Gages, J. M. HENRY. Machy (N.Y.) v28 Mar 1922 p 545-6. Shows various set-ups in the Pratt and Whitney measuring machine. Van Keuren Thread-Measuring Wires. Am Mach v56 June 1 1922 p 833. Machine lapped wires, accurate as to roundness, uniformity, and size, furnished packed in glass bottles to protect against rust, loss, or breakage. Measurement of Worm Threads, A. FISHER. Machy (London) v20 Aug 10 1922 p 591-2 3 figs. Reply to an inquiry as to formulas for measuring the addendum and thickness of multiple-threaded worms with gear tooth calipers. Discussion by E. A. Limming, Machy (London) v22 Sept 20 1923 p 794-5 1 fig as to the different chords involved. The Normal Thickness of a Worm Thread, E. A. LIM- MING. Machy (London) v20 Sept 7 1922 p 707-8 1 fig. Develops a more nearly correct mathematical formula for the normal thickness of a worm thread at a particular radius R, defined as the thickness in the plane normal to the lead helix of that particular radius. The Normal Chordal Thickness of a Worm Thread, A. FISHER. Machy (London) v21 Oct 26 1922 p 118-9 4 figs. A further discussion of preceding articles by Lim- ming and Fisher in which it is concluded that very accu- rate measurements with gear tooth calipers are obtained with difficulty. The dimension usually taken is the min- imum thickness obtained when the calipers are allowed to choose their own angle. 206 Notes on Worm-Thread Formulas, P. A. FREDERICKS. Am Mach v55 Dec 1922 p 1043. Discusses three-wire measurements. The Exact Calculation of Worm-Thread Dimensions, H. E. MERRITT. Machy (London) v21 Dec 14 1922 p 330-1 2 figs. Discusses preceding articles by Fisher and Limming. Proposes an exact calculaion of worm-thread dimensions. Normal Thickness of a Worm Thread, E. A. LIMMING. Machy t N.Y. ) v21 Dec 21 1922 p 360-2 4 figs ; Machy ( Lon- don) v22 Apr 1923 p 114-5 1 fig. Derives equation for the calipered chord of a screw thread which is identical with the contact chord of the best-size ball of its contact nut. (They are identical with Vogel's [see below] cor- responding equations for the best-size ball measurement of internal threads.) Discussion by A. FISHER, Machy (London) v21 Mar 15 1923 p T59. States basis of defini- tions in Fisher's preceding articles. The Gauging of Involute Threads, H. E. MERRITT. Machy (London) Apr 5, 19 July 26, Aug 2 1923 p 11-3 79- 81 525 569 13 figs. Deals with : gaging straight-spur teeth by tooth caliper, rack-generated gears corrected for under- cut, gaging straight-spur teeth by the plug or wire method, applications of the plug method, zone and line contact between spiral gear and rack, application of the plug method to spiral gears, helical gears. Discussion : E. A. LIMMING Apr 26, May 10 p 114. 191 ; C. PETTIT May 17 p 210; H. E. MERRITT May 24, 31 p 251, 275; E. A. LIMMING June 7 p 307 ; H. E. MERRITT June 21 p 376 ; A. FISHER July 5 p 442 ; E. A. LIMMING July 12 p 475 ; H. E. MERRITT July 26, Aug 2 p 525, 569. Measurement of Pitch Diameter of Screw Thread Gages. NBS Letter Cir n23 July 14 1923 60 p 16 figs. Discusses measurement of pitch diameter of straight and taper threads by means of wires, measurement of thread angle by wires, and gives derivations of various wire formulas in the appendix. Cvlinders and Spheres for Gauging Worm or Screw Threads, E. A. LIMMING. Machy (London) v23 Jan 3 1924 p 466-7 2 figs. Derives formula for -angle between axis of wire and axis of screw. Also diameter of wire which will touch at a given radius of thread. The Gauging of Finish-Ground Worms bv Cylinders, H. E. MERRITT. Engr vl38 Aug 8 1924 p 162-3 3 figs. Shows that from certain fundamental worm dimensions size and position of a cylinder to gage any point on thread contour may be calculated, and in spite of apparent diffi- culty of problem, solution . is very simple and easy of application. Correction for Elastic Compression in the Measurement of Screws with Small Cylinders, G. A. TOMLINSON, NPL. Machy (London) v28 Aug 26 1926 p 616-8 2 figs. Points out that in accurate measurements of small screw, correction should be applied on account of compression that ordinarily occurs ; nomogram for computing com- pression correction in effective diameter measurement. See also "Notes on Screw Threads". The National Physical Laboratory, 1930; Proc Inst Engrs n4 p 1031-6. Correction for Rake in Screw-Thread Measurement, G. A. TOMLINSON, NPL. Inst Mech Engrs Proc n4 1927 p 1031-6 4 figs. Simple method of computing necessary rake correction based on exact geometrical considerations and equations, which is now being used at National Physical Laboratory for threaded work of large lead angle, measured by means of wires. Die Abplattungvon Stahlkijgeln und Zylindern durch den Messdruck (The Oblateness of Steel Balls and Cylinders due to Measuring Force), H. BOCHMANN, Zeit fiir Fein- mechanik and Pr'azision v35 Apr 1927 p 95 14 figs. English translation available. Contents : The Hertz theory ; re- view of literature ; experimental arrangements ; experi- ments on steel balls between planes ; experiments on steel wires between planes ; experiments on gages between planes ; general evaluation of the several cylinder tests ; experiments on crossed cylinders ; groove tests on steel wires ; summary. L'emploi des "Piges" pour la Determination Rationelle des Elements dun Filetage ( Use of Wires for Proper Determi- nation of the Elements of a Screw Thread), L. FRAICHET. Genie Civ v92 Feb 11 1928 p 138-40 2 figs. Use of wires for measuring pitch diameter is described ; errors of measurement ; measuring thread angle. Measurement of the Thickness of Involute Gear Teeth, A. H. CANDEE. Am Mach v68 n9, 11, and 14 Mar 1, 15 and Apr 5 1928 p 365-8, 463-7, and 573-6 12 figs. Mar 1 : Formulas for pin measurement developed ; measuring distance across round pins or plugs placed between teeth on opposite sides of gear to determine tooth thickness ; tables from which dimension across pins for standard involute spur gears can be obtained very easily ; direct methods of calculation given for special cases of spur gears and for helical gears. Mar 15 : Calculations for pin measurement with standard pin sizes ; simplification of calculations by means of standard tables for both ex- ternal and internal gears ; center of pin generally will not come on pitch circle ; for given pitch and number of teeth dimensions between centers of diametrically opposite pins will vary with tooth thickness and pressure angle. Apr 5 : Development of formulas for measuring thickness of helical gear teeth by standard pin method and their application to typical case ; in case of odd number of teeth certain advantage is lost because two pins cannot be placed symmetrically opposite each other ; importance of correct tooth form. Determination Rationelle des Elements d'un Filetage a l'Aide de "Piges" (Rational Measurement of Elements of a Screw-Thread with Wires), L. FRAICHET. Genie Civ v93 Sept 8 1928 p 238-40 3 figs ; Bui Technique, Service Technique et Industriel de L'Aeronautique, n51 Oct 1928. Principles of thread pitch and diameter measurements of screw threads by means of wires and micrometers, and formulas used are described. Measuring Acme Screw and Worm Threads bv Means of Wires or Cylinders, W. RICHARDS. Machy (London) v32 Sept 13 1928 p 787-90 5 figs and discussion v33 Dec 6 1928 p 302-4 4 figs. Fundamental factors involved in measurement of Acme and worm threads by means of wires or cylinders are given with formulas which take into account variation due to inclination of thread with axis of screw or lead angle. Further discussion by F. W. SHAW, Oct 18 1928 p 80 ; E. A. LIMMING Dec 27 p 405 ; W. RICHARDS Feb 14 1929 p 637. Measuring Worm Threads by Means of Cylinders, E. A. LIMMING. Machy (London) v33 n846 Dec 27 1928 p 405-10 9 figs. Discussion of formulas developed by W. Richards in v32 p 787 of this magazine ; method said to be theoretically incorrect because geometrical principles un- derlying conditions of contact between sides of threads and cylinders have not been completely taken into ac- count ; other formulas are developed. Measuring Acme Screw and Worm Threads bv Means of Wires or Cylinders, W. RICHARDS. E. A. LIMMING. Machy London) v33 n853 Feb 14 1929 p 637-40, 4 figs and discussion v34 nS62 Apr 18 1929 p 82-5 5 figs. Answer to comments made by E. A. LIMMING appearing in Dec 27 issue of magazine upon author's articles which were pub- lished in Dec 6 and Sept 13 issues ; criticism of data for design of worm tools and production of worm thread refuted. La Mesure des Filetages des Vis a Filet Triangulaire ( M ea s u r i n g Triangular Screw Threads) , P. A. 207 LAURENT. Genie Civ v94 nl4 Apr 6 1929 p 333-6 9 figs. Precision method of French Navy described ; it is com- bination of wire measurements of angles, diameters and pitch and mathematical derivations therefrom ; precau- tions to be taken and errors resulting (±1 micron). Messfehler durch Abplattung beim Gewindemessen (Er- rors Through Flattening in Measuring Screw Threads), H. BOCHMANN. Zeit InstrumKde v49 n4 Apr 1929 p 188-203 4 figs. Errors in measuring screw threads by ball or wire method due to flattening of measuring wires or balls. English translation available. The Measurement of Screw Elements. Machy (London) v34 n884 Sept 19 1929 p 789-93 7 figs. Description of methods employed in measuring pitch diameter of screw threads with wires and verifying thread angle by two different diameter wires ; charts are given for use in checking thread angle of U.S. Standard, Whitworth, S.I., and British Association threads by using set (of three) of each of two different diameter wires. Measuring Pitch Diameters of Taper Threads, C. KUGLER. Am Mach v74 May 7 1931 p 730. Gives a prac- tical procedure for measuring pitch diameter at a defi- nite point with three-wire system. Includes formulas. Measuring Cycle Engineer's Institute Standard Screw Thread by the Three-Wire Method. Machy (London) v38 May 14 1931 p 212-3. Derivation of formulas for measurement over wires and the best size of wire. Table of wire sizes. Flankenmessungen an Schnecken und Trapezegewinden, (Measurement of Pitch Diameter of Worms and Trape- zoidal Threads). A. RICKENMANN. Maschinenbau/ Betrieb v 10 Oct 1 1931 p 619 4 figs. A cone and vee micrometer is used. Discusses corrections to measure- ments and gives curve for lead angle corrections. Determination of Thread Diameters by the 3-Wire Method, G. BERNDT. Zeit InstrumKde Nov 1931 p 560- 74. Describes method, derives equations for pitch diam- eter. Corrections are also obtained for the flattening of the wires and for the case of oblique threads, and tabu- lated. Three-Wire Measurement of Screw Threads, J. R. CORNELIUS. Am Mach v74 May 21 1932 p 805 ; discus- sion by W. S. ROWELL v75 Sept 10 1932 p 416. Gives tables. Helical Gear Tooth Measurement, S. TRIMBATH. Am Mach v76 Aug 31 1932 p 966-7. Advantages of sizing heli- cal gear teeth by measuring across pins ; standard form. Die Bestimmung des Flankendurchmessers nach der Drei- drahtmethode (The determination of pitch diameter by the three wire method), G. BERNDT, Zeit InstrumKde v51 Nov 1932 p 560-74: Maschinenbau/Betrieb vll Apr 1932 p 133. Advantages, methods of making measurement, calculations, and discussion of errors. Korrektionen bei der Messung von Innengewinden (Cor- rections for the measurement of internal threads) , J. WIL- HELM. Feinmechanik und Prazision v41 Oct 1933 p 147^52. Derivation of factors for correcting the measure- ment of internal threads by means of balls, V-blocks, and size blocks taking into consideration the deformation of the balls and the errors relating the helix. Analytisches Verfahren zur Ermittlung der Giinstigsten Messdrxihte fiir die Sogenannte "Dreidrahtmethode" (Analytical method for determining the most suitable measuring wires for the so-called "three-wire method"), N. GUENTHER. Zeit InstrumKde v53 Sept 1934 p 373. Das Messen von Saegegewinden (The Measurement of Buttress Threads.), W. KNEDEL. Werkstattstechnik v29 Feb 1935 p 50-2. The method of measuring Buttress threads by the three-wire method. Explanation of calcu- lations involved. Bestimmung des Flankendurchmessers von Gewinden nach der Dreidrahtmethode bei unsymmetrischem Profil (De- termination of pitch diameter of screw threads of un- symmetrical profiles by the three-wire method), G. BERNDT. Werkstattstechnik v29 June 1935 p. 237-9. Die Messung Konischer Gewinde (The measurement of tapered threads), G. BERNDT. Bauer and Schaurte Neuss 1937 81 p. Various calculations. Size Measurement of Gears, W. L. CHESLEY, Tool Engr v5 n9 Jan 1937 p 14-5. Easily understood method pre- sented of calculating sizes over pins or balls for spur or helical gears. Neuartige kopfkreisfreie Zahndicken-Messungen fiir Schragzahnrader und Evolventen-Schnecken (Novel Method of measuring tooth thickness for involute helical gears and involute worms without use of addendum circle), W. F. VOGEL. Werkzeugmaschine v41 nil June 15, 1937 p 253-61. Mathematical analysis of span meas- urements and its application to both spur- and helical in- volute-shaped tooth forms. A section "Tauehkorper- Messungen" (Dive-Body Measurements) deals first with pin- and ball-measurements of involute spur teeth. Exten- sion of the analysis to ball-measurements of helical in- volute gears and involute worms leads to the introduction of the author's "Substitute- (thin) Disk Method", which reduces the measurement simply to that of involute spur gears. The same simplified method and equations have later been applied to pin-measurements of all involute screws. ( VOGEL 1945 see subsections 10.1.2 and 10.1.3 and ZAHORSKI in Van Keuren Handbook 33 1945. ) Bibliog- raphy. Errors in Wire Measurement, O. E. KOEHLER. Am Mach v82 n9 May 1938 p 367. When lead is great, as with Acme or multiple V threads, consideration of lead angle should be included when measuring by wire method. Pin Method of Measuring Worms and Helical Gears, E. BUCKINGHAM. Machy (N.Y.) v45 nl Sept 1938 p 1-7 2 figs. Gives general formulas for pin diameter and meas- urement over pins ; general formulas for screw threads and helical gears ; application to screw threads and to a helical gear ; compensation for possible deflection of pins or wires ; errors in tooth thickness resulting from pin de- flection ; relation between a formula for screw threads and the simplified general formula. Compiler's comment : Formulas take lead angle into account but are not exact, as stated. They are approximations similar to those of Jeffcott. (See reference above.) NBS formula (10) quoted on p 5 is likewise not exact as here stated. In the original B523 reference it was stated to be a close approxi- mation for screw threats. (See BUCKINGHAM below.) Gauging Screw Threads by Wire Method. Machy (Lon- don) v53 nl359 and 1360 Oct 20 1938 p 71^ and Nov 3 p 133-8. Screw threads can be measured with precision by making use of calibrated wires ; direct reading charts and tables prepared by Society Genevoise d'Instruments de Physique, Geneva, for use in conjunction with standard calibrated wires and measuring instruments, are given. Includes formula for computing values, correction factor for obliquity, method of computing best diameter, correc- tions for elastic deformation of wires. Gaging Multi-Start Threads by the Wire Method. Machy (London) v53 Nov 17 1938 p 200. Formulas for determi- nation of best wire diameter in measuring multi-start threads and threads with very large lead angles. Checking Screw Threads and Vehicle Gears by Measure- ment over Pins. E. BUCKINGHAM. Machy (N.Y.) v45 n4 Dec 1938 p 273. Compiler's comment : This article was 208 obviously in answer to reader objections to the author's preceding September article. Particularly, the author's allegedly exact theory was incompatible with the exact contact conditions of pins and balls used in the measure- ment of involute screws, as analyzed and published by A. H. Candee 1928. In this article the author tries to explain these contradictions by his obviously honest belief and statement that the behavior and contact geometry of a pin in the thread groove of an involute screw are basically different from those in other types of screws. More re- cent developments disprove this concept as well as the author's theorv of bending deformations of the pins and their needed compensations. See TOMLINSON 1927, VOGEL 1947, and MARRINER and WOOD 1958, this subsection. Die Messung der Flankendurchmesser mehrgangiger Ge- winde mit drei Drahten (Measurement of Flank Diameter of Multiple Threads with Three Wires), N. GUNTHER, H. ZOLLNER. Feinmechanik und Priizision v47 n9 1939 p 129-31 2 figs. Contents : The three-wire method ; the theory of screw surfaces ; contact conditions with deriva- tion of exact transcendental equation ; the approximation process ; summary, and buttress threads. Ball Measurement of Helical Gears, A. ZAHORSKI. Am Mach v83 nl4 July 12 1939 p 520-2. Method developed consisting of substituting real ball by imaginary roll, which will permit carrying out computation of measure- ment of tooth thickness of helical gears in same manner as done for spur gears ; formulas and examples illustrated and described. Same as the Vogel "substitute disk method" 1937. Die Bestimmung des Flankendurchmessers von Gewinden mit symmetrischem Profil nach der Dreidrahtmethode (The Determination of Flank Diameter of Threads with Symmetrical Profile by the Three- Wire Method), G. BERNDT. Zeit InstrumKde v59 nil Nov 1939 p 439-48. Determination of flank diameter of screw threads with symmetric profile according to three-wire method ; mathe- matical and geometrical considerations and applications. The algebraic and geometrical considerations of the meth- od and the influence of various sources of error are considered. Die Bestimmung des Flankendurchmessers von Gewinden mit Unsymmetrischem Profil nach der Dreidrahtmethode (Determination of Pitch Diameter of Threads with Un- symmetrical Profile by Means of the Three-Wire Method), G. BERNDT. Zeit InstrumKde v60 Jan 1940 p 14-22. Theoretical principles and application of method, influence of errors, smallest and greatest possible wire diameters, numerical examples, detailed explanation of calculations involved. Die Anlagekorrekturen bei der Bestimmung des Flankendurchmessers von symmetrischen und unsymme- trischen Aussen und Innengewinden (Corrections of Posi- tion in Determination of Flank Diameter of Symmetric and Asymmetric External and Internal Threads Accord- ing to Three-Wire Method or By Means of Two Spheres), G. BERNDT. Zeit InstrumKde v60 n5, 6, 7, 8 and 9 Mav 1940 p 141-54, June p 177-86, July p 209-20, Aug p 237-48 and Sept p 272-8 ; Werkstattstechnik und Werksleiter v34 nl7 Sept 1 1940 p 277-82. Detailed theoretical mathe- matical study ; approximate formulas for corrections of position presented. Bibliography. Durchmesser der Draehte fuer das Dreidrahtverfahren (Diameter of Wires for the Three-Wire Method), etc. G. BERNDT. Werkstattstechnik und Werksleiter v36 n23, 24 Dec 1942 p 507-19. Diameter of wires for three-wire method of determination of flank diameter of single threads with symmetrical profile ; determination of flank diameter without regard to non-perpendicular position of wires to thread axis ; influence of position of measuring wires inclined toward thread axis. Calculating Screw Thread P. D., W. T. TAYLOR. Tool Engr vl2 n8, 9, Aug 1943 p 87-9 ; Oct p 99, 101, 103, 105. Purpose is to simplify general formulas for overwire (3- wire) dimension, to present formulas in terms of basic pitch diameter and basic major diameter, to show best wire sizes which may be used for any particular num- ber of threads per inch and to show permissible plus- minus limits on wire diameter for Whitworth 55° thread so that American wire sizes can be used to practical ad- vantage; method of calculating and measuring even and odd fluted taps. Involutometry and Trigonometry, W. F. VOGEL. Mich- igan Tool Co., Detroit 1945 325p 28 figs 33 refs. Contains simple exact equations, with derivations, for pin and ball measurements of involute-shaped spur gears and splines, also of involute screws (e.g. helical gears, helical involute splines and involute worms). Forms with step by step calculations are provided for various purpose measurements of spur toothed products. All measure- ments are explained as applications of a complete geo- metrical system of involutometry (see abstract in Sub-Sec- tion 10.1.2) and are tailored to be used with the large Main Table and a great variety of other numerical tables (see abstracts in Sub-Section 10.1.3). Larmar Three-wire Measuring Instrument for Screw Threads. Machy (London) v66 nl684 Jan 18 1945 p 75-6. Illustrated description of apparatus manufactured by Larmar Eng Co ; to obviate difficulty in positioning three wires prior to measuring over them with micrometer, wires are held to micrometer anvil and spindle faces by clamps. Checking Pitch Diameters of Precision Screw Threads, E. BUCKINGHAM. Machy (N.Y.) v52 nl Sept 1945 p 162-4. Consideration of three classes of screw thread profiles af- ecting measurement in checking pitch diameter of screw thread by measuring over pins or wires ; involute-helical gear formula provides theoretically correct results when applied to screw thread of involute helicoidal form and very close approximations for threads having intermed- iate profiles ; applicable formulas given. Compiler's comment : This is a new idea for attacking the intricate problem of measuring screw threads over pins or wires. The author is to be commended for his proposal to utilize the simpler expressions of the corresponding measurement of involute screws (e.g. helical involute gears and involute worms) for this purpose. Simple ex- act equations for pin- and ball-measurement of involute screws have been known before (e.g. Candee 1928, Vogel 1937 and 1945 etc., of this subsection). They offer the great advantage of free pin selection and also yield the exact contact points between pins (or balls) and the helical tooth surfaces. Any attempt, however, to pre- scribe the size of the contact radius of the involute screw not only kills the free selection of the wire size but also leads to strictly transcendent exact equations of the whole measurement. The same is true for the exact measure- ment-equations with best-size wires of all screw types, since such wires are meant to contact the screw exactly at the pitch cyclinder. (See Vogel 1947 and 1955 in this subsection.) Buckingham's equations of the pin measurement of heli- cal involute gears in his Manual of Gear Design, vol. 3, 1937, p. 150 were given without derivation and explanation except the statement that they were meant for contact at a given cylinder of the gear. Referring to those (non- transcendent) expressions the author now admits in this article that those two formulas for both the pin-size and the over-pin dimension were only approximations. Si- multaneously claiming very small errors of those ap- proximations, he proposes to utilize the pin-size formula as best-size wire formula for screw threads. This claim was not borne out in later comparative error investiga- 209 tions of various best-size pin formulas (see Vogel 1947, in this subsection). In his new Thread Measuring Method, Buckingham es- tablished a best-size wire by an approximate formula, but abandons completely his previous approximate formula for the over-wire dimension of an involute screw. Work- ing with the thus established best-size wire, he uses it like a freely selected pin dropped into an involute screw and instead, applies an exact equation for establishing its over-pin dimension. The method would be strictly exact, if the best-size wire had exactly the theoretically needed diameter, but as this was not the case, the whole method is only an approximation, whose accuracy ob- viously is influenced by the error of the used best-pin size formula. The author himself was aware "of this. In his first "numerical example" he utilized the approximate best-pin size formula from his manual of Gear Design, 1937, as initially recommended. In his second numerical example he silently discarded his own recommendation and specified (without calculation) a wire size, which happens to correspond to that of a formula proposed in another of his previous publications, namely 1938. His preferred latter approximation is also used exclu- sively in his representation of his new method in Ma- chinery's Handbook, 17th ed. 1964 on p. 1217-20. Accord- ing to Vogel (1947 of this subsection) the latter best-size pin is always undersize, while the best-size pin formula used in the first example always leads to an oversize for the wire. The quoted references and Van Keuren Handbook 36 (1955) also contain newer developments of simple exact best-pin measurement equations, numerical tables, and more precise approximations. The compiler hopes his cross-references will result in a more nearly up-to-date presentation in the next edition of Machinery's Handbook. Three-Wire Thread Gaging Simplified, J. J. MEADOWS. Iron Age vl57 nl6 Apr 18 1946 p 51-7. Formula for check- ing thread size using three-wire method, based on major thread diameter; charts and tables commonly involved and cover National Fine and National Coarse series, Whitworth standard, British Assn, British Standard Fine, and French standard thread forms. Effect of Elastic Modulus on Measurement of Thread Wires. D. E. WILLIAMSON. Prod Eng & Mgmt vl8 n2 Aug 1946 4 p 5 figs. Analyses the various factors relating to the use of Carboloy wires. Wire Dimensions for Screw Threads, J. W. LEE. Tool Engr vl8 nl Feb 1947 p 36-8. Develops formulas for calculating wire measurements of pitch diameter, taking the lead angle into account. These are based on the as- sumption that the contact points of the wire with the thread are located on the normal to the central pitch helix of the thread (which assumption gives more accurate re- sults than assuming contact in an axial plane but still is not exactly true). Presents relations between screw dimensions and measurement data. plications to screw threads, worms, and hobs ; in regard to thread measurement, considerable amount of space de- voted to wire methods. Eng Soc Lib, N.Y. Determination of the Thickness of the Teeth of Worms and Spiral-Toothed Wheels with the Help of Rollers and Balls, F. L. LITVIN. Acad Sci (Russia) vlO n39 July 6 1950 p 22-7 18 figs 4 refs. English translation available at NBS and Van Keuren Co. A distinction is made be- tween convoluted, Archimedean, and evoluted helical surfaces. Develops exact relationship between position of the roll in the thread space of the worm, the lateral surfaces of the teeth, and the thickness of the teeth. De- velops relationships connecting variation in the position of the roll and variation in thickness of teeth. Position of Contacting Sphere Between Teeth of Helical Gear, N. J. C. PERES, Machy (London) v77 nl977 Sept 21 1950 p 324 1 fig. Derives equation for angle between center of pin and point of contact of pin and tooth. (Ob- viously the author was unaware of the existence of much simpler exact equations offered in the "Substitute Disk Method", see Vogel 1937 and 1945. ) On Precision Screw Threads, M. OGAWA. Rep Inst Indus Sci Univ of Tokyo v2 nl ser 10 Apr 1951. Trans- lation of Chapter 1 on Theory on the Three- Wire Method is available from Eng. Metrology Section, NBS. Chapter has 11 figs 10 refs. Contents of chapter : General theory ; states of contact between measuring wires and a helicoidal surface ; conditions for the stable contact ; general solu- tions ; the most accurate ordinary solution ; the best wires; errors in the three wire method. Priifen und Messen von Gewinden (Testing and Measure- ment of Screw Threads) F. WOLF, Munich 1952. Analysis of Screw Thread Measurement, W. H. HARRISON. Mach v96 Apr 2 1952 p 602-4 2 figs. Gives analysis intended to make clear the exact conditions of contact of measuring cylinders to thread flanks, with- out taking account of deformation of work or measuring cylinders. Solve example by iteration. New Thread Measuring Formulas, W. F. VOGEL. Cata- log and Handb n36 Appendix D The Van Keuren Co 1955. Exact equations of the trigonometric solution of the Best- Pin method are provided with numerical tables (by the Van Keuren Co) based on it. Die Berechnung der Gewinde-Anlagekorrekturen, M. GARY, PTB. Forschnng auf dem Gebiete des Ingenieur- wesens v21 n4 1955 p 107-17 5 figs 7 refs. Calculation of rake corrections in screw thread measurements ; condi- tions governing contact of spheres and cylinders in helical grooves of thread ; resulting transcendental equations solved by iteration for all threads with straight flanks in axial sections ; formula established for best pilot wire diameter for asymmetrical thread profiles. The Best Wire for Over Wire Measurement of General Screws, W. F. VOGEL. The Van Keuren Co. Watertown, Mass. Sept 9 1947 56 p. Develops universal theory of screw measurements over pins, including prerequisites for a general screw measurement, significance of the involute screw, the exact equations for general screw measure- ment (i.e. for cylindrical screws of any symmetrical thread profile) , number of pins and balls to be used, and formulas for routine calculations. Monograph copies deposited at Library of Congress, National Bureau of Standards, De- troit Public Library, and Wayne State University. Thread Grinding and Measurement, A. C. PARKINSON, W. H. DAWNEY. Sir Isaac Pitman & Sons, London, and Pitman Publ Corp, New York, 1949 227 p illus diagrs charts tables. Thread terms and definitions are classi- fied and explained ; limit systems and their special ap- Geometrische Probleme bei der Vermessung von zylin- drischen Evolventen-Schnecken und Evolventen-Schrag- stirnriidern (Geometric Problems in the Measurement of Cvlindrical Involute Worms and Involute Helical Gears), M. GARY, PTB. Konstruktion v8 nlO 1956 p 412-8 2 figs 4 refs. Methods are outlined for measurements of the standard gage with balls or measuring wires of cylindri- cal involute worms and involute helical gears. For sym- metrical involute worms a method is given for determina- tion of the base cylinder radius and the tooth thickness. Contents : Equations for the position of a cylinder in an involute worm (1) cylinder with predetermined inclina- tion to the worm axis; (2) cylinder at minimum dis- tance from the worm axis. Equations for the position of a ball in an involute worm. Computation of the base cylinder radius and tooth thickness from the results of two diameter determinations over cylinders or balls. Three numerical examples. 210 Screw Thread Standards for Federal Services. NBS Handb H2S (1957) Parts I and III and 1963 Supplement. Supt. of Docs, Government Printing Office, Washington 25, D.C. Appendix 4, Wire Methods of Measurement of Pitch Diameter of 60° Threads. Appendix 13, Three-Wire Method of Measurement of Pitch Diameter of 29° Acme, 29° Stub Acme, and Buttress Threads. Effect of Differences between U.S. and British Practices in Measuring Screw Gages for Unified Threads, L. W. NICKOLS. Machy (London) v90 n2315 Mar 29 1957 p 723-5; Metalworking Prod Mar 29 1957 p 539-41 2 flgs. American and British methods of measuring effective di- ameters of screw plug gages and setting plugs ; effective diameter measurements made at single specified position on each of five screw plug gages having Unified threads in order to determine experimentally effect of differences be- tween two methods. Precise Formulas for Over-Pin Measurements of Helical Forms, E. C. VARNUM, S. J. JOHNSON. Tool Engr v38 n6 June 1957 p 116-20 ; Also Letter to the Editor of the Tool Engr v39 n2 Aug 1957 p 183 by W. F. VOGEL ; also AGMA Paper 239.03 June 1957. (The print is an author- ized AGMA paper only if it carries a sticker giving credit to preceding exact solutions by W. F. Vogel in Van Keuren publications.) Gives a desk calculator routine for com- puting over pin measurements by iteration. Discussion des methodes de mesure du diametre sur flanes des flletages coniques males (Discussion of methods of measuring diameter of conical screw threads on their flanks). J. SIMONET. Revue Universelle des Mines vl4 n3 Mar 1958 p 73-9. Five methods of measurement are examined ; in each case there is serious difficulty in cali- bration of measuring instrument ; advantages and disadvantages of each method, and domains of their application. Over-Pin Measurements of Worms, L. D. MARTIN. Tool Engr v41 nl July 1958 p 50-4. Simple approximate for- mula for over-pin measurement of worms presented which yields results within practical limits affected by workpiece elasticity, measuring pressure, profile deviations and ob- servational error. Criticism by J. SILVAGI, Nov 1958 p 195-6. Rake Correction in the Measurement of Parallel External and Internal Screw Threads, R. S. MARRINER, MRS. J. G. WOOD. Inst Mech Engrs (London) July 1958 9 p 6 figs 2 refs. Formulas are derived for calculating the rake correction for a ball seated in the helical groove of an in- ternal screw thread and a ball or cylinder in an external thread. The equivalence of a ball and cylinder in an ex- ternal thread is discussed. A simple approximation for- mula, and an exact equation are derived for determining occurrence of double contact, between the cylinder and thread flank. Determination of Helical Gear Sizes by the Two-Roller Method, I. P. NEZHURIN. Russian Eng J v39 n8 1961 p 11-3 3 figs. English translation by PERA. Describes a method of calculation of the size over rolls which ensures an easy criterion of their displacement in the tooth groove of helical gears with an odd number of teeth. Demonstrates the existence of the "oddness effect", that is : In contrast to even-numbered helical gears, the axis of the micrometer when measuring over two rolls is askew to the axis of the odd-numbered helical gear ; it neither intersects the axis nor is its location in a plane of rotation of the gear. The correctly recognized geometry of the problem was evaluated in exact equations for the measurement. For one of them an approximate simplification is offered. (Unfortunately, one of the exact equations was found to be erroneous. See correc- tion by KHALEBSKII, 1963, and acknowledgment by NEZHURIN, 1963, in this subsection, p. 212. New Equations Simplify Pin Measurement of Gears, J. H. GLOVER. Prod Eng v32 nil Mar 13 1961 p 80-1 4 figs 3 refs. Gives equations for calculating over-pin and be- tween-pin measurements of ideal involute tooth forms of external and internal spur gears. The equations also es- tablish measurements for desired variations in tooth thickness and pin size. This will be very valuable if the calculations are made with the assistance of numerical tables giving over- or between-dimensions only for a speci- fied thickness (usually: standard thickness) and for a specified theoretical value of the pin size, which may not be available at the needed accuracy. The same equations can be used for external helical gears only if they have an even number of teeth. Internal helical teeth cannot be measured by pins. If balls are used for their measure- ment then the mentioned equations can be applied to both even and odd numbered internal helical gears. (The author claims that his way of formulating the known-basic exact equations simplify the measurement, but the simple basic geometry of the measurement can no more be recog- nized in this presentation). Further Report on the Effect of Differences between U.S. and British Practice in the Measurement of Screw Gauges for Unified Threads, P. W. HARRISON, NPL, Machine Shop Mag v22 n4 Apr 1961 p 207-9. The application of rake correction to measurements made by American meth- ods improves their agreement with the British values in seven out of eight cases and reduces the mean difference to one quarter of its previous value. Getting Bugs Out of 3-Wire Measurement, R. T. PAR- SONS. Am Mach/Metalworking Mfg vl05 nl4 July 10 1961 p 86-8. Three sources of error in 3-wire method of measuring thread gages and threaded parts are discussed including lead angle effect, calibration and accuracy of measuring wires and computation of correct constants, and measuring instruments and pressures ; 60° single- start threads with lead angles of less than 5° are con- sidered only. Study on a Ball Screw (Part 3), Z. MURASE, J Japan Soc Prec Eng v28 n6 1962 in Japanese. There are many reports on the measuring method about the triangular heliciodal surface, but rather few about generalized heli- coidal surface. In the Part 3, the mechanical measuring method of the radius from the screw axis to any point on the race-way surface (generalized helicoidal surface) of the nut or the threaded shaft of the ball screw, using the balls or the cylinders as the measuring feelers, is studied. And the exact equations, by which the correc- tion value of the measuring results will be calculated, are deduced. These corrections are necessary, because the elastic deformation at the contact point of the race-way with the measuring feelers and the diametral error of the feelers are always existent more or less. New mathemat- ical method of determining the race-way surfaces, the exact equation of the principal direction and principal curvature on the contact point of the ball-race with the ball, and the theoretical calculation of the elastic ap- proach between the ball-race and the balls of the ball screw are the fundamentals of the studies on this part 3. and they are reported in the previous two parts of this series. Sonderfragen zur Geometrie der Gewindeflanken ( Spe- cial Problems in the Geometry of Screw Thread Flanks ) . H. HAAKE. Werkstattstechnik v52 n4, 7 Apr 1962 p 180-6, July p 339—43. Special problems concerning geom- etry of flanks of threads ; it is shown how diagrams can be drawn which make possible general view of entire thread series and facilitate calculation in measuring flank diameter with three wires. Apr. Thread with unsym- metrical profile considered. July. Taper threads dis- cussed. Measurements of Helical Gears with Pins or Balls, Analy- sis of Pitfalls and their Elimination, A. S. BEAM, C. E. 211 HALL. AGMA 129.15 June 1962 7 figs 1 ref. Clarifica- tion of the geometry of measurements from center of gear over one pin. Useful mathematical formulations are pre- sented as a new tool in the art of gear inspection. It is shown that when pins are used on helical gears with even numbers of teeth, the prevalent belief that the distance between the axes of the two pins assumes an extreme value which can be found as a low or high point of the measurement is an oversimplification. The discussion covers: (1) Measurement over one pin or ball ; (a) meas- urement from the center over one pin and (b) measure- ment from the outside surface over a pin or ball placed in an opposite tooth space. (2) Measurement over two pins or balls when (a) gears have even numbers of teeth and (b) gears have odd numbers of teeth. (3) Measurement over three pins of spur and helical gears. Neues Verfahren zum Messen von engtolerierten Innen- gewinden (New Method for Measuring Close-Tolerance Internal Threads), G. VOENEKY. Werkstratt u Betrieb v95 nil Nov 1962 p 755-8. Explanation of 2-ball method used in measuring effective diameter of internal threads is followed by comparison with method using contact arms and with that of caliper microscope : application of internal thread measuring device in connection with shop microscope and universal comparator is described. Determining the Size of Helical Gears by Rollers, N. T. KHALEBSKII. Russian Eng J v42 nlO 1963 p 10-1. English translation by PERA. Alleges an error in one of Nezhurin's (1961) exact equations and presents simpler approximations. Measuring Helical Gears with an Odd Number of Teeth by Rollers, I. P. NEZHURIN. Russian Eng J. v42 nlO 1963 p 11-3 2 figs 2 refs. English translation by PERA. Calculations as given in previous articles have been sim- plified by means of a' nomogram which yields highly accurate values fully consistent with those derived by KHALEBSKII. Specification for Screw Thread Measuring Cylinders. Brit Standards Instn— Brit Standard 3777 1964 17 p. Standard relates to two grades of screw thread measur- ing cylinders intended for use in checking external screw threads by means of pitch diameter measuring machines ; first part gives bases for diametral tolerances of Grade A and Grade B screw thread measuring cylinders and rela- tive merits of these grades ; second part gives complete specification for both grades of cylinders suitable for forms and pitches of screw threads shown. 9.4. Tables for Ball, Pin, or Wire Measurements See also subsection 10.1.3 for similar tables for gears. Note. The following references are either completely tables or contain tables along with other material. Gcwindemessen mit Drahten (screw thread measurements with wires) , J. REINDL. Betrieb vl nl4 Aug 1919 p 361- 5 11 figs. Gives tables for Whitworth, International Metric, and Lowenherz threads for pitch diameter and angle measurements with wires. Correction for Elastic Compression in the Measurement of Screws with Small Cylinders, G. A. TOMLINSON, NPL. Machy ( London ) v28 Aug 26 1926 p 616-8 2 figs. Contains nomogram for computing compression in "effective diam- eter" measurement. Checking Gear Size by Measurement Over Pins, K. E. BAUERLE. Machy (N.Y.) v44 n6 Feb 1938 p 353-7. Tables simplifying application of this precise and gener- ally available method to external and internal spur and helical gears. Tables for Precise Measurement of Screws, H. L. VAN KET'REN. Catalog and Handb n34 1948 The Van Keuren Co., Watertown, Mass. See also Handbs n35 1952 and n36 1955. The tables, meant for wire contact exactly at the pitch cylinder of the screw, were computed with the Vogel (1948) approximate formulas Nos. 662 and 710 and spot- checked and (where necessary) corrected by applying the exact equations of Vogel's Best-Wire Method, 1947 and 1955, referred to in subsection 9.3, p 210. The tables cover a wide range of standardized and non-standardized screws, including single-start and multiple-start threads and worms. Gauging and Measuring Screws. National Physical Labo- ratory, Teddington, 1951. Section VII, Formulae and Corrections for Use in the Measurement of the Effective Diameter of Parallel Screw Plug Gauges by Means of Small Cylinders, p 23-32 5 figs. Includes charts for lead angle correction and compression correction. Screw r Thread Standards for Federal Services. NBS Handb H28 (1957) Parts I and III and 1963 Supplement. Snpt. of Docs. Government Printing Office, Washington, D.C. Appendixes 4 and 13 contain tables for wire meas- urements for 60°, 29° and Buttress threads. Machinery's Handbook 17th ed 1964 2104 p. The Indus- trial Press, N.Y. A section on measuring screw threads p 1208-25, contains tables of wire sizes and constants for wire measurements of Unified, Whitworth, and Acme Screw threads. Addendum to Section 9 9.3. Wire and Ball Measurements of Screw Threads and Other Helicoidal Features Compiler's comment: TOMLINSON (see p 207) deserves credit for apparently having derived the first exact solu- tion for the over-wire measurement of "Archimedean Screws" by means of freely selected wires. The solution is applicable to all screws, helical splines, and worms having symmetrical straight flanked axial profiles. General Equations for the Conditions for Single Contact between a Measuring Pin and a Screw, R. A. MacDON- ALD. A thesis submitted to the College of Engineering of Wayne State University, Detroit, Michigan in partial fulfillment of the requirements for the degree MS in En- gineering Mechanics. Approved Nov 1 1965 33p 9 figs 12 refs. The author first offers a general procedure, includ- ing new exact equations, for location of a freely selected ball or measuring wire in a thread groove of a cylindrical "general screw" having any contour which is a continuous function of y that has at least a first derivative. The second part of his procedure established the necessary cri- teria for examining multiple contact in any plane of those screws and changing the wire size, if necessary, to obtain single contact. 212 X^i* Section 10. Measurement of Gears CONTENTS Page 10.1. Gear metrology, general 213 10.1.1. Standards and nomenclature 213 10.1.2. Textbooks and handbooks dealing partially with measuring methods 215 10.1.3. Numerical tables 217 10.1.3.1. For involute calculations and plotting 217 10.1.3.2. For uniform angular indexing 219 10.1.3.3. Other tables for uniform subdivision of the circle 220 10.1.3.4. For pin and ball measurements of involute spur gears and spur splines 220 10.1.3.5. For span measurements 221 10.1.3.6. Tables of base tooth dimensions 222 10.1.3.7. Miscellaneous gear tables 222 10.1.4. Technical papers on gear measurement, general 222 10.2. Spur and helical gears 228 10.2.1. Involute form measurement 228 10.2.2. Master gears; composite deviation testing 230 10.2.3. Lead measurements 232 10.2.4. Pin and ball measurements of spur gears and splines 232 10.2.5. Tooth index position measurement 234 10.2.6. Tooth thickness, pitch, and span measurements 234 10.3. Bevel, hypoid, spiroid, and worm gears or drives 238 10.1. Gear Metrology, General 10.1.1. Standards and Nomenclature Note : Most of the references in this subsection do not deal with measurement, but they provide geometrical information which is essential to the measurement of gears. Standards are revised so frequently that readers should consult the latest edition of the reference listed. Proposed Standard Practice for the Inspection of Gears. Am Mach v70 nl7 Apr 25 1929 p 657-60 10 figs ; Power Transmission v34 no May 1929 p 37^0 10 figs. Proposed American recommended practice for inspection of gears, including worms hobs, and other cutters, compiled by Sub-committee No. 9 of Committee on Standardization of Gears ; gear inspection of cylindrical and tapered holes ; keyways for Woodruff keys, shafts, shifter grooves, small size spur, helical, internal and bevel gears, backlash, in- volute curves, angular velocity, thread inspection, external threads, internal threads and worm inspection ; hob in- spection, inspection of gear cutters (shaper and disc). Machine cut gears, C. Worm gearing, BS 721 : 1937. Stand Inst. Available from ASA. Brit Machine cut gears. A. Helical and straight spur. BS 436 : 1940, with amendments. Brit Stand Inst. Available from ASA. Fine Pitch Gears. Product Eng vl6 n9, 10, 11, Sept 1945 p 598-601, Oct p 710-13, Nov p 758-60. AGMA Standard 234.01 May 1945 for inspection and tolerances of gears of 20 diametral pitch and finer. Sept : Scope of standard, general specifications and classifications and spur and helical gears covered. Oct : Details pertaining to worms, worm gears, bevel gears and backlash in gears. Nov : Inspection and tolerance. Gear Tolerances and Inspection ( AGMA 231.01, 232.01, and 233.01). ASA B6.6-1946, out of print. New High-Speed Helical and Herringbone Gear Standard. Machine Design vl9 nl2 Dec 1947 p 157-8. Standard practice set forth by AGMA for use primarily in design of self contained speed reducer units, but equally valuable in design of other types of high speed helical gear drives falling within this classification. British Standard Specifications for Gearing, W. A. TUP- LIN. Engr vl85 n4819 June 4 1948 p 549. Discussion of Specifications 436, 545 and 721. Bevel Gears (Machine Cut). BS 545: 1949 36 p. Brit Stand Inst. Available from ASA. Applies to machine- cut, conical gears connecting intersecting shafts, the teeth being either straight or curved, pressure angle 20°. Three classes of accuracy are covered and tolerances are given. Ein System fuer Verzahnpassungen (A System for Tooth Fits), O KIENZLE. Werkstattstechnik und Maschinen- bau v39 n5 1949 p 129-39. DIN tolerance system for spur gears with involute teeth ; report of work carried out at end of war under auspices of German Standards Com- mittee ; general principles of fit system ; errors in gear teeth tolerances ; system developed, known as "unit dis- tance between axes" ; tolerances given in 12 degrees of accuracy ; tables, diagrams. Bibliography. Fine-Pitch Straight Bevel Gears (AGMA 206.03 ) —Ameri- can Standard B6.8-1950. Publ ASME, New York 1950 9 p out of print. Standard covering generated straight bevel gears of 20 diametral pitch and finer, for all shaft angles, with numbers of teeth equal to or greater than 1 %6, 15 /i7. 14 /20- 13 /3o for 90° shaft angle ; standard is iden- tical in technical content with AGMA standard on Fine Pitch Straight Bevel Gears. 213 Gears for Traction. BS 235: 1951. Brit Stand Inst. Available from ASA. For drives of vehicles running on rails. Gears For Instruments and Clockwork Mechanisms: BS 978 : Part 1 : 1952, Involute, spur, helical, and crossed helical gears. BS 978 : Part 2 : 1952, Cycloidal type gears with Addendum 1, Double circular arc types. BS 978 : Part 3 : 1952, Bevel gears, Brit Stand Inst. Available from ASA. Gears for Turbines and Similar Drives. BS 1807 : Part I: 1952 Accuracy. BS 1807: Part 2: 1958 Tooth form and pitches. Brit Stand Inst. Available from ASA. Simplified Standards for Gears, W. A. TTJPLIN. Engr vl93 n5017 Mar 21 1952 p 394-7. Standard gear defined as one that may be generated by standard cutter; it is desirable to use simple system of gear design that permits full use to be made of versatility of standard involute generating tools ; any calculation procedure that demands accuracy beyond that offered by 10-inch slide rule is (according to the author) not well conceived; diagrams. Worm Gear Design, H. WALKER. Engr vl94 n5035 July 25 1952 p 110-14. B S Specification 721 gives recom- mendations satisfactory for worm gears having involute helicoid thread form, but there is range of multi-thread worms of high lead angle not adequately covered by specification ; experience has shown desirability of de- fining more clearly method of spacing gear designs so as to reduce total number of new hohs and tools without over-restricting choice of available designs ; proposals provide means for overcoming difficulties. Development of Gearing Standards, W. A. TUPLIN. Machy (London) v81 n2090 Dec 5 1952 p 1173-7 ; see also Engr vl94 n5048 Oct 24 1952 p 538-42. Author's proposal that blank diameter of gear should be one essential in manufacture is now being considered by British Stand- ards Instn for spur, helical and worm gears ; procedure for designing pair of helical gears to work at specified center distance and to have specified velocity ratio ; present standards for worm gears critically examined ; features of proposed new standards. Before Brit Gear Mfr's Assn. Straight-Sided Splines (for Cylindrical Shafts), Nominal Dimensions in Millimeters. ISO Recommendation R14- 1953. Available from ASA, $0.60. Proposed Standard Design for General Industrial Coarse Pitch Cylindrical Worm Gearing, F. G. EAST. ASME Trans v76 n2 Feb 1954 p 163-72. Suggested method of standardizing general industrial coarse pitch cylindrical worm gear drives, particularly worm diameter and tooth proportions, to eliminate present difficulties where no recognized standard exists ; proposals do not insist on single worm diameter for each pitch or center distance but rather, limited group of worms that will cover range of good design. Letter Symbols for Gear Engineering. ASA B6. 5-1954. Available from ASA, $1.50. Identical with AGMA 111.02. Gear Nomenclature, Terms, Definitions, and Illustrations ASA B6.10-1954. Available from ASA, $1.50. Identical with AGMA 112.03. System for Straight Bevel Gears (AGMA 208.01) ASA Am Stand B6.13-1955. Publ ASME, New York, 1955 9p $1.50. Standard covering recommended tooth proportions and dimensions of blanks for generated straight bevel gears of tooth ratios in general industrial use ; data given is development from system originated by Gleason Works and adopted by AGMA in 1922, revised in 1940, and with further changes in 1955 revision. Stand der Verzahnungsnormung (Status of Gear Stand- ardization), A. BUDNICK. VDI Zeit v97 nll-12 April 15 1955 339-43. Status of gear standardization and its further development ; standardization of spur gears ac- cording to DIN 3960 ; tolerances for spur gear based on DIN 867; DIN 3974 standard for worm gears; status of international standardization. 20 Degree Involute Fine-Pitch System for Spur and Heli- cal Gears. ASA Am Stand B6.7-1956. Publ ASME, 1950 16 p, (AGMA 207.04) out of print. 'Standard fine pitch series includes gears of 20 diametral pitch and finer hav- ing 20° pressure angle; data concerning pinion enlarge- ments. Design for Fine- Pitch Worm Gearing. (AGMA 374.03) ASA AM Stand B6.9-1956. Publ ASME, 1950 18 p, $1.50. Standards covering worms and worm gears with axes at right angles, comprising cylindrical worms with helical threads, worm gear being hoboed for fully conjugate tooth surfaces ; it does not include helical gears used as worm gears ; data for standard axial pitch range of 0.030, 0.040, 0.050, 0.065, 0.080, 0.100, 0.130 and 0.160. Inspection of Fine-Pitch Gears ASA B6.11-1956, out of print. AGMA Stand 236.05 June 1956 41 p 27 figs. Avail- able from AGMA, $2.50. Includes a section on pin meas- urements of fine-pitch involute spur gears. Inspection of Coarse-Pitch Spur and Helical Gears. AGMA Stand 231.02 July 1956 18 p. Available from AGMA, $1.50. Inspection of Coarse-Pitch Bevel and Hypoid Gears, AGMA Stand 232.02 Aug 1956 lip. Available from AGMA, $1.50. Inspection of Coarse-Pitch Cylindrical Worms and Worm- gears. Tentative AGMA Stand 234.01 Aug 1956 12 p. Available from AGMA, $1.50. Whither British Standards for Gears? H. E. MERRITT. Engr v202 n5256 Oct 19 1956 p 547-9. Attention directed to difficulties encountered in attempting to revise certain standards for toothed gears, and to prompt wide based dis- cussion which may help to stimulate action in revision of standards. Normung, Tolerierung und Messen von Verzahnungen ( Standards, Tolerances, and Measurement of Gear Teeth ) , R. NOCH. Konstruktion v8 nlO Oct 1956 p 406-12, Reference to German DIN standards ; tooth defects and their measurement. Basic Rack of Cylindrical Gears for General Engineer- ing. ISO Recommendation R53-1957. Available from ASA, $0.60. See also ASA B6.1-1932, out of print. Modules and Diametral Pitches of Cylindrical Gears for General Engineering. ISO Recommendation R54-1957 Available from the ASA, $0.60. American Standard Drafting Manual— Gears, Splines, and Serrations (Section 7) ASA Y14. 7-1958. Available from ASA, $2.00. Gears for Turbines and Similar Drives. Brit Stand Inst BS nl807 pt 2 1958 7 p. Pt 2 : Tooth form and pitches ; standard specifies basic tooth forms and standard pitches of helical gears for high speeds, but should not be taken to suggest that they are unsuitable for other speeds; diagrams. Fine-Pitch On-Center Face Gears for 20-Degree Involute Spur Pinions. AGMA Stand n203.01 Feb 1958 20 p, Design of face gear and its pinion; recommended method of de- lineation of face gear on detail drawings ; two information 214 sheets show tooth proportions for pinions with less than 12 teeth, and one covering alternate method of calculating outside diameter of face gear. Tooth Proportions for Coarse-Pitch Involute Spur Gears. AGMA Stand System 201.02 Mar 1958 21 p. Available from AGMA. $1.50. Standard provides tooth proportion information required in designing spur gearing with 20° and 25° pressure angle full depth tooth forms; two infor- mation sheets on tooth proportions for 14%° full depth and 20° stub involute, and 1±M>° composite coarse pitch spur gears, and formulas and limitations for coarse pitch spur gear tooth proportions. Zerol Bevel Gear System. AGMA Stand System 202.02 July 1958 19 p. Available from AGMA, $1.00. New Standards for Gears Span Wide Range of Quality, L. D. MARTIN, Prod Eng v29 n52 Dec 22 1958 p 46-9. All-inclusive standard presented that can be applied to spur and helical gear specifications without conflicting with present AGMA standards ; 15 classes established with logarithmic sequence resulting from detailed exam- ination of thousands of gears. System for Spiral Bevel Gears. AGMA Stand 209.02 June 1959 11 p. Available from AGMA, $1.00. Involute Splines, Serrations and Inspection. ASA B5.15- 1960. Available from ASA, $5.00. New Formula Simplifies Worm-Gear Ratings, J. E. GUTZWILLER. Iron Age vl86 nl3 Sept 29 1960 p 116-17. AGMA 440.03 is designation for new worm gear rating standard to replace separate standards AGMA 213.02 and AGMA 440.02 ; new standard includes formula for rating worm gearinng which is complete departure from previ- ously used ratios ; standard also provides specifications for design of worm driven speed reducers. Straight-Sided Splines and Gauges, Dimensions in Inches, ISO Recommendation R232-1961. Available from ASA, $7.50. Design for Fine-Pitch Worm Gearings. (AGMA 374.03). ASA B6.9-1956 (R 1962). Available from ASA $1.50. Nomenclature of Gear Tooth Wear and Failure. (AGMA 110.03) Jan 1962 15 p 31 figs. Available from AGMA $1.50. Specification for Master Gears. Brit Stand Instn — Brit Stand 3696 1963 8 p. Standard relates to 2 classes of spur master gears for use as reference and inspection standards with pitches in range 2 to 64 normal diametral pitch inclusive ; class A master gears are intended to test precision class product gears and Class B to test gears for general purposes; specification may also be applied to helical master gears so far as tolerances are concerned, but tolerances given have been chiefly derived from infor- mation from spur master gears. Specification for Worm Gearing. Brit Standards Instn— Brit Stand 721 1963 34 p. Standard applies to worm gearing and comprises cylindrical involute helicoid worms and worm-wheels conjugate thereto, dimensions of which are expressed in inches; 4 classes of gears are provided which are related to function and precision; range of modules is given in convenient steps from 0.052 to 1 ; it does not refer to pairs of cylindrical gears connecting nonparallel axes known as crossed helical gears. 10.1.2. Textbooks and Handbooks Dealing Partially with Measuring Methods Note: For further abstracts of most of these books see subsection 10.1.3, Numerical Tables. Zahnrader (Gears). A. SCHIEBEL. Julius Springer Verlag, Berlin, 1913, 1922, 1930. Authoritative German presentation of theory and principles. See also 4th ed. by Lindner, 1954, abstracted in subsection 12.1. Spur Gears. E, BUCKINGHAM. McGraw-Hill Book Co. Inc., 370 7th Ave., New York, N.Y., 1928. Chapter 9 on measuring gear teeth includes descriptions of gear-tooth vernier, gear-tooth micrometer, roll measurement, tooth thickness and root diameter by vernier caliper, methods of measuring tooth spacing and involute contour, the odontometer, projection methods, composite tests, rack type tester. Schraubgetriebe, ihre mogliche und ihre zweckmassigste Ausbildung ( Screw Drives, Their Possibilities and Their Most Suitable Development). F. G. ALTMANN. VDI- Verlag GMBH Berlin NW7 1932 30 p 73 figs 36 refs. Con- tents : Introduction ; fundamentals of toothing of screw drives ; the screw surfaces of cylinder screws ; the inves- tigation of different cylindrical screws as to suitability for forming lubrication film ; the production of involute screws and the corresponding worm wheels ; operation results of drives with involute screws ; summary. Analytische Untersunehung des zylindrischen Schnecken- triebes mit gerader, die Achse schneidender Erzeugender (Analytical Investigation of Cylindrical Worm Drive with Straight, Axial Worm Profile), W. F. VOGEL. Omni- typie-Gesellschaft, Stuttgart, 1933. Doctoral Dissertation submitted to the Technische Hochschule Berlin on July 3, 1931 and endorsed Nov. 2, 1932, 62 p 52 figs bibliography. ( Exactly the same text published on the book market by the author (in 1933) under the industrial title: "Ein- griffsgesetze und analytische Berechnungsgrundlagen des zylindrischen Schneckentriebes mit geradflankigem Schnecken-Achsenschnitt" is now out of print.) Ana- lytical computation methods are developed for cylindrical worm-wheel mechanisms with straight-lined axial worm profile (Archimedean worms). All such mechanisms are reduced to dimensionless Unit- Worm-Drives having unit pitch-radius "one" of the pitch cylinder. The equations of the helicoidal surfaces of the worm are developed in rectangular as well as cylinder-coordinates. From them equations of the imaginary "Surface of Contact" were derived, yielding a complete analysis of the laws of con- tact between worm and wheel, including exact expressions for the (utilized) "Field of Contact," undercut limita- tions, the contact ratio, the surfaces of the wheel-teeth, and frictional velocities. Several particularly simple graphical constructions, especially for the paths of con- tact in longitudinal planes of the mechanism also are revealed for the first time. The equations of the worm's thread surfaces are also those of the customary cylindri- cal fastening and power screws and were later used by the author for the establishment of exact equations and the analysis of several tool profiles for all of these prod- ucts. (See 6 abstracts: Vogel 1933, 1934, and 1935 in subsection 12.6.3, p 272. ) Manual of Gear Design, E. BUCKINGHAM. 3 vols Machy (N.Y. ) 1935. In vol 2, p. 26-9, are given equations relating measurements over rolls and diameter of rolls to arc tooth thickness, and pressure angle at a given radius for involute spur gears. Compiler's comment: In vol 3, p 150, are given formulas, (which are not exact equations), relating diameters of rolls and measurement over the rolls to diameter, tooth thickness and pressure angle at the given diameter of a helical gear. (For errors of these approximations, which are not negligible for small numbers of teeth, see abstract of Buckingham, 1945, in subsection 9.3, p 209. ) Grundlagen fuer die Messung von Stirnraedern (Funda- 215 771-846 O — 66 mentals of the Measurement of Spur Gears, G. BERNDT. Berlin, Julius Springer, 1938 155 p diagrs charts tables. Measurement of involute toothed gears discussed ; fol- lowing determination of ideal gear wheels, methods for measuring contact angles and tooth flanks are given ; determination of flank shape, tooth slope and circular division of gear wheels covered, and effect of impulse blows of teeth on running of gear considered ; testing and inspection methods included. Involutometry and Trigonometry, W. F. VOGEL. Michi- gan Tool Co. Detroit 1945 325 p 28 figs 33 refs. Main Table provides columns of the natural trigonometric func- tions and involute functions conveniently arranged along- side each other. Complete sets of angular conversion tables and involute and cycloid tracing tables followed by other numerical and algebraical tables presenting geo- metric relations of gear dimensions and gear tooth pro- files. Exact step-by-step calculations for measurements of external and internal spur and helical teeth over freely selected balls and pins. Appendix gives a complete sys- tem of involutometry, classified as : ( 1 ) Geometry and calculations of involutes of base circles and related curves; (2) involutoids. namely surfaces containing a multitude of such curves; and (3) solids bordered fully or partially by involutoids. Gears. Gear Production and Measurement, A. C. PARK- INSON, W. H. DAWNEY, Pitman Publ Corp, New York and Chicago 1948 260 p. Book intended for those in trade who have gear problems, but who have little or no background of basic knowledge of sear forms, and of range of manufacturing and measuring methods; spe- cial attention paid to inspection procedure. Eng Soc Lib, NY. Analytical Mechanics of Gears, E. BUCKINGHAM. McGraw-Hill Book Co. Inc. 1949 546 p. The first chap- ters give an analysis of conjugate gear-tooth action, na- ture of the contact, and resulting gear-tooth profiles of the several types of gears. These include spur, internal, heli- cal, spiral, worm, bevel, and hypoid gears. The last chap- ters give analyses of gear teeth in action including frictional heat of operation and its dissipation, friction losses and efficiencies, dynamic loads in operation, beam strength or resistance of the teeth to breakage and fatigue, surface-endurance limits of materials, and the limiting wear loads or the potential resistance to surface disinte- gration and excessive wear. Zahnradgetriebe (Gear Drives), R. RITTER. Verlag Leeman, Zurich, 1950 184 p 49 figs 34 tables 250 refs. Developed in three parts : ( 1 ) Assembly of the standard drive with special consideration of the combined drive; (2) tooth forms and tooth corrections, — the 20° standard system, null, Vo, and V (variable center) drives; (3) cal- culation of gear wheels as to strength and wear life. De- voted to the concepts of the interchangeable manufacture of gear wheels, and tested specifications for the shop draw- ings and the manufacturing tolerances, in order to meet the requirements of the technical bureaus and the workshops. Practical Gear Design, D. W. DUDLEY. McGraw-Hill Book Co., Inc. New York 1954 335 p 158 figs. Contents : Gear design trends ; preliminary design considerations : design formulas ; gear materials : gear-manufacturing methods ; design of tools to make gear teeth ; the kinds and causes of gear failure ; special design formulas. Metrologie D' Atelier (Workshop Metrology), L. COM- PAIN. Editions Eyrolles, Paris 1952- 261 p 91 figs bibli- ography. Chapter 6, Verification of Gears, p 144-92, treats the following subjects : Verification of tooth pro- file, spacing, tooth thickness and tooth span, eccentricity, distortion ; geometrical tolerances of cylindrical gears. The Barber-Colman Hob Handbook. Barber-Colman Co., Rockford, 111., 1954 388 p 25 refs. Contains general engi- neering data, trigonometric and involute relationships, plotting involute tooth profiles and engineering data for fine-pitch gear hobs, spline and serration hobs and cutters, worm and worm gear hobs and cutters, and sprocket hobs and cutters. Gears, H. E. MERRITT. 3d Ed. 1955 527 p 29 tables 30 charts 32 refs. Sir Isaac Pitman and Sons, Ltd. Lon- don. Includes chapters on the geometry of involute spur, helical, spiral, conical involute, bevel and worm gears. Derives formulas for roll diameters and measurements over or between rolls for involute spur gears on p 114-6; also for helical gears on p 149-50. The Involute Curve and Involute Gearing. The Fellows Gear Shaper Co. 1957. Covers the application of the involute curve to gear teeth ; design, cutting and checking of involute gears ; definitions of gear-tooth elements, etc. A Treatise on Gear Wheels, G. B. GRANT. Philadelphia Gear Works, Inc., 20th ed 1958 (copyright 1899) 105 p 169 figs. Subject headings are (1) Theory of tooth action. (2) The spur gear in general. (3) The involute system. (4) The cycloidal system. (5) The pin tooth system. (6) Twisted, spiral, and worm gears. (7) Irregular and elliptic gears. (8) The bevel gear. (9) The skew bevel gear. Presents condensation of geometry which is basic to measurement of gears. Basic Gear Geometry — Reference Information, ALLAN H. CANDEE, AGMA 115.01 July 1959 25 p 37 figs. Available from AGMA, $1.50. The information presented has been collected and arranged to make the important geometrical relationships as easy to see as possible to provide a sound basis for a thoroughly logical and comprehensive system of gear geometry. A clear and accurate understanding of the elements involved is indispensable to all who deal with the design, dimensioning, cutting, and measurement of gear teeth. Introduction to the Kinematic Geometry of Gear Teeth, ALLAN H. CANDEE. Chilton Company, Book Division, Philadelphia and New York, 1961 204 p figs refs. Con- tents : Introduction and general principles ; general ideas of tooth design ; cutting and generating spur gears ; invo- lute teeth and the involute curve ; fillet curves ; layout and construction of involute profiles, rectangular coordi- nates; involute racks and involute tooth thickness; changes in center distance in involute gears; geometrical strength factor for spur gear tooth; profile errors, modi- fications, variations ; involute approximations ; six tables of involute coordinates, rectilinear and circular with derivations of equations. Gear Handbook, D. W. DUDLEY. 1962. McGraw-Hill Book Co., Inc. 24 chapters. Presents key information to solve the design of a gear, plan tooling for a gear job. analyze a gear failure, or select an appropriate manufac- turing process. Chapter 23 deals with inspection or measurement of the various standard types of gears. Maag Gear Book. Maag Gear-Wheel Company Ltd. Zur- ich. Dec 1963 576 p charts figs tables 168 refs. Deals with gear geometry and load capacity, gear drives, gear cutting, gear grinding, inspection of gears, gear materials and their heat treatment, gear dictionary, and bibliography. Modern Methods of Gear Manufacture. National Broach and Machine Co., Detroit. 3rd ed 1950 revised 1964 164 p 170 figs. See abstract under 12.1. 216 10.1.3. Numerical Tables Note : The references listed in this subsection are abstracted here only with respect to their numeri- cal tables. For additional other abstracts of such references see subsections 9.3, 9.4, 10.1.2, and 10.1.4. Index of Mathematical Tables, A. FLETCHER, J. C. P. MILLER, L. ROSENHEAD, L. J. COMRIE. 2d ed, 1962. Addison-Wesley Publishing Co., Inc. Reading, Mass. The most complete worldwide bibliography of important math- ematical tableworks, systematically referenced, cross- referenced, and abstracted. Note : Its standard indication for range and table progress of the entering column, for instance : 0° (0.01° ) 60°, was adopted in some descriptions of our lists of numerical tables. 10.1.3.1. Tables for Involute Calculations and Plotting Note : Involute functions are needed for the cal- culation of the involute (of a base circle), which is the principal part of transverse tooth profiles of most spur gears, helical gears, and other involute screws (including involute worms). Outside of these fields of application the involute functions are still almost unknown, although they had been tabulated in large numerical table works for more than three decades. This justifies a short intro- ductory description (see fig. 1). Unit Involute FIG. 1.— INVOLUTE AND UNIT INVOLUTE e Polar Angle, Pressure Angle, e Roll Angle Line sections, and curve sections of any involute are r b times their corresponding values of the unit involute. Authorized reproduction from W. F. VOGEL. "Involu- tometry and Trigonometry" 1945. Courtesy Michigan Tool Co., Detroit, Mich. Any given single dimension of the unit involute (of base radius "one") determines all of its shown dimensions. For instance : = inv 0=tan — =e— a rctan e ev 0=sec 0=V 1 + ? 2 Any one of these dimensions can be and has been used by different authors as the entering column of numerical tables for the Unit-Involute. For any other involute (of base radius r b ) Vogel's polar equation of the involute reads simply: r=r b Xev B Spur Gears, E. BUCKINGHAM. McGraw-Hill Book Co., New York, 1928. An extensive presentation of theory, problems, and solutions, particularly about involute gears. Contains probably first extensive table of the involute function : inv0, namely the polar angle in radians to 6 sig- nificant figures (without differences) plotted against the pressure angle 0°0' (1') 60°0'. Laying Out and Checking Involute Tooth Forms, F. W. SHAW. Machy (London) v 35 Jan 2 1930 p. 441-446 and Jan 16 p 513-9 11 figs. For an abstract of the first article see subsection 10.2.6. The second article is also on in- volute spur gears and gives numerical tables as follows : Table 1 lists tooth thickness-semiangles of gears (for standard thickness). For details see subsection 10.1.3.3. Table 2 gives 8-declmal values of the involute's polar angle S=inv [in radians], tabulated against the pres- sure angle in degrees, namely 0=0° (0°.5) 45°. Other columns tabulated alongside list 8-decimal values for arc . No differences are given in the table. Table 3 contains functions for the lay-out of involute teeth using their axis of symmetry as one axis of the rectangu- lar coordinate system, while the other axis passes through the center of the base circle. The table refers to Unit- Involutes of base radius "one" and is immediately usable only for standard-thickness gears (without backlash). The following functions; arc, sin, arc-sin; vers=l — cos and log vers are tabulated at seven decimals (without differences) against their variable profile-thickness semi- angle in the range 0°5' (5') 15°0'. Examples for the utilization of the 3 tables for lay-outs and even for calculation of span-measurements are given. The publication is chronologically remarkable for that early date, but the calculations are too cumbersome in the light of more recent and much more convenient numerical tables. Manual of Gear Design, 3 vols, E. BUCKINGHAM.. Publ., by Machy (N.T.) 1935 vl, Mathematical Tables, contains the following tables : Gear ratios, factors of numbers to 6000 ; 8-place trigonometric functions : sin, cos, tan, cotan, with differences, plotted against 0=0°. 00 (0° .01) 90° .00; 8-decimal radian table: arc plotted against 0=0°. 00 (0°.01)45°; 8-decimal values of inv =0°.00'(0°.01)90°. The fact that the radians, arc f, are also tabulated alongside, actually provides also the six reversed functions arcsin , arccos is tabulated in radians without differences, against the pressure angle : 6 decimals for 0=0° (0°.l) 75°; 5 decimals for 0=76° (0°.1.82°; 4 decimals for 0=83° (0M) 87°; 3 decimals for 87° (0°.l) 89° ; 2 decimals for 89° (0°.l) 89°.9. (For greater than 29°, linear interpolation of the table leads to uncertainties larger than 0.5 unit of the last decimal and can lead to intolerable errors in some part of the range.) 218 Table 24-14, p 24.24 and 24.25, Polar Angle of the In- volute, R. T. PARSONS. Seven-decimal table, with differ- ences. 0=inv

larger than 4.8° and grows with increasing values of a ) involute systems, covering N-values and any helix angle between 0° and 45°. The selector values are based on the assumption of stand- ard thickness at the pitch cylinder. He also gives tables of some auxiliary functions for facilitating the final cal- culation of the helical span-dimension. MAAG Gear Book 1963 p 442-3 gives 2 selector-nomo- grams, one for 15° and the other for 20° normal pressure angle system, respectively ; both covering N-values and any helix angle between 0° and 45°. By contrast to the two preceding tables, this selector-graph also covers a range of varying modification coefficients featuring de- liberately and considerably modified tooth thicknesses. An elaborate system of numerical tables p 444—507 pro- vides auxiliary values facilitating the final calculation of the helical span dimension. 10.1.3.6. Tables Of Base Tooth Dimensions referring to the base cylinder of involute shaped teeth Base Thickness Semi-Angles and Base Space Semi-Angles. Tables are valid only for gears having standard thick- ness at the pitch circle. For angles in radians their equations read, respectively : T °=2N +inV i M and <7b= 2|a ~~ mv *m where 0m is the Main Press Angle (in the plane of rotation) at the pitch circle. Tables for angles in radians : To 6 decimals : PETERS 1937 & 1951 p 195-202 for M = 14.5° ; 15° ; 20° and N=l to 250. To 7 decimals: VOGEL 1945 p 273-85 M =14.5° and 20° ; and N=l to 300. Tables for angles in degrees ; To 5 decimals of the degree : VOGEL 1945 p 273 to 85 0m= for M =14.5° and 20°, and N=l to 300. Tables for Linear Base Tooth Dimensions : in inches for diametral pitch or in millimeters for module one. To 4 decimals : PETERS 1937 and 1951, p. 191-3, base circle diameters for M =14.5°, 15°, and 20° and N=l to 250. To 7 decimals : VOGEL 1945 p 273-85. Base radii, base diameters, base tooth thickness and base space. (The latter two dimensions are meant only for gears having standard thickness at the pitch radius. ) All dimensions for (/>m=14.5° and 20° and N=l to 300. Table of Base Helix Angles, MAAG Gear Book 1963 p 444-507. The base helix angles of the 15° and 20° ( M involute systems) are tabulated in degrees, minutes, and seconds against the pitch helix angles: 0°0'(1')45°0'. 10.1.3.7. Miscellaneous Gear Tables Analysis of Stresses, New Departure Engineering Data, General Motors Corporation, 2 volumes, Bristol, Conn., 1946. The second volume gives extensive curves for numerical evaluation of the pertinent Hertz equations. for the contact of two solid elastic bodies under compressive force. See also KOZMA etc., 1962, on this page. The Sevolute, A New Function for Use in Involute Gear Calculations, J. J. WILLIAMSON. The Fellows Gear Shaper Co., Springfield, Vt. 1949. Also Supplements nl and n2. Tabulates the function sev =sec <£— inv = eve— 6 at 5 decimals to simplify the problem of calculating 'full-radius' fillets or tips. Geometrical significance is given to the function in the first supplement. The second supplement discusses the sevolute and the "extended sevolute" in connection with pin measurements of gears and splines. Calculation of Testing Center Distance, J. L. WILLIAM- SON. Pub Fellows Gear Shaper Co., Springfield, Vt., 1957. Six decimal values of polar-angle deviations A(inv0), (differences Ainv=anv0 n om — inv^.ctuai ) are tabulated for varying ratios cos0aetuai/cos0 n „minai ; also printed with six decimals in small tables headlined each by a constant nominal pressure angle. From table to table the head- lined (nominal) pressure angle changes: 0„on.inai=13° .0- (0.1) 24°. 1. The tables are valuable for fixture-setup and/ or for numerical evaluations of gear testing by rolling fix- tures employing master gears. Tables for Calculating the Compressive Surface Stresses and Deflections in the Contact of Two Solid Elastic Bodies Whose Principal Planes of Curvature do not Coincide, A. KOZMA, H. CUNNINGHAM. Industrial Mathematics, Detroit vl2 1962 p 31-40. The tables, based on the per- taining theory by Heinrich Hertz, are intended to fa- cilitate the use of his equations. In that respect they may be particularly valuable for numerical computation of the influence of surface deformations on the results of pin and ball measurements of precision-screws, gears, and worms. Simultaneous stress analysis could benefit from the establishing and/or standardization of load limits for these measurements. Table of Diametral Pitches and Modules with the Cor- responding Pitches and Base Pitches, Maag Gear Book 1963 p 39-41. The circular pitch and the circular base pitch are tabulated each in inches and in mm against two entering columns, giving in "bold face" standardized values of the diametral pitch or the metric module, re- spectively. The values for the base pitches are printed for the 15° as well as for the 20° involute spur gear sys- tem. All dimensions are given to 5 or 6 decimals. 10.1.4. Technical Papers on Gear Measurement, General A Spur-Gear Anglemeter, W. M. WILSON. Am Mach v28 Apr 13 1905 p 479-82 3 figs. An illustrated description of an instrument designed for determining the variation in the angular velocity ratio of gears, explaining its use. Gaging and Inspecting Gears, D. T. HAMILTON, Machy ( N. Y. ) v23 Apr 1917 p 679-88 25 figs. Good discussion of fixtures for testing pitch, pitch diameter, tooth shape, tooth thickness and concentricity with photographs and illustrations. Subjects taken up in detail are : Inspecting gear blanks ; templets for gear blanks, bevel protractor for testing bevel gear blanks, gear tooth templets and calipers; tolerances for bevel and spur gears; testing cen- ter distances, pitch diameter and concentricity of spur gears ; fixtures for testing pitch diameter, concentricity, thickness of spur gears, transmission gears and pinion shafts ; testing bevel drive gears and spur gears for noise under load; testing bevel drive ring gears; fixture for testing involute curve of spur gear teeth ; testing ground faces of bevel ring gears, testing fixtures for steering worm sectors. Backlash in Gearing and Methods of Its Measurement. Automotive Indus v42 May 6 1920 p 1058-60. Shows that some backlash is necessary to provide free action between teeth. Describes and illustrates methods of measurement. Inspection of Involute Spur and Helical Gear Hobs, C. G. OLSON. Machy (N.Y.) v20 Sept 1921 p 11-13, Oct 1921 p 138-40 ; Machy ( London ) vl9 p 90. Testing the accuracy 222 of hob and tooth parts, hobbing test, involute test, jump test, roll test, and three tables of base circle disk diameters. Inspection of Mill Reduction Units, R. H. RAUSCH. Iron Age May 25 1922 p 1440-2. Testing of tooth shape, check- ing helix angles, shaft alinement and other points. Testing Gear and Gear-Cutter Teeth, R. E. FLANDERS. Maehy (N.Y.) v28 June 1922 p 817-9 6 figs. Description of screw-thread comparator for quickly detecting imper- fections. (Abstract). Paper read before AGMA conven- tion. Adaption of Hartness comparator for inspection of gear cutters, testing uniformity of form cutter teeth, test- ing accuracy of a hob, method of projecting and testing gear shaper cutters, method of testing spur gears. Some Causes of Gear-Tooth Errors and Their Detection, K. L. HERRMANN. SAE J vll Nov 1922 p 391-7 14 figs. Discusses different gear noises, gives examples of defects that cause noise, and describes device for checking tooth spacing ; also instrument for analyzing tooth forms that produce noises. Quality Control in Gear Manufacture, S. O. BJORNBERG. Machy (N.Y.) v29 Apr 1923 p 623-6 7 figs. Equipment employed for inspecting hob, hobbing machine, and finished gear. Fig 1, machine for testing the profile of hob teeth. Fig. 3, machine for testing the correctness of lead, by com- parison with a master screw, and concentricity of cutting edges. Fig. 6, fixture for checking the radial height and the face of teeth on resharpened hobs. Zahnraderpriifung (Gear Testing), M. KURREIN. Werk- stattstechnik vl7 Apr 15 1923 p 225-32 29 figs. Describes various types of testing apparatus. The Gaging of Involute Threads, H. E. MERRITT. Machy ( London) v22 Apr 5 and 19 and July 26 1923 p 11-13, 79-81 and 525-8 13 figs. Apr 5 and 15 : Gaging straight-spur teeth by tooth caliper, and by plug or wire method. July 26 : Geometry of finished-ground worm thread ; funda- mental dimensions ; application of some of the properties of thread surface to gaging problems. See also p 191, 210, 251, 275, 307, 376, 475, and 569. Gear-Measuring Machine. Eng vll6 July 27 1923 p 104-9 28 figs. Gear-measuring machine designed and constructed at Nat. Physical Laboratory, for measuring individual specimens, such as spur and helical, plain and spiral bevel and worm wheels, and for recording errors in running of combined gears. Gear-testing Machine at the National Physical Laboratory. Machy (London) v22 Aug 2 1923 p 579-83 8 figs. Elements in gear teeth ; wheel clamps ; use of machine for straight spur gears ; helical and bevel gears. Zahnriiderpriifung und Sonderherstellung (Gear Testing and Special Production), A. STEINLE. Werkstatts- technik vl8 Mar 15 1924 p 169-73 22 figs. Optical testing methods and instruments. Wickman Gear Measuring Machine. Engr vl38 Sept 5 1924 p 272-3 4 figs ; Automobile Engr vl5 Jan 1925 p 25-6 3 figs. Designed to differentiate between errors of spacing and errors of concentricity and parallelism. Societe Genevoise Gear Testing Machine. Am Mach v61 Oct 16 1924 p 635 2 figs. ; Machy (London) v24 1924 p 831 ; Eng Production v7 Nov 1924, p 317-8 4 figs. For testing pitch, eccentricity, and tooth profiles of gear wheels. May be used on bevel and helicoidal gears, and spur gears with straight or helical teeth. Universal Gear Testing Machine, F. JOHNSTONE- TAYLOR. Machy (N.Y.) v31 Dec 1924 p 289-91 7 figs. Machine developed under the direction of G. A. Tomlinson by NPL of Great Britain which may be used for any kind of gear and for recording errors in running of meshed gears. Steel Tapes for Measuring Large Diameters, G. C. REIL- LEY. Am Mach v62 Jan 1 1925 p 26. Used for testing outside diameter of gears for turbine reduction-gear sets. Machine for measuring tapes also described. Measuring Gear Teeth, J. L. WILLIAMSON. Am Mach v63 Oct 15 1925 p 609-12 7 figs. Points out that to check eccentricity, points of contact should be as near as possible to ends of teeth ; to check spacing, points of contact should be near pitch circle ; comparative readings cannot be ob- tained on different testing fixtures unless diameter of ball and pressure angle of rack tooth is same on both machines. Testing Spur and Helical Gears or Cutters. Machy (N.Y.) v32 Jan 1926 p 382-3 4 figs. Describes two ma- chines used in tool room of Maxwell Motor Corp., Detroit, Mich., for determining accuracy of spur and helical gears and gear-shaped cutters ; how test is made ; using machine as comparator; checking spacing and concentricity of teeth ; using optical micrometer. Measuring Inaccuracy in Gear Teeth, J. L. WILLIAM- SON. Can Machy v36 July 29 1926 p 15-7 7 figs. Dis- cusses common errors in checking inaccuracies in gear tooth form and spacing and describes simple methods of determining errors. Paper read before Am. Gear Mfrs. Assn. Machining and Measuring Gear Teeth, E. BUCKING- HAM. Am Mach v66-67 May 26 June 9, 23, July 7, 14, Aug 11, 18, 25, Sept 15, 29, Oct 20, 27 and Nov 10 1927 p 879-82 969-72, 1051-4, 7-10, 49-52, 233-7, 265-9, 313-6, 419-22, 497-8, 617-20, 657-9, and 733-6 83 figs. Accuracy in Gear Teeth. Automobile Engr vl8 Apr 1928 p 136-8 8 figs. Maag method of measuring along common normal between successive tooth faces ; routine testing of pitch and profile ; instrument gives direct indication and record of departure of actual tooth profile from true theoretical involute ; checking backlash between pair of gears ; testing gears for concentricity. Illinois Universal Hob and Worm Testing Machine. Am Mach v68 June 28 1928 p 1068-9. Head arranged to test the lead, the pressure angle, and the contour of the teeth in both straight and helically fluted hobs, and of corre- sponding parts of worm threads. Will also test the concen- tricity of the relief clearance of hob teeth, and the spacing of threads or starts in multiple threaded hobs and worms. Societe Genevoise Gear-Testing Machine. Machy (N.Y.) v35 Oct 1928 p 147-8 3 figs. ; Automotive Indus v59 Dec 8 1928 p 842 1 fig. Am Mach v69 1928 p 558. Gear-testing machine designed for quick inspection of gears for errors in pitch, concentricity, and tooth profiles, developed by Soc Genevoise Instrum Phys Geneva, Switzerland, is described. A Gear Cutter Comparator, S. TRIMBATH. Am Mach v75 p 296 Aug 20 1931 2 p 2 illus. An arrangement whereby the rack angle can be determined from a given pitch circle and the involute. Discussion by F. W. SHAW. Am Mach v75 p 803 Nov 26 1931 1 p 1 illus. Cutter rolls in relation to steel tapes upon its base circle instead of upon its pitch circle ; pressure angle is zero and angle of testing rack tooth zero; device utilized also for testing accuracy of tooth spacing. Further discussion by S. TRIMBATH. Am Mach v76 p 229 Feb IS 1932 1 p 2 illus. Author further describes and defends his design. Zeiss Gear Testing Machine, Geo. Scherr Co. Inc. N.Y. Am Mach v76 Feb 11 1932 p 218. Measuring precision to 0.0001 in. combined with rapid operation are features of this instrument. The gear tester will take spur, bevel. 223 helical and worm gears and test the following elements : circular pitch, eccentricity, uniformity of tooth spaces, and uniformity of tooth thickness. The gear is placed be- tween centers, where it can be revolved to bring successive teeth into position. New Methods of Inspecting Gears for High-Speed Trans- mission, D. T. HAMILTON. Machy (N.Y.) v38 Aug 1932 p 932-8. Procedure followed in checking spur, helical, and herringbone gears for shape, spacing, pitch diameter, and eccentricity on machine designed bv Fellows Gear Shaper Co., Springfield, Vt. Fellows Gear Measuring Machine, Am Mach v76 Aug 3 1932 p 920. Various elements of a gear tooth that can be checked on this machine are : involute profile or shape, circular pitch, pitch diameter and eccentricity ; also the lead or corresponding helix angle on helical gears, guides, and the helically splined members. The column is posi- tioned by gage blocks. Work is held on a vertical arbor. The fixture, which carries the dial indicator and the various inspection units, can be moved about on the table. This machine has a capacity for measuring gears from 2 to 7 in. pitch diameter. Pruefen von Zahnraedern (Testing of Gears). Maschi- nenbau vl2 n 13 /i 4 July 1933 p 361-2 4 figs. Testing of gears ; outline of test with regard to division, thickness of tooth, true running, engagement axle distance, involute curve. Gear Shaper As Inspection Tool, S. TRIMBATH. Am Mach v77 nl7 Aug 16 1933 p 517-21. No. 6 Fellows gear shaper can be used in checking accuracy of spur and heli- cal gears and also spur and helical cutters ; machine had been replaced by No. 7 high-speed gear shaper for cutting purposes and then converted into measuring machine at nominal cost. New Lees-Bradner Gear Tester. Iron Age vl33 p 33 Feb 1 1934 1 p 2 illus. Gear tester will check tooth contour, arc of action, length of line of action, tooth to tooth spac- ing, cumulative error and eccentricity of both spur and helical gears. Methods for Checking Gears, D. T. HAMILTON, R. BEARDSLEY. Iron Age vl36 n3, 5 July 18 1935 p 14-7, 92 and 94 and Aug 1 p 20-2 and 94; Steel v97 n3 July 15 1935 p 32-5 and 67. Principal requirements to be con- sidered in production of accurate gears ; devices for check- ing individual gear-tool elements illustrated and de- scribed ; automatic inspection of all errors in combina- tion, by means of recording machine. Before Am Gear Mfrs Assn. Messverfahren und Messgeraete der Zahnradfertigung (Measuring Methods and Equipment of Gear Finishing), H. GREGOR. Maschinenbau vl5 ny 2 Jan 1936 p 17-21. Measuring methods and equipment in manufacture of gears ; reference to paper by A. SODEN indexed in Engi- neering Index 1933 p 532 from VDI Zeit Mar 4 1933 on noise in gears ; measuring equipment used for this purpose is described by present author. Zahnradpruefung (Gear Testing), G. ZIEHER. Werk- stattsteehnik und Werksleiter v31 n3 Feb 1937 p 49-53. Practical article on various methods of testing of gears with respect to isolated flaws, impact failures, thickness and width of teeth ; testing of pins ; overall tests. Fehlerpruefung bei Zahnraedern (Error Testing of Gears), R. BOCK. VDI Zeit v81 Feb 27 1937 p 267-72. Testing methods and equipment are described and analyzed. Testing of Gears for Errors, R. BOCK. Eng Progr vl8 n9 Sept 1937 p 197-202. Notes on design and preliminary operations, machine and tools, hardening, drawings, bores and splineways, number of testing instruments required, checking for centricity, pitch and tooth thickness, tooth form ; axle spacing and engagement conditions of meshing gears. Grundlagen der Pruefverfahren fuer gerade Zahnraeder mit Evolventenverzahnung (Testing Method for In- volute Spur Gears), G. BERNDT. Werkstattstechnik und Werksleiter v31 n23 Dec 1 1937 p 522-34. Extensive treatise on principles of various measuring methods and equipment and their application ; methods developed may be applied to other forms of gears. Quiet Gears, S. O. BJORNBERG. Steel vl02 Feb 7 1938 p 46-50. Accuracy in gear teeth is real answer to quiet- ness, and correct inspection methods are means of ob- taining such accuracy; describes inspection methods of testing machines manufactured by Illinois Tool Works for involute profile, tooth spacing, composite errors, and lead of spur or helical gears. Slide Rule for Variable-Center Distance System Gears and Measurement of Amount of Profile Shift, T. NAKATA. Soc Mech Engrs Japan Trans v5 n21 Nov 1939 p IV^l-9. Slide rule devised for computing center distance and other dimensions of pair of involute spur or helical gears ; giving number of teeth and amount of profile shift ; using such method, further generalization of variable center distance system is developed ; amount of profile shift in such gear, of which tooth proportion is unknown, can be estimated by roller method. ( In Japanese. ) Pruefen von Innenverzahnungen auf der Bearbeitungs- maschine (Testing of Involute Internal Gears on Produc- tion Machine During Manufacture ) , P. KLU WE. Maschi- nenbau vl9 nil Nov 1940 p 477-9. Illustrated description of special measuring methods and gages employed for this purpose ; determination of nominal and actual dimensions. Adaptable Gear-Testing Machine. Machy (London) v57 Feb 27 1941 p 599 3 p 3 illus. Description of machine manufactured by Monarch Tool Co., Huddersfield, de- signed for testing spur, helical, bevel, spiral and worm gearing ; suitable for either laboratory or shop use ; gears tested by rolling together thereby eliminating many in- dividual measurements ; simple and easily mounted at- tachments enable whole range of gearing specified to be tested. Instrumentation at Nuttall Gear Works. Instrum vl4 n5 May 1941 p 117-20. Pictorial presentation of instruments ranging from simple gages to control systems and uses from intermittent single measurements to continuous au- tographic tests and automatic control. Gear Inspection Methods, D. T. HAMILTON, Iron Age vl48 nl6 17 Oct 16 1941 p 29-34 and Oct 23 p 38-^4. Methods of measuring individual tooth elements, like tooth shape, tooth spacing, tooth thickness and eccentric- ity, are discussed ; how gear errors may be checked in combination ; factors causing gear noise analyzed ; use of helical gears is solution to noise problem and calls for special checking apparatus ; importance of tooth bearing is emphasized. Measurements of External and Internal Helical Involute Gears, H. PELPHREY. Tool Engr vll n4 Apr 1942 p. 64. Simplified method for calculating proper dimensions where accuracy is vital. Compiler's comment : The method is based on strict geometry and on exact equations for the ball measurement of involute screws which are, however, not simpler than Vogel's (1937) in subsection 9.3. It per- mits free ball selection and most of its equations could be applied unchanged to more easily executed pin measure- ments of these products, [e.g., Candee (1928) and Vogel ( 1945 ) in subsection 9.3] . 224 Whv Does a Gear Sing? How Can Singing be Avoided? A. MEHDAHL. Brown Boveri Rev v29 n9/10 Oct/Sept 1942 p 284-9. Results of measurement on large helical gears ; pitch of note ; shadow lines ; table drive measurement. Measuring Errors in Involute Spur Gears, S. CORNELL. Iron Age vl53 nl2 Mar 23 1944 p 68-73, 144. In order to set up measuring standards for spur gears, author presents picture of ideal gear which has no errors and using this imaginary gear as reference point, presents general clas- sification of spur gear errors and outlines method of re- cording and evaluating deviations. Improved Gear Tooth Vernier. Passenger Transport J v91 n2305 Sept 8 1944 p 129-30 ; Transport Wld v96 n3073 Sept 14 1944 p 226. Illustrated description of simplified type developed by David Brown & Sons (Huddersfield) Ltd ; instrument has advantage of only requiring setting to linear dimension between fixed and moving anvils ; measurements are over number of teeth and, as anvils are tangent to tooth flanks definite "feel" is obtained as in using micrometer on cyclindrical object, no height meas- urement being involved. How to Improve Accuracy and Efficiency in Measurement and Testing of Gears, K. BUERGER. Engrs' Digest (Brit Ed) v5 n9 Sept 1944 p 275-9; Engrs' Digest (Am Ed) vl nil Oct 1944 p 637-41. Illustrated description of methods and equipment for testing form of teeth ; testing surface of flanks ; testing circular pitch and chordal pitch ; thickness and width of teeth, and width of space ; parallelism of teeth; testing with regard to collective de- fects. English abstract from Maschinenbau (Betrieb) v22 n3 Mar 1943 p 101-7. Recent Developments in Gear Inspection Methods, D. MONCRIEFP. Instrum vl9 n 10 Oct 1946 p 586-8. Meth- ods of producing accurate gears that are quiet and smooth running ; problem of heat treatment distortions, checking tooth profile, hob contour checking ; tooth spacing tests ; helical gear lead and spur gear tooth alignment check ; hob lead checking ; size and concentricity ; speeder test. Profile and Surface Analysis. Aircraft Prod v8 n97, 98 Nov 1946 p 509-12, Dec p 557-60. Nov : Napier technique of checking gear teeth by combination of mechanical and optical magnification described. Dec: Some variants of method as applied to surfaces of certain other components, including valve sleeves, are dealt with. Measurement of Errors in Gears for Turbine Reduction Drives, C. TIMMS, Instn Mech Engrs Proc vl57 (War Emergency Issue n35) 1947 p 418-32 (discussion) 432-51, 2 supp. plates. Review of work carried out at National Physical Laboratory in development of methods for meas- uring errors of large gears for turbine reduction drives by means of series of portable instruments ; relationship between errors and inaccuracies of gear nobbing machines and gears cutting holes ; methods of determining in- accuracies. Practical Design of Gears and Gear Cutting Tools, H. PELPHREY. Michigan Tool Co., Detroit, Michigan 1947 31 p 50 figs. Gives analyses of gear design based on both the involute system and straight-sided spline section. In- cludes a set of exact equations for measuring involute spur and helical gears using balls or pins. Controle des Engrenages a Denture en Developpante (Gaging of Involute Gear Teeth), C. MACABREY. Pra- tique Indus Mecaniques v30 nl Jan 1947 p 3-11. Method based on characteristics of development of circle and simple formulas ; derivation of formulas applicable to any arc. Inspection of Helical Involute Gear, W. H. WITTRICK. Instn Engrs Austral J vl9 n2 Feb 1947 p 43-4. Inspection of gear for aircraft supercharger drive ; data on inspection device used for determination of distance from axis where ball should seat and of tolerance on dial gage reading for any given tolerance in tooth thickness. Some Gear Cutting Inaccuracies and Their Effect on Gear Loads and Gear Noises, S. F. DOREY, G. H. FORSYTH. North East Coast Instn Engrs & Shipblds Trans v63 pt6 Apr 1947 p 267-330, (discussion) pt 8 July p D183-D208. Study of causes underlying gear failures ; measurement of magnitude of errors in gear hobbing machines ; gaging of errors in finished gears ; measurement of undulations along tooth flanks ; equipment and apparatus used ; tooth form errors. Equations for the Normal Profile of Helical Gears, A.F. ZAMIS. Am Mach v91 Sept 25 1947 p 82-4 4 figs. De- rives equations for the normal section of an involute heli- coid for application in checking the profiles of large heavy gears and in verifying the operation of standard involute machines on smaller machines. From the equations rec- tangular coordinates of the normal section may be calcu- lated. See also PERES (1959) and WATERS (1961), both on p. 227 in this subsection. Gear Tooth Inspection Method As Index of Performance, L. D. MARTIN. Prod Eng vl9 n2 Feb 1948 p 87-9. Ele- ments that constitute good spur gear and fundamental principles of involute curve outlined ; analysis and inter- pretation of inspection data obtained by pin measurement method and master gear or rack method of checking ac- curacy of gear tooth elements. Le Controle des Engrenages (Gear Measurements), M. WOLPER. Rev Universelle des Mines v91 n2 Feb 1948 p 196-205. Testing methods and apparatus described and illustrated ; results tabulated. Comparator Chart Layout Checks Involute Gears, F. E. BROWNING. Am Mach v92 nil May 20 1948 p 89-92. Quick, accurate checking of involute gears is done on comparator with master chant laid out by calculating points outlining tooth profile; advantages of optical pro- jection ; method is illustrated by calculation worked out for gear having following specifications : 20° full depth spur gear, 30 teeth, 8 diametral pitch, 3.750 in. pitch diam and 4.000 in. basic outside diam. Measurement of Periodic Errors in Gear-Hobbing Ma- chines, C. TIMMS, A. A. KING, L. E. JEANS. Eng vl66 n4315 Oct 8 1948 p 337-40. Record of latest form of G. A. Tomlinson's instrument and method for measur- ing errors of controlling movement of hobbing machines while in motion ; equipment consists of notched disk which actuates microswitch and impulses from "make and break" are recorded by piezoelectric record cutter on smoked plate carried slowly round on machine table. Helical Gear Nomograph, W. A. RING. Prod Eng v20 nil Nov 1949 p 159. Chart giving center distance and normal pitch from helix angle and number of gear and pinion teeth. Autographic Recording of Errors in Gear Hobbing Ma- chine Tables, C. TIMMS. Machy (London) v76 nl947 Feb 16 1950 p 237-41; Engr vl89 n4909 Feb 24 1950 p 251-3 ; Eng vl69 n4390 Mar 17 1950 p 307-S. In inves- tigation, table movement is linked to rotation of hob spindle by means of friction drive, any variation in rela- tive movement being amplified electrically and recorded autographically on chart paper ; results of measurements on commercial gear hobbing machines and on Pfauter gear hobbing machine, type R.S.00, are plotted on charts. Communication from Nat Physical Laboratory. Hob Flank Angle Measuring Machine. Engr vl90 n4932 Aug 4 1950 p 131. Machine developed by Coventry Gauge 225 and Tool Co for checking by direct measurement form of involute helieoids and other helicoids straight sided in normal or axial planes; indicator is mounted on pillars on which it is adjusted vertically for setting stylus to correct plane by means of standard height block. Analysis of Gear-Tooth Undulation Records, P. M. GILET. Eng Vl72 n4469 Sept 21 1951 p 373-6. Method used in testing turbine reduction wheel ; appendix gives modifi- cation of undulation in recording ; diagrams. Pin Measurement of Face Gears, J. SILVAGI, V. FRANCIS. Am Mach v96 May 12 1952 p 183-7 4 figs ; Van Keuren Catalog and Handb n36 1955 p 248-50 2 figs. Describes method of measuring the tooth thickness of a face gear by measuring over a single cylindrical pin placed in a tooth space to some locating plane such as the back mounting face of the gear. A pin will rock in the same manner as a pin in the space of a helical gear. Analytical Gear Checking. Illinois Tool Works 1954. Discusses lead, involute, spacing, and composite checks. Geometry of Involute Helicoidal Hob and Gear Teeth, N. J. C. PERES. Austral J App Sci v5 n4 1954 p 309-29 1 fig. 9 refs; vlO nl 1959 p 17-24 1 fig 4 refs. In the 1954 paper the geometry of the involute helicoid is treated quite generally in terms of familiar gear param- eters. It is shown how the radius of curvature of the axial section becomes very large when the pitch helix angle is large, and in the particular case of hob threads with helix angle approximately 87°, the axial section becomes practically straight sided. The coordinates of any point on the curve of intersection of a plane normal to the pitch helix and the surface have been derived. These enable the theoretical normal section of an in- volute worm or helical tooth flank to be plotted for com- parison with the normal profile as traced out on a smoked glass plate by the pantographic technique of measure- ment. The equations for various other sections of the surface, often given in texts without adequate proof, fol- low immediately from the general treatment. In the 1959 paper entitled "Involute Gear Geometry" the vector treat- ment has been extended from the particular to the general case along similar lines to include every tooth and space in any gear. The general geometry holds for internal as well as external spur and helical gears, and particular properties follow from the general treatment. See also PERES (1959) in subsection 10.1.4, p 227. A Precise Technique for Accurate Checking of Gear Dimensions, W. S. TANDLER, AGMA 239.02 Oct 1954. Describes Probograph method. The Universal Probo- graph consists of a base unit, an automatic rotary head, tailstock, a probing head for longitudinal, transversal, and vertical measurements, and additional units includ- ing one for automatic stationing and a reciprocating stylus unit especially for gear measurements. May be used for several types of gears for all gear dimensional characteristics. Measurement of Gears, C. TIMMS. Eng vl78 n4C38 Deo 17 1954 p 789-92 (Editorial comment) p 779. Instn Prod Engrs J v34 nl2 Dec 1955 p 792-801 (discussion) 801-4. Existing methods of gear measurement and various meas- uring machines in use; recent developments and possible future trends ; establishment of unified system of pitch tolerances based on results obtained from comprehensive series of pitch measurements, proposed. From paper be- fore Brit Gear Mfrs Assn. Checking Accuracy of Gears. Eng vl79 n4643 Jan 21 1955 p 85. Machine made by David Brown Tool Co for check- ing concentricity, tooth contact center distance and tooth thickness of internal and external spur and helical gears ; machine will accommodate spur gears up to 24 in. in diam. Examining Machined Surfaces by Interferometry, J. DY- SON. Eng vl79 n4696 Mar 4 1955 p 274-6. Interferom- eter microscope applied to study of experimental double helical pinion to investigate differences in surface finish produced by hobbing and by shaving; overall profile of tooth surface is much improved in smoothness by shaving, but fine surface structure is made considerably worse. Gear Gaging Goes Automatic, T. S. GATES. Tool Engr v36 n5 May 1955 p 95-9. Application of automatic, in- process inspection to gears; requirements of automatic gear gages and their function ; basic factors of gear gages and their application ; sound testing of gear ; future of automatic gear gages. Selecting Effective Gear Inspection Methods, F. BOHLE. Tool Engr v34 n6 June 1955 p 111-4. Determination of most economical checking procedure; functional gear cheeking ; values for runout listed, with tolerances grouped according to pitch, pitch diameter and speed range ; advantage of analytical comparators ; other gear inspection procedures. Der Einfluss von Werkstoff, Maschine und Werkzeug an die Oberflachenguete der Zahnflanken (Influence of Ma- terial, Machines, and Tools on Surface Quality of Gear Teeth), W. HAGExN. VDI Zeit v97 n25 Sept 1 1955 p 849-59, Sept. 21 p 956-62. Test method and surface roughness of tooth surfaces ; photomicrographs. Messen der Verzahnungen an grossen Raedern, E. WAG- NER, K. H. WEBER. VDI Zeit v98 n8 Mar 11 1956 p 304-8. Measurement of large gear teeth, survey of de- velopment of measuring methods and instruments in Ger- many and other countries. Production and Metrology of Gearing, R. L. COWEE. In- spection Engr v20 n5 Sept-Oct 1956 p 98-103. Elementary design principles of involute gearing; production process on shapers and bobbers ; preparation of gear blanks and production of gears; errors in machines and tooling and their results on gears produced ; hand measuring tools ; instruments and machines available for gear metrology. Methods of Specifying Precision of Spur Gears, G. W. MICHALEC. Prod Eng v27 nl2 Nov 1956 p 135-42. An- alytical and functional methods of specifying gear size and tolerance, including : over-pins measurements ; ver- nier gear tooth measurements ; block gaging methods ; Am Gear Mfrs Assn and modified methods ; converting from one system to another. Tooth Gearing and Research, S. A. COULING. Engr v202 n5266 Dec 28 1956 p 915-8. Attempt made to stimulate interest in research, with view to remedying some of pres- ent defects ; fundamental and applied research ; tooth measurement, lubrication and other problems requiring research. Vereinfaehte Berechnung von Messweiten fuer aussenver- zahnte Gerad- und Schraegzahnraeder mit Evolentenzaeh- nen (Simplified Calculation of Measuring Width Stand- ards for Externally Toothed Straight and Helical Gears with Involute Teeth ) , H. HARTSCHEN. Werksstatt und Betrieb v90 n3 Mar 1957 p 187-90: Methods for determin- ing standard measuring width of O-type and V-type gears with or without flank and radial clearances, formulas and tables. Surface Roughness of Large Gear Wheels for Ship's Tur- bines, W. DE BRUIN. Ingenieur v69 n3 Aug 16 1957 p W115-8. Application of interference microscope with im- mersion cuvette for measuring surface roughness of tooth flanks; study was made in connection with installation of new gear hobbing machines in plant of N. V. Konink- lijke Maatschappij "De Schelde" at Flushing; relatively small roughness found which compares very favorably with that shown in previous tests ( in English ) . 226 Equipment for Testing Involute Gears, E. SCHULTHESS. Microtecnic vl2 nl Feb 1958 p 1-7. High accuracy instru- ments for measuring distance between centers and for checking true running; single flank rotary type instru- ments; equipment for pitch measurements; instruments for testing gear flanks; device for measuring angle of tooth ; micrometers for chordal measurements ; compound and universal types of instruments ; testing equipment for bevel gears. New Hope for Angular Accuracy in Precision Gear Trains, F. FREUDENSTEIN. Prod Eng v29 n23 June 9 1958 p 70-1. Four equations are offered for measuring angular errors in gearing, where suitable inspection methods are lacking ; besides predicting magnitude of error, equations indicate corrective measures for eccentricity, wobble, pro- file errors and thickness and pitch errors. Measurement of Large Gears, C. TIMMS, Inst Mech Engrs (Advance copy July 28 1958). Discusses surface finish of gear teeth ; adjacent, short span, and cumulative pitch errors ; tooth lead or helix angle ; tooth profile ; and gear hobbing machine errors : 29 ref s. Probleme der Grosszahnradmessung (Problems in Meas- urement of Large Gears), A. BUDNICK. VDI Ber v32 1959 p 57-67. Two most important questions are stated to be those of stability and accuracy of test instruments ; survey of English and German measuring methods and devices, accompanied by illustrations. 23 refs. Die theoretische Grundlage fuer die Pruefung von Kegel- raedern ( Theoretical Principles for Testing Bevel Gears ) . G. ZIEHER, VDI Ber v32 1959 p 89-98. Straight bevel gear and its manufacture ; measurement of tooth profiles. On the Difference between the Normal Plane Helical Gear Profile and the Virtual Spur Gear Approximation, N. J. C. PERES. Australian J. App Sci vlO nl 1959 p 17-24 1 fig 4 refs. Helical involute gears are sometimes milled with rotary cutters or ground with formed grinding wheels, whose form corresponds to the tooth space profile of an imaginary "virtual" or "equivalent" involute spur gear in the plane normal to the pitch cylinder helix. The present paper gives equations for the difference between the profile so produced and the correct normal plane profile and shows that in some cases the approximation is not sufficientlv accurate. See also PERES paper (1954) p. 226; ZAMIS (1947) p. 225 and WATERS (1961) p. 227 in this subsection. Messen und Pruefen von Kleinstzahnraedern (Measuring and Testing Miniature Gears), L. MEYDING, VDI Ber v32 1959 p 77-88. Gear errors in watch movements and other small mechanisms ; measuring instruments de- scribed. 23 refs. On the Difference between the Normal Plane Helical Gear Profile and the Virtual Spur Gear Approximation, N.J. C. PERES. Australian J. App Sci vlO nl 1959 p 17-24 1 fig 4 refs. Helical involute gears are sometimes milled with rotary cutters or ground with formed grinding wheelsr whose form corresponds to the tooth space profile of an imaginary "virtual" or "equivalent" involute spur gear in the plane normal to the pitch cylinder helix. The present paper gives equations for the difference between the profile so produced and the correct normal plane pro- file and shows that in some cases the approximation is not sufficiently accurate. See also PERES paper (1954) p. 226; ZAMIS (1947) p. 225 and WATERS (1961) p. 227 in this subsection. Vereinfachte Berechnung der Zahnweiten und der Grund- kreisdurchmesser, insbesondere bei korrigierten Schraeg- verzahnungen nnd Eingriffswinkeln, die von 20° abweichen ( Simplified Calculation of Width of Teeth and Base Circle Diameters, Particularly in Case of Corrected Helical Gears and Pressure Angles Which Deviate from 20°), H. BERGMANN. Werkstatt und Betrieb v92 nl Jan 1959 p 10-14, Diagrams and/or numerical tables for pressure angles of 15°, 20°, 22°30', and 30° in standard and special gears presented. Der neue GOST-Standard ueber Messmittel fuer Stirnrae- der (New GOST (Russian) 5638-58 Standard of Meas- uring Instruments for Spur Gears), K. BOEHM. Stand- ardisierung v5 n4 Apr 1959 p 1/152-6. Outline of Soviet standards and comparisons with East German standards in this field. Measuring Gear Teeth Errors Under Load, B. WOOD. Eng vl87 n4861 May 8 1959 p 614. Errors measured for pair of spur gears defined as deviation from uniform rota- tion of one gear when other gear is rotated uniformly; measuring apparatus consisted of two 2% in. diam steel disks and two 1%-in. diam steel rollers; practical diffi- culties. Measuring Kinematic Errors of Gears, M. BARASH, P. OXLEY. Machy (N.Y.) v66 n2 Oct 1959 p 139-40. Of two instruments developed in Soviet Union, one measures relative rotation between standard gear and gear being tested while they are simultaneously run in mesh with third gear, and second instrument is designed for check- ing fine pitch gears ; their design and operation. Die erweiterte Anwendungsmoeglichkeit des Taylorschen Grundsatzes (Possibility of Extended Application of Tay- lor's Fundamental Principle), H. WEINHOLD, Magde- burg Hoschschule Schwermasehinenbau Wiss Zeit v4 n2 1960 p 139-45. It is shown that this principle can also be applied to testing of gears, if complex notion of func- tion is defined beforehand. Vybor toehnosti izmeritel'nykh sredstv dlya kontralya zub- chatykh koles, B. A. TAITS, N. N. MARKOV, Stanki i Instrument v31 nl Jan 1960 p 20-4, see also English trans- lation in Machines & Tooling v31 nl 1960 p 22-6. Develop- ment by Interchangeability Bureau of Committee on Standards, Gauges and Measuring Instruments of guide for selection of accuracy of measuring devices used for quality control of spur gears. Geometricheskii raschet tsiTindricheskikh zubchatykh koles s pomosch'yu spetsial'nykh tablits (Geometrical Cal- culation of Cylindrical Gears Using Special Tables), G. I. KOGAN. Stanki i Instrument v31 n2 Feb 1960 p 24-32 ; see also English translation in Machines & Tooling v31 n2 1960 p 26-34. Calculation method proposed is uni- versal and simplifies direct calculations ; its use eliminates calculations of intermediate values ; especially when deter- mining only individual features which characterize pinion or gear ; examples of calculation of spur and helical gears given. Brief Description of New Single-Face Gear Testing Device. F. LOBE. Microtecnic vl4 n3 June 1960 p 101-12. Meth- ods of measuring gear teeth accuracy are reviewed ; manner in which control is performed on new single face testing device for coping with all types of transmission elements is described ; design and construction of proto- type for testing worn gears by single face method is dis- cussed ; photographs and sketches. Exact Equations for any Normal Profile of an Involute Helical Gear, W. C. WATERS. Apr 24 1961 63 p 7 figs 6 refs. An essay submitted to the Graduate Council of Wayne State University in partial fulfillment of the re- quirements for the MS degree in the Dept of Mech Eng. Object is to investigate the errors inherent in the equiva- lent gear approximation. Subject headings include : De- rivation of general equation set ; test on equation accu- racy ; computer program formulation ; computer results ; section normal to central tooth pitch helix ; section normal to lateral pitch helix ; discussion of computer results : appendix. See also ZAMIS (1947) p. 225 in this subsection. 227 Ein Beitrag zur Pruefung der Zahnrichtung an Zahnrae- dern (Study of Tooth Direction in Gears). W. ROM- MERSKIRCH. Werkstattstechnik v51 nlO Oct 1961 p 529-33. Measuring methods and devices for testing straight toothed and helical gears, and internal toothing described ; checking of measuring instrument. Achsabstand und Profllverschiebungen in Evolventen — Stirnradgetrieben (Backlash and Profile Displacement in Involute Spur Gears), R. NOCH. Tech Zeit fur prakt. Metallbearbeitung v56 n7 1962 p 365-71 5 figs 7 refs. Diagrams are given from which the corresponding values for the axial clearance and the profile displacement can be read out, in many cases, to a sufficient number of decimal places. Pribor dlya knotrolya kinematicheskoi tochnosti zubcha- tykh peredach (Instrument for Testing Kinematic Accu- racy of Gears), YU. A. FEDUKIN. Stanki i Instrument n5 May 1962 p 29-30 ; see also English translation in Machines & Tooling v23 n5 1962 p 32-3. Description of method developed in Saratov Heavy Gear Cutting Machine Works; how continuous record of measurements was ob- tained by means of standard recorder ; method is based on comparison of length of piano wires being wound (or unwound) on drums mounted on gears tested. Gear Measurement, Inspection Equipment and Practices. AGMA 129.15, June 1962. Seven papers presented at the 46th annual meeting of the AGMA. (See GREEVE and DEVOS references below in this subsection and BEAM in subsection 9.3.) Die Fertigung von Genauigkeits-Grosszahnraedern (Pro- duction of Large Marine Gears of High Precision), W. DREYHAUPT. Werkstatt und Betrieb v95 nil Nov 1962 p 733-43. Details of gear hobbing machine and operating conditions, manufacturing procedure and measuring and safety devices employed ; numerous measurement results presented indicate accuracy of gears. Pruefung der wichtigsten Verzahnungsgroessen an Stirnraedern (Testing Most Important Sizes of Spur Gear Teeth), A. BANHART. Werkstatt und Betrieb v95 nil Nov 1962 p 745-54. Whole field of testing spur gears for individual and cumulative errors is discussed in detail, and testing methods and apparatus employed are de- scribed. Teilungsmessungen an Verzahnungen in der Praxis (Pitch Measurements on Gear Teeth in Practice), H. A. KOOP. Werkstattstechnik v52 nl2 Dec 1962 p 646-52. Installa- tions and devices employed are described ; interpretation of measuring results with regard to various types of errors is explained. Measuring Method of Gear Accuracy, bv Means of Two Feelers, J. ISHIKAWA, H. OHMURA. Japan Soc Mech Engrs Trans v28 nl96 Dec 1962 p 1655-69. New method in which 2 feelers contact simultaneously on two adjacent tooth surfaces and draw error curves in same way as with usual tooth profile tester : center distance of 2 feelers is set equal to normal pitch of gear, so that two curves of profile errors are recorded : curves are superposed to give entire error ; method is applicable for spur gears ; curves for meshing and angle position errors were derived. In Japanese with English abstract. New Instruments for Measuring Accuracy of Gears and Gear Trains, K. STEPANEK. Czechoslovak Heavy In- dustry nlO 1963 p 34-42. IMO-S equipment developed in Czechoslovakia makes it possible to determine exactly inaccuracies of gear hobbing machines, shapers, and grinders ; apparatus is portable and measures gears directly on machine ; -results obtained are presented graphically and analyzed ; accuracy of indexing gears can be assessed with high precision by means of thorough analysis of results or additional tests. Gear Checking Equipment, E. F. FABISH. ASTME Creative Mfg Seminars— Tech Paper 586 1963-64 9 p. Gears should be checked under conditions simulating actual operation mounting conditions ; of two basic types of test equipment, functional and analytical, first is avail- able in all ranges from manual to fully automatic ; effi- ciency of hand and semi- and fully-automatic gear rollers ; analytical type equipment is exemplified by helical lead- measuring instrument and tooth-space comparators; sources of gear errors are pointed out. Equipment for Measuring Driving Gears of Diesel and Electric Locomotives, YU. V. IVANOV. Meas Techns 1962 n8 Feb 1963 p 643^1 2 refs. Translated from Izmer Tekh n8 p 19-20 Aug 1962. Discusses equipment needs for measuring large railway gears. Determination of Cyclic Errors in Cylindrical Spiral Gears, B. YA. VERKHOTUROV, N. N. MARKOV. Meas Techns 1962 nl2 July 1963 p 988-91 4 figs 5 refs. Trans- lated from Izmer Tekh nl2 p 5-8 Dec 1962. Discusses the use of waviness meters for checking cyclic errors, which is the basic parameter for smooth operation of spiral gearing in GOST 1643-56. Goulder Mikron No. 4 Analytical Gear Tester. Machy (London) vl04 n2678 Mar 11 1964 p 594-5. Design and operation of apparatus for checking gears for concentric- ity, involute profile, lead and pitch ; it incorporates Taylor-Hobson electronic recording equipment of paper strip type, which gives 6 magnifications from lOOx to 5000x ; gears up to 48 in. diam by 10 in, wide, and weigh- ing up to 3000 lb can be tested ; separate attachment is available for carrying out dual-flank rolling tests. Improved Gear Measurement Techniques for the Correla- tion of Gear Error with Noise, C. H. McDOWELL, A. MARK. J. SPENCE. Res and Development Rep nl, Naval Boiler and Turbine Laboratory, Philadelphia, Penna, Apr 1964 19 p plus 26 figs. Reports on project to establish accurate methods and techniques to measure undulation and pitch errors. The laboratory has devised a measuring technique wherein undulations along a gear tooth can be measured and recorded on a continuous strip chart and analyzed with a sensitivity capability of better than 5 fiin. Also, the measurement of pitch error by a differential technique may be made to an accuracy equal to that of the divided table used for small diameter gears and superior accuracy with large diameter gears. 10.2. Spur and Helical Gears 10.2.1. Involute Form Measurement Gear-Testing Machine, G. WIRRER. Machy (N.Y.) v26 Mar 1920 p 633-5 8 figs. ; Machy (London) vl5 Apr 1 1920 p 862-4 8 figs. Description of a machine designed to test spur gears for accuracy of tooth profile and concentricity by comparing the rolling action of the pair of intermeshing gears with the rolling action of two accurate base circle disks. The result of this comparison is graphically re- corded by the machine. "Kavle" Correct Involute Contour Indicator. Am Mach v52 Mar 25 1920 p 698, 2 figs. Used to test the accuracy of the form of gear teeth. Operation employs the same principle as used in laying out a true involute tooth form. As the straight edge is rolled about the base circle plug, the short arm follows the tooth form while the long arm 228 remains in contact with the indicator plunger. If the tooth is of true form the pointer will not move. If the tooth is not of true form the indicator will show any de- viation from within 0.0002 of an inch. Gear-Testing Machine. Machy (London) vl5 Apr 1 1920 p 862-4 8 figs. Machine designed to test spur gears for accuracy of tooth profile and concentricity. Principle on which machine operates is comparison of rolling action of pair of gears under test with rolling action of two circular disks, result being recorded on chart. Inspection of Involute Gear Hobs, C. G. OLSON. Machy (X.Y.) v28 Oct 1921 p 138-40 6 figs. Describes involute contour tester for spur and helical gears used by the Illi- nois Tool Works. Gives three tables of base circle disk diameters. Lees Bradner Gear-Tooth Testing Machine. Am Mach v58 Apr 26 1923 p 640-1 4 figs; Machy (N.Y.) v29 Apr 1923 p 649-50 4 figs. Measures the accuracy of that por- tion of the tooth contour that conforms to an involute curve, and also measures the spacing of the teeth of the gear. A disk on the work arbor is of the same diam- eter as the base circle of the gear to be inspected. A tangent bar or straightedge is held against the base circle under spring tension by two ball bearings on the slide frame. As the slide frame is rotated upon the work arbor, the tangent bar rolls about the base circle and the point of the contact lever traces the involute of this base circle. The straightedge carries a bracket on which are mounted the contact point, magnifying levers, and a dial indicator. The contact point engages successive teeth of the gear, and if the tooth curve is a perfect involute the hand of the indicator attached to the device will stand at zero while the contact point travels from the base to the point or outside edge of the tooth. American Grinder Co. Gear Tester. Am Mach v59 Aug 30 1923 p 346-7. For checking and charting involute curves and testing tooth spacing. The machine consists of a base with a longitudinal slide upon which a trans- verse slide is mounted and constrained by tapes to move a distance equal to the peripheral motion of the base circle disk. Both slides are moved by screws with hand wheels and micrometer heads. On the transverse slide are mounted the contact finger and an indicator. "National-Cleveland" Tooth Form Tester. Am Mach v64 Mar 25 1926 p 495. For measuring tooth spacing and pro- file of an involute gear shaper cutter or a gear. The gear or cutter is mounted on a spindle and held by a stop while the contact point on the lower end of a lever touches the tooth to be measured. The indicating lever is mounted on a slide that is moved by steel tapes from a pulley on the back end of the spindle that carries the gear being tested. Moving this slide turns the gear and the contact follows the tooth form as the gear rolls in unison with the movement of the slide. Any inaccuracy in the tooth form is shown by the indicators at the upper end of the pointer. Gear Measuring Equipment. Machy (London) v28 June 17 1926 p 301^ 9 figs. Gear-measuring instrument made by Maag Co., Zurich, Switzerland ; measurements ob- tained with this instrument are made with reference to theoretically correct involute curves ; instrument for ex- amining involute tooth profiles and comparing these with correct theoretical shape ; also serves to examine sym- metry of two profiles of tooth. Involute Gear Tester. Machy (London) v29 Mar 31 1927 p 838-9 4 figs. Zeiss tester is designed for accurate test- ing of involute profile curve of gear teeth ; instrument will accommodate all spur gears with involute teeth up to 16-in. diameter; it is also possible to determine base dia- meter of gear if this is not known, it being only necessary to find diameter which gives smallest deviation. Co-ordinates of Involute Teeth. Machy (London) v34 n860 Apr 4 1929 p 6 2 figs. Method of determining co- ordinates of involute teeth is described with formulas ; in one particular type of gear grinding machine, application of mathematics of tooth curve of setting of machine will greatly facilitate set-up. National-Cleveland & Gear Checking Machine. Am Mach v72 Mar 6 1930 p 434. Improvements on the Model B gear checking machine permit readings to 0.0001 in. with a one-to-one lever arm mounted on ball bearings. Ball bearings are also used on the work spindle and the base circle disks. In addition to checking involute tooth forms, the machine has been found adaptable to checking the concentricity of the involute curved tooth with the bore of the cutter, by checking through an arc of 180 de- grees. The machine is also arranged to check the spacing of the teeth. It is made in 4-, 6-, and 8-inch sizes. Involute Gear Tooth Testing Instrument. Eng vl33 Jan 1 1932 p 22 ; Engr vl53 Jan 29 1932 p 138. Instrument produced by D. Brown and Sons, is simple, but accurate and reliable, mechanism for testing involute profile of teeth on spur and helical gears ; capable of accommodating gears up to 12 in. in base circle diam., and records driectly on to dial with sensitiveness to one ten-thousandth of in. any deviations from correct involute form. Orcutt Involute Measuring Machine. Engr vl55 n4032 Apr 21 1933 p 408. Machine developed by Gear Grinding Co., Birmingham, England, to meet its own requirements ; machine will measure any involute struck from any base circle between 1 and 13 in. in diam. Die Bestimmung des Evolventenfehlers von Zahnraedern ( Determination of Involute Error of Gears ) , E. BOLBRINKER. Maschinenbau vl8 n% Feb 1939 p 73-5. Valuation of flank test ; diagrams of involute testing apparatus. Charted Accuracy Minimizes Errors in Gear Profiles. Elec Mfg. v31 nl Jan 1943 p 90, 92, and 120. Gen Electric and Fellows Gear Shaper collaboration has lead to auto- matic electric chart recording of involute gear profiles in Fellows involute measuring machine which is illustrated and described. Involute Checking Machine for Large Helical Gears, D. W. DUDLEY. Machy (N.Y.) v54 n2 Oct 1947 p 142-5. Details of entirely new machine designed for checking large industrial and marine gears ; gear profiles are checked in normal section by special checking head which is moved across tooth profile and transmits deviation from straight line to recorder ; setup and typical applica- tion explained. Master Gaging for Involute Curve, C. H. BODNER. Tool Engr vl9 n5 Dec 1947 p 25-8 ; Am Mach v21 n26 Dec 18 1947 p 87-90. Proposed optical projection method and recommended practice for checking involute profile ; method requires use of master spline chart gage pattern, separate chart for each spline size; proposal limited to side bearing involute with 30° pressure angle, but can be applied to any involute profile whether straight or helical. Selection of Measuring Rolls for 30-degree Involute Splines, J. SILVAGI. Tool Engr v22 n2 Feb 1949 p 26-8. Method used to determine correct size of cylindrical measuring rolls for contour gaging involute spur gears and involute spur splines ; graphs simplify roll selection for standard SAE or SAS involute splines ; they are based on standard tooth space widths ; they can also be used to determine location of contact; table gives general equa- tion for determining roll diameter to contact at given diameter on nonhelical gear. 229 Epures Mobiles Universalis pour le Trace des Profils en Developpante ( Universal Movable Calculators for Outline of Involute Tooth Profiles) J. BERGERE. Pratique des Industries Mecaniques v32 nlO Oct 1949 p 311-7. Design and application of calculators and gages which permit rapid and accurate tracing of tooth profile; illustrations. Simple Linkage Which Generates Close Approximation to Involute, E. R. WIGAN. Machy (London) v86 n2204 Feb 11 1955 p 321-5. Linkage described provides simple method of gaging profiles of involute spur gears ; geometry and parameters of linkage; tabulation of involute and mechanism parameters ; sources of error in mechanism designed to conform to geometry of presented view. Involute and Helix Tester for Large Gears. Engr v202 n5256 Oct 19 1956 p 561. Tester, "Model PGZ," intro- duced by W. Ferd. Klingelnberg Soehne, Remscheid, Germany, stated to make possible testing of profiles on tooth flanks of gears too large for existing standard equipment. Ermittlung des zu einer Evolventen-Sehragzahnflanke gehorenden Grundzylinderradius (Investigation of the Base Cylinder Radius Belonging to an Involute Helical Gear Flank), M. GARY. Konstruction v9 nlO 1957 p 397-9. Calculation, measuring process, and example. Measurements of the Form Error of Small Gears Under Working State (Operating Conditions), K. YAMAMOTO. Report of the Central Inspecton Institute of Weights and Measures, Japan, v8 n3 Report 19 1959 in Japanese. There have been many measuring methods of gears, but few of them are applicable for small gears, because their minuteness necessitates an extraordinary accuracy in de- tecting form error of small gears. For example if the ac- curacy of measurement of gears with module three is to be required one micron, the equivalent measuring accuracy of small gears with module 0.3 must be 0.1 micron, and the detection of such a small dimensiion is very difficult. On the other hand the demand for such a high measuring accuracy grows greater and greater as the fine instru- ments are developed. For the above reasons a method for measuring form errors of spur gears is developed. The principle of the method is based on the fact that the driv- ing torque of a gear train is fluctuated by sliding friction and form errors of gear teeth contacting each other. A gear and a pinion are meshed together and a loading torque is applied on the pinion and then gear is driven so slowly that the angular motion of the gears can be as- sumed to be in an equilibrium state, and equilibrium can be obtained, one pair of which are equations when the gear is driven clockwise and the other when the gear is driven anti-clockwise. From these equations the reaction forces Q + and Q~ acting on the pinion from its bearings can be shown analytically, and Q + is the reaction force when the gear is driven clockwise and Q" is the reaction force when the gear is driven anti-clockwise. The fluc- tuations of (Q + + Q~) are brought about mainly by the form error of the gears but little by the sliding friction, while with the fluctuations (Q + — Q") the reverse hap- pens. And hence the friction and form error can be ob- tained if Q + and Q- can be obtained. The apparatus to obtain the forces Q + and Q" is shown, and some ex- amples of records of Q + and Q~ are also shown. It is proved that the form error, the friction and the actual contact of the gear and the pinion can be analyzed suc- cessfully. Die Ueberpruefung von Evolventenpruefgeraeten und das pruefen von Stirnraedern mit sehr kleinen Zahnezahlen (Examination of Involute Checking Devices and Testing of Spur Gears with very small Numbers of Teeth), W. ROMMERSKIRCH. Werkstattstechnik v49 nil Nov 1959 p 674-6. Methods for checking accuracy of recording device : nomogram as aid in testing of spur gears. Pribor dlya kompleksnogo odnoprofil'nogo kontrolya zub- chatykh koles, A. T. DRAUDIN. Stanki i Instrument v31 nl Jan 1960 p 24-6; see also English translation in Ma- chines & Tooling v31 nl 1960 p 27-8. Design of single profile testing machine BV-963 with universal setting for center distance from 2.756 in. to 9.843 in. and transmission ratios from 0.33 to 3.0 developed by Bureau of Inter- changeability. Investigating the accuracy of evolventometers, G. S. SIMKIN, G. Y. GAFANOVICH. Meas Techns 1961 n6 Dec 1961 p 435-8 1 fig 4 tables 3 refs. Translated from Izmer Tekh n6 p 8-10 June 1961. ■ Investigaton of several foreign make involute testers. Conclusion is that it is necessary to produce new instruments for measuring gears of high accuracy by GOST standards. It is also necessary to develop a more reliable method of setting the measuring tip for a given base circle diameter. Gear Checking Method Eliminates Errors in Setup, J. W. GREEVE. Tool & Mfg Engr v48 n5 May 1962 p 121-4. ( See next reference by DeVos. ) Ford Pin Type Master for Involute Gears, L. DeVOS. AGMA 129.15 June 1962 5 p 4 figs. New geometrically constructed masters use highly accurately ground and posi- tioned pins of circular cross section instead of involute- toothed master to qualify checking instruments at the Ford Motor Co., with the aid of calculated deviations. Thus the involute-master is removed as a source of error in accurate measurement. This important basic principle was suggested by Albert S. Beam (then chairman of the Gear Panel of the Industrial Mathematics Society, Detroit). Die neue Evolventen- und Steigungspriifmaschine Modell PFS-U (The New Involute and Lead Testing Machine Model PFS-U), K. H. WEBER. Klingelnberg-Nachr vl3 n32 Dec 1964 4 p 5 figs. Describes function in detail and how this model evolved from PFS 500 and PFS 600. 10.2.2. Master Gears; Composite Deviation Testing Device for Testing Truth of Cut Gears. Machy (N.Y. ) vl5 Jan 1909 p 374-5. Device for rotating gear with master gear and indicating changes in center distance. Testing Gear for Automobiles, M. E. HIDIEGAN. Am Mach v32-2 Aug 26 1909 p 389-90 3 figs. Illustrated de- scription of a device for the final testing of all spur-cut gears, either soft or hardened for out-of-roundness, etc., by rotating in mesh with a master gear. Device for Testing and Measuring Gears, C. BOELLA. Machy (N.Y.) vl8 Apr 1912 p 635 2 figs. An indicating device for operating spur gears in mesh and determining eccentricity. Testing Spur and Bevel Gearing. Internal Combustion Eng Oct 16 1912 p 341 4 figs. British machine by Park- inson and Sons in which bevel gear and pinion are run together and errors are recorded on a chart. Inspection of Spur Gears, D. V. WATERS. Machy (N.Y.) v28 Feb 1922 p 465-6 4 figs. Describes rolling fixture of Gould & Eberhardt, Newark, N.J., in inspecting spur gears, with particular reference to uniformity of tooth spacing and concentricity of pitch circle relative to axis of gear. Testing Involute Spur Gears, M. ESTABROOK. Mech Eng v45 Jan 1923 p 32^1 and 81 14 figs. Describes Saurer gear-testing machine, a Swiss development by means of which accuracy of tooth curves, spacing, and eccentricities can be determined with high degree of precision ; and odontometer, American instrument for quickly and accu- 230 rately testing gears for tooth curves and spacing, and with which it is possible to locate troubles in machines or tools. Gleason Spur Gear Testing Machine. Am Mach v73 Oct 16 1930 p 645. Running qualities of spur gears up to 14% in. pitch diameter can be tested on this machine. The machine can be used for testing cluster gears as well as gears with integral shafts ; also helical, herringbone, and internal spur gears. Heads are adjustable horizontally by means of a lead-screw graduated to 0.001 in. A 5-hp. motor drives the spindle. Specifications : distance between noses of spindles on brake and drive heads, min., 3 in., max., 18 in. ; distance from center of brake-head spindle to center of drive-head spindle, min., 3 in., max., 10 in. ; distance be- tween adjustable tail center and nose of brake-head spindle, min., in., max., 14% in. floor space, 61% by 77 in., and net weight, 4,000 lbs. Gear testers designed to show combined errors. Iron Age vl33 p 27 Apr 26 1934 1 p 1 illus. Parkson gear tester is designed to show composite errors of spur, helical, and bevel gears as well as of worm gears and worms. Meister-Zahnraeder als Normale fuer die Abrollpruefung (Master Gears as Standards for Rolling-Off Test), K. BUERGER, Werkstattstechnik und Werksleiter v34 n24 Dec 15 1940 p 427-33. Principles governing method and standards for acceptance testing of large numbers of gears ; measurement of master gears of different makes ; recommended tolerance for tooth dimensions of master gears. Bibliography. Adaptable Gear-Testing Machine. Machy (London) v57 nl481 Feb 27 1941 p 599-601. Description of machine manufactured by Monarch Tool Co, Huddersfield, designed for testing spur, helical, bevel, spiral, and worm gearing ; it is suitable for either laboratory or workshop use ; gears are tested by rolling together, thereby eliminating many individual measurements ; simple and easily mounted at- tachments enable whole range of gearing specified to be tested. Master Gears, H. WALKER. Machy ( London ) v58 nl486 Apr 3 1941 p 9-11. Description of standard set of master gears and their uses in testing spur and helical gears during manufacture. Ein neues Einflanken-Abrollpriifgerat fur Zahnrader (A New Single Plank Rolling Apparatus for Gear Wheel), K. BURGER PTB, Werkstattstechnik und Werksleiter v36 n% Jan 1942 p 54-61 ; VDI Zeit v87 nl7/18 May 1 1943. Illustrated description of new and improved type developed at Physikalisch Technische Reichsanstalt ; ad- vantages over double-flank system pointed out. Abstract from Werkstattstechnik v 36 1942 p 54-61. Some Facts About Master Gears, G. H. SANBORN. Am Mach v89 n!4 July 5 1945 p 116-7. Study of master gears and their application in inspection of work gears during and after production ; details of instrument used in meas- urement of tolerances; concentricity of teeth and back- lash; factors concerning selection and design of master gears. Gear "Rolling," G. W. BIRDSALL. Steel vll7 n8 Aug 20 1945 p 126-7, 164, 166. Description of essential ele- ments of gear rolling fixture for checking spur, helical, spiral and worm gears ; gear under test is fully meshed with master gear and change in center to center distances read on dial gage as gears are rolled against each other ; explanation of operational details ; illustrations of modi- fied designs for checking various types of gears included. New Concept of Gear Inspection, L. D. MARTIN. Tool & Die J v 15 n4 July 1949 p 42-5, 67-8. Description of model 1-S Conju-Gage intended primarily for checking all types of spur gears commonly used in meter, instru- ment and watch industries, and of 4-U model incorporat- ing features which increase ease and rapidity of inspecting larger gears up to 4% in. pitch diam ; advan- tages of master worm section used in connection with Conju-Gage over circular master gears ; electronic chart- ing device charts radial displacements occurring between master and work. Functional Checking of Gear Teeth, L. D. MARTIN. Machy (N.Y.) v56 n8 Apr 1950 p 208-13. Procedures and fixtures for checking various types of gears ; variable center distance fixtures, Gleason fixture, Fellows Red Liner, etc. described and illustrated ; features of new Kodak "Conju-Gage" for checking spur or helical gears pointed out ; factors to be considered when measuring backlash of gears. Functional Checking of Backlash in Gear Trains, L. D. MARTIN. Machy (N.Y.) v56 nil July 1950 p 161-5. Charts of reliable 'backlash cheeks made by rotating gear being checked in contact with master of known accuracy and measuring their radial displacements, are presented ; data sheets shown developed for finding change in center distance required to correct backlash in mating gears. Functional Gear Checking. Illinois Tool Works 1952. Describes various types of rolling fixtures and their uses. Functional Gear Checking, F. BOHLE. Machy (N.Y.) v58 n8 Apr 1952 p 170-5. Evaluation of gear inspection and its practice; gear rolling fixture designed for func- tional inspection of internal spur and helical gears ; ar- rangement for making angular velocity test under load : recording of errors on charts ; advantages of combining graphic inspection with functional gear checking ; photographs. Die Einzelfehler von Evolventen Stirn- und Kegelradern im Fehlerschaubild der Ein- und Zweiflankenwalzpriifung (The Single Errors of Involute Spur and Bevel Bears in the Error Presentation of the One and Two Flank Roll Testing), G. ZIEHER. Werkstattstechnik und Ma- schinenbau, v42 n6 June 1952 p 242-8 6 refs. What Errors Can a Gear Have? Eastman Kodak Co. Presents Conju-Gage as more accurate than a master gear for the same test. Standard Master Gears. AGMA Pu'bl. 236, 04, June 1956. Tables Simplify Calculation of Gear- Testing Center Dis- tances, J. L. WILLIAMSON. Machy (N.Y.) v64 nl Sept 1957 p 170-1 ; Machy ( London ) v91 n2353 Dec 20 1957 p 1445-6. Simple method for computing testing center dis- tance developed by Fellows Gear Shaper Co., Springfield. Vt ; difference between involute functions of nominal pressure angle and active pressure angle is first calculated from formulas ; numerical value for ratio of cosine of nominal pressure angle to cosine of pressure angle at meshing position is then found by referring to table; example. Toward More Economical Gear Inspection, F. BOHLE. AGMA 239.05, Oct 1957. Discusses principally various types of rolling checks. Measurement Errors in Gear Roll Testing. Machy (N.Y. i v66 n9 May 1960 p 145-50. Nature of errors in roll test measurements described ; methods of obtaining most accu- rate results from roll testing equipment. Complex Checking of Spur Gears in Single-Profile Mesh- ing with a Measuring Screw, M. N. BOKIN. Meas Techns 1960 n3 Dec 1960 p 179-80 1 fig 4 refs. Translated from Izmer Tekh ix3 p 1-2 Mar 1960. Method of cheeking the kinematic error of spur gears in single-profile meshing with a floating measuring screw has the following advan- tages as compared with the existing methods : the greater 231 771-846 O— 66 precision of measuring screws as compared with reference gears makes it possible to measure gears of any degree of accuracy ; the possibility of using the measuring screw for checking gears of any diameter providing they are of the same module. Master Gears and Their Importance in Gear Manufac- turing, R. NOOH. Microtecnic vl5 nl Feb 1961 p 20-3. Report on present state of development of using standards in form of master gears for determining cumulative errors of gear wheel by employing suitable gear testers ; newest trends of development indicated. Handbook for the Calculation and Design of Master Gears. Quality Assurance : Pamphlet ORDP 608-MC-14. Army Tank Automotive Center, Detroit, Mich., Nov 5 1962 72 p. Deals with fundamental inspection concepts, master gear design preparations and instructions, the master gear drawing, wire sizes, root clearance, and calculation sheets. Specification for Master Gears. Brit Standards Instn — Brit Stand 3696 1963 8 p. Standard relates to 2 classes of spur master gears for use as reference and inspection standards with pitches in range 2 to 64 normal diametral pitch inclusive ; class A master gears are intended to test precision class product gears and Class B to test gears for general purposes; specification may also be applied to helical master gears so far as tolerances are concerned, but tolerances given have been chiefly derived from in- formation from spur master gears. Checking Backlash in Gears, M. S. BRUNO. Am Mach/ Metalworking Mfg vl07 nil May 27 1963 p 77-81. How to obtain precise data on overall gear quality ; roll testing spur gear; standard procedure for inspecting backlash, total cumulative error, and tooth-to-tooth error simultane- ously ; converting to circular tooth thickness, with exam- ple ; how to calculate center distance limits : setting center distance limits : master gears inscribed with "test- ing diameter" value; finding correlated testing diameter. Das Lehrzahnrad als Mess- und Pruefmittel fuer Stirn- raeder, G. LICHTENAUER. Werkstatt u Betrieb v96 nil Nov 1963 p 807-11. Master gear as measuring and testing device for spur gears ; importance of double flank total composite error test devices, and of measuring noise and testing contact pattern with master gears is pointed out : design and construction of master gears. Goulder Mikron No. 4 Analytical Gear Tester. Machy (Lond) vl04 n2678 Mar 11 1964 p 594-5. Design and operation of apparatus for checking gears for concen- tricity, involute profile, lead and pitch : it incorporates Taylor-Hobson electronic recording equipment of paper strip type, which gives 6 magnifications from lOOx to 5000x ; gears up to 48 in. diam by 10 in. wide, and weigh- ing up to 3000 lb can be tested ; separate attachment is available for carrying out dual-flank rolling tests. Sammelfehlermessung von Stirnradern (Cumulative Er- rors of Spur Gears), R. NOCH. Archiv fiir Tech Messen V834-2 May 1964 p 105-8 9 figs 35 refs. Deals with form and position errors of gear teeth as detected by rolling. Considers both single and dual-flank contacts. Master Gears. Proposed Tentative AGMA Information Sheet. AGMA 235.03 June 1964 18 p. Covers masters for checking spur and helical gears operating on parallel axes. Rights and Wrongs of Gear Checking Pressure, L. D. MARTIN. Indus Quality Control v21 n4 Oct 1964 p 197- 202. Physical procedures are described which are helpful in determining optimum checking pressure for small pin- ions and gears with small bores where bending in either pinion journals or checking pin may be expected. Lehrzahnrader und ihre Bedeutung fiir die Zahnradfer- tigung (Master Gears and their Significance for Finish- ing of Gear Wheels), R. NOCH, VDI Braunschweig. Preprint available from author 4 p 6 figs 10 refs. De- scribes master gears and various types of rolling testers. 10.2.3. Lead Measurements All references under this heading are included in sub- section 9.2. 10.2.4. Pin and Ball Measurements of Spur Gears and Splines References to helical gears are given in subsection 9.3, p. 205. References to tables of numerical measurement values are given in subsections 9.4, p. 212 and 10.1.3.4, p. 220. Ring and Wire Gage for Measuring Fine-Pitch Gears, A. W. CHAPPELL. Am Mach v41 Oct 15 1914 p 689. Wire method of measuring gear pitch diam. Correction, A. W. CHAPPELL, Am Mach v41 Nov 5 1914 p 825. Correction, S. T. DORT, Am Mach v42 Jan 28 1915 p 167. Pin Measurement of Spur Gears, R. TRAUTSCHOLD. Machy ( N. Y. ) v24 Jan 1918 p 406-9 5 figs. Principles gov- erning pin measurement and derivation of formulas used ; finding size of pin ; discussion of formulas ; allowance for backlash. Table of sizes of pins used in measurement of 1 D. P. gears. Methods for even and odd numbers of teeth. Measuring Gears by the Use of Wires, W. S. HUDSON. Am Mach v49 Aug 15 1918 p 291-2 6 figs. Simplified for- mulas and tables presented. Method involves use of wires or pins, the diameter of which is constant for all gears of the same pitch, irrespective of the number of teeth. A single gage for testing large num'bers of gears of the same size is also described, comprising a suitably shaped holder having two holes suitably spaced, into which pins are pressed. Criticism bv J. W. LEE, Am Mach v50 Jan 16 1919 p 123-4. Formula for Measuring Spur Gears by the Pin Method, M. D. WILSON. Machy (London) vl8 Apr 21 1921 p 92^4 4 figs. The Gauging of Involute Threads, H. E. MERRITT. Machy (London) Apr 5, 19 July 26, Aug 2 1923 p 11-3 79-81 525 569 13 figs. See abstract under subsection 9.3. Standardized Roller for Checking Spur Gears, W. H. FOLDS. Machy ( London ) v23 Mar 13 1924 p 765-7 3 figs. Writer proposed to standardize to some extent, roller- check method by use of tables of factors, which makes it possible to use any size roller that will form contact on tooth faces or flanks, and from given diameter of roller overall measurement over roller as it is located in teeth of gear can be calculated. The Design and Inspection of Gear Teeth for Wear, P. M. GALLO. Blast Furnace & Steel Plant vl3 Sept and Oct 1925 p 368-9 and 392^1 2 figs. Presents roller formulas and explains their application to determining the defor- mations of gears under load. Checking Gears by the Wire Method, H. G. THUESEN. Am Mach v63 Nov 19 1925 p 824-5. Gives method and formulas. Normal Pitch the Index of Gear Performance, G. M. EATON. Mech Eng v48 Jan 1926 p 27-32 13 figs. Brings out certain departures from previously accepted practice which are useful in manufacture of heavy involute gear- 232 ing, as thej - ease performance during breaking-in stage of operation ; shows that material improvement in perform- ance may be secured by adopting proper relation between normal pitches of driving and driven gears, measured at point of tooth engagement; outlines development of nor- mal-pitch indicators. Measurement of the Thickness of Involute Gear Teeth, ALLAN H. CANDEE. Am Mach v68 n9, 11, 14 Mar 1, 15 and Apr 5 1928 p 365-8 463-7 573-6 12 figs. See abstract under Subsection 9.3. Constant Chord Gaging, S. TRIMBATH. Am Mach v73 n20 Nov 13 1930 p 769-793. Methods of sizing gear teeth by means of one pair of rolls or pins per pitch, and microm- eters ; chart giving size for 1 diametral pitch gears with seven different pressure angles. Pin Inspection of Tooth Profiles, S. TRIMBATH. Am Mach v76 May 26 1932 p 673-4. Method of checking tooth form by measurement across pins placed between teeth ; as two teeth contact with four involutes at same time, errors in tooth form caused by difference in pressure angle will be amplified approximately four times by measuring across pins. Helical Gear Tooth Measurement. S. TRIMBATH. Am Mach v76 Aug 31 1932 p 966-7. See abstract under sub- section 9.3. Checks on Gear Tooth Accuracy, I. J. GRUENBERG. Am Mach v78 n3 Jan 31 1934 p 123-4. Pin measurement at constant chord is recommended for final inspection of spur and helical gears. Size Measurement of Gears. W. L. CHESLEY. Tool Engr v5 n9 Jan 1937 p 14-5. See abstract under subsec- tion 9.3. Neuartige Kopfkreisfreie Zahndicken-Messungen fur Schragzahnrader und Evolventen-Schnecken (Novel Method of Measuring Tooth Thickness for Involute Helical Gears and Involute Worms without Use of Addendum Circle), W. F. VOGEL. Werkzeugmaschine v41 nil June 15 1937 p 253-61. See abstract under subsection 9.3. Ball Measurement of Helical Gears, A. ZAHORSKI. Am Mach v83 nl4 July 12 1939 p 520-2. See abstract under subsection 9.3. Pruefung von Kerbverzahnungen mittels Draehten (Test- ing of Stop Gears with Wires), H. ZOELLNER. Werk- stattstechnik und Werksleiter v33 Nov 1 1939 p 503-5. Development of equation by which gears may be tested by 3-wire method. Controle des Cannelures au Moyen de Goupilles Cylindri- ques (Checking Gear Size by Measurement Over Pins). Pratique des Industries Mecaniques v22 n4 Jan 1941 p 84-6. As applied to straight and involute flanks ; deter- mination of tolerances. Measurement of Spur Gear Teeth, W. T. TAYLOR. Aero Digest v49 n3 May 1 1945 p 90-3 150, charts on p 94-96. Over- or between-pin measurement of involute spur and helical gears is employed to determine circular thickness of gear teeth ; simplified involute function spur gear for- mulas for determining dimensions to center of measuring pins and dimensions over or between pins, presented. Engineering of Involute Splines, G. L. McCAIN. Chrysler SAE Trans v54 1946 p 245 310. Wire measurements. Selection of Measuring Rolls for 30-degree Involute Splines, J. SILVAGI. Tool Engr v22 n2 Feb 1949 p 26-8. See abstract under 10.2.1. Position of Contacting Sphere Between Teeth of Helical Gear, N.J.C. PERES. Machy (London) v77 nl977 Sept 21 1950 p 324 1 fig. See abstract under subsection 9.3. Gauging Involute Teeth or Splines over Rolls, F. W. HALIS. Machy (London) v78 n2012 June 7 1951 p 952-3. Formulas developed for checking external involute gears and involute splines by roll or wire method ; graph and table for selection of roll diameter presented. On the Influence of Surface Deformations in Over-Pin and Over-Ball Measurements of Spur Teeth, B. W. CART- WRIGHT. Nov 25 1952 50 p 12 figs 5 refs. An essay submitted to the Graduate Council of Wayne State Uni- versity in partial fulfillment of the requirements for the MS degree in the Dept of Mech. Eng. Subject headings include : Methods of spur booth measurements ; location and character of contact ; compressive stress and strain in the contact of solids ; special equations adapted to tooth specifications and special relations for standard thickness ; establishment of maximum micrometer force ; permissible micrometer loads based on stress limitations ; permissible micrometer loads based on deflection limita- tions ; conclusions ; appendix. Gears and Splines . . . Checking Pin Measurement Data, J. SILVAGI. Tool Engr v35 nl July 1955 p 93-8. Five double-check methods and associated formulas presented ; checking methods are simple and accurate, and avoid repitition of same type of error. Geometrische Probleme bei der Vermessung von zylindri- schen Evolventen-Schnecken und Evolventen Schragstirn- riidern ( Geometric Problems in the Measurement of cylin- drical involute worms and involute helical gears), M. GARY, PTB. Konstruktion v8 nlO 1956 p 412-8 2 figs 4 refs. See abstract under 9.3. Inspection of Fine-Pitch Gears. American Standard ASA B6.11-1956 41 p 27 figs. Publ by ASME, New York. Sec- tion 8, Pin measurements of fine-pitch involute spur gears contains 4 tables for external and internal 20° involute spur gears. American Standard Involute Splines, Serrations and In- spection. ASA B5.15-1960 108 p. Contains extensive data and tabulations relative to measurements over or between pins for space width and tooth thickness for in- volute serrations and splines and straight-sided serrations. Determination of Helical Gear Sizes by the Two-Roller Method, I. P. NEZHURIN. Russian Eng J v41 n8 1961 p 11-3 19 3 figs 2 refs. Translation pub by Product Eng 1957. See abstract under subsection 9.3. Computing the Displacement of the Initial Contour of Gears When Thev Are Checked bv Means of Balls, P. M. DANILYUK. Meas Techns 1960 n7 Feb 1961 p 585-6 2 figs. Translated from Izmer Tekh 19(50 n7 p 25-6 July 1960. Measurement of spur gears by means of balls. Ob- tains an expression for the radius vector in checking gears in both an even and odd number of teeth. Involute func- tion tables are not required. New Equations Simplify Pin Measurement of Gears, J. H. GLOVER. Prod Eng v32 nil Mar 13 1961 p 80-1 4 figs 3 refs. See abstract under subsection 9.3. Vereinfachte Berechnung der Masse fuer die Messung ueber Rollen bei Aussen- oder Innenverzahnungen mit Ein- griffswinkel 20° (Simplified calculation of dimensions for measurements over rollers of external or internal gears with 20° angles of pressure) , H. BERGMANN. Werkstatt und Betrieb v94 n6 June 1961 p 341-9. Methods are de- 233 scribed and their application explained by diagrams, nu- merical tables, and examples. Measurements of Helical Gears with Pins or Balls, Analy- sis of Pitfalls and their Elimination, A. S. BEAM, C. E. HALL. AGMA 129.15 June 1962 7 figs 1 ref. See abstract under subsection 9.3, p. 212. Computation of Ball Diameters for Testing Gearing, P. M. DANILYUK. Meas Techns 1962 n5 Nov 1962 p 371-3 2 figs 8 refs. Translated from Izmer Tekh n5 May 1962 p 12-3. Describes methods of computing diameters of balls and checking dimensions for all the cases encount- ered in testing involute spur gears. A table of involute functions is not required. 10.2.5. Tooth Index Position Measurement See also subsections 6.1 and 6.4. For angular spacing tables see subsection 10.1.3. A Scheme for Making the Universal Dividing Head Uni- versal, W. A. WARMAN. Am Mach v25 May 15 1902 p 698-9. Sketches and description of a device that gives accuracy. A Hobbing Machine and Dividing-Head Tests, Am Mach v31 Jan 2 1908 p 10-15. Illustrated description of how ac- curate worm wheels for dividing heads are hobbed in a special machine and the heads afterward tested. Various tests are illustrated. Die Priifung von Zahnradern auf Exzentrizitat und Teilungsfehler (Examination of Gears as to Eccentricity and Error of Pitch ) , G. BERNDT. Maschinenbau v4 Dec 17 1925 p 1232-6 7 figs. Shows that usual methods of testing by means of radially and tangentially displaeeable cones or cylinders are of no advantage; radial displace- ment gives greater accuracy. "Zeiss" Optical Dividing Head. Am Mach v65 July 1 1926 p 36. Obtains the division of the circle from a glass dial mounted directly on the spindle carrying the work. Indexing Head for Highly Accurate Spacing, F. C. DUS- TON. Machy (N.T.) v36 nl Sept 1929 p 14-6 3 figs. De- sign of precision indexing head employed in making accurate gears and perforated disks required for tele- vision equipment. Precision Angular Work. Machy (London) v39 Jan, 14 1932 p 493-500. Accurate master dividing plate made for 23 divisions, obtained by 23 individual ring sectors ; design and use of precision taper gage machining and assembling operations. Notes on Testing of Workshop Dividing Head, F. H. ROLT, C. O. TAYLERSON. Machy (London) v51 nl.311 Nov 25 1937 p 229-31. See abstract under 6.4. Compudex. Compudex Engineering Co., Chicago, 111. 1946 8 p. A computer to be used with indexing heads and rotary tables. Indexes every number from 1 to 1100 and every even number from 1100 to 2198. Effects of Alignment Errors in Dividing Heads, C. T. BUTLER. Machy (London) v83 n2144 Dec 18 1953 p 1211^. See abstract under 6.4. Automatic Indexing Machine for Measuring Gear Tooth Pitch Errors, C. TIMMS, C. A. SCOLES. Engr vl99 n5169 Feb 18 1955 p 229-31 ; Eng vl79 n4649 Mar 4 1955 p 271-4; Machy (London) v86 n2209 Mar 18 1955 p 597- 602. Tomlinson hob and gear measuring machine from which automatic pitch testing machine has been de- veloped at Mechanical Engineering Research Labora- tory, East Kilbride; it is largely pneumatically operated and functions entirely without presence of observer; repetitive accuracy per cycle found to be of order of 0.000005 in. Before Brit Gear Mfrs Assn. How Auto-Collimators Measure Gear Errors, T. R. KNOWLES. Machy (N.Y.) v63 n4 Dec 1956 p 137^3; Machy (London) v90 n2312 Mar 8 1957 p 519-24 8 figs. Two Watts auto-collimators used in one of special weapons laboratories of Northrop Aircraft measure directly errors in gears and gear trains in seconds of arc ; errors caused by pitch circle eccentricity (runout) ; determining random errors ; errors in gear trains. Line-of-Action Dontometer Inspects Spur Gears to plus or minus 1 sec of Arc, R. J. ROSS, J. P. WRIGHT. Am Mach vl02 nl Jan 13 1958 p 113-7. Use of gear analyzer at Sperry Gyroscope Co., Great Neck, NY for checking ultra-precision spur gears to maximum permissible non- adjacent tooth spacing error, for entire active profile, to within 1 sec of arc ; design, construction and operation of instrument. New Dividing Head, E. I. FINKEL'SHTEIN. Meas Techns n.3 Mar 1959 p 164-6 (English translation of Izmer Tekh ) see abstract under 6.4. World's Most Accurate Dividing Head. Vinco Corp., De- troit, Mich., Bui 56 1960 8 p figs. Vinco optical master inspection dividing head was created in 1937. States total index error at spindle or face plate as 2 seconds. States tolerances on spindle runout, spindle end face, and surface plates ; available in several models. New Method of Testing Divided Circles, C. KUHNB. Rev. Sci Instrum v31 n8 p 882-5 Aug 1960. See abstract under 6.4. Zur Messung der Kreisteilungsfehler an Zahnraedern und Teilscheiben (Measurement of Errors in Circular Pitch Distribution of Gears ) , R. NOCH. Werkstattstechnik v51 n3, 4 Mar 1961 p 142-7, Apr p 188-93. Problems of geom- etry, sources of errors and accuracy of measurements ; description of measuring installations ; temperature changes which occur and their influence on accuracy. 25 refs. Widening Applications of Radial Diffraction Gratings, W. H. P. LESLIE. Machy (London) v99 n2559 Nov 29 1961 p 1269-70. Reference made to application at Na- tional Engineering Laboratory, of gratings to measure- ment and subsequent reduction of errors in gear hobbing machine ; method is now used to apply overall correction betwen hob spindle and table; further application of radial gratings, now under active development at NEL is for singleflank checking of gears. Abstract of paper before 2d Internat Machine Tool Design and Res Conf, Manchester College of Science and Technology. New Road to Index Error Evaluation, H. R. RONAN, Jr. ASME-Paper 62-WA-39 for meeting Nov 25-30 1962 10 p. Index error measurement by theodolite system, gradu- ated plate measurements, and pitch variation measure- ments ; in making latter measurements, most important observation is that quantity measured is actually differ- ence between two points on index error curve; use of Laplace transform is explained and illustrated by ex- amples; in addition to providing means to index error plots, analysis technique is suitable to major purpose of span and pitch variation checks, cyclic error analysis; comparison is made of pitch variation system and two approaches in use. 10.2.6. Tooth Thickness, Pitch, and Span Measurements See Subsection 9.3 for tooth thickness measurement of helical gears. See also subsection 10.2.4 for tooth thick- ness measurement. 234 A Micrometer Gear Tooth Gage. Am Mach v23 Aug 30 1900 p 842. Two micrometers at right angles to measure tooth thickness at the pitch line. A Worm and Spiral Gear Tooth Gage, E. J. LEES. Am Mach v26 June 18 1903 p 875-6. Illustrates and describes a gear tooth caliper provided with scales for measuring circular pitch and normal pitch, and a protractor for reading the angle of the spiral. The Measurement of the Teeth of Gears, G. W. BURLEY. Prac Engr Jan 16 1913. Describes the measurement by means of the gear-tooth caliper, giving formulas and curves. Gaging Teeth of Involute Gears, H. E. TAYLOR. Am Mach v38 June 26 1913 p 1071-3. Makes use of vernier calipers. Gives derivation of pertinent equations. ( Prob- ably the earliest publication on span measurements of involute gears.) See table under subsection 10.1.3.5. Teilungsuntersuchung fur Zahnrader (Testing the In- dexing of Gears), F. GOPEL. Werkstattstechnik v7 1913 p 643 and 675; Zeit InstrumKde v34 Mar 1914 p 84-91 5 figs. A simple apparatus is described for the de- termination of the correctness of toothed wheels employed in instruments of precision. The errors are plotted as diagrams showing the correction necessary at any point. Measurement of Gear Wheels with Ball Micrometer, W. H. COWLIN. Machy vl5 (London) Mar 11 1920. The Wickman Pitch Measuring Machine. Automobile Engr vlO Dec 1920 p 481 4 figs ; Am Mach v53 Dec 2 1920 p 1068a. Machine is designed to measure tooth spacing at pitch line as well as concentricity of pitch circle with bore. Recent Developments in Gauging Apparatus. Eng Prod v2 Jan 13 1921 p 40-^4 12 figs. Machines recently in- troduced by Alfred Herbert, Coventry, England, notably gear pitch and concentricity measuring machine and uni- versal gage measuring machine. The Odontometer for Testing Gear Teeth. E. BUCKINGHAM. Machy (N.Y.) v27 July 1921 p 1029-31 6 figs; Machy (London) vl8 July 7 1921 p 412-3 6 figs. Apparatus consists of section of straight-sided rack with two parallel effective faces, one being fixed and other movable. Third face, set at angle to two working faces, is used to hold fixed working face in contact with flank of gear tooth. Developed by Pratt and Whitney Company. The Sykes Gear-Tooth Comparator. Eng vll2 July 15 1921 p 103 3 figs; Machy (London) vl8 July 14 1921 p 454-5 3 figs. Instrument consists of short bar fitted with one fixed and one sliding jaw, arranged with needle of a dial indicator between the two, and is used for compari- son of thickness of gear teeth and uniformity of pitch. Pratt and Whitney Odontometers. Machy (N.Y.) v28 Aug 1922 p 1010-11 2 figs ; Iron Age vllO July 27 1922 p 204. Instrument for testing gear teeth for uniformity of profiles and spacings. Odontometer for gears from % to 4 diametral pitch is shown in fig. 1, and from 10 to 24 diametral pitch in fig. 2. The Normal Chordal Thickness of a Worm Thread, A. FISHER. Machy (London) v20 Aug 10 1922 p 591-2 3 figs; Machy (London) v21 Oct 26 1922 p 118-9 4 figs. See abstracts under 9.3. Machine for Measuring Gear Teeth. Eng vll4 Sept 29 1922 p 410-1 9 figs. Describe machine by Vickers, for measuring errors in axial pitch and circumferential pitch of helical pinions. The pinion to be tested rests on rol- lers, and alongside and parallel to it is arranged a straight cylindrical shaft resting freely in vees and bear- ing an indicator. The Van West Portable Gear Tooth Testing Appliance. Eng vll5 Jan 19 1923 p 74. Simple and handy device for testing the accuracy of the axial pitch of helical gear teeth, and also the truth of the alinement of the pinions and wheels when in place. Normal Pitch as a Basic Factor in Computing Involute Gears, E. SHELDON. Am Mach v58 Feb 22 1923 p 285-7. A factor based upon parallelism of involutes; does away with many complications and takes account of profile er- rors as well as errors of spacing ; normal pitch easy to measure. Measuring Tooth Thickness of Involute Gear, E. VVILD- HABER. Am Mach v59 Oct 11, 1923 p 551-2 1 fig. New method for involute spur gears which is not affected by errors in outside diameter ; ordinary vernier caliper used ; formula for standard measurement. Measuring Tooth Thickness of Helical Involute Gears, E. WILDHABER. Am Mach v59 nl6 Oct 18 1923 p 587-8 2 figs. There are straight lines along involute surfaces having an inclination equal to the helix angle in the base circle. For actual involute surfaces all of the straight contour lines of the teeth in any one gear are parallel and equidistant. The tooth thickness of helical involute gears may be determined easily and accurately by measuring the distance between the straight contours of outside tooth surfaces, using an ordinary vernier caliper. Zeiss Optical Gear Tooth Micrometer. Am Mach v59 Dec 27 1923 p 964. For direct reading of the chordal thickness of the tooth at the pitch line, and the addendum. In setting the jaws the tool is held close to the eye and two clear scales, engraved on glass, are seen by looking through the small aperture at the center. The range is from 18 to 1% diametral pitch and graduations read to 0.001 in., estimating to 0.0001 in. Measuring Variations in the Pitch of Gear Teeth, G. A. LUERS. Machy (N.Y.) v30 June 1924 p 799-800. Indi- cating gage for testing the spacing of groups of gear teeth. Normal Pitch — the Index of Gear Performance, G. M. EATON. ASME Trans v47 paper 1973 1925 p 587-617 20 figs. Brings out certain departures from previously accepted practice which are useful in manufacture of heavy involute gearing, as they ease performance during breaking-in stage of operation ; shows that material im- provement in performance may be secured by adopting proper relation between normal pitches of driving and driven gears, measured at point of tooth engagement ; outlines development of normal pitch indicators. Normal pitch and chordal pitch indicators are illustrated. A Quick Method for Obtaining Gear Tooth Caliper Set- tings, H. WALKER. Machy (London) v29 Oct 7 1926 p 17 1 fig. Usual method of measuring size of gear tooth is by means of calipers placed across tooth ; points of cali- pers touch tooth profiles where latter are intersected by pitch line ; gives close approximate method for obtaining correction for height of arc which renders reference to such tables unnecessary. Formulas for constant chord gaging. Gleason Tooth-Spacing Tester. Machy (N.Y.) v33 Nov 1926 p 230 2 figs. Gears of any type can be conveniently checked for accuracy of tooth spacing by means of tester now being placed on market by Gleason Works, Rochester, N.Y., which is equipped with optimeter, an optical device having scale graduated to 0.00005 in. Now Possible to Measure "Normal" Pitch of Involute Gear. B. WHEELER. Automotive Industries v57 Aug 6 1927 p 186-90 17 figs. Instruments designed to gage distance 235 between corresponding involute contours on consecutive teeth measured along line perpendicular or normal to con- tours. Detailed description of use of a normal pitch indicator, which is provided with a locating leg. Measurement of the Thickness of Involute Gear Teeth, A. H. CANDEE, Am Mach v68 Mar 15 and Apr 5 1928 p 463-7 7 figs and 573-6 2 figs. For abstract see sub- section 9.3. Laying Out and Checking Involute Tooth Forms, F. W. SHAW. Machy (London) v35 Jan 2 1930 p 441-446 Jan 16 p 513-9 11 figs. Jan. 2: How spur tooth forms can be set out or checked by their coordinate dimensions : fallacy of proposition that Grant Odontograph for 15-deg. involute might be usable for 20-deg. involute if contour arcs as tabluated were described from centers on base circles corresponding to obliquity of 20 deg. Trigonometrical functions and the involute function, inv <£, (although not yet designated by that symbol, coined by Buckingham in 1928) are used in calculations based on numerical tables given (with examples) in the second article (Jan. 16). For details of these tables see abstracts in subsections 10.1.3.1 and 10.1.3.3, p 217 and 220. The span measurement of involute spur teeth is covered in both articles but with- out the benefit of special numerical tables. A Simple Method of Determining the Tooth Thickness of Spur and Spiral Gears. J. W. HAYES. Machy (London) v36 Apr 17 1930 p 69-71 2 figs. Discussion Machy ( Lou- don) v36 May 29 1930 p 279. Method is not as universally applied to measuring of above types of gears as its sim- plicity merits ; it eliminates the necessity of using pins or rollers placed in tooth spaces, and abolishes tedious cal- culations involved in ascertaining distance over rollers : disadvantages of roller method : advantages of present method. Checking Gear Teeth for Smoother Operation, E. N. TWOGOOD. Machy (London) v36 Apr 17 1930 p 82-3 3 figs. Describes methods and fixtures used in checking the concentricity and uniformity of spaces and thicknesses of teeth. Constant Chord Gaging, W. A. J. CHAPMAN. Am Mach v72 May 8 1930 p 753^ 3 figs ; v73 n7 Aug 7 p 250-2 3 figs. Constant-chord method differs from means of tooth meas- urement now in use solely in computations involved ; sub- stitution of constant for variable measurements of gears ; since pitch and pressure angle are uniform in set or train of gears, whereas tooth number usually differs, measure- ments are greatly simplified by possibility of using con- stant dimensions for chordal length and depth. The Involute as a Conic Section, F. W. SHAW. Machy (London) v36 June 26 1930 p 405-8 and July 17 p 492-5 13 figs. June 26 : How involute functions ; points on producing involute ; relationships between circular and rectilinear movement in involute cams ; varying stroke of involute cam. July 17 : Description of method for rectify- ing involute and relation of arcs and sectors ; kinematics of involute cam ; notes on involute as parabola. Sykes Model E Gear-Tooth Comparator. Am Mach v73 July 10 1930 p 70-1. This gear-tooth comparator uses the chordal method and eliminates the necessity of having to use an instrument with two scales. The instrument is a development of the Sykes gear-tooth vernier caliper. Both jaws of the instrument are movable, but the dial indicator spindle is stationary. In addition, the dial gage is ad- justable in the holder. Consequently, it is not necessary to change the plunger or spindle of the dial gage for gaging fine and coarse pitch gears. Constant Chord Gaging. Am Mach' v73 n6 Aug 7 1930 p 250-2 4 figs. Summary of comments received on W. A. J. Chapman's article published in Am Mach v72 p 753. V-jawed caliper can be used with existing gear tables ; gear-tooth vernier is proposed to use constant chord prin- ciple without special computations. Gear Cutter Comparator, F. W. SHAW. Am Mach v75 n22 Nov 26 1931 p 803 1 fig. Cutter rolls in relation to steel tapes upon its base circle instead of upon its pitch circle ; pressure angle is zero and angle of testing rack tooth zero; device utilized also for testing accuracy of tooth spacing. New Gear Tester. Automobile Engr v23 n307 June 1933 p 198. Design of S. I. P. optical gear tester evolved for measurement of inaccuracies in pitch and eccentricity. Messen von Zahndicken bei Stirnraedern (Measurement of Tooth Thickness of Spur Gears), H. HEINSSEN. Maschinenbau vl2 nl7-18 Sept 1933 p 454-5. Indirect method by measurement of difference between teeth with aid of cylindrical gages ; example of application. New Machine for Measuring Normal Pitch of Gears. Machy (N.Y.) v40 n9 May 1934 p 545. Semiautomatic machine built by Illinois Tool Works, Chicago, 111., for rapid measurement or normal pitch and space of spur, helical, worm or bevel gears. Pitch Measurement of Gears I and II, F. W. SHAW. Mech Wld v98 n2549 and 2550 Nov 8 1935 p 451-2 and Nov 15 p 475-6. Possible errors, measurements that can be taken, and instruments that can be used, offer more ways of attempting to check accuracy than are useful : problem analyzed and practical methods discussed. Contribution a l'Etude des Engrenages (Contribution to Study of Gears), RENAUDIN. Arts & Metiers nl91 Aug 1936 p 161—4. Outline of method for measurements of tooth thickness. Neuartige kopfkreisfreie Zahndicken-Messungen fuer Schraegzahnraeder und Evolventen-Schnecken (Novel Method of measuring tooth thickness for involute helical gears and involute worms without use of addendum cir- cle), W. F. VOGEL. Werkzeugmaschine v41 nil June 15, 1937 p 253-61. Theoretical mathematical analysis of methods and their application to ball and span measure- ments. Deals also with pertinent involute spur gear measurements. Bibliography. See detailed abstract in subsection 9.3. Zur Messung des Summenteilungsfehlers an Zahnraedera und Teilscheiben (Measurement of Error in Overall Cir- cular Pitch Distribution on Gears), K. BUERGER. Werkstattstechnik und Werksleiter v31 nl8 Sept 15 1937 p 406-8. Outline of methods and description of new test- ing equipment. Zur Praxis der Zahndicken- und Lueckenweite-Messver- fahren fuer Evolventen-Stirnraeder (Practical Hints and Outline of Methods for Measurement of Tooth Thickness and Spacing Between Teeth of Involute Gears). K. BUERGER. Werkstattstechnik und Werksleiter v32 n7 Apr 1 1938 p 169-76, 10 figs. Contents : The classification of the different common measuring methods. The concept of the effective tooth thickness (influence of the eccentric- ity errors). The necessary basic equations for the single measuring methods. Method la: Direct measurement of the tooth thickness as a chord of a circular segment. II Direct measurement of tooth thickness with notched meas- uring piece. Ilia and Hlb Direct measurement of the toi »th sparing willi inserted plug gages. IV Measurement of tooth span. Results of investigation. Conclusions. The Chordal Gaging of Spur Gear Teeth, R. PARKES. Machy (N.Y.) v45 n5 Jan 1939 p 326-7. Deals with span measurements for a given number of involute spur teeth, diametral pitch, and pressure angle for control of backlash. Includes selector-table and table of span dimen- 236 sions for 1 DP. For details see summary table under subsection 10.1.3.5. Cheeking Spur Gear Teeth, F. W. SHAW. Mach Wld vl05 n2725 Mar 24 1939 p 2S9-91. Base tangent system described; method (sometimes designated as "span meas- urement") obviates uncertainties attendant on use of or- dinary tooth vernier caliper ; measurement is unaffected by differences in diameters of blanks or their eccentricity or by wear in instrument. Application of Involute Trigonometry to Gear Gauging, F. W. SHAW. Machy (London) v55 nl427 Feb 1940 p 545-7. Complementing information contained in E. Buck- ingham's "Manual of Gear Design" (Machinery Publish- ing Co.), article aims mainly at facilitating calculation of caliper measurement of gears by certain of systems therein described ; Buckingham's notation employed, but some additions have been made ; theoretical mathematical study. Improved Method of Measuring Thickness of Spur Gear Teeth, R. OLDFIELD. Machy (London) v57 nl471 Dec 19 1940 p 321-3. Details of system of tooth measurement which will eliminate disadvantages of gear tooth caliper method ; diagrams given. Constant Chord Gear-tooth Caliper Settings for Corrected Gears at Standard or Extended Centres, E. E. DAVIES. Machy (London) v58 nl507 Aug 28 1941 p 595-9. Ex- planation of method of finding correction factor for gear to be measured ; from this correction factor, correspond- ing gear tooth caliper settings can be obtained from tables which are given. Measuring Gear Tooth Thickness, C. A. YOUNG, Am Mack v86 n7 Apr 2 1942 p 278-9. Simple method described, which avoids errors resulting from variation in gear dia- meters ; two rolls, T-bar and conventional gear tooth cal- iper used and calculation necessary can be made in draft- ing room. Method of Measuring Thickness of Helical Involute Gear Teeth, J. REIMER. Machy (London) v64 -nl639 Mar 9 1944 p 266-8. Cheeking tooth thickness of helical gears by method of measuring across number of teeth ; method is independent of outside diameter; it does not require special measuring instruments : it can be applied easily without removing gear from cutting machine ; faces of gage, and not corners of edges, are used for measuring. Improved Gear Tooth Vernier. Passenger Transport J v91 n2305 Sept 8 1944 p 219-30 ; Transport Wld v96 n3073 Sept 14 1944 p 226 ; Engr vl78 n4625 Sept 1 1944 p 170. Illustrated description of simplified type developed by David Brown & Sons (Huddersfield) Ltd. for span meas- urement ; instrument has advantage of only requiring set- ting to linear dimension between fixed and moving anvils ; measurements are over number of teeth and, as anvils are tangent to tooth flanks definite "feel" is obtained as in using micrometer on cylindrical object, no height meas- urement being involved. Gauging of Involute Gear Teeth. Eng vl58 n4116 Dec 1 1944 p 426 : Engr vl78 n4640 Dec 15 1944 p 479. Illustrated description of micrometer for checking tooth thickness of spur or helical gears, developed by David Brown and Sons, Huddersfield ; method is commonly known as base tangent method. Chordal Measurement of Corrected Gears, F. A. BIRCHER. Machy (London) v70 nl799 Apr 17 1947 p 399^101. Explanation of geometry of engagement of en- larged or reduced gears, and use of standard tables show- ing how appropriate table sizes may be adjusted to suit corrected gears. Le "Ve-Comparateur" pour le Controle de l'Epaisseur des Dentures ( V-Comparator for Control of Gear Tooth Thick- ness), J. BERGERE. Pratique Indus Mecaniques v30 n8, 10 Aug 1947 p 235-42, Oct p 303-11. Description of device and method which can be applied without removing gear from machine; practical applications to various types of gear. Measuring Chordal Dimension of Helical Involute Gears, A. BUDNICK. Machy (London) v73 nl870 Aug 26 1948 p 314-6. Equations and application of method based on characteristics of circular involute, that normals to tooth flanks are tangent to base circle of gear ; measurement is made over definite number of teeth, and gives sum of integral number of pitches and thickness of one tooth, measured on line of action or on base circle. Checking Gear Tooth Thickness with Variable Center- Distance Gage, L. D. MARTIN, Machy (N.Y.) v 60 n2 Oct 1953 p 205-6. Span Measurement of Involute Gear Teeth, J. E. VAN ACKER. Machy (London) v86 n2200, 2204 Jan 14 1955 p 66-73, Feb 11 p 292-7. Before AGMA. Span system of measurement involves measurement over two or more teeth, and possesses universal application and high degree of accuracy ; formulas presented which are applicable to all spur and helical gears of all proportions and under all conditions of operation ; tables of involute and trigono- metric functions provided to facilitate span measurement calculations ; worked out examples show use of formulas and tables. See also numerical details under subsection 10.1.3.5. Inspection of Cumulative Circular Pitch on High-Precision Gears, J. LOXHAM. Inst Mech Engrs (advance copy Aug 6, 1958). Describes Sigma gear measuring machine. Base-Tangent Measurement of Gear-Tooth Thickness, W. A. TUPLIN. Machy (London) v94 n2424 Apr 29 1959 p 948-50. Basic dimensions of involute, spur and helical gears ; derivation of base tangent measurement over pins or rollers of given diameter ; converse problems ; caliper settings ; formulas are expressed in terms of lengths that are either given or can be calculated and no reference to trigonometric tables is necessary. Hoefler Electronic Inspection Equipment for Gears. Machy (London) v98 n2526 Apr 12 1961 p 829-31. De- scription of German-built EVZM measuring head set up on Lieherr L. 3200 nobbing machine for checking large diameter helical gear for tooth thickness and concentric- ity ; measuring head, and others in Hoefler range, is in- tended to be connected to electronic base unit incorporating paper strip recorder ; equipment may be employed also for checking spur gears, worms, bevel gears, and racks, for pitch accuracy. Datchik dlya kontrolya izmeritel'nogo mezhtsentrovogo rasstoyaniya na odnom zube (Gage for Checking Measured Center Distance Over 1 Gear Tooth), I. V. MAZURENKO. Stanki i Instrument n9 Sept 1962 p 19-21 ; see also English translation in Machines & Tooling v33 n9 1962 p 22-5. Gage and electric circuit described are suitable for auto- mating inspection of center distance variations over 1 gear tooth ; rejection errors during tests on gage did not exceed plus or minus 3 n ; consequently, gage is suitable for inspecting gears with accuracy not exceeding 7th Class. 237 10.3. Bevel, Hypoid, Spiroid, and Worm Gears or Drives For measurement of worms see also subsections 9.2, 9.3 and 9.4. German Bevel Gear Testing Device. Machy (N.Y.) vl4 Feb 1908 p 377. Protractor for testing the accuracy with which the teeth of bevel gears are cut. Comprises two pivoted arms which are provided with sliding blocks carrying pivots on which are mounted the gears to be tested. Testing Spur and Bevel Gearing. Internal Combustion Eng Oct 16 1912 p 341 4 figs. British machine by Park- inson and Sons in which bevel gear and pinion are run together and errors are recorded on a chart. Making and Testing Bevel Driving Gears. Am Mach v38 June 5 1913 p 945-52 12 figs. Method of the White Co. on large bevel driving gear of rear axle. Testing of paral- lelism of front and back faces is shown in fig. 7. Device is an indicating fixture having a row of balls in a hori- zontal race just large enough in diameter to support the gear by its outer edge. Fig. 8 shows a fixture for testing tooth bearing of mating bevel gears. Fig 9 shows testing spur gears on bench centers with an indicating surface gage. The Testing of Worms and Worm Wheels. Mech Engr Nov 14 1913. Illustrated description of apparatus designed by Percy Brown and Francis J. Bostock for the purpose of ascertaining the accuracy of worms and worm wheels. Spur and Bevel Gear Testing Machine at the National Physical Laboratory, T. E. STANTON. Eng vl09 Mar 12 1920 p 334—5 7 figs. Describes Daimler-Lanchester worm- gear testing machine for direct measurement of ratio of torque of driving and driven shafts. Chordal Thickness of Tooth and Corrected Pitch Depth of Bevel Gears, C. W. MAPES. Machy (N.Y.) v27 Oct 1920 p 169-70 1 fig. Diagram showing dimensions and angles used in determining chordal thickness and corrected pitch depth of bevel gear teeth. Testing the Accuracy of Teeth of Bevel Gears (Messrs. Saurer). Machy (London) vl8 1921 p 717. The Saurer Bevel Gear Testing Machine. Eng vll3 Feb 24 1922 p 228-9 9 figs. Bed of machine is heavy, cir- cular casting, upon which a pair of sliding heads can be locked in any position, so that angle between axes of heads corresponds to that of bevels to be tested, a range from 52 to 150 deg. being obtainable. The Normal Thickness of a Worm Thread, E. A. LIMMING. Machy (London) v20 Sept 7 1922 p 707-8 1 fig. ; v21 Dec 21 1922 p 360-2 4 figs. Apr 21 p 114 ; May 10 p 191 ; July 12 p 475 and Sept 20 p 795. See abstracts under 9.3. The Normal Chordal Thickness of a Worm Thread, A. FISHER. Machy (London) v21 Oct 26 1922 p 118-9 4 figs. Points out that problem of determining normal is not same as determining minimum chordal thickness, and that common term, normal thickness, appears to have dif- ferent interpretations. Dial Gage Device Used with Success to Test Spiral Bevel Gears, P. M. HELDT. Automotive Indus v48 May 17 1923 p 1088-9 4 figs. Machine developed to determine in- accuracy of tooth outline and errors, of indexing adapted to check correctness of curvature. Double Helical Bevel Gear-Testing Jig. Machy (London) v23 Feb 28 1924 p 711 3 figs. Special jig for testing both accuracy and truth of apex in double helical bevel wheels, as used in automobile back-axle drives. Testing and Adjusting Spiral Bevel Gear Drives for Auto- mobiles. Am Mach v61 Nov 27 1924 p 848-9 14 figs. Printed by permission of The Gleason Works, Rochester, N.Y. Worm Gear Inspection and Testing, G. H. ACKER. Auto- motive Indus v57 Oct 29 1927 p 662-3 1 fig. Potential sources of error in worm gearing that must be guarded against by suitable inspection are : eccentricity and cor- rect sizing of worm, index, lead, and profile of worm thread, angle of gear, eccentricity of gear and silence. Gleason 90-Inch Bevel Gear Testing Machine. Am Mach v67 Dec 1 1927 p 882 ; Machy (N.Y.) v34 Dec 1927 p 311 1 fig. ; Iron Age vl20 Dec 1 1927 p 1522 1 fig. Machine for testing for quietness and proper tooth bearing of bevel gears up to 90-in. diameter. The machine is driven by 10 h.p. motor mounted on the drive head, and the spindle may be revolved in either direction. A friction brake on the driven spindle permits testing the gears under load. Gleason Combination Lapping and Testing Machine. Machy (N.Y.) v35 Dec 1928 p 303 1 fig. Details of 18-in. combination testing and lapping machine developed by Gleason Works, Rochester, for use in production of spiral-bevel and hypoid gears ; gears are first tested in this machine after being cut, to determine tooth bearing ; after hardening, they are again tested, both for bearing and noise ; brake on gear or driven head enables gears to be tested under load. Gleason 3-In. Bevel Gear Testing Machine. Am Mach v73 Aug 21 1930 p 335-6. This machine is designed to test running qualities of straight and spiral bevel gears of smaller sizes whose shafts intersect at 90 deg. Bevel gears are tested by running them together in pairs or with a reference gear, to check the cutting machine for cor- rect set-up. Gears are also tested after hardening for both tooth bearing and noise, and to determine if the heat-treatment has made changes that must be compen- sated for in cutting. Gears can be tested with or without load as desired. The pinion spindle is power-driven, and is operated in either direction by push button control. The pinion head is adjustable horizontally on the frame Gleason 18-in. Hydraulically Operated Testing and Lap- ping Machine. Am Mach v73 Oct 16 1930 p 642-3. Both spiral bevel and hypoid gears can be tested and lapped on this 18-in. machine. After the gears are placed on the spindles, the machine is entirely automatic in operation. It is hydraulically operated, and the automatic features and timing are electrically controlled. The automatic control mechanism reverses the direction of rotation of the gears after a predetermined length of time. Time of lapping may be adjusted from 30 sec. to 33 min. per side, and the total time may be varied. The driven head is mounted on a column adjustable horizontally on the frame. This driven head has a vertical adjustment also to permit lapping hypoids. An adjustable back-lash brake, operating on the gear spindle, is provided to maintain an even load during lapping. Gleason No. 13 Universal Gear Testing Machine. Am Mach v73 Dec 4 1930 p 903. Straight and spiral bevels with any shaft angle, hypoids, helicals, angular helicals, internal, herringbone and spur gears can all be tested on the No. 13 universal testing machine. The driver or pinion spindle can be run in either direction. It is mounted on a head which can be adjusted vertically. The gear or drive head has three adjustments. Specifi- cations : Capacity, 13 in., range of off-set, above center 8 in., below center 2 in. ; max. center distance for spurs, 238 worms, and worm-wheels, 8 in. ; minimum and maximum position of nose of drive spindle from cone center of gear to be tested, 4 and 10 in. ; minimum and maximum posi- tions of nose of brake spindle from cone center of gear to be tested —5 and +10 in., and net weight 3,500 lbs. Accuracy in Gaging Gears. J. A. POTTER. Am Mach v74 Feb 19 1931 p 325-7 8 figs. Detailed description of methods of determining depth of tooth at pitch line of spur, bevel, and helical gears by means of a micrometer having a conical measuring contact. Also illustrates a bevel-gear measuring device which uses a dial indicator with sine-bar angle adjustment. Schranbgetriebe, ihre mogliche und ihre zweckmassigste Ausbildung (Screw Drives, Their Possibilities and Their Most Suitable Development), F. G. ALTMANN. VDI Verlag GMBH Berlin NW7 1932 30p 73figs 36 refs. See abstract in subsection 10.1.2, p. 215. Compiler's com- ment: This paper contains the most complete bibliography on worm gear drives to an incl. 1932. Zeiss Gear Testing Machine. Am Mach v76 p 218 Feb 11 1932 2 p 5 illus. Measuring precision to 0.0001" combined with rapid operation are features of this instrument. The gear (tester will take spur, bevel, helical, and worm gears and test the following elements ; Circular pitch, eccentricity, uniformity of tooth spaces, and uniformity of tooth thickness. The gear is placed between centers, where it can be revolved to bring successive teeth into position. Analytische Untersuchung des zylindrischen Schnecken- triebes mit gerader, die Achse Schneidender Erzeugender (Analytical Investigation of Cylindrical Worm Drive with Straight, Axial Worm Profile), W. F. VOGEL. Omni- typie-Gesellschaft, Stuttgart 1933. See abstract in sub- section 10.1.2. p. 215. Eins neues Messgeraet fuer Waelzfraeser (New Measur- ing Gage for Worm Hob Milling Cutters) . A. FIESELER. Werkstattstechnik und Werksleiter v29 n 14 July 15 1935 p 276-8. Equipment and its application for measurement of profile of pitch, circular pitch and testing of cutting face. Gauging of Worm-Gears, N. CUMBERLAND. Machy (London) v60 nl536 Mar 19 1942 p 218-9. Description of gage fixture in which component is held between cen- ters, one fixed and other adjustable in use, work is placed between centers and roller or plug is passed between teeth of work and pad. Messeinrichtungen fuer den Austauschbau von Kegelrae- dern mit geraden Zaehnen. (Measuring Equipment for Interchangeable Manufacture of Bevel Gears with Straight Teeth.) G. APITZ. VDI Zeit v87 n23/24 June 12 1943 p 366-7. Recommendations made for selection and operation of apparatus for this purpose. Basic Relationships of Bevel Gears, E. WILDHABER. Am Mach v89 n20 21 22 Sept 27 1945 p 99-102, Oct 11 p 118-21, Oct 25 p 122-5. Analysis of bevel gear relation- ships ; characteristics, as compared to spur gears ; review of basic bevel gear formulas ; gear generating principles discussed. Oct 11 : Observation of tooth normals in pro- viding relative curvature analysis for estimating load capacity of gear tooth surfaces. Oct 25 : Special analysis of gear mesh for clarifying curvature conditions of spiral bevel gears wherein individual curvature radii at all points of line of contact are immediately apparent. Basic Relationship of Hypoid Gears, E. WILDHABER. Am Mach v90 n4 5 6 12 13 15 16 17 Feb 14 1946 p 108-11, Feb 28 p 131-4, Mar 14 p 132-5, June 6 p 110-4, June 20 p 150-2, July 18 p 106-10, Aug 1 p 104-6, Aug 15 p 122-8. Feb 14: Relative motion, kinematic pitch angles, relative translation and direction of instantaneous axis and instantaneous turning motion about it, con- sidered and determined by geometrical calculations pointed out. Feb 28 : Required pressure angles for bal- anced tooth action indicated. Mar 14 : Generation of hypoid pairs ; helical segment formulas. June 6 : Discus- sion of tooth contact and development of method for finding required tooth profile curvature. June 20 : Conju- gate action of hypoid gears, and its effect on their capac- ity explained. July 18 : Gear tooth sliding. Aug 1 : Screw hypoid gears. Aug 15: Design for duplex cutting: formulas ; examples. Universal Worm Gear Testing Machine. Engr vl84 n4788 Oct 31 1947 p 418 ; Eng vl64 n4269 Nov 21 1947 p 488 • Automobile Engr v38 n499 Mar 1948 p 117-8. Illustrated description of new machine being made by David Brown Tool Co. to provide accurate yet rapid means of checking all dimensions upon which performance and interchange- ability of worm depends, and for testing finished wheels in conjunction with master worm. Pruefen und Tolerieren bei der Fertigung von Getriebe- schnecken (Testing and Gaging in Worm Gear Manu- facture), H. M. HIERSIG. Werkstatt und Betrieb v81 n9 Sept 1948 p 242-7. Measurement of errors in profile, pitch and eccentricity ; accuracy conditions for inter- changeability, grinding of involute profiles by shaped and flat wheels; pitch errors more important than tooth thickness errors ; backlash between worm teeth and wheel must be greater than in cylindrical wheels ; diagrammatic drawings. Pin Measurement of Face Gears, J. SILVAGI, V. FRANCIS. Am Mach v96 May 12, 1952 p 183-7 4 figs ; Van Keuren Catalog and Handb n36 1955 p 248-50 2 figs. See abstract under 10.1.4. Beveloid Gearing, A. S. BEAM, Mach Design v26 Dec 1954 p 220 (15 p) 23 figs 2 refs. The beveloid gear is an in- volute gear with tapered tooth thickness and, in most cases, tapered outside diameter. All sections normal to the axis have a common base-circle diameter and thus the same involutes, but the tooth thickness at any diameter in- creases linearly from the front to the back faces of the gear. Beveloid gears represent the most general form of involute gearing, and they can be engaged with spur gears, helical gears, worms, racks, and other beveloid gears. They can be used with parallel, intersecting, or skew shafts and offer advantages in precision, versatility, and backlash control not previously anticipated. Compiler's comment: Beveloid Gears have been known as Conical Involute Gears (Merritt 1955 and earlier editions, see sub- section 10.1.2), but were exclusively proposed for mesh- ing with each other in parallel-axes gearing with the purpose of eliminating backlash. Only for this type of mutual axis arrangement will beveloid gears yield line- contact. The Mathematical Background of Spiroid Gears, O. SAARI. Industrial Mathematics, Detroit, v7 1956 9 figs. Spiroid gears are considered as a generalized form of worm gearing. Develops the general first-order gear tooth action law and its application to skew-axis gear design. Design of Worm and Spiral Gears. E. BUCKINGHAM, H. H. RYFFEL. Industrial Press, New York 1960 450 p figs tables. Provides (1) a step-by-step guide to the de- sign of worm and spiral gear drives (crossed-axes helical gears) with all-recess action and (2) presents certain basic principles and practices which enter into the suc- cessful design and manufacture of gears and gear drives of several types. Chapter 1 deals specifically with worm gear geometry. Inspection of the Common Normal Generating Lines of Sraight Bevel Gears. P. M. DANILYUK. Meas Techn 1958 n6 Mar 1960 p 633-8 5 figs. Translated from Izmer 239 Tekh n6 Nov-Dec 1958 p 18. New method of common nor- mal checking, eliminating need for teeth faces to make contact with flat surface of measuring device, which re- duces accuracy of conventional methods by indirect in- spection of tooth thickness of spur gears ; suggested meth- od is suitable for measuring various types of small, medium and large module gears. Checking Thickness of Straight-Tooth Bevel Gear Teeth By Their Edges, P. M. DANILYUK. Meas Techn 1960 nl Nov 1960 p 17-9 3 figs 2 refs. Translated from Izmer Tekh nl 1960 p 14. Theoretical basis of new method-of checking size of straight bevel gear teeth by using balls which run over their edges and measuring distance between extreme points of two balls, inserted into diametrically opposite tooth spaces of gear wheel, these spaces being formed by crossing of side bevel surfaces with additional external bevel surface. Goulder Testing Machines for Worms and Worm-Wheels. Machv (London) v98 n2537 June 28 1961 p 1473-5. Three machines described; type 2H "long bed" lead tester for worms up to 8 in. diam, with integral shafts up to 54 in. long ; No. 3 testing machine for large-diameter hobs and worms; No. 4/3 machine specially designed for checking worm drives which have wheels ranging from 3 to 48 in. diam ; light- and heavy-duty saddles are provided which are brought into use as required, according to size of worm gears to be tested. Mesure de L'Epaisseur de Dent des Dentures D'Engrenages coniques droits (Measurement of Tooth Thickness of Straight Bevel Gears), H. L. DEBY. Rev M v8 nl 1962 p 1-6. How method used for cylindrical gears may be extended to bevel gears by changing one term in formula. Narezanie vysokokachestvennykh konicheskikh zubcha- tykh koles na stankakh mod. 5A27S3 i 5A27S4 (Cutting high quality bevel gears on model 5A27S3 and 5A27S4 machines), N. F. KABATOV. Stanki i Instrument n4 Apr 1962 p 12-18 ; see also English translation in Machines & Tooling v33 n4 1962 p 14-20. Machine setting calculations are given on which jobbing method developed by W. Gleason is based, and that insures reliable check of width, height and inclination of field of contact when cutting spiral bevel gears with teeth reducing in depth ; gear and pinion are cut by cutters with alternating teeth, and hav- ing number of teeth considerably greater than calculated number. Mesure de l'epaisseur de dent des dentures d'engrenages coniques droits (Measurement of tooth thickness of straight bevel gears), H. L. DEBY. Rev M v49 n4 1963 p 156-62. Reference is made to description of method in author's article indexed in Engineering Index 1963 p 804 ; tables are presented which make it possible to eliminate all complex calculations, thereby considerably facilitating application of this method. Wormgear Standardization Envisages, W. A. TUPLIN. Engr v215 n5603 June 14 1963 p 1066-9. Recently published Brit Standard Specification for Worm Gearing (BS 721, 1963) is considered in relation to worm gear design with regard to both form and dimensions, and in relation to earlier standards ; advance made in present standard in defining worm-thread form in terms of basic rack of B.S. 436 is especially mentioned, but it is also noted that worms of "preferred" and "second-choice" dimensions have 5600 different normal pitches. Addendum to Section 10 10.1.1. Standards and Nomenclature Die DIN-Verzahnungstoleranzen und ihre Anwendung (The DIN Gear Tolerances and their Application), G. APITZ, A. BUDNICK, K. KECK, W. KRUMME, H. K. HELLMICH. Friedr. Vieweg und Sohn, Braunschweig 4th ed 1960 31 p 25 refs plus 13 illus and DIN 3960 to 3964 and 3967. No. 13 of series of publications issued by Fachgemeinschaft Getriebe und Antriebselemente im Verein Deutscher Maschinenbau-Anstalten. Contents : The economic significance of gear tolerance systems. Construction of the DIN-tolerance system. Gear qualities in reference to transmission capability, quietness, and accuracy of form. Gear qualities in reference to cost of manufacture. Influences of the gear fits : tooth thickness, tooth space, and axial distance. Establishment of the quality and gear matching. Calculation of general toler- ance specifications in the DIN-System specifications. Relationship between tolerances and production processes. Comparison of the German standards for gear tolerances with those of other countries. Glossary. 10.2.5. Tooth Index Position Measurement Gear Inspection, J. F. JONES, Jr. AGMA 129.15 June 1962 15p 19 figs. Fellows No. 8 tooth index measuring instrument is illustarted in Figs. 1 to 5. It is stated that the recording system in the machine has sufficient sensi- tivity and magnification to provide indications to 0.00001 in. The chart produced by the machine has graduations which can be calibrated to 0.000010 in. and obviously estimating is possible. 240 Section 11. Measurement of Thickness of Thin Films CONTENTS Page 11.1. Interferometric methods 241 11.2. Polarimetric methods (ellipsometry) 247 1 1 .3. Miscellaneous methods 249 Addendum to Section 11 255 11.1. Interferometric Methods Optische Experimental-Untersuchen ; ueber Newton'sche Farbenringe und totale Reflexion des Lichtes bei Metallen (Optical Experimental Investigations; Regarding New- ton's Colored Rings and Total Reflection of the Light by Metals) G. QUINCKE. Ann der Phys und Chemie vl29 n2 1866 p 177-218 6 figs. To determine the thickness of a metal layer on a plane glass plate the author applied two different methods, both of which are based on the obser- vation of Newton's rings. Experimental results using silver and gold are given. Ueber die Bestimmung der Constanten fiir die Absorption des Lichts in Metallischen Silber (Regarding the Deter- mination of the Constants for the Absorption of Light in Metallic Silver). W. WERNICKE. Ann der Phys und Chemie 2ser v8 nl 1878 p 65-82 5 refs. Deals with the production of plane-parallel layers of silver, measure- ment of the absorbed light, and determination of the thickness of the thin layers, by interference methods. Ueber die Phasenanderung des Lichtes bei der Reflexion und Methoden zur Dickenbestimmung diinner Blattehen (Regarding the Phase Change of Light by Reflection and Methods for Determination of Thickness of Thin La- minae), O. WIENER. Ann der Physik und Chemie 3ser v31 n8 1887 p 629-72 13 figs. Discusses previous methods of Quincke and Wernicke for thickness determination of thin laminae in general. Develops new methods for both metallic and nonmetallic laminae. Investigates questions as to whether phase change at perpendicular reflection is a retardation or acceleration. Evaluates interference method and determines relation of thickness and color to the amount of phase change. Describes more accurate experiments. Draws five conclusions. Ueber die Phasenanderung des Lichtes bei der Reflexion an Metallen ( Regarding the Phase Change of Light by the Reflection on Metals), P. DRUDE. Ann der Phys und Chemie 3ser voO nl2 1893 p 595-624, v51 1894 p 77-104 6 figs. See abstract in subsection 2.2.5. Ueber normale und anomale Phasenanderung bei der Re- flexion des Lichtes an Metallen (Regarding Normal and Anomalous Phase Changes with the Reflection of Light by Metals), W. WERNICKE, Ann der Phys und Chemie 3ser vol n3 1894 p448-59 6 figs. See abstract in subsec- tion 2.2.5. Ein einfaches Interferometer zur Messung kleiner Schicht- dicken ( Simple Interferometer for Measuring Small Laver Thickness), H. FROMHERZ, W. MENSCHICK. Zeit Phys Chem v2 abt B Apr 1929 p 399-404 2 figs. Apparatus and method of operation are described ; layer thicknesses of 2 flat bulbs of about 10 and 50 microns thickness were measured to.0.2 per cent. Silica Gauge for Measuring Thickness by Means of Inter- ference Colors, K. B. BLODGETT. Rev Sci Instrum vl2 nl Jan 1941 p 10-4. Details of construction of gages for measuring thickness of monomolecular films by means of interference of light ; monolayers of various substances can be deposited on top of silica film, and thickness of mono- layer determined from change in intensity of reflected light produced by added thickness ; equations are given for calculating thickness. Measurement of Thickness of Thin Films, A. F. GUNN, R. A. SCOTT. Nature (London) vl58 p 621 Nov 2 1946. Tolansky's technique was used to measure the "step" at the edge of films of collodion, silica and gold of thickness of 100A and above, supported on a smooth glass plate (e.g. lantern slide cover). Discussion by K. W. PLESS- NER, Nature (London) vl58 Dec 21 1946 p 915 1 fig 2 refs. Interferometric Determination of Apparent Thickness of Coatings, W. K. DONALDSON, A. KHAMSAVI. Nature (London) vl59 Feb 15 1947 p 228-9 1 fig 6 refs. Describes techniques for depositing film on a high-grade flat and using the reflected film system for measuring thickness. Coating Thickness Measurement by Interferometry, M. F. BECHTOLD. J Opt Soc Am v37 Oct 1947 p 873-8. * Thick- ness measurements of thin transparent coatings on thick transparent bases by reflection interferometry are made possible through use of an immersion medium of the same refractive index as the base to intensify interference. A convenient interferometer comprising three essential parts, a "pocket" spectroscope, an incandescent lamp and a cylindrical immersion tank, is described. Its use for rapid, precise measurements of thickness of single and double layer coatings and films in the range of 0.2 to 50/i is illustrated with spectra. Thickness of Inhibiting Films on Glass Electrode Surfaces, D. HUBBARD, G. F. RYNDERS. J Res NBS v41 Sept 1948 p 163-8. The thickness of voltage-inhibiting films produced on glass surfaces by heat treatment after leach- ing has been studied by means of the glass electrode and the interferometer. The glass electrode gave conspicuous voltage departures (errors) and alternations (swelling) of the surface that were just detectable by the interferom- eter. This corresponds to approximately 0.01 fringe, or 4X the unit cell dimension for cristobalite. The inhibiting effect of films of electric conductors, such as metallic Ag, has been qualitatively compared with the inhibiting effect of films prepared from electric non-conductors, such as petrolatum and silicone stopcock grease. 241 Interferometric Determination of the Apparent Thickness of Thin Metallic Films, D. G. AVERY. Letter in Nature (London) vl63 June 11 1049 p 916. In connection with the method for determining' film thickness by depositing an opaque reflecting layer over the edge of the film and then ( inter ferometrically) measuring the step, evidence is presented showing that there is a "packing-in" effect. Presumably this is due to filling up of the interstices in the film. It is suggested that use of this method may lead to errors of up to 30%. Interferometric Evaluation of Thicknesses of Thin Films, S. TOLANSKY. J Phys Radium vll July 1950 p 373^. A study is made of the validity of the multiple-beam in- terferometric method for measuring the thickness of thin films. For a Ag film the deposit is made to cover part of an optical flat, and over this is evaporated a much thicker metal film. The step height is measured interferometric- ally. It is shown that the height measured is affected by the nature of the superposed metal. When Ag is super- posed on an Ag film the final step value found is 25% less than that when Cr is deposited on an Ag film. The effect is considered to be due to bedding in of the superposed film on to the porous thin film. Studies are made with in- termediate films of cryolite and MgF». Interferometric Method for Accurate Thickness Measure- ments of Thin Evaporated Films, L. G. SCHULZ. J Opt Soc Am v40 nlO Oct 1950 p 690-2. Fabry-Perot interfer- ometer used directly to measure thickness of uniform thin films to accuracy of ±15A ; separation of D-lines of so- dium light used as standard of length ; method evaluated by comparison with other methods and in terms of appli- cations and limitations. The arrangement for the Measurement of Small Film Thicknesses, G. C. MONCH. Optik v8 nl2 1951 p 550-60 in German. A description is given of optical arrange- ments for measuring thin film thicknesses by making use of the interference double prism of Kosters. Methods are described whereby the thicknesses of evaporated metal films and also of thin celluloid films and varnish films can be made. Full constructional details are supplied for the mounting. Measurements can be made with white light or with monochromatic light. The Investigation of "Thick" Metal Films and Their Sur- face Layers With the Aid of the Absolute Phases, H. SCHOPPER. Zeit Phys vl30 n4 1951 p 427^4 in German. A method is described for the determination, of the re- fractive index within metal layers and by this means the refractive index for Ag is found to be 0.11 for the green Hg line. In addition the thickness of the transition layer between the metal and support of the surface film on the air side are evaluated. The surface layer can be followed down to thickness of only a few molecules. The method described is an interference method using slits. Data are reported for Ag on quartz and for silver-iodide surface layers. Some Applications of Interferometry to the Examination of an Eleetrodeposited Film, S. TOLANSKY. J Eleetro- depos Tech Soc v27 Paper 6 1951 8 p. Multiplebeam in- terference methods are applied to the examination of bright tin-nickel electrodeposit on polished brass. It is shown by precision interferometry that the electrodeposit contours surface irregularities as small as 1 micro-inch, although the deposit is thick as 200 micro-inches. The thickness of the deposit can be measured by the fringes to within 1 micro-inch by visual inspection alone. Some hardness micro-indentation tests are reported using a Vickers pyramid. Although the pyramid penetrates the deposited film yet an apparent increase in surface hard- ness is found. The Effect of Phase Changes in White Light Inter- ferometry, L. G. SCHULZ. J Opt Soc Am v41 Apr 1951 p 261-4. The phase change accompanying the reflection of white light from metal films was studied experimen- tally by interferometric methods. As predicted by electro- magnetic theory, the phase change was found to vary with the wavelength of light. Corrections for this variation must be made in white light multiple-beam interferometry if the full sensitivity of the method is to be used in making thickness measurements. Practical suggestions are given for making the required corrections. It is demonstrated experimentally and theoretically that these corrections are practically independent of the film thick- ness. Precise measurements of phase changes on Ag films gave results closely consistent with those calculated from published values of the optical constants of Ag. No such agreement was found for Al. Measurement of Thickness of Thin Films by Multiple- beam Interferometry, O. S. HEAVENS. Phys Soc-Proc v64 pt5 n377B May 1 1951 p 419-25. Study of measure- ments of thin films by multiple beam Fizeau fringes in order to assess accuracy attainable ; application of method to examination of small scale irregularities on surfaces of glass plates and flats used in thickness determinations ; measurements of films of lithium fluoride and of silver using five different metals as reflecting layers. The re- sults for the different reflecting layers show agreement to within the observational error provided that measure- ments are made within a short time of the preparation of the film. With Ag as the reflecting layer an accuracy of ±10 A can be expected if suitable precautions are taken. Bibliography. The Measurement of Thin Film Thickness by Inter- ferometry, S. TOLANSKY. Letter in J Opt Soc Am v41 June 1951 p 425-6. A critical analysis of a method re- cently proposed by Schulz for measuring thin film thick- ness by a Fabry-Perot interference method. A number of optical defects are pointed out. These apply mainly if the method is used in transmission with thin metal films. A number of the objections raised do not apply if measurements are made on dielectric films, or on metal films using reflection instead of transmission methods. Interferometer for Thickness Measurement of Thin Transparent Film, N. SIDJAK. Can J Technol v29 n7 July 1951 p 362-70. Interferometer described ; measure- ment involving only counting of dark interference bands in continuous spectrum is particularly suited to measure- ment of mica and other thin transparent materials used for windows on counters and apparatus employed in work on radioactive substances. The Interference of Thin Films and the Estimation of Their Thickness, G. C. MONCH. Optik v9 n2 1952 p 75-83 in German. A rapid estimation of the thickness of thin films from interference colours is described. A simple interferometric system involving slits permits the approximate thickness to he derived from the table of interference colours given. The table is calibrated by means of altering the angle of inclination of the light on the thin film. Interference colours are given for films of thickness from 0-900 A. There is a good deal of ob- jective judgment required in estimating the colours. Measurement of Thickness of Microscopic Objects Using Three-Beam Interference, B. MENZEL. Note in Naturwiss v39 nl7 1952 p 398-9 in German. A microscope modifica- tion of a technique formerly described, wherein the thick- ness of a thin lobject is obtained from change in localization of fringes produced hy three slits. A micro- scopic reduced image of the three slits is projected on to the small object on the microscope stage and by observing changes in localization of fringes with beams going through and missing the microscopic object, thicknesses can be measured as small as 100 A units. The Limit of Accuracy in the Measurement of the Thick- ness of a Thin Film Using the Kdsters Interference Double 242 Prism, U. ZORLL. Optik v9 nlO 1952 p 449-55 in Ger- man. An arrangement permitting the application of photometric methods is described. Fringe width is nar- rowed by multi-photographic copying and this permits an accurate measurement of fringe separation. Three photo- metric methods of evaluating displacements are described. The method permits the measurement of the thickness of deposited thin films. A square centimetre film can be measured with the thickness down to about 20 mp. A Discussion on Friction : An Optical Method of Meas- uring the Thickness of Adsorbed Monolayers. J. S. COURTNEY-PRATT. Proc Roy Soc A v212 May 22 1952 p 505-8. The interferometric techniques developed by Tolansky have been used to study films adsorbed on solid surfaces. A monomolecular layer of fatty acid was spread by the retraction technique over part of a selected facet of a piece of mica. A highly reflecting layer of sil- ver was then deposited on both sides of the mica specimen, and the thickness of the acid layer determined by multi- ple reflection interferometry. The values so obtained were in agreement with X-ray data on the length of the fatty-acid molecule. Examination showed that the layers were uniform in thickness ; polymolecular layers were absent. The method provides direct and independ- ent evidence that molecules of a fatty acid, spread by the retraction technique, are adsorbed on a solid surface as a uniform monomolecular layer. Ein interferenzoptisches Gerat zur Messung der Dicke diinner Metallschichten (An Interference Apparatus for Measurement of the Thickness of Thin Metal Layers), M. DUHMKE, G. GEORGI. Metall v7 n23/24 1953 p 1000-2 7 figs. 4 refs. Describes an interference method and ap- paratus for measurement of layer thicknesses in the range from several microns to a few millimicrons within an un- certainty of 4-1 m/i. An Interferometer Microscope for the Accurate Measure- ment of Optical Thickness. J. DYSON. Letter in Nature (London) vl71 Apr 25 1953 p 743^. A polarization- interference microscope arrangement is described for the determination of the thickness of thin transparent films. The interferometric phase difference is determined with a modified half-wave plate. Settings to within a quarter degree can be made, corresponding to a path difference of 0.003 wave-lengths in interference film. Film Thickness Measurement for Grating Blanks, F. A. McNALLY. Letter in J Opt Soc Am v43 June 1953 p 540. A simple interferometric method for the measurement of the thickness of metallic films deposited on grating blanks is described. The method can be applied to films greater than 500 A in thickness. Fringes of Equal Reflection Coefficient Ratio and Their Application to Determination of Thickness and Refractive Index of Monomolecular Finns, R. E. HARTMAN, R. S. HARTMAN. K. LARSON, J. B. BATEMAN. J. Opt Soc Am v44 n3 Mar 1954 p 192-206. Production of families of spectral fringes by use of surfaces having equal reflection coefficient ratios ; applications in determining thickness and refractive index of monomolecular films ; determina- tion of thickness and refractive index of barium stearate double layers. Films prepared by the method of Blod- gett, but using a different piston oil, were found to have a thickness of 45.7 A and an ordinary refractive index of 1.508. Simple Interference Prisms for the Evaluation of the Thickness of Thin Films, G. C. MONCH. Optik vl2 n5 1955 p 226-32 in German. A variety of prisms in inter- ferometric arrangements is described using in each case right-angled prisms. The systems are somewhat related but different from that of the Kosters double prism. The prism mounts are described in detail and illustrated schematically. Application of the interferometric system to the measurement of thin films is considered and an example quoted. Tolansky Gauge for Rapid Measurement of Film Thick- ness, T. M. GREEN, L. N. HADLEY. Letter in J Opt Soc Am v45 n3 Mar 1955 p 228-9. A device is described which speeds up the measurement of thin film thickness when using the method of multiple-beam interference fringes. It is based on the displacement produced by an inclined glass plate. An image of the fringes is projected on to a glass plate which is itself viewed by a lens system. The angle to produce one fringe shift is determined. The angle to eliminate the fringe shift due to the stepped film is then measured. From these the mean fringe displacement from several fringes is rapidly evaluated. An accuracy of 50 A in film thickness obtains. The Influence of Dispersion on the Optical Determination of the Thickness of Thin Films, G. KOPPELMANN, K. KREBS. J Phys vl45 n4 1956 p 486-95 in Russian. The dispersion in reflectivity measurements of vacuum-evapo- rated ZnS films was determined and the effect of the dis- persion on the thickness determination was investigated theoretically and experimentally. The results are ex- pected to hold in general for any thin film showing inter- ference effects. Neuere optisehe Verfahren zum Bestimmen der Dicke diinnster Schichten (New Optical Methods for Determin- ing Thickness of Very Thin Films) , H. SCHOPPER. For- schung auf den Gebiete des Ingenieurwesens (Ed B) v22 n2 1956 p 56-62. Includes corrosion films ; new interferom- eter arrangements, which include intensity compensation, or with which phase can be measured by comparison of intensity ; examples of thickness measurement of thin metal layers and tarnish films. Bibliography. Interferometric Evaluation of Thickness and Shape Using the Two-Sided Technique, G. SCHULZ. Optik vl3 n9 1956 p 404-10 in German. A method is described for meas- uring the thickness of transparent or opaque thin films using a Michelson interferometer type of arrangement (interference microscope )with incident illumination. A knowledge of the refractive index is not needed. The interference pictures obtained are sharpened by the equidensity photographic procedure. Fringe patterns from the two sides are copied on to one plate and this offers information about thickness variations from point to point. A CdS microcrystal is examined as an example. On the Thickness and the Dispersion of the Refractive Index of Thin Aluminium Oxide Layers, M. HENNIG. Zeit Phys vl44 nl-3 1956 p 296-^310 in German. The dependence of the thickness of the layer of aluminium oxide films on the oxidation voltage is studied interfer- ometrically. Measurements are made for different am- monium citrate concentrations. The relation is found be- tween the film thickness and the formation voltage. The refractive index measurements are made for different wavelengths. The refractive index in the range 3600 to 6500 A decreases from 1.577 to 1.560. In the region 4360 A a dispersion anomaly is established. Measurement of the Thickness of Thin Films bv Multiple- Beam Interference, C. WEAVER, P. BENJAMIN. Na- ture (London) vl77 June 2 1956 p 1030-1. Experiments have been carried out on the measurement of the thickness of thin silver films, using both silver and chromium as the overlayer material. A standard experimental pro- cedure was adopted for the deposition of these films, which were evaporated on to selected glass microscope slides. The thicknesses of the silver films were measured by mul- tiple-beam interference fringes of equal thickness viewed in reflection. The results indicate that when the chromium overlayer is opaque, then there is no discrepancy in the thickness of the silver films as measured by the two differ - 243 ent overlayers. However, when the chromium overlayer is not opaque, then a discrepancy of the type found by Avery occurs. The discrepancy in the thickness measure- ments when a non-opaque chromium layer is used may be caused by a difference in the phase change at reflection on the two sides of the step-edge since the underlying sub- stances are different. Recent Attempts to Determine the Thickness and Refrac- tive Index of Unimolecular Films, R. D. MATTUCK. J Opt Soc Am v46 n8 Aug 1956 p 615-20. The Hartman method for measuring the thickness and refractive index of nonabsorbing unimolecular Alms is investigated. Both theoretical and experimental evidence lead to unfavour- able conclusions. A test experiment is reported in which the Hartman method is used to measure the optical con- stants of barium stearate multilayers from 50 A to 250 A in thickness. The results obtained disagree with the rela- tively wellknown properties of barium stearate films. To determine the cause of the disagreement, the method is investigated theoretically. It is shown by numerical cal- culation and algebraic analysis that, in terms of the present accuracy of the optical measurements involved, the Hart- man method is too insensitive to be of practical use for films of molecular thickness. The use of an Interference Microscope for Measurement of Extremelv Thin Surface Layers, W. L. BOND, F. M. SMITS. Bell Systems Tech J v35 no Sept 1956 p 1209-21. A method is given for the thickness measurement of p-type or w-type surface layers on semiconductors. This method requires the use of samples with optically flat and reflect- ing surfaces. The surface is lapped at a small angle in order to expose the p-w junction. After detecting and marking the p-n junction, the thickness is measured by an interference microscope. Another application of the equipment is the measurement of steps in a surface. The thickness range measurable is from 5X10" 8 em to 10~ 3 cm. Calculator for Thin Film Measurement, W. A. FEIBEL- MAN. J Opt Soc Am v46 nil Nov 1956 p 994-5. The design and operation of a calculator for determining thin film thicknesses measured by the multiple beam inter- ferometer method is described. A photograph of the in- strument and layout of the calculator dial are included. Thickness Measurement of Microscopic Objects by Three- Slit and Two-Slit Interference (Probe Method), E. MEN- ZEL. Optik vl4 n4 Apr 1957 p 151-64 in German. A commercial microscope for direct and reflected illumina- tion is adapted for the measurement of thickness by triple- slit interference. The object plane together with the re- duced image of the triple slit is projected to infinity and observed by means of a telescope. The characteristic planes of interference are now equidistant and will appear in the telescope after insertion of a cylindrical lens the axial displacement of which may be read off. Phase con- trast facilitates the required covering of the two slits. A filament lamp together with filters provide the light source. The arrangement may also serve to measure longer path-differences using then the double-slit inter- ference. The two methods are particularly suitable for the measurement of the thickness of microtome sections and thin films. Corrections of Interference Thickness Measurements of Thin Films on Account of Boundary Reflections, P. J. LINDBERG. Optica Acta v4 n2 June 1957 p 59-68. Multiple-beam interferences show a remarkable effect owing to boundary reflections when a transparent film is interposed between the interferometer flats. Similar con- ditions occur in all interferometric thickness measure- ments of transparent films. The phase-shift so caused is calculated and represented in diagrams with rolling circles. Measurements were made with multiple-beam interference on zinc sulphide films deposited on silver, and the results agreed satisfactorily with the calculations. If the boundary reflections are neglected in the case of multiple-beam interference, the error in the determi- nation of the film thickness is at most about \/2w, even if the difference in refractive index is small. The consequences of this are considered for the interfer- ometric measurement of biological specimens. The Measurement of Thin Films by Interferometry, J. DYSON. Physica v24 n6 1958 p 532-7. In view of the high accuracy of comparison of path-differences attain- able in polarimetry, experiments were made to achieve some of this accuracy in thin film measurements. It is shown experimentally that setting accuracies are obtain- able corresponding to an error of thickness measurement of ±1 A. Measurement of Thickness of Films Using Equal-Chro- matic-Order Lines, I. N. SHKLYAREVSKII. Optika i Spektrosk v5 n5 1958 p 617-19 in Russian. In 1945 Tolan- sky used equal-chromatic-order lines in the study of the topography of almost plane surfaces, using white light. Later Sinel'nikov and Rapp (1950) and the author (1954, 1956) applied Tolansky's method to the thickness measure- ment of films deposited in vacuo on glass plates. A scratch is made across such a film. The film is then covered (by vacuum deposition) by an opaque layer of silver which repeats the scratch contours forming a small step. The height of this step is equal to the original film thickness. A second glass plate is covered by a semi- transparent layer of silver. The two plates are pressed together and are placed in front of a spectrograph slit in such a way as to position the step, referred to above, at right angles to the slit. These plates are illuminated with a parallel beam of wmite light. An achromatic lens is used to focus the air gap between the glass plates on to a spectrograph slit. In the focal plane of the spectro- graph camera objective two systems of equal-chromatic- order lines are observed and the separation between the two systems of lines is a function of the original film thickness. The paper gives formulae necessary for the calculation of thickness from the observed interference pattern. Remarks on the Three Slit Method, A. C. S. VAN HEEL. Physica v24 n6 1958 p 529-31. The three-slit method of Zernike is adapted to the Francon crystal interferometer for the measurement of the thickness of a thin film of area as small as 0.1 mm 2 . The advantage of placing the slits in the frontal focal plane is discussel. Thickness changes with time are reported for MgF 2 films. The Determination of the Thickness, Dielectric Constant, and Other Properties of Anodic Oxide Films on Tantalum from the Interference Colours, L. YOUNG. Proc Roy Soc A v 244 Feb 25 1958 p 41-53. The thickness of anodic oxide (Ta 2 5 ) films on chemically polished tantalum was determined from the wavelengths of the minima in the specular reflectivity using a value of the refractive index of 2.20 ±0.02 at 5900 A which was measured on detached flakes of the oxide by the immersion method. An auxil- iary measure of increments of thickness was required for the analysis of the spectrophotometric measurements. This was provided by the quantity (QA(1/C) )%, where Q was the charge which was required to form the incre- ment of thickness, and A (I/O) was the corresponding increase in the reciprocal capacity. This measure of thickness, like that provided by the colours, is independ- ent of the area. The analysis gives the refractive index between 2800 and 6000 A, the net phase-change in the two reflections (with certain assumptions), and a value of e/p. where e is the effective dielectric constant under the conditions used, and p is the density ; p was deter- mined by weighing specimens in air and water. The value obtained for p was 7.93 ( error ± 3% ) , which gives €=27.6 (error ±5%), at 1 kc/s. The effective surface area was then calculated, and was found to be very little different from the apparent area. The field strength dur- ing the formation of oxide at 9.55 mA/cm 2 and 25.8° C 244 was found to be 6.61 X 10 6 V/cm and to be constant within experimental error, independent of thickness. Optical Apparatus for Depth Sensing, U. GERHARDT. Optik vl5 n2-3 Feb-Mar 1958 p 132^, in German. An interference microscope was used to determine the dis- tance between two nearly coplanar parallel faces of two metal end gauges wrung together. Using both white light and monochromatic light, accuracy of a fraction of a micron is claimed. Observations could be made at up to 70 cm from the gauges. Some Methods for Measurements on Thin Films, A. C. S. VAN HEEL, A. WALTHER. Optica Acta v5 n 1-2 Mar- June 1958 p 47-52. Four modifications of Francon's inter- ference eyepiece are given which enable one to measure the step in a wave-front and at the same time the light- loss. As it is possible to carry out measurements while depositing the layer, the methods described can be used for monitoring purposes, the non-optical windows not do- ing much harm to the appearance of the field of view. With the available apparatus a precision in the determi- nation of the light path of X/200 is easily obtainable for all layer thicknesses. Nondestructive Interferometric Thickness Measurement of Thin Transparent Films, R. L. SAUER. J Opt Soc Am v48 n4 Apr 1958 p 275. The thickness of anodic oxide coating of Al is measured interferometrically in the range 0.00005 to 0.01 inch. An Application of Tolansky's Method to the Measurement of Films with Variable Thickness, A. HEISEN. Zeit InstrumKde v66 n5 May 1958 p 87-91 in German. Multiple-beam fringes of equal thickness are applied to the evaluation of step heights (film thickness). It is shown how the method can be applied to a film of constant thickness, or to a wedge film in which there is regular increase of thickness, or an irregular change. It is de- scribed how measurements can be made when the steps are either perpendicular to, or alternately in the direction of, the change in thickness. With thin films which are not too absorbing the refractive index can be obtained. Eine Anwendung des Tolanskyverfahrens zur Messung von Schichten mit sich aendernder Dicke (Application of Tolansky Techniques to Measurement of Films with Varying Thickness), A. HEISEN. Zeit InstrumKde v66 no May 1958 p 87-91. Thickness measurement by means of multiple beam fringes of equal thickness on steps par- allel and normal to direction of increasing thickness. Thickness Measurement of Epitaxially Grown Films, O. S. HEAVENS. D. C. PANDEYA. Nature (London) vl81 May 17 1958 p 1394. The thicknesses of Fe and Ni films grown on a rocksalt substrate were determined by float- ing the film off the rocksalt on to a glass flat where, by silvering the film edge and using Fizeau fringes, the step- height was measured. The results agreed, within the accuracy of measurement (±20 A), with those for simi- lar films deposited simultaneously, but directly, on glass. The films were deposited at room temperature and were 130 to 450 A thick. Measurement of the Optical Constants of Thin Dielectric Films by Means of Frustrated Total Reflection, B. P. SAN- FORD. J Opt Soc Am v48 n7 July 1958 p 482-6. It is shown that the transmission of light through a thin dielectric film under conditions of frustrated total reflec- tion can be used to measure the refractive index and thickness of the film. The refractive index and thickness were measured for each of several magnesium fluoride films. The thickness was checked in each ease by mul- tiple beam interference and the refractive index compared with the results obtained by other authors for similar films. It appears that many present concepts on which the theory of the optical properties of thermally evapo- rated films is based are inadequate for the problems involved. The Interferometric Measurement of Metal Oxide Films, J. C. KELLY. Optica Acta v5 n3-^ Sept-Dec 1958 p 75-8. A method is described for investigating oxide Alms in situ on the metal surface. The method yields the surface finish of the inside and outside surfaces of a metal oxide film, its volume ratio, its thickness and the location of the original surface with respect to the two oxide sur- faces. All this information is contained in a single photo- graph provided the refractive index of the oxide is known. Some results for anodic oxide films on aluminium are given. Errors in the Measurement of Film Thickness bv Multiple- Beam Interferometry, C. WEAVER, P. BENJAMIN. Na- ture (London) vl82 Oct 26 1958 p 1149-50. It is shown that an error in estimating thin-film thickness by inter- ferometry can arise, if the step edge is produced on the film by a scratching technique. The substrate (glass) can be deformed appreciably, to an extent depending on the scratching load. Even light loads of as low as 5 gm can induce error or as much as 18 A and a 100 gm load leads to a 273 A error. This method of scratching the film is considered unsatisfactory. Obtaining Low Orders of Interference in Measuring Film Thicknesses by Multiple Beam Interferometry. G. D. SCOTT. J Opt Soc Am v48 nil Nov 1958 p 858. In multiple-beam interferometry as used for the measure- ment of the thickness of thin films it is desirable to use low orders by bringing the surfaces very close together. A holder is described for mounting on a microscope stage which permits easy manipulation for this purpose. A Haidinger Interferometer with Linear Scale for Thick- ness Separation of the Plane Parallel Plates, R. RIEKHER. Optik vl5 nl2 Dec 1958 p 713-23 in German. An instrument for measuring separation between plane parallel plates is described, using Haidinger's rings. By employing a parabolic mechanical linkage the instrument works on a linear scale. Use of the system is described. Errors are discussed. Measurement of the Thickness of Very Fine Transparent Films by the Interference Method, B. GADZUK. Slabo- proudy Obzor v20 n2 1959 p 85-7 in Czech. A beam of white light is directed, at an angle of less than 90°, on to the film, and the interference fringes observed, the number of the fringes being directly proportional to the thickness of the film. The method is suitable for the measurement of the glass foils in image orthicons having a thickness of l-10/i. It can also be employed for the measurement of films up to 100,u. Zero Point One, A. M. DEXTER, JR. ASTE 59 Tech Paper 195 1959 20 p. Presented at the April 29, 1958 meeting of the American Society of Tool Engineers. Hart- ford Chapter. Describes and discusses wringing films of various media between gage blocks and measurement of film thicknesses. Control of Thickness of Evaporated Layers During Evap- oration, G. PAPP. Rev Sci Instrum v30 nlO Oct 1959 p 911-12. Method for control of evaporated layer thick- ness for transparent substances : progress of evaporation can be checked by method at any moment, simply by counting number of interference fringes on control plate located in vicinity of target. A Thickness Measurement Technique Using a Three-Beam Interference Arrangement for Objects of Thickness Less than 1 Micron, H. WESTMEYER. Exper Tech Phys vS nl 1960 p 18-25 in German. It is often required to know the thickness of an ultramicrotome section. An applica- tion of the Zernike three-beam interference method for 245 doing this measurement is described. The elementary theory of the method is reviewed, adjustments are de- scribed and a simple setup is discussed. Measurement of the Optical Thickness of Absorbing Spe- cimens with the Three-Beam Interferometer, P. HARI- HARAN, D. SEN. J Sci Instrum v37 nil Nov 1960 p 417- 19. A simple modification of the three-beam interfer- ometer is described which permits measurements of the optical thickness of absorbing specimens .with a high de- gree of accuracy. Interference Method for Measuring the Thickness of Epi- taxially Grown Films, W. G. SPITZER, M. TANEN- RAUM. J App Phys (USA) v32 n4 Apr 1961 p 744-5. Since the dielectric constant of semiconductors is de- pendent on the carrier concentration, radiation can be reflected from the boundary between a heavily doped semi- conductor and a lightly doped layer deposited on it by an epitaxial process. Interference effects will occur between the radiation reflected at the boundary and that reflected from the surface of the epitaxial layer, and the thickness of the layer can be deduced from the reflection spectrum. Results are given for layers of germanium and silicon. Thickness Measurement of Epitaxial Films by the Infra- red Interference Method, M. P. ALBERT, J. F. COMBS. J Electrochem Soc (USA) vl09 n8 Aug 1962 p 709-13. The infrared interference measurement has proved to be an accurate and nondestructive means for evaluating the thickness of epitaxially grown films on silicon. The measuring technique is discussed and the necessary rela- tionships are presented. A fringe wavelength versus film chart is constructed, which enables rapid thickness deter- mination without calculation. The chart is derived for use with silicon films of relatively low carrier concentra- tion deposited on silicon substrates of high carrier con- centration (0.007 ohm cm N-type). The chart is most useful for low order interference fringes including 12th order. Similar charts are applicable for other semicon- ductor materials. Ein Interferenzflaechenpruefer als Schichtdickenmess- geraet (Interference Device for Surface Testing Used as Film Thickness Measuring Device), M. DUEHMKE. Zeit InstrumKde v70 nl2 Dec 1962 p 300-2. Application of interference microscope as multiple beam interferom- eter to measure thicknesses of thin films with accuracy of plus or minus 0.001 /mi. Apparatus for the Determination of the Thickness of Thin Films, YU. A. DURASOVA, E. N. RYBAK. Pribory i Tekh Eksper (USSR) 1963 nl p 195-6 Jan-Feb in Rus- sian. English translation in : Instrum exper Tech (USA). Tolansky's fringes were used to determine the thickness to within 10-15 A. Thin Film Thickness Measurement Using Silver-Modified Newton's Rings, B. J. STERN. Rev Sci Instrum v34 n2 Feb 1963 p 152-5. Interference technique for measure- ment of electric films is described that consists of silvered lens placed over stepped film with silver overlay ; re- sultant interference pattern, when viewed in reflection, is series of sharp dark rings against bright background; step in film to be measured causes shift in rings from which thickness is calculated ; step heights in silver films, vacuum deposited on fire-polished microscope slides, of 160 and 780 A were measured . Interference Method of Measuring the Thickness of Thin Transparent Flms, V. F. SHVETS. Meas Techns 1962 n7 Feb 1963 p 538-^0 1 fig 1 ref. Translated from Izmer Tekh n7 p 5-6 July 1962. Method based on observing two sets of white light fringes, one from the film and one from the back surface. Various advantages are cited. Interferometric Evaluation of Thickness of Canada Balsam and Collodion Films and Its Relation to Concen- tration of Solutions, N. BARAKAT, A. A. A. MOHAMED, A. EL BIALY, K. A. AZIM. Brit J. App Phys vl4 n3 Mar 1963 p 144-6. Thin films of collodion and Canada balsam were prepared on water surfaces. Their thick- ness was evaluated interferometrically over the range Vsr-Vbo^ and the relation between concentration and thick- ness studied. The effect of temperature on film thickness was evaluated at 25, 100 and 150° C. Very Precise Thickness Measurement of Thin Films, J. DYSON. Nature (GB) vl97 Mar 23 1963 p 1193. Equality of path length between two polarized light beams in a modified interference microscope is detected photo- electrically, and film thickness may be determined to better than 1 angstrom unit. Comparaison de Deux M£thodes de Mesure des Couches Minces d'Oxyde de Silicium (Comparison of Two Methods for Thickness Measurement of Silicon Oxide Thin Films), J. ENCINAS. Vide vl8 nl04 Mar-Apr 1963 p 95-9. Thick- ness determined from Newton's color scale using normal incidence; interference order is obtained by counting green rings which appear when each pit is made by fluorhydric acid droplet; second method consists of measuring displacement of monochromatic interference fringes; both methods are in very good agreement for thickness range 0.16-1.5 /j.. Dichroic Multiple Beam Interferometer Microscope, M. J. IRLAND, E. B. SOHERMER. Appl Optics (USA)-v2 n5 May 1963 p 540-1. A description is given of the pre- paration of multilayers of high abrasive resistance suit- able for reflectors in multiple-beam interferometry es- pecially for the measurement of the thickness of thin films. The reflector used for germanium measurement consists of a triple layer built from Ti0 2 and Si0 2 . This has a reflectivity of about 65% in the green and is almost transparent near 4700 A. The abrasion resistance is found to be extremely good and is more satisfactory than any metal or dielectric film previously used, remaining unmarred after 100 applications, whereas other films have shown significant damage after this much use. Diffused Light Interferometry for Measurement of Iso- pachics. P. S. THEOCARIS. J Mech Phys Solids (GB) vll May-June 1963 p 181-95. A simplified optical method, based on interference phenomena of diffused light, is described for the determination of isopachic patterns. The procedure consists in using a monochromatic diffused light beam to illuminate the model surface. If an op- tically flat glass plate, used as datum plane, is brought in contact with the model front surface an interference pat- tern is produced related to the thickness of the air-film between the datum plane and the surface of the model. Interference patterns before and after loading of the speci- men allow the determination of isopachics. Curves of variation of interference fringes throughout the surface of the specimen, before their use for the determination of thickness variation, must be readjusted in a convenient scale as well as for the elimination of superimposed simple interference patterns due to arbitrary inclination of the datum optical plane before and after loading. The method does not necessitate a complicated equipment. It is straightforward and very sensitive. It can be ap- plied to transparent as well as to opaque models made of metal sheets. It can also be used as a supplementary means to measure thickness-strains in the birefringent coating method. The surface of the model, though polished, could not be obligatorily optically flat. The method was applied to several illustrative examples with transparent and opaque models. The results obtained are in good agreement with those yielded by theoretical or other experimental solutions. Interference Microscopy of Thin Films and Semiconductor Structures, A. E. FEUERSANGER. Solid State Design v4 nlO Oct 1963 p 29-32. Operating principles of dual beam interferometer are outlined, and its potential for 246 applications in measurements on variety of electronic devices in solid state research is discussed, including thickness and uniformity measurements of metallic and dielectric layers. Nondestructive Determination of Thickness and Refractive Index of Transparent Films, W. A. PLISKIN, E. E. CON- RAD. IBM J Res & Development v8 nl Jan 1964 p 43-51. Simple interferometric methods of determining thickness and refractive index of films on reflective substrates ; sensi- tive method of obtaining thickness of films less than 1 /i by combined use of monochromatic filters and interfer- ence pattern chart ; color chart for thicknesses of ther- mally grown SiCh films up to 1.5 n thick. 11.2. Polarimetric Methods (Ellipsometry) Ueber Oberfiachenschichten (Regarding Surface Films), P. DRUDE. Ann der Phys und Chemie 3ser v36 n2 and 4, 1889 p 532-60, 865-97. Develops equations for relation- ships among optical constants and film thicknesses of transparent thin films, applying polarimetric methods. Eine Methode zur Bestimmung der Dicke und optischen Konstanten dursichtiger Metallschichten (Determining Thickness and Optical Constants of Transparent Metal Films), W. BETZ. Ann d Physik vl8 n8 Nov 21 1905 p 590-605. (Extract from Dissert, Leipzig, 1905.)— The required quantities were calculated from the elliptic polarisation of the transmitted light and observations of intensity, the method enabling the thickness, index, and coefficient of absorption to be determined simultaneously. The author's formulae were derived from the theoretical investigations of VOIGT and DRUDE [Wied. Ann 25, p 25 1885 ; and 43 p 126 1891]. His measures of elliptic polari- sation were made with the spectrometer described by DRUDE [Optik p 238] and a banded compensator, as a compensator with homogeneous field gave too little light. A table of results for three silver and two copper mirrors is given. With gold and platinum, consistent results could not be obtained. Under the microscope with strong homogeneous immersion, a grain-like structure was dis- covered in the gold films, the grains being apparently diffraction phenomena due to small holes. The Thickness of Spontaneously Deposited Photoelec- trically Active Rubidium Films Measured Optically, H. E. IVES, A. L. JOHNSRUD. J Opt Soc Am and Rev Sci Instrum vl5 Dec 1927 p 374—81. Measurements were made of the thin films which deposit in a high vacuum on polished platinum or glass, which are invisible, but which are photoelectrically sensitive to the same extent as thick layers. Plane polarised light, polarised at an azimuth of 45°, was directed on the surface, and the re- flected light examined with a Babinet compensator and nicol prism, the shift of the azimuth or phase caused by the film being measured. The theory of the calculations of the thickness has been given by T. C. FRY. The result is that the layer of rubidium formed on glass is about one atom thick, but as the theory may not hold exactly for such thin films, it is possible that the actual thickness may be five or even ten atomic diameters. The effect of such a rubidium film on the optical behaviour of platinum is so small as to lie within the errors of observation, and this could not be measured. Elliptical- Reflexion and the Optical Studv of Thin Lavers, R. DE MALLEMANN, F. SUHNER. Rev. Dpt (Theor Instrum j v23 Jan-Mar 1944 p 20-38 in French. A lengthy survey is given of the theory and the derivation of formu- lae for the state of polarization of the reflected light in the case of two media in contact. The general case is considered for both isotropic and anisotropic media, after which the special case of thin layers is dealt with Cfrom a thickness of 10 A up to several microns ) . The argument is on geometrical lines. Details are also given of the ex- perimental determination of the thickness and refractive index of thin layers, deposited on solids, using elliptic-ally polarized light. Ellipsometer. Apparatus to Measure Thickness of Thin Surface Films. A. ROTHEN. Rev Sci Instrum vl6 n2 Feb 1945 p 26-30. Apparatus designed to determine thick- ness of films deposited on metal slides is described ; based on measurement of change that takes place in ellipticity of light reflected after slide has been coated with film ; apparatus is capable of measuring film thickness within ±0.3 A. Optical Methods of Studying Films on Reflecting Bases Depending on Polarization and Interference Phenomena, A. B. WINTERBOTTOM. Trans Faraday Soc v42 June- July 1946 p 487-95. The optics of metals and of film- covered surfaces is discussed and a description given of the techniques employed in polarimetric investigations. A detailed account is also given of the methods of comput- ing thickness/reflectivity curves and interference thick- nesses based on strict film optics. The Reflexion of Light from Glass with a Transparent Homogeneous Surface-Layer, M. BRDICKA. Bui Int Acad Tcheque Sci v48 1947 p 63-70. The electromagnetic- equations are applied to a beam of light incident upon a thin surface layer on glass. These equations are trans- formed into a 5th order algebraic equation which can be solved to give the thickness and refractive index of the layer from practical measurements of the angle of refrac- tion, the elliptical polarization of the reflected beam and the phase difference between the two components. Polarimetric Methods for the Determination of the Refrac- tive Index and the Thickness of Thin Films on Glass, A. VASlCEK. J Opt Soc Am v37 Mar 1947 p 145-53 623. A general method and various modifications are developed for the determination from polarimetric measurements of the reflected light, using plane polarized incident light. The mathematical problem involved cannot be solved in explicit form but, as shown by numerical examples, exact results can be obtained by graphical interpolation. The Reflexion of Light from Glass with a Natural Trans- parent Inhomogeneous Surface Layer, M. BRDICKA. Bui Int Acad Tcheque Sci v49 1948 p 81-9. The reflected beam from a glass-air surface shows elliptical polariza- tion which is believed to be due to the presence of a sur- face layer. The dielectric constant is assumed to vary within the layer in a regular manner with the distance from its surface. The electromagnetic equations then allow the mean refractive index and thickness of the layer to be determined from the amount of elliptical pola- rization and the phase differences. Experimental results show good agreement with calculated values. Optical Determination of Thin Films on Reflecting Bases in Transparent Environments, A. B. WINTERBOTTOM. J Opt Soc Am v38 nl2 Dec 1948 p 1074-82. The classical theory of metal and film optics is recapitulated and its implications in connection with various optical methods of studying films and surfaces are indicated. The experi- mental technique of determination of thin films in situ from the change produced in the reflection of a polarized wave is then outlined. Optical techniques are not advo- cated to supplant other methods of studying surfaces such as weight increment, gas absorption, electron diffraction. X-ray diffraction and electrochemical analysis, but rather to supplement these in selected cases. In particular, the optical techniques are of value in making continuous studies of films in situ in transparent environments when 247 771-846 O— 66- -17 conditions render the application of other methods diffi- cult. Examples of application are given. Optical Measurements of Surface Films. I. A. ROTHEN, M. HANSON, Rev Sci Instrum vl9 Dec 1948 p 839-11. Prac- tical information is given concerning the calibration of an instrument called the ellipsometer, which is used to measure thicknesses from 1 A up to >1000 A of trans- parent films deposited on polished metal slides. It is a half-shadow instrument taking advantage of the ellip- ticity of polarized light reflected from film-coated metallic surfaces. The half-shadow is produced by depositing a different thickness of transparent material on the lower and upper part of the slides, or by evaporating a thin layer of Au directly on the lower part of Cr slides. The Apparatus for Measuring the Thickness of the Thin Film on Metal Plate, Y. YONEYAMA, K. IMAHORI. Sci Papers College Gen Education Univ Tokyo v3 Dec 1953 p 145-50. The thickness of a film of denatured protein (1-300 A) deposited on a metal slide is found by measure- ment of the change in ellipticity of light reflected from the slide before and after deposition. Standard polarized light techniques are employed using a half -shade analyser. Films of barium stearate of known thicknesses are used to calibrate the instrument. Improved Method to Measure the Thickness of Thin Films with a Photoelectric Ellipsometer, A. ROTHEN. Rev Sci Instrum v28 n4 Apr 1957 p 283-5. Describes the ad- vantages of a photoelectric ellipsometer over a visual in- strument for the measurement of the thickness of films from 1 A up to many thousand A. Experimental curves are given showing the unambiguous correlation between film thickness and position of two rotating elements, a X/l plate and an analysing Nicol prism. Note on the Limits of the Polarimetric Method of Thin Film Measurements, A. VASICEK. J Opt Soc Am v47 n6 June 1957 p 565-6. Details are given to support the state- ment that the method is able to indicate the existence of films having atomic dimensions and should permit accurate measurements for a film of thickness 10 A. Comment on the Rothen Photoelectric Ellipsometer, R. D. MATTUCK. A ROTHEN. Rev Sci Instrum v28 nlO Oct 1957 p 844-5. Mattuck states that to determine film thick- ness d by the Rothen method a value for the refractive index n is essential. Refractive indexes cannot be deter- mined for values of d less than 300 A, so that for such thicknesses the Rothen method cannot be used. Refer- ence is made to a method that gives d and n simultaneously for the range from 10 to 250 A. Rothen states that his method refers to optical thicknesses, and for these the instrument is sensitive to changes of 0.1 A in the range from to 300 A. Application of the Standardized VaSicek procedure to Nonabsorbing Singly Evaporated Films on Glass Sub- strates, J. RASSOW. Zeit Phys (Germany) vl70 n4 1962 p 376-92 in German. The author modified Vasicek's polarimetric theory to a graphic method for determination of optical constants of thick homogeneous films on glass substrates. The method is verified for single layers de- posited by heating salts. The kind of salt determines the gradient of the refractive index. This gradient and the state of the surface of the glass are responsible for devia- tions from the theoretical curves. A suitable method was found for determining the refractive index and the thick- ness of the deposited film. In a modified form the method can also be used for inhomogeneous films. Sometimes it is possible to determine a change in thickness less than 10 A during the deposition of the film. The thickness can be calculated accurately only by measuring at three dif- ferent light-frequencies, because the curves are periodic. The values for the different light-frequencies agree well with each other, differing only by about 5%. The agree- ment is much better for films thicker than 10 000 A. The thickness of the films as obtained by applying this.method is almost identical with the one given by an interference microscope. Testing the Standardized Vasieek Procedure, for Inhomo- geneous Nonabsorbing Films on Glass Substrates. J. RASSOW. Zeit Phys (Germany) vl70 n4 1962 p 393-408 in German. In the use of Vasicek's polarimetric method for a single layer, differences from the theoretical curves have been observed which can not be explained theoreti- cally. These differences can be increased experimentally by the deposition of double films. The author suggests four rules, by which the inhomogenity of the films can be calculated from the measured curves. It is possible to determine the thickness and refractive index quantita- tively and the index gradient approximately. For the same salt all the four possible types of inhomogenity can be produced. With the rules the differences in the results can be eliminated. The fifth rule limits the applicability of the four other rules. Automatic Optical Thickness Gauge for Thin Film Meas- urements, T. P. MURRAY. Rev Sci Instrum (USA) v33 n2 Feb 1962 p 172-6. An automatic ellipsometer for meas- urement of the thickness of thin films in the monomolecu- lar range is described. The instrument is capable of push- button operation by untrained personnel, and has been in use in an industrial laboratory for about two years. Theoretical Treatment of Ellipsometry, F. PARTOVI. J. Opt Soc Am v52 n8 Aug 1962 p 918-25. Exact expressions are obtained in closed form for the phase and amplitude of the reflected light when a light beam is incident upon a multilayer of a number of homogeneous media. The assumption is made that Maxwell's equations and Ohm's law hold. These equations are applied to the special case of dielectric coated metals and the results are com- pared to ellipsometry measurements made in chromium slides covered with barium stearate films of known thick- ness. When the conductivity and the dielectric constant of the metal are allowed to assume complex values, and when precautions are taken to reduce the inaccuracy in- troduced by the residual oxide and gas layer on the metal, the agreement is good. Determination of the Properties of Films on Silicon by the Method of Ellipsometry, R. J. ARCHER. J Opt Soc Am v52 n9 Sept 1962 p 970-7. The use of exact reflection theory to interpret data allows the application of ellip- sometry to the determination of the thickness and optical constants of surface films without the thickness limita- tions of approximate theory. Ellipsometer measurements as a function of the thickness and optical constants of a variety of different films on silicon substantiate the pre- dictions of exact theory and yield the properties of the films. Theory of Frustrated Total Reflection Involving Metallic Surfaces, T. R. YOUNG, B. D. ROTHROCK. J. Res NBS (USA) v67A n2 Mar-Apr 1963 p 115-25; J Opt Soc Am v51 n9 Sept 1961 p 1038-9. The theory for frustrated total reflection was developed for the case where the third medium is metallic of complex index. Using paral- lel polarized light a unique minimum in reflectance occurs at a definite film thickness. Experimental verification of the theory is made and indicates the theory applicable to the precise measurement of thin contact films existing between metallic and dielectric surfaces. Measurement of the Thickness and Refractive Index of Very Thin Films and the Optical Properties of Surfaces by Ellipsometry, F. L. MoCRACKIN, E. PASSAGLIA, R. R. STROMBERG, H. L. STEINBERG. J Res NBS (USA) v67A n4 July-Aug 1963 p 363-77. The use of the ellipsometer for the measurement of the thickness 248 and refractive index of very thin films is reviewed. The Poincare sphere representation of the state of polariza- tion of light is developed and used to describe the reflec- tion process. Details of the operation of the ellipsometer are examined critically. A computational method is pre- sented by which the thickness of a film of known refrac- tive index on a reflecting substrate of known optical constants may be calculated directly from the ellipsome- ter readings. A method for computing both the refrac- tive index and thickness of an unknown film is also developed. These methods are applied to the determi- nation of the thickness of an adsorbed water layer on chromium ferrotype plates and on gold surfaces. In the former case the thickness was 23-27 A, and in the latter was 2 to 5 A. The measurement of the thickness and refractive index of barium fluoride films evaporated on chromium ferrotype surfaces is used as an illustration of the simultaneous determination of these two quantities. Some Observations on the Use of Elliptically Polarized Light to Study Metal Surfaces, F. P. MERTBNS, P. THEROUX, R. C. PLUMB. J Opt Soc Am v53 n7 July 1963 p 788-96. Measurements and calculations using elliptically polarized light to determine the thickness and index of refraction of barium stearate films on a variety of substrates are described. Attention is focused especially upon problems associated with the study of very thin films, that is, films which are less than 100 A thick. Measurements of the optical constants of metal substrates are presented. An apparent dependence of the index of refraction n and extinction coefficient k and independence of the absorption coefficient k upon the angle of incidence is observed and is discussed. Several effects, including accuracy and sensitivity, of the angle of incidence in studying film growth are noted. It is shown that there exists a characteristic angle of incidence at which the growth of a film produces a negligible change in the ellipticity, and it is shown how advantage may be taken of this to facilitate measurements of rapidly changing surfaces. It is demonstrated that extraneous films are satisfactorily accounted for in measuring thin films by means of the Drude equations through their effects upon the apparent optical constants of the sub- strate. Advantage may be taken of this fact to extend the thickness range over which the Drude linear equa- tions are applicable by a computational procedure. The problem of the anomalous index of very thin films as determined by the Drude equation is considered. It is concluded that the anomalies revealed by the Drude equations are associated with the system under study and are not caused by any inherent limitation in the Drude equations. It appears that at the interface be- tween a dielectric layer and metal system there is an absorbing region which produces the anomaly in the refractive index calculated by the Drude equations and for which explicit allowance must be made in order to make accurate measurements of the thickness of very thin films. Photoelectronic Device for Measuring the Thickness of Thin Films, V. D. PEREVERTAEV, V. M. KUPRIYANOV, M. S. METSIK. Pribory Tekh Eksper (USSR) 1963 n3 May-June p 193-5 in Russian. English translation in lustrum Exper Tech (USA) n3 May-June 1963 ; publ. Nov. 1963 p 568-70. Describes an improved modulation method for anlyzing polarized light which is reflected from a ma- terial coated with a thin film. Ellipsometry — A Valuable Tool in Surface Research, K. H. ZAININGER and A. G. REVESZ. RCA Rev (USA) v25 nl Mar 1964 p 85-116. Ellipsometry is a technique that allows the determination of the optical properties of a surface, or the optical properties and thickness of a thin film, by measuring the effect of reflection on the state of polarization of polarized light. In this paper, the funda- mental equation governing ellipsometry is developed starting from the problem of reflection and refraction of light at a boundary between two homogeneous, isotropic media, and reflection from a film-covered surface. A pic- torial representation and the classical mathematical speci- fication of polarized light is given. Various solutions of the ellipsometry equation are discussed, the actual ellip- someter is described, and experimental techniques are out- lined. Areas of applications are summarized and the value of ellipsometry is examined in terms of possible errors and obtainable accuracy. Finally, some of the deviations in the optical properties of thin films from those of the bulk are briefly outlined. Ellipsometry for Frustrated Total Relection. T. R. YOUNG, J. M. FATH. NBS Misc Publ 256 Sept 15 1964 p 349-59 4 figs 7 refs. The practical length of a gage block is dependent upon the thickness of the film between two contacting surfaces. The relationship between this wringing film thickness and its effect upon incident paral- lel and perpendicular polarization has been theoretically determined for the case where the light is incident upon the first or transmitting surface at an angle greater than the critical angle and where the second surface is metallic (complex index). The theoretical results indicate that when the optical constants of the two contacting surfaces and the wringing film are known, a polarization analysis of the reflected light by the methods of ellipsometry offers an extremely sensitive and unique determination of the wringing film thickness. Attempts to verify the theory experimentally are discussed. Ellipsometry in the Measurement of Surfaces and Thin Films, Symposium Proceedings Washington 1963, E. PAS- SAGLIA, R. R. STROMBERG, J. KRUGER. NBS Misc Publ 256 Sept 15 1964. A symposium on the Ellipsometer and its Use in the Measurement of Surfaces was held at NBS in Sept 1963. This volume contains 19 of the papers included in the program, together with any discussions which followed oral presentation. Topics covered in- clude historical review, theory, computational techniques, measurement techniques, and the use of ellipsometry in measuring metal surface oxide films and organic films. 11.3. Miscellaneous Methods Eine neue Methode zur Dickenbestimmung diinner Blatt- chen (A new Method for Determining the Thickness of Films), C. H. SHARP. Ann Phys v3 n2 Oct 1900 p 210- 20. The thickness of a thin deposit is obtained by making a model of it in a mixture of equal parts of colophonium and burgundy pitch. At the place where the thickness is to be determined, a small portion of the film is removed, and the mixture is laid on and warmed to 75° in a ther- mostat. It is lightly pressed in with the finger, after which the whole is allowed to cool slowly, and the impression is lifted off. It has a brilliant black surface. It is pressed on to a glass plate, and two systems of interference fringes are seen, one corresponding to the film and the other cor- responding to the blank space. The discontinuity between the two systems is indicated by a displacement of the fringes, and the amount of the displacement measures the thickness. The author has devised a special spectrometer arrangement for exact measurements. He has measured the thickness of various layers of gelatine by this method. When the impression is lifted off, it does not stick, owing to a slight contraction on cooling. This contraction, while sufficient to facilitate detachment, is not large enough to interfere with the correctness of the measurements, since the mixture remains practically liquid until it arrives at the ordinary temperature. New Method of Thickness-Measurement of Metal Films, S. TANAKA. Tokyo Imperial Univ Aeronautical Re* 249 Inst Rept v7 n91 Jan 1933 p 291-306 3 supp plates in English. Optical measuring methods and equipment for determining thickness of extremely thin sprayed on or chemically deposited metal films, applicable to thicknesses of less than 0.01 micron. Thickness Measurement of Thin Coating bv X-ray Absorp- tion, H. FRIEDMAN, L. S. BIRKS. Rev. Sci Instrum vl7 Mar 1946 p 99-101. The method is applicable to coat- ing thicknesses in the range 10~ 5 -10~ 2 cm on crystalline bases. An X-ray source and a Geiger counter are both situated on the same side of the coating. The X-rays pass through the coating and are reflected at a Bragg diffraction angle from the base, back to the counter, their intensity being reduced by absorption due to the double transmission through the coating. The thickness of the coating is computed from the measured absorption. On A Method for Measuring the Thickness of Thin Coat- ing Films by Means of X-ray Reflex Photography, F. REGLER, Elektrotech und Maschinenbau [EuM] v65 July-Aug p 109-13 Sept-Oct 1948 p 148-52 in German. The general fundamentals of X-ray reflex photography and some known methods for the measurement of film thicknesses are discussed. A new method is described for measuring the thickness of a film deposited on a crystal- line base. It utilizes the difference of absorption of X- rays diffracted by the base under different glancing angles. The measurement is preferably made by photo- metric evaluation of pictures taken with a conical or ring-film reflex system. The photometric method may be replaced by ionometric intensity measurement. Dis- turbances caused by the coincidence of lines, by a coarse grain structure or irregularities in the lattice structure of the base, may be overcome by special experimental means which are described in detail. Direct Electron Microscopic Thickness Determinations of Ultramicroscopically Thin Crystals. J. H. L. WATSON, W. HELLER, W. J. WOJTOWICZ. Chem Phys vl6 Oct 1948 p 999-1000. A procedure is described for measuring the thickness of platelets formed from a solu- tion of tungstic acid. Intense electron bombardment of the supporting film (Formvar) near the platelet selected for measurement generally results in the film rupturing in a direction parallel to the major axis of the platelet. If the platelet adheres to the film, the net result is a ro- tation of the platelet about its major axis, from which its thickness may be determined. For a particular speci- men the observed dimensions were 14.6/i long, 5.0/i wide and 0.35^ thick. In certain cases, the method may be used to compare the rigidity of colloidally thin crystals. X-ray Measurement of the Thickness of Thin Films de- posited on Mierocrystalline Supports, C. LEGRAND, OR Acad Sci Paris v227 Oct 27 1948 p 831-3 in French. The method of Friedman and Birks is modified to avoid the necessity of constant tube output. Two reflections from the support are measured, the angle of incidence of the X-ray beam being chosen so that one emerges at a small angle on (~3°), the other at a larger angle ) between the lines given by the intersection of the plane of incidence with (a) the surface, and (h) the reflecting planes of the matrix crystal. If a surface layer is present, both incident and reflected beams suffer absorption. A general expression is quoted for the intensity ( which falls to zero when

to greater than 200/1 in film thickness. The Measurement of the Thickness and the Optical Con- stants of Very Thin Metal Films, H. WOLTER. Zeit Phys vl47 nl 1957 p 1-23 in German. For a thin metal film on a glass substrate one may calculate the reflection from each side and the transmission in terms of n, the refractive index, k, the absorption coefficient, and A, the thickness. A phase change is associated with each of these intensities, and at normal incidence the six quanti- ties depend, to a high accuracy, only on the product ndk. Measurement of any two of the quantities gives the other four, as they are interdependent. The errors involved are discussed and tabulated. At non-normal incidence, with the electric vector parallel to the plane of the film, similar considerations apply. Using light at glancing in- cidence with the magnetic vector parallel to the plane of the film, a different combination of n, k and d can be measured. Photometric Determination of Thickness of Semitrans- parent Metal Layers, L. S. PALATNIK, G. V. FEDOROV. Dokl Akad Nauk SSSR vll3 nl 1957 p 100—3 in Russian. Measurement of Thickness of Thin Carbon Films, A. W. AGAR. Brit J App Phys v8 nl Jan 1957 p 35-6. Refer- ence to use of evaporated carbon films prepared by method of D. E. Bradley widely used in electron micros- copy ; nearly linear relationship has been found to exist between optical density and thickness of evaporated car- bon films ; determination of film . thickness by density measurements is shown to have number of advantages over measurement by interferometry particularly for very thin films. Different Methods for Determination of Thickness of Sil- ver Film, P. SEN, P. S. RAO. Glass Indus v38 n2 Feb 1957 p 89, 112. Comparison of methods for silver film deposited on glass surface, including : volumetric analy- sis (by titration), direct weighing, and Fizeau's iodine crystal test. On the Reflection Coefficients of Thin Lacunal Films, P. DUMONTET, M. PERROT. J. TORTOSA. CR Acad Sci Paris v244 n20 May 13 1957 p 2488-91 in French. It is pointed out that the-observed variation, with thickness, of the complex reflection coefficient for the substrate side of a silver film deposited on a transparent support differs markedly for thicknesses less than 100 A from that ex- pected theoretically. A transitional layer at the substrate is suggested as the cause of the anomaly. Optical and Electrical Methods of Measuring Thickness of Thin Metallic Films, Y. G. NAIK, E. M. BALSARA. Indian J Phys v31 nl2 Dec 1957 p 607-10. Measurement of thickness of chemically deposited thin films of silver are made from (i) the study of the absorption of light and ( ii ) from the electrical conductivity of these films. It is shown that the thicknesses determined by the two methods are of the same order. Film Thickness Determination From Substrate X-Rav Reflections, D. T. KEATING, O. F. KAMMERER. Rev Sci Instrum v29 nl Jan 1958 p 34-6. A method is given for the determination of the thickness of films using X-rays diffracted from the substrate. The X-rays pass through the film and are diffracted by the substrate back to the counter, the intensity being reduced by absorption due to the double transmission through the film. No assumptions need be made about the substrate reflection. Unknown conditions of the substrate are eliminated by measurement of the intensity of two orders of a reflec- tion, or measiirement of the intensity of a reflection using two different incident radiations. The method is suitable for all types of film, and is particularly useful in meas- urements of films containing elements of the substrate for which cases X-ray fluorescence techniques are of little value. The procedure is illustrated with a measurement of the thickness of zirconium nitride on a zirconium substrate. Swept Frequency Eddy-Current Device to Measure Over- lay Thickness, E. A. HANYSZ. Rev. Sci Instrum v29 n3 May 1958 p 411-5. An instrument is described which enables nondestructive measurements to be made of film and overlay thicknesses. It utilizes the change in electri- cal impedance of a composite sample resulting from dif- ferences in the thickness of the material being measured to cut-off a swept-frequency oscillator at a frequency deter- mined by that thickness. Operating frequencies from 200 kc/s to 20 Mc/s have been used with frequency-sweep widths, or deviations, up to 10% to measure overlay thick- nesses ranging from 0.00005 to 0.007 in. on composite samples in which the conductivity-to-permeability ratio of the base and overlay differ by at least a factor of two. Equations are developed to illustrate the conditions for which a reactance-tube oscillator is employed in a unique manner to make the measurement automatic. The Measurement of Critical Thickness of Aluminium Films, V PUCALKA. Czech J Phys v9 n5 1959 p 668-9 in German. The critical thickness referred to is that at which a finite electrical conductivity can be measured. The value measured in vacuum is smaller than that in air because oxidation will isolate particles which make good contact in vacuo. In vacuo the critical thickness is about 23 A and the transparency is about 73%. Semiempirical Method of Determining Thickness Along Wedge-Shaped Thin Layer, M. P. LISITSA, V. M. MAEV- SKII. Instrum & Exper Techns (English translation of Pribory i Tekhnika Eksperimenta ) n3 May-June 1959 252 p 459-66. Method makes it possible to determine thick- ness distribution along wedge-shaped thin layer deposited on hard base layer; formulas, taking into account coeffi- cient of substance accommodation on base layer, variation of layer density with thickness, imperfections of evapora- tor construction, and other factors. Calculation of Thickness of Films Resulting From Vapori- zation in Vacuum, A. P. RUMYANTSEV. Instrum & Exper Techns (English translation of Pribory i Tekhnika Eksperimenta ) n5 Sept-Oct 1959 p 802-5 17 refs. Distri- bution functions for thickness of thin films, taking into account commensurability of dimensions of vaporizer and distance from it to point of condensation, as well as spatial distribution law for vaporization products. Measuring the Thickness of Thin Celluloid Films, I. S. DMITRIEV, YA. A. TEPLOVA, V. S. NIKOLAEV, L. N. FATEEVA. Pribory i Tekh Eksper. (USSR) 1959 n6 p 131 Nov-Dec in Russian. A photometric method was developed for measuring the thickness of organic films in the range 2-20 g/cm 2 . Although their light-absorption coefficient is so small, use was made of the effects of interference in reducing considerably the transmitted intensity ; the transmitted intensity first falls with increas- ing thickness of the film, reaching a minimum at about 0.1/i thickness, after which it begins to rise again and vary periodically. In addition, the colour of the reflected light gives a guide to the particular absorption cycle corre- sponding to the measured intensity, thus eliminating in- determinacy. A formula relating the transmitted inten- sity to the incident intensity in terms of film thickness, refractive index, absorption coefficient, and illumination wavelength is given. [English translation in: Instrum Exper Tech. (USA) n6 p 987-8 Nov-Dec 1959 ; publ. Sept I960]. Measurement of the Thickness of Thin Foils, G. M. OSETINSKII, M. V. SAVENKOVA. Pribory i Tekh (USSR) 1959 n6 p 114-6 Nov-Dec in Russian. The thick- ness of thin foil windows for gas target applications was measured in terms of the sharp fall off in absorption of Po 210 a-particles at the end of their range. The foils were introduced into a vacuum chamber between a polonium source and a ZnS crystal with photomultiplier detector. The particle count taken at various air pressures in the range 100-760 Torr was plotted with and without the foil in position to obtain complete absorption curves. The displacement of the curves in terms of differences in air pressure (at half height) could be interpreted directly in terms of the equivalent foil density in mg/cm 2 . The apparatus was used for nickel foils from 0.8 to 1.5/* (0.9- 1.6 mg/cm 2 ). The achievable accuracy was investigated by comparison with weighed samples and was estimated to be of the order of 1.5% for foils of similar thickness to a standard and 3-4% if samples are of considerably dif- ferent thickness. [English translation in : Instrum Exper Tech (USA) n6 p 971-3 Nov-Dec 1959; publ Sept I960]. A New Device for Measuring Thickness of Evaporated Metal Film by Use of X-Ray Interference Fringes, Y. FUJIKI, T. YOSHIDA. J Phys Soc Japan vl4 nl2 Dec 1959 p 1828. A modification of Keissig's method is de- scribed, in which a comparatively broad source of X-Rays can be used. i On the Possibility of Determining the Optical Constants and Thicknesses of Very Thin Metal Films Using Meas- I urements at Normal Incidence, C. SCHWINK, H. PEH- I LAND. Zeit Phys vl58 nl 1960 p 12-25 in German. A ' theoretical examination of the deductions possible from a knowledge of the complex amplitudes transmitted, and reflected from either side. If the thickness d is assumed to be small with respect to the wavelength, the equations expanded in powers of d and the first terms only taken, then a complete solution is impossible ; by taking into ac- count higher powers, d and the optical constants n and k can be calculated, but for small d the equations are ill-conditioned ; in general only the product nkd can be calculated with good precision when d is small. It is shown also that Schopper's three-line method is invalid since the method involves taking only the first terms in the above expansion. If d is known then n and k can be calculated. Messung kleiner Schichtdickenunterschiede in duennen nichtmetallischen Schichten (Measurement of Small Thickness Differences of Thin Non-Metallic Films), G. KOPPELMANN. Ann Phys v5 n7-8 1960 p 397^04. Apparatus based on recording of reflections from various points measured ; results for cryolite evaporation charac- teristics of particular furnaces ; application of method to multiple layers and to dispersion effect of film substances. Variation des Constantes optiques du Bismuth en Couche Mince, en Fonction de l'Epaisseur, entre 2.5 et 10/j. (Variation of Optical Constants of Thin Bismuth Films as Function of Thickness Between 2.5 and 10/i), R. BUR- TIN. CR Acad Sci v250 nil Mar 14 1960 p 1998-2000. X-ray and electron microscopic study of films evaporated in high vacuo; thickness measurements; calculation of indices n and k. Simple Method of Determining the Thickness or the Re- fractive Index of Thin Films, K. V. KRISHNA RAO. Am J Phys v28 n5 May 1960 p 447-9. A simple method of determining the thickness or the refractive index of thin films using double-slit Fraunhofer diffraction fringes is described. To illustrate the method, the thickness of grey photographic film and the refractive index of a cellulose acetate film have been determined. Measurement of Thickness of Thin Transparent Films Using Fluorescence, B. P. BUNT. Brit J App Phys vl2 n4 Apr 1961 p 175-7. Molecular fluorescence method of comparing thickness of transparent films (in range 3 X 10" 6 to 10 2 cm ) is described ; instrument for use in middle of this range (10 _1 cm) is also described; results show that accuracy is better than plus or minus 2% ; applicability e.g. to organic coating of tinplate or etc. A Determination of Thin Oxide Film Thickness by In- tegrated Intensity Measurements, B. BORIE, C. J. SPARKS. Acta Cryst (Int) vl4 Pt6 June 1961 p 569-70. The thicknesses of thin single-crystal oxide films are determined by integrated measurements in absolute units. The method is illustrated with measurements of OihO films grown on copper single crystals. Thicknesses de- termined from two different Bragg maxima agree well with each other, and are reasonably consistent with the thicknesses determined from the line shapes. The Use of X-Ray Fluorescence in the Nondestructive Measurement of Thin Film Composition and Thickness over Small Areas, R. WEYL. Zeit angew Phys (Germany) vl3 n6 June 1961 p 283-8 in German. The beam from a tungsten fine-structure tube was reduced to about 1 mm 2 at the specimen using a diaphragm. The fluorescence radiation was analysed in a vacuum using lithium fluoride crystal ; a proportional counter was used as a detector. The intensity variation of the excitation radiation was also analysed in the same way using a scintillation counter and pulse-height analyser. Calculations showed that the mass distribution of thin nonhomogeneous films could be determined by taking into account the intensity distribu- tion of the exciting radiation, the fluorescence field and all losses in fluorescence radiation on the way to the detector. The accuracy of the method was tested for nickel-iron layers of thickness up to 1000 A. In a theo- retical investigation it is shown that secondary excitation can be neglected in the case of thin films. In films con- sisting of two types of atoms the intensity ratio of the secondary to the primary fluorescence radiation of the lighter element is proportional to the mass coverage of the heavier element and independent of the mass cover- age of the lighter element. 253 Measuring Thickness and Composition of Thin Surface Films by Means of Electron Probe, B. W. SCHUMACHER, S. S. MITRA. Proc Electronic Components Conf 1962 p 152-61. Tests to show that thickness measurements with electron probe, utilizing range-energy relations for elec- trons, can be of same order of resolution that can be attained with multiple beam interferometry ; lateral reso- lution of electron probe may be even better; results of experiments with gaging probe are also of interest in con- nection with microprobe X-ray analysis of thin films. Measurement of the Thickness of Vacuum Deposits Using the Electron Microscope, D. CHESCOE, J. S. HALLIDAY. Nature (GB) vl93 Feb 3 1962 p 434-7. Shows that the thickness of vacuum-deposited films ranging from 20 to 2000A can be determined accurately in the electron micro- scope. The method is that of Bradley in which a layer of condensed hydrocarbon molecules is used as a marker against which the deposited material piles up. The film thicknesses measured in this way are in good agreement with those obtained by optical interference methods. A Note on Silicon Oxide Film Thickness Measurement, H. M. ROBERTSON, J. E. MONAMARA, R. M. WARNER, JR. J App Phys (USA) v33 n9 Sept 1962 p 2909. A standard interferometric technique can be used to measure the thickness of an unmetallized silicon oxide film if al- lowance is made for the film's optical properties. Use of Frustrated Total Internal Reflection to Measure Film Thickness and Surface Reliefs, N. J. HARRICK. J. App Phys (USA) y33 n9 Sept 1962 p 2774-5. When total internal reflection of light occurs, radiation pene- trates beyond the reflecting surface into the rarer medium where the intensity decreases with distance from the interface in an exponential manner. Since the degree of coupling to this radiation can be controlled by adjust- ing the proximity of another object to this interface, it is possible to utilize this phenomenon in the measurement of film thickness and to obtain high contrast images of surface reliefs. Film Thickness Determination with a Scintillation Counter, H. R. LUKENS, JR. Analyt Chem (USA) v34 nil Oct 1962 p 1396-7. A long-lived luminescence induced in organic lubricant films by ultraviolet light has been employed to determine the thickness of the films. The luminescence is measured and recorded with a multiplier phototube and scaler, and has been found to be propor- tional to film thickness. The phenomenon, long-lived luminescence, has been observed in many organic mate- rials, which indicates that the method should be widely applicable. The Use of Ferromagnetic Domain Structure to Deter- mine the Thickness of Iron Foils in Transmission Electron Microscopy, D. H. WARRINGTON, J. M. RODGERS, R. S. TEBBLE. Phil Mag (GB) v7 Oct 1962 p 1783-90. The thickness of foils of f.c.c. metals can be determined in the electron microscope by observations on slip systems or twin boundaries. In b.c.c. metals these methods fail, and estimates from extinction contours are not very accu- rate. A method is proposed for iron which relies on the deviation of the electron beam in passing through a mag- netized layer. The specimen is positioned so that a do- main boundary is in the beam, which thus passes through two regions in which the orientation of the magnetic vec- tor differs. The beam is split into two parts, giving two diffraction spots, the angular separation of which is a function of the film thickness as well as of the angle be- tween the magnetic vectors. By selecting simple domain configurations in which the magnetic orientation is clear, the film thickness can be found from the spot separation. The specimen must be placed outside the magnetic field of the electron lens. Results are given of a comparison between this method and the extinction distance method. Examination, of. Surfaces With Ajd of X-Ray Reflection, R. SCHE7.DEGGER. Brown Boveri' Rev v49 nll-2 Nov- Dec 1962 p 555-68. Description of asymmetrical X-ray reflection method ; calculation of layer thickness of dif- fracting surfaces ; features of Legrand camera and use i i of counting-tube goniometer for examination of surfaces ; examples of how method can be applied in practice ; quan- titative investigations on crystalline powders. Method for Measuring Thickness of Thin Bent Foils in Transmission Electron Microscopy, P. DELA VIGNETTE, R. W. VOOK. Physica Status Solidi v3 n4 1963 p 648-53. New method of thickness measurement of thin mono- crystalline foils in range of 1000 A ; method is based on observation of Kossel-Moellenstedt fringes in transmis- sion electron microscopy ; it differs from classical Kossel- Moellenstedt method by fact thatr no divergent beam is needed ; however, foil should be bent and method is based on measurement of radius curvature. Nondestructive Method of Measuring Thickness of Trans- parent Coatings, T. M. MANSOUR. Matls Res & Stand v3 nl Jan 1963 p 29-32; Quality Engr v 27 n2 Mar-Apr 1963 p 46-9. Method utilizes commercially available optical instrument, Zeiss light-section microscope; it is applicable to thickness measurement of transparent coat- ings of 0.1-10 mils, over both metallic and non-metallic substrates ; main limitation is its ineffectiveness with substrates that are highly light diffusing; comparison with other methods is shown for aluminum oxide on Al, clear synthetic enamel on steel, clear plastic and micro- scope slide glass on air. Activation Method of Measuring Thickness of Thin Films and Foils, F. P. DENISOV. Instrum & Exper Techns (English translation of Pribory i Tekh Eksper) nl Jan- Feb 1963 p 146-8. Simple method of measuring thick- ness of film, with and without backings, is based on use of artificial radioactivity and can be used to measure films with thickness down to 1/ig/sq cm. Determination of the Thickness of Coatings by Recording Scattered Beta Radiation, YU. S, ZASLAVSKII, G. I. SHOR, A. D. STUKIN, E. D. STUKIN. Pribory i Tekh Eksper (USSR) 1963 nl p 149-52 Jan-Feb in Russian. English translation in: Instrum Exper Tech (USA). A simple beta-ray back-scattering gauge, incorporating an end-window Geiger counter and a l^c source, is described. A Simple Method for the Measurement of Small Thick- nesses and Length Variations, A. H. BOERDIJK. Ned Tijdschrift Natuurkde (Netherlands) v29 n2 Feb 1963 p 53-5 in Dutch. The apparatus uses a convex lens and a glass plate — a sort of inverted spherometer — to meas- ure the thickness of thin wires etc. Length changes can also be measured. Interferometric Evaluation of Thickness of Canada Bal- sam and Collodion Films and Its Relation to Concentra- tion of Solutions, N. BARAKAT, A. A. A. MOHAMED, A. EL BIALY, K. A. AZIM. Brit J App Phys vl4 n3 Mar 1963 p 144-6. Films prepared using fixed area of water surface; graphs and tables enable preparation of thin films of known thickness for electron microscope tech- niques in which exact thickness of carbon or silicon repli- cas deposited on films is required ; effect of temperature on film thickness studied ; heating films enabled produc- tion of thinner films of known thickness. Sur l'Epaisseur limite au-dessous de Laquelle on ne Peut Plus Determiner separement les constantes optiques et l'Epaisseur d'une Couche Mince Absorbante (Thickness limit below which it is not possible to measure sepa- rately optical constants and thickness of absorbent thin films'), D. MALE. CR Acad Sci v256 n21 May 20 1963 p 4381-3. Method of normal incidence cannot be used below certain thickness because curves giving factors of 254 reflection, transmission, and phase change may be actually confounded with their tangent lines. Measurement of Thickness of Foils and Films by Means of Soft X-Rays, S. I. LOBOV. V. A. TSUKERMAN. Instrum & Experimental Techniques (English translation of Pribory i Tekhnika Eksperimenta ) n4 July-Aug 1963 p 757^61. Soft bremsstrahlung and characteristic X-ray emission excited by tritium are used to measure thin foils and films in thickness range 10~ 2 -10~ 5 cm ; Geiger counter is used as detector; sensitivity of 3X10~ 6 g/sq cm can be obtained with method when wavelength of charac- teristic emission is chosen to correspond with selective absorption at K, L, or M levels of foil material ; method is effective for measurement of metal foils and opaque films in mass range (5-30)10~ 6 g/sq cm. Method for Continuous Measurement of Thickness and Deposition Rate of Conducting Films during Vacuum Evaporation, J. A. TURNER, J. K. BIRTWISTLE, G. R. HOFFMAN, J Sci Instrum v40 nil Dec 1963 p 557-61. In method described, operational amplifiers are employed to monitor change in resistance of deposited layer, and their outputs used to serve control deposition rate and automatically cut off vapor stream, when deposit has reached predetermined thickness ; equipment allows close control of deposition rate and thickness, thereby increas- ing uniformity of deposited layers during successive evaporations. Survey of Methods of Measuring Thin Film Thicknesses and Surface Irregularities, P. WRIGHT. Electronics Reliability & Micro-miniaturization v2 n3 Dec 1963 p 227- 33. Methods of measuring thin film thickness and sur- face irregularities are evaluated ; 2-beam interference microscope and multiple grid light profile technique are found to be most useful in research ; other methods and their properties are summarized in chart. Determination Simnltanee des Indices et de l'Epaisseur des Couches Minces Absorbantes, D. MALE. J de Phys- ique v25 nl-2 Jan-Feb 1964 p 74-7. Simultaneous deter- mination of optical constants and thickness of absorbent thin films ; it is advanced that optical indices of metallic thin films determined before 1950 are not valid ; graphical method is indicated for simultaneous determination of optical constants and thickness ; method uses three measurements at normal incidence of intensities and phase differences ; method cannot be applied to very thin layers ; results are compared with those of other authors. Microscopic Observation of Film Cross Sections Having Steep Contours, B. R. FRIEDEN. App Optics v3 n3 Mar 1964 p 395-8. New method is proposed for microscopic observation of thickness distribution across thick ( greater than about 12 /n) transparent film; quality of observation is analyzed by expressing resolution error, image inten- sity, and depth of focus in terms of refractive index and geometrical constants of thickness distribution; con- straints are derived governing design of viewing system by algebraically demanding that resolution error be suffi- ciently small, and image intensity and focal depth be sufficiently large; constraints upon system parameters seem to be physically realizable. Instrument Measures Thin Film Thickness. Electronic Products v7 n6 Nov 1964 p 36 127. Probe and circuit design of measuring instrument for detection and thick- ness measurement of nickel, cobalt, aluminum, copper, and iron thin films; instrument has 0.001 in. full-scale reading with minimum increment of 20 /xin. ; it is applic- able to nondestructive testing and can be used as flaw detector to determine cracks and imperfections in metal strips. Film-Thickness Measurements, J. G. COLLIER, G. F. HEWITT. ASME— Paper 64-WA/HT-41 for meeting Nov 29-Dec 4 1964 19 p 53 refs. Methods which have been applied to estimation of thickness of liquid films in various types of film flow can be divided into two gen- eral classes — measurements of average thickness over con- siderable length of film — measurements of local thickness ; both types of determination have been used to obtain temporal mean averages and second type has been used to present information on time variation of thickness ; practical problems associated with application of various techniques are discussed ; relevance to lubrication is noted. Optical Constants of Thin Films, P. ROUARD, P. BOUS- QUET. Progress in Optics, E. WOLF, North-Holland Pub. Co., Amsterdam, v4 1965 p 145-97 26 figs 184 refs. A review article dealing with optical constants and structure of transparent thin films and optical constants of absorbing thin films. Routine Mass-Thickness and Nonuniformity Determina- tions of Thin Films, K. F. WYLIE, and G. R. HAGEE. Nuclear Instrum Methods ( Netherlands) v32 n2 Feb 1965 p 201-3. A routine technique to rapidly determine the thickness and uniformity of thin plastic films and of thin plastic films coated with beryllium was developed. The thicknesses of Formvar films approximately 20 to 100 fig/ cm 2 and beryllium coated films (approximately 20 to 70 Mg/cm 2 of beryllium) were determined using alpha-particle attenuation techniques. Film thicknesses were deter- mined by both alpha counting and destructive weighing. The difference between the two techniques was within the experimental error of 7.5%. Addendum to Section 11 11.2. Polarimetric Methods (Ellipsometry) Optical Measurement of Oxide Thickness on Titanium, R. C. MINARD. General Mills, Inc., Electronics Group, Research Dept., Minneapolis, Minn. J Opt Soc Am v52 n4 Apr 1962 p 427-31 4 figs 18 refs. Reflectance of thermally oxidized, mechanically polished titanium surfaces was measured with a spectrometer at 5889-5895 A. The prin- cipal aim of the experiments was to furnish an optical means of measuring the thickness of thermal oxide layers on titanium. These measurements also provided a method for determining the optical constants of the metal and the thermal oxide. Error in Dielectric- Film Ellipsometer Determinations due to Neglect of Film Absorption, D. W. PETERSON, N. M. BASHARA. J Opt Soc Am v55 n7 July 1965 p 545-50 13 figs 13 refs. The error in the calculated refractive index of an absorbing dielectric film, which is determined by approximate equations that neglect absorption, is influ- enced by the true refractive index of the film and the con- trollable parameters — substrate and measuring wave- length. Such equations give two relations for calculation of thickness. It is shown why one of these equations gives an insignificant error when small absorption is present and an independently determined refractive index is used in the thickness calculation. 255 Section 12. Measurement and Production Techniques for Accurate In- Process Control of Size and Form CONTENTS Page 12.1. General 257 12.2. Machine tools 259 12.3. Automatic control 262 12.4. Grinding ■ 265 12.5. Lapping 266 12.6. Manufacture of precision measuring tools and components 268 12.6.1 General 268 12.6.2. Scales and gratings 270 12.6.3. Worms and power screws, including lead screws 271 12.6.4. Screw thread gages 273 12.6.5. Other gages 274 Addendum to Section 12 276 12.1. General On Plane Metallic Surfaces or True Planes, J. WHIT- WORTH. Pub. in Miscellaneous Papers on Mechanical Subjects, J. WHITWORTH, Longman, Brown, Green, Longmans, and Roberts, London 1858. Paper read at meeting of the British Association in Glasgow, 1840 p 3-19. Describes method of generating a true plane by matching three surfaces. Problem of the Theoretically Correct Involute Hob, N. TRBOJEVICH. Machy (N.Y.) v25 Jan 1919 p 429-33 3 figs. Discusses interchangeable involute gears, gener- ating an involute surface, analysis of involute tooth sur- face, theory of pressure angles, correct tooth curve of straight-gashed hobs, and hob versus spiral gear. Hobbing Spiral Bevel Gears, N. TRBOJEVICH. Machy (N.Y.) v23 n582 Nov 22 1923 p 225-35 16 figs 6 refs. De- scribes a hobbing process for producing accurate spiral bevel gears or hyperboloidal gears having spiral teeth. It is stated that gears produced by this method are more nearly correct than any so far produced. The Pratt and Whitney Gear-Shaving Process, H. D. TANNER. Machine Shop Practice (ASME Trans) v50 n27 Sept-Dec 1928 p 17-22 22 figs ; Automotive Industries v59 nl8 Nov 3 1928 p 625-7 12 figs; Am Mach v69 nl7 Oct 25 1928 p 659-61 11 figs ; Iron Age vl22 nl6 Oct 18 1928 p 949. Practical method of generating involute spur or helical gears at zero degrees which was invented by J. H. BARNES, Dayton, Ohio. Active profiles of gear teeth are generated by rolling gear in mesh with zero- degree rack ; active profiles of this rack are top edges of its teeth, which coincide with cutting edges of tools ; tools have straight cutting edges slightly longer than face of gear to be cut. Mechanical Generation of Form. Eng vl56 n4049 Aug 18 1933 p 163—4. Definition of word generation in sense used by engineer ; author inclines to belief that true gen- eration of forms other than primitive forms demands use of mechanism involving nothing but link work and that only those forms which are capable of being expressed by combination of links are capable of being generated in true and proper sense. Precision Workshop Methods, H. J. DAVIES. London, Edward Arnold & Co. ; New York, Longmans, Green & Co. 1935 306 p illus diagrs charts tables. Essential ideas upon which precise machining of machine parts depends ; meth- ods of setting out work, devices for setting work for machining, graduating and indexing, screw cutting, pro- filing, cutting gear teeth, and lapping and grinding limit gaging, testing machine tools, and related topics discussed. Eng Soc Library N.Y. Instruments in Machine Tool Industry, B. R. HILL. West- ern Machy & Steel Wld v27 n9 Sept 1936 p 328-9. Quanti- ties which must be easily and quickly determined by operator to obtain most from any motorized production tool ; application of instruments ; selection of ratings ; measurement of speed and position ; position shown elec- trically. From talk before representatives of 40 machine tool manufacturers. The Honing Process for Cylindrical Bore Finishing, J. E. ANDRESS. Tool Engr v6 n2 June 1937 p 14-5, 26 28-9 4 figs ; Machy (N.Y.) v43 n8 Apr 1937 p 526-9. Work adapt- able to honing ; preparation ; metals and holes honed ; hon- ing angle of cross hatch ; hydraulic dwell ; strokes and cycles ; size and position of holes honed ; connecting rod honing ; coolant. Bearbeitungsfragen der Feinmechanik (Machining prob- lems in precision parts manufacture), H. HEMSCHEIDT. Maschinenbau vl6 nl3/14 July 1937 p 343-6. Illustrated description of modern methods and tools for machine cutting and stamping operations on precision parts ; meas- uring and testing methods. Materials for Precision Machinery, C. FUJIL. Japan Nickel Rev v6 nl Jan 1938 p 53-76. In English and Japanese. Requirements for precision machines and tools and properties required in materials for this purpose ; ma- terials for beds of machine tools and measuring instru- ments, for spindles, guide screws, bearings, gears, standard scales, gages, etc ; use of nickel in these materials emphasized. Generating Small Precision Gears, A. THOMPSON. Tool Engr v9 nl May 1940 p 9-12 85 14 figs ; Can Machy v51 n3 Mar 1940 p 70 72 74 116. Essentials of gear tooth generat- 257 ing considered ; fundamentals of cutting teeth ; cutting gears on turret lathes ; cutting precision gears. Tolerance and Dimensional Control — Its Effect Upon Air- plane Production, H. ADAMS. Mech Eng v65 nlO Oct 1943 p 739-40. Major problem confronting aircraft indus- try is attempt to eliminate rework required on assembly to make parts fit ; handwork is required because of cumula- tive errors in wrong dimensions and wrong tolerances : major part of solution lies in engineering, by designing to avoid overconstraint, exact dimensioning and application of correct tolerances ; tooling steps should be reduced in number and improved in accuracy. Generation of Conic iSeotions with Machine Tools, R. T. HINKLE. Prod Eng vl8 n8 Aug 1947 p 162-5. Applica- tion of two theorems from projective geometery duplicated by kinematic linkages, for generation of ellipse, hyper- bola ; kinematic schemes for generation in accordance with these theorems are illustrated ; basic machine di- mensions are analyzed and conversion of design dimensions of parts into machine settings for production is described. New Appliance for Measuring Angles of Pieces Being Machined, G. KANN. Microtecnic v3 n5 Sept-Oet 1949 p 232-3. Illustrated description of appliance designed for checking dimensions and angles of pieces in course of manufacture without separating them from machine. Modern Methods of Gear Manufacture. National Broach and Machine Co., Detroit. 3rd ed 1950 revised 1964 164 p 170 figs. Contents : Gear design principles ; gear formu- las ; selection of gear steels ; heat treatment of gear steels ; machining gears ; advanced production practices ; special gear problems and case histories ; red ring products ; gear broaching. Chapter 6 on advanced production practices describes in detail the shaving process of finishing gear teeth. Method of Controlling Profiles, A. MIRATJ. Rev Opt v32 July 1953 p 418-22. In French. Control method for ma- chining profiles, giving about 0.01 mm accuracy for pieces several centimeters in size. Zahnriider: Stirn- und Kegelrader mit geraden Zahnen (Gear Wheels: Spur and Bevel Gears with Straight Teeth), W. LINDNER. Springer-Verlag 1954 133 p 183 figs 37 refs. Consists of two main parts: (1) the kine- matic and mathematical tooth cutting in the radial plane; (2) application of the mathematical fundamentals. Con- tains a chapter (p 96-108) on the production of gears by form milling, form grinding, rolling, and lapping, and the errors involved. Ein Beitrag fiir Ermittlung von Schleifseheiben- und Fra- serprofilen zum Erzeugen geradflankiger Gewinde (A Con- tribution for the Ascertainment of Grinding-Wheel and Milling-Cutter Profiles for the Production of Straight- Flank Screw Threads ) , M. GARY. Werkstattstechnik und Maschinenbau, v46 nlO Oct 1956 p 510-3 2 figs 7 refs. With a given position of the grinding-wheel or milling- cutter axis with respect to the thread axis, the article develops the fundamental equations for calculating the workpiece profile in an axial section. The process is ap- plicable to both straight and taper threads, external and internal. How to do Precision Machining in Uncontrolled Tempera- tures, H. K. EITELMAN. Am Mach vl03 n21 Oct 5 1959 p 96-8. Problem of eliminating heat expansion which can move part dimension completely out of tolerance; simple temperature correction method described which makes it possible to standardize machining and gaging when perfect temperature control is impossible ; how and when to compensate ; type of equipment needed. Determination of Errors in Mechanisms with Lower Pairs, i V. A. SHISHKOV. Meas Techns 1958 n6 Mar 1960 p I 626-9 5 figs. Translated from Izmer Tekh Nov-Dec 1958 I p 12. In the calculation of errors in a real mechanism the permissible variations in the dimensions of its links and the deviations in the positions of the centers of pins ] or slots on the column are usually given. The errors in position of other links for the given position of the driv- ing link have to be found. The method developed by the ] author makes possible the construction of a single poly- I gon of small displacements without drawing the trans- I formed mechanism. The polygon of small displacements ; provides the complete solution of the problem of deter- I mining the effect of all links upon the position error of the driven link (and also upon the position error of any • of the links of the mechanism ) . Making Parts to Millionths, R. LeGRAN, H. SOKOLSKY. i Am Mach/Metalworking Mfg vl06 n4 Feb 19 1962 p 105-8. i How Raytheon Co. made sudden switch from experimental 1 output to full-scale production of missile servos, to ac- ' curacies of 10 millionths in. for size, roundness, and taper; major steps in making missile control valves. Development of Modern Electrical Instrument-Making, I A. M. DAMSKI, G. I. KAVALEROV. Meas Techns 1962 : nl June 1962 p 4-9. Translated from Izmer Tekh nl Jan ] 1962 p 4-8. Discusses many phases of the design and i production of electrical instruments. States that the j automation of production control raises a number of prob- ' lems in the production of specialized devices and systems s which would provide, in addition to normal measurements, | the control of complicated aggregate specialized measur- ! ing equipment operating with controlling computers. I Die Fertigung von Genauigkeits-Grosszahnraedern (Pro- duction of large marine gears of high precision), W. i DREYHAUPT. Werkstatt und Betrieb v95 nil Nov 1962 j p 733-43. Details of gear hobbing machine and operating i conditions, manufacturing procedure and measuring and j safety devices employed ; numerous measurement results j presented indicate accuracy of gears. Female Centers Influence True Roundness, G. L. DANNE- j HOWER. Tooling and Production Jan 1964 3 p 7 figs. ; Stresses the importance of true geometric center holes, established alinement of axis, and close dimensioning j tolerancing between centers. Temperature Variation Effects on Dimensional Accuracy 'j in the Machining of Aluminum, D. WEISMAN. Tool and j Mfg Engr v52 Feb 1964 p 91-6. This paper is an investigation of temperature variation effects on di- mensional accuracy in the machining of aluminum. It examines the thermal expansion differences between aluminum and steel and discusses the techniques of I controlling the aluminum work-steel gage dimensional 1 difference. Tolerance ranges are presented for appraisal I of the dimensional error with reference to ±0.000050", ±0.0001", and ±0.00025". This investigation is signifi- cant for manufacturing capability in the manufacture of ' precision components. Application of the Least Squares Method for Evaluating the Precision of the Technological Operation in the Process Control of Components' Dimensions, I. V. DUNIN- BARKOVSKII. Meas Techns n5 Nov 1964 p 374-8 1 fig 5 refs. Translated from Izmer Tekh n5 p 10-3 May 1964. A method for evaluating the precision of technological operations with process control of component sizes based on the least squares method is suggested in this article. The method is convenient in practice and avoids the theoretical difficulty in selecting the number of observa- tions which would ensure a given precision and reliability in evaluating for instantaneous distribution parameter without at the same time distorting its value by variations with time in the position of the size dispersion center. 258 12.2. Machine Tools Checking Lathes for Accuracy, American Tool Works. Machy (N.T.) v30 Nov 1924 p 195-9 12 figs. Discusses testing lathe beds for straightness and parallelism, inspec- tion of lead screws, checking of headstock spindle, in- spection on the erecting floor, truing the faceplate and set- ting the compound rest, alining the taper attachment, and other detail tests. NPL Test on Carson Jig Boring Machine. Machy (Lon- don) v33 Nov 8 1928 p 186; Am Mach v69 1928 p 113. Gives results of tests on motion of table, motions of drill- ing head along slide, other motions, flexure of supporting column, abutment faces for gages, squareness of drilling spindle to table, measurements of sample jig produced on machine. Refinements in Finishing Cylindrical Bores, J. W. HINDES, J. G. YOUNG. ASME Advance Paper for meet- ing June 9-12 1930 9 p; Automobile Engr v20 Aug 1930 p 303-4 ; Abrasive Industry vll Aug p 25-7 and Sept 1930 p 28-30 6 figs. Limitations of boring, reaming, burnish- ing, and broaching; outline of grinding practice; opera- tion and advantages of hone ; coolant and abrasive. Das Arbeiten mit Messeinrichtungen neuzeitlicher Waagerecht-Bohr- und Fraeswerke (Application of meas- uring Equipment to Modern Horizontal Boring and Mill- ing Machines), E. ZIEGENHALS. Werkstattstechnik v27 n6 Mar 15 1933 p 114-7. Accuracy obtainable with special regard to application of end measures and record- ing scales ; examples of practical application. Precision Finish Machining, O. SCHLIPPE. Eng Progr vl6 nl Jan 1935 p 29-32. Trend of development in design of fine turning and boring machines, cutters, lapping and honing machines ; illustrations. Boring Equipment Adapted for Close Limit Machining of Automotive Pistons and Cylinders, W. F. WISE. Iron Age vl35 n9 Feb 28 1935 p 20^3. Precision boring equip- ment arranged for diamond turning of pistons with ellip- tical and tapered skirt to limit of 0.00005 in. on major and minor diameters and on taper, and set-up for single- point finish boring of cylinders to unusually close limits. Internal Surface Finishing to Finer Limits, A. W. SCHNEIDER. Can Machy v46 nil Nov 1935 p 13-5, 32. Development of standard precision boring machines due to rigid requirements of manufacturers of automobiles, air- planes and electric refrigerators for increased accuracy without increased cost ; automatic control. Der heutige Stand der Feinstbearbeitung ( Present status of precision working), C. BUETTNER. Zeit Metallkunde v28 n4 Apr 1936 p 91-6 ; (discussion) Metal Progr v30 n6 Dec 1936 p 54-5. Results of investigation of precision boring, cutting, lapping and grinding ; purpose of precision machining demonstrated by examples of journal bearings, Diesel-engine fuel pumps, etc. Etude des Dispositifs de Mesure des Deplacements Line- aires (Study of Equipment for Measurement of linear Displacement in Machine Tools), L. COMPAIN. Me- canique v22 n280 Sept-Oct 1938 p 205-12. With special reference to use of micrometer calipers in certain proc- esses of precision production : Das Mechanische Schaben von Flaechen (The Mechanical Scraping of Surfaces). Werkzeugmaschine v43 n4 Feb 28 1939 p 86, 88. Mechanical scraping of surfaces in ma- chine tool manufacture; advantages over manual opera- tion ; description of scraping machines ; rotating table for mounting of work piece. Optik an einum Lehrenbohrwerk (Optical gages on pre- cision drilling machine). E. ROTZOLL. Werkstattstech- nik und Werksleiter v33 n9 May 1 1939 p 238-40. For accurate centering of hole, discussed as example showing usefulness of optics for practical application on machine tools. Influence of Temperature on Lathes, G. SCHLESINGER. Am Mach v86 n9 Apr 30 1942 p 379-81. Observation on changes in alignment of machine tools during warming up period ; compensation for misalignments is discussed ; illustrations show arrangement of dial gages for measure- ment of spindle movement during warming up tests, and method of mounting dial indicator for testing alignment of tool holes and recesses in turret faces by turn around method. Accuracy Requirements for Heavy Machine Tools, J. H. RIVERS. Machy (London) v70 nl802 May 8 1947 p 486- 90 7 figs. Discusses spindle bearing design ; cambering mechanism used on a roll grinding machine ; instrument designed to accurately measure roll camber. Measurement of Progressive Errors in Machine Tools by High-Speed Photography, C. TIMMS, NPL. Machy (Lon- don) v75 Dec 15 1949 p 27-31 6 figs 1 ref. Describes an investigation of the errors in the linear movements of the hob saddles of a gear hobbing machine, using a camera of simple design to record errors relative to a divided scale of known accuracy by direct comparison. Describes recording equipment and gives test results. Les Fabrications Mecaniques du Point de Vue de leur Precision (Machining from Viewpoint of Precision), O. PETERS. Rev Gen Mecanique v35 n29 May 1951 p 160- 3. Influence of position of tool, and angle of projection of cutter ; effect of control. Roll Generation of Approximately Plane Surfaces, P. GRODZINSKI. Mech Wld vl32 n3396 July 1952 p 12-5. Principle used hitherto mostly for describing ellipses has been applied to generation of approximately flat surfaces by increasing ratio of elliptic axes ; method explained and kinematic basis of method analyzed; mechanism on Wick- man multiple spindle automatic ; extension of kinematic principle to arbitrary number of cutting points and poly- gons ; Tellschow mechanism. Machine Tool Metrology, D. F. GALLOWAY, NPL. Eng Dimensional Metrology, Proc of Symposium held at NPL, 2 vols, Her Majesty's Stationary Office (London) 1955. Paper nl7 p 289-301 4 figs. Discusses deflection tests, temperature effects, spindle bearings, vibration, testing of slides. Discussion. Testing the Accuracy of Jig Boring Machines, T. R. OAK- LEY, NPL. Proc of Symposium held at NPL, 2 vols, Mer Majesty's Stationery Office (London) 1955. Paper nl8 p 303-21 7 figs test chart. Discusses measuring equip- ment, testing site, temperature, preparation for tests, worktable, co-ordinate movements, and calibration. Dis- cussion. Fixture Generates Large Radius, H. OSTRANDER. Am Mach vlOO nl4 July 2 1956 p 118-9. Fixture constructed of Meehanite castings generates true circular arc with good accuracy and reliability, and is adaptable to various standard machine tools ; fixture is designed so that work will occupy position at arbitrarily convenient distance from center of large circle and be fixed to small circle so that it will rotate with it. Tough Problems Solved with Tricky Tooling, F. P. BROWN, C. E. PELANDER. Machy (N.Y.) v64 nl Sept 1957 p 149-55; Machy (London) v91 n2349 Nov 22 1957 259 p 1199-1204. Ingenious attachments developed in Shops Division at National Bureau of Standards for producing scientific instruments and equipment are described and illustrated; wide angle taper turning attachment; verti- cal milling machine adapted to jig boring; roll forming of thin wall conical components ; special tool holder and base developed for ceramic tools. Practical Alignment of Machine Tools by Means of Opti- cal Equipment, R. OSWALD. S African Mech Engr v8 n6 Jan 1959 p 194r-200. Alignment of machine tools, both in initial setting and during course of their lives ; im- portance of sufficiently thick concrete foundations, and use of vibration absorbers such as rubber, cork, or systems of springs to reduce shock impact ; principle of optical auto-collimator and its application in setting up and maintaining alignment. Optische Moglichkeiten der Positionierung an Werkzeug- maschinen (Optical Possibilities of Positioning on Ma- chine Tools), K. HERKT. 4 FoKoMa, Munich Oct 1959 p B93. The advantages of embodiment of optical meas- uring equipment for positioning of machine tools were placed under proof over a decade by the installation of this equipment on a jig borer. Das statische und dynamische Verhalten von Werkzeug- maschinengestellen (Static and Dynamic Behavior of Machine Tool Frames), J. BIELEFELD. Acta Technica (Prague) v5 n4 1960 p 311-29. Method for investigating rigidity of elements of metal cutting machines ; optimum design of machine frames. A Kinematic Method of Making Details with Curvilinear Cross Sections and a Technique of Evaluating Its Accu- racy, N. M. KARELIN. Meas Techns 1959 n8 July 1960 p 586-92 4 figs 1 ref. Translated from Izmer Tekh n8 Aug 1959 p 9. The author aims to develop a method of constructing kinematic devices for nonduplicating machin- ing of cylindrical details with curvilinear cross sections (such as cams, templets, outside surfaces of noncircular wheels, polyhedrons, etc. ) Developing kinematic schemes on this basis leads to a problem of the theory of function approximations. Optical Oheck-Out of Machine Tools for Missile Produc- tion, G. W. DONALD. Machy (N.Y.) v66 n8 Apr 1960 p 149-51; Machy (London) v97 n2491 Aug 10 1960 p 333-5. In checking out machine tools such as horizontal boring mills and jig boring machines in Ordnance De- partment of General Electric Co, first bedway flatness is established with optical instruments ; flatness of table on large boring mill checked with auto-collimator, corner mirror, and mirror carriage; column squareness with table determined by using alignment telescope, stride level, pentaprism, and target attached to spindle. Machine Tool Research at the Technological University of Munich, F. EISELE. Int J Machine Tool Design Res vl 1961 p 249-74 35 figs. Discusses typical examples of vibration research and reports the scope, content, and the most important results on subjects as follows : stiffness investigations and their practical application, mechanisms of excitation, the avoidance of vibration, disturbance re- search, investigation of structural groups and elements, foundation investigations, damping and stability investi- gations, research on cutting forces, methods of measure- ment and measuring instruments, and electrical analogies. Machine Tool Research, Design, and Utilization, D. F. GALLOWAY. Machy (London) v98 n2515 Jan 25 1961 p 196-204 ; Engr v210 n5475 Dec 30 1960 p 1081-2 ; Chart- ered Mech Engr v8 n2 Feb 1961 p 72-83 95 133. Reference is made to criteria of performance, terminology and speci- fication, necessity for increased static and dynamic stiff- ness of machine tool structure, vibration, automation, and ergonomics. Abstract of James Clayton Lecture before Instn Mech Engrs, Dec 14 1960. A Kinematometer for Screw Cutting Lathes, Y. M. AN- DRUSHEVICH, M. K. KLEBANOV, M. Y. TSLAF, A. L. RABHIN. Meas Techns 1960 n7 Feb 1961 p 588-9 2 figs. Translated from Izmer Tekh n7 July 1960 p 27-8. De- scribes an instrument for measuring the degree to which the errors of separate elements of the screw-cutting lathe kinematic chain affect the accuracy of the thread. Ex- perimental investigations were made. UPPS for Ultraprecision Machining. Du Pont Eng Dept Mech Development and Mech Res Labs July 1961 5 p 5 figs. Defines ultraprecision machining and discusses importance of precision, program results, accuracy of motion, accuracy of positioning, machining sequence, and applications. Graphical Method for Determination of Dvnamic Stability of Machine Tools, J. P. GURNEY, S. A. TOBIAS. Int J Machine Tool Design & Res vl nl-2 Sept 1961 p 148-56. Use of harmonic response locus, so far applied with most effect in electrical engineering is considered very useful to describe characteristics of machine structure ; method be- ing essentially graphical, is equally applicable when modes of structure are not well defined, and it takes effect of rotational speed of tool or workpiece into account ; stability conditions for regenerative chatter determined by this method are set out in form of stability charts. Zmniejszanie Obciazen Dynamicznych W Mechanizmach Obrotu Maszyn Roboczych Ciezkich (Reduction of Dy- namic Loads on Drives of Machine Tools), H. HAWRY- LAK. Archiwum Budowy Maszyn v9 nl 1962 p 29-54. Analysis of dynamic overloads and possibility of reducing them by introducing spring elements in drive ; choice of spring elements ; theoretical considerations are based on two-mass model ; for experimental verification test stand has been constructed ; description of stand ; measurement methods and apparatus : analysis of measurement results. English summary. Dynamic Acceptance Tests for Machine Tools, S. A. TO- BIAS. Int J Mach Tool Design & Res v2 n3 July-Sept 1962 p 267-80. It is proposed that dynamic quality of machine tools, in particular of radial drilling machines, be measured by coefficient of merit ; this coefficient is prod- uct of static stiffness between tool and workpiece, in direc- tion of cutting thrust, and nondimensional ratio deter- mined from harmonic response locus of machine structure ; determination of coefficient for radial drilling machines is discussed and its relationship with stability chart of drilling process elucidated ; it is shown that coefficient of merit is proportional to maximum drill diameter which is stable at all speeds. Ispytanie stankov obshchego naznacheniya na vibrousto- ichivost pri rezanii (Vibration Resistance of General- Purpose Machine Tools During Cutting), V. A. KUDINOV, T. S. VOROB'EVA. Stanki i Instrum n8 Aug 1962 p 8-12 ; see also English translation in Machines & Tooling v33 n8 1962 p 11-15. Laboratory investigations and shop tests are reported on basis of which method for investigating vibration resistance of center lathes and knee j type milling machines was developed by ENIMS. Koroblenie chugunnykh basovykh detalei pretsizionnykh stankov i metody ego ustraneniya (Warping in Main Castings of Precision Machine Tools and Methods of Eliminating It), O. YU. KOTSYUBINSKII, A. M. GER- CHIKOV, YA. I. OBERMAN, S. A. SHEVCHUK, E. CH. GINI. Stanki i Instrum n9 Sept 1962 p 1-5; see also English translation in Machines & Tooling v33 n9 1962 p 2-6. Investigation was carried out into warping of iron castings used in precision machine tools (aged naturally and artificially) ; fact that even in case of high level of residual stresses iron casting may retain its dimensional stability, is extremely important in determining condi- tions for artificial aging ; aging before rough machining is inadvisable, because it does not insure subsequent sta- bility in shape of machined components. 260 I Prirueuenie teorii podobiya dlya rascheta metallorezhu- | shchikh stankov na ravnoinernost podachi (Applying The- 1 ory of Similarity When Calculating Working Traverses in Machine Tools), B. G. LUR'E. Stanki i Instrum nil Nov 1962 p 11-14 ; see also English translation in Machines U & Tooling v33 nil 1962 p 13-16. New data on problem | of uniform slow motion of machine tool units are de- lft sjribed ; problem is solved on basis of experimental data, [l with help of theory of similarity ; method suggested for ^ experimental and theoretical analysis of nature of slow 3 movements in machine tools, and for determining slide- way and feed drive parameters necessary for designing I machine tool with small movements of required degree of ] uniformity and accuracy. Role of Tracer Attachments in Contour Machining, L. S. MAGOR. Automat vlO n5 May 1963 p 83-5. Discussion of modern tracer attachments that can be mounted on A existing machine tools to control automatically contour ] machinery. On New Feedback Controlled Precision Gear-Hobbing j Machine, T. NAKADA, T. MASUDA, S. MIWA, T. MAT- 4 SUMOTO, Y. FUKUDA, Y. MORITA. Japan Soc Mech : Engrs— Bui v6 n23 Aug 1963 p 556-67. Basic analysis , and design of new hobbing machine ; average and mini- | mum of angular position error is 20 sec and 11 sec, I respectively, when gear module is one pitch circle, diam- ■ eter is 72 mm ; such accuracy is obtained by virtue of i electrohydraulic servomechanism that corrects error of I driving worm wheel ; mechanism performance is analyzed | and experimental results discussed. Results Obtained When Using Vibrating Tools and In- formation on Energy Dissipation in Machine Tool Vibra- i tion from Russian Sources, R. WEILL. Int Prod Eng Res Conf Proc Sept 9-12 1963 p 459-64. Published by ASME. Variation of cutting forces during vibration is discussed, and results obtained in this field reviewed ; Russian work on defining and measuring damping capacity of various machine tool components is discussed ; f rac- tural energy loss per cycle of vibration was measured for number of materials, and machine tool components ; by setting energy loss equal to energy input, due to re- generative copying of surface waves on workpiece, method of predicting stability is obtained. Stability of Machine Tool against Self-Excited Vibration in Machining, J. TLUSTY, M. POLACEK. Int Prod Eng Res Conf Proc Sept 9-12 1963 p 465-74. Published by ASME. Influence of characteristics of machine tool on occurrence of self-excited vibration is described, in order to be able to get higher stability of machine tools at mini- mal weight ; theory of self -excited vibration presented explains all basic characteristics of this phenomenon, and some of effects of changes in machine tool on vibration ; example of change of orientation in case of boring bar with rectangular cross section is described. What Can Vibration Research Contribute to Machine Tool Development, J. PETERS. Proc Int Prod Eng Res Conf Sept 9-12 1963 p 486-93. Published by ASME. Surface roughness produced in turning operations is shown to be related to natural modes of spindle and lathe bed ; struc- tural weaknesses contribute to surface roughness, espe- cially when forced vibrations from gears, ball bearings, etc. are small ; chatter studies. Applied Vibration Research on Lathes, K. E. WETZEL, R. DORNHOFER. Int Prod Eng Res Conf Proc Sept 9-12 1963 p 494-501 23 refs. Published by ASME. Re- sults of dynamic studies of new lathe designs are reported, including vibration behavior of lathe beds, and studies of saddle and cross-slide and self-excited vibration on slide ways ; methods of raising stability of headstock spindle ; vibrational correct design of tailstock and center point ; sources of severe vibrational disturbances are reviewed including forced vibrations, vibrations from high speed drives, belt drives etc ; chatter problems of boring tools and self-excited vibrations of gun drills. New Concepts Concerning Machine Tool Structures, F. KOENIGSBERGER. Int Prod Eng Res Conf Proc Sept 9-12 1963 p 535-42. Published by ASME. Effects of im- portant parameters, such as design shapes and loads, ma- terials properties, methods of manufacture, joint design and efficiency and stiffness-to-weight ratios are described, and problems of accuracy discussed, particularly that of alignment error correction; application of results to de- signs in past and present, and possible future develop- ments considered ; some results of recent research work are reported. High Precisiion Components-Analysis of Engineering De- sign and Manufacturing, J. LOXHAM. Proc Int Prod Eng Res Conf Sept 9-12 1963 p 634-44. Conditions neces- sary for obtaining precision products within allowed tol- erances are discussed, including design of machine tools, as illustrated by design of grinding machine ; product measurement problems in design of machine and inspec- tion. Osevaya zhestkost shpindel'nykh uzlov vysokotoehnykh metallorezhushchikh stankov (Axial rigidity of precision machine tool spindle units), A. M. FIGATNER. Stanki i Instrument nl2 Dec 1963 p 1-5; see also English transla- tion in Machines & Tooling v34 nl2 1963 p 2-6. It has been established by calculations and by experiments that axial rigidity of such units depends to great degree on accuracy of manufacturing of bearings and adjoining parts; methods of calculations and graphs for determi- nation of axial rigidity are given ; high axial rigidity is assured by selection of high precision bearings with axial play not exceedng 1-3 fi ; recommendations for selection of bearings are given. Errors in Measuring Geometrical Accuracy of Machine Tools by Means of Automatic Checking Devices, A. SADOWSKI. Microtecnic vl8 n2 Apr 1964 p 45-53. Analysis of errors when measuring machine tool accuracy by means of dial gages, leads to conclusion that dial gages with 1/100 mm divisions have large intrinsic error and should be replaced by micro-indicators with error not exceeding two microns ; revision of international standards for testing machine tool accuracy should in- clude metrological indications relative to measuring equipment such as dial comparators, precision squares and rules, test mandrels, and universal stands. Some East German Machine Tool Developments, R. E. GREEN. Machy (Lond) vl05 n2698 July 29 1964 p 302-9. New designs of grinding, lapping, and honing machines shown at 1964 Leipzig Spring Fair; automatic universal thread-grinding machine fitted with equipment for automatic loading and unloading of taps of 0.394 in. diam ; new design of shoe cencerless grinding machine with automatic feeding and diameter size control ; ma- chines for rough- and finish-grinding of ball raceways by plunge-cut method ; internal grinding machines fitted with recently developed HF spindles running at 24,000 rpm ; grinding machine for gears employing generating principle; Naumburg flat-lapping machine; semiauto- matic vertical honing line. Optical Setting Devices for Machine Tools. Machine Shop v25 nlO Oct 1964 p 484-6. Despite recent develop- ments in electronic measuring methods, optical devices are still favored for many applications ; direct reading microscope has now been replaced by projection type unit consisting of precision divided scale and micrometer pro- jector; either element can be part of moving equipment 261 or remain stationary ; two units manufactured by Hilger & Watts are described. Das Multiprismat — ein neuartiges optisch-elektronisches Positioniersystem (The Multi-Prism — A New Optical Electronic Positioning System), W. SELIGER. Optik (Germany) v21 nlO Oct 1964 5 figs p 546-50 in German. The multiprism itself is a glass plate with a parallel array of 90° prisms cemented to one face. A grating is imaged by an optical system, via the multiprism, onto a receiving grating and then to a photocell. Movement of the multiprism then gives a sinusoidal output which can be used to determine the position of the multiprism. The resolution of the system is about 10 /*. Some possible uses are described, particularly in the machine tool industry. 12.3. Automatic Control Where Close Timing of Operations Rests on Machine Con- trols. Elec Mfg vl5 n6 June 1935 p 23-4. New gear- tooth lapping machine of Fellows Gear Shaper Co., for lap- ping gear teeth after heat treatment, is designed for full electric control ; automatic timing of machine opera- tions and shut-down upon completion of cycle of effective work are two control problems carefully developed in new designs. Electronic Control and Its Relation to Machine Tool Oper- ating Cycles, E. H. VEDDER. Steel vlOO n21 May 24 1937 p 64-5. Typical industrial applications of photo- electric control to indicate possible machine tool applica- tion. Before machine tool electrification forum, held under auspices of Westinghouse Elec & Mfg Co. Successful Electronic Controls, R. A. POWERS. Elec Mfg v20 n6 Dec 1937 p 50-1 96-7. General discussion of fundamentals of theory and application of photoelectric control machine tool operation. Steuerung von Werkzeugmaschinen durch Fotozellen (Control of Machine Tools by Photoelectric Cells), R. SPIES. Werkzeugmaschine v42 nl8 Sept 30 1938 p 391-9. Types and operating principles of cells; replacement of mechanical control equipment by photocells ; control of photocells and templets ; circuits. Air Size-Control, J. E. KLINE. Machine Design vl9 nlO Oct 1947 p 88-91. Features of gaging device which meas- ures workpiece during machining or other operations ; application to honing machines as exemplified by 6-spindle machine which simultaneously finishes all cylinders in block, or single spindle machine in which gaging control automatically indexes fixture, transferring operations through successive bores. Thickness Gage for Moving Sheets, J. W. HEAD. Elec- tronics v21 n5 May 1948 p 90-2. How glass and other non-magnetic sheets ranging in thickness from % in. to 1 in. can be continuously gaged to close tolerances ; mate- rial is run between primary and secondary of measuring transformer ; variations in material thickness change cou- pling, upset bridge balance and are directly indicated. Dimensional Control. Aircraft Prod vll nl32 Oct 1949 p 339. Technique developed by Sigma Instrument Co to provide operator with continuous dimensional informa- tion of component being produced and at economical price, consists of employing Sigma vertical comparator with range of fixtures so constructed that all dimensions on component can be measured as distinct from being gaged, without resetting comparator; it is particularly intended for checking of large quantities of parts produced on automatic machinery. Automatic Positioning Device Allows Precision Machining of Delicate Optical Instruments, E. E. JEFFERY. West- ern Metals vlO nlO Oct 1952 p 54-6. Design of 340-T Giddings & Lewis boring, drilling and milling machine in- stalled recently at Northrops Anaheim division ; number of operations can be performed from single setup posi- tion ; machine used for manufacturing main housings of range finders, machining jigs and fixtures for productiou of optical instruments, etc. ; how positioning cycle operates. Machine-Control Gaging, L. O. HEINOLD, JR. Machy (N.Y.) v63 n3 Nov 1956 p 217-22; Machy (London) v90 n2308 Feb 8 1957 p 299-303. Discussion of gaging which performs functions of inspecting work, changing speed or direction of machine tool spindle or slide, and signaling needed resetting of machine tool member ; in-process and post process gaging : four available control systems in- clude pre-process gaging, combination gaging, electric and air electric, and electronic and air electronic gaging systems. Kontinuierliche Pruefmethoden in der industriellen Fer- tigung (Continuous Testing Methods in Industrial Manu- facturing), M. DUEHMKE. Metall vll n7 July 1957 p 579-82. Continuous testing methods in work shops, par- ticularly in interchangeable manufacture ; statistical con- trol by sampling; built-in control apparatus in machine tools ; examples of most recent developments in continuous automatic control. A Critical Evaluation of High-Precision Electromechani- cal Linear Measuring Systems, F. BROUWER. Elec Mfg v60 n2 Aug 1957 p 128-41 28 figs 5 refs. Discussion of accuracy, linearity, resolution and sources of error in posi- tion measuring transducers suitable for closed loop ma- chine tool controls, including : differential transformers and capacitors ; linear potentiometers ; ultransonic sys- tems ; lead screw and rack systems with rotary signal pickoffs ; optical systems : digitally coded scales ; and pro- prietary Pratt & Whitney "Electrolimit", Farrand "In- duetosyn" and Canadian Westinghouse "Nultrax." Dimensional Controlling Systems, R. A. SOULER. Auto- |i mat v4 nil 1957 p 76-80, v5 nl 3 Jan 1958 p 81-4, Mar p 73—4. Nov 1957 : In-Process Gaging Provides Reliable Machine Control. Jan 1958 : Post Process Gaging Pro- vides Versatile Machine Control. Mar : Combination Gag- ing Systems. Basic Gages and Gaging Considerations for Automatic Machine Control, J. W. HOPPER. ASME-Paper n58- AUT-6 for meeting Apr 14-16 1958 4 p. Consideration of basic concepts of measuring manufactured parts, specifi- cally for purpose of controlling manufacturing machine ; problems of compartor type gages and control systems ; air gaging ; electromechanical-type gaging ; precision gaging. Gage Modules Advance Machine-Control Design. Elec Mfg v62 nl July 1958 p 110-13, 258. Adaptation of basic design principles, such as modular construction, plug-in component and connects, and sliding panel circuit sub- assemblies to gaging instruments and controls; applica- tion of gages to machine tools, parts segregation systems, and automatic assembly machines. Instruments for the Control of Kinematic Accuracy of ; Linkages and Machine Tools, B. A. TAITS, V. P. KOROT- KOV. Meas Techns 1959 n6 June 1960 p 406-10 7 figs. Translated from Izmer Tekh n6 June 1959 p 12. De- scribes instruments for the accuracy control of linkages 262 and machine tools and, especially, the method without standards provides for a high-accuracy control of the kinematic accuracy of gears, lead screws, and kinematic chains. However, a further improvement is necessary. An Automatic Method of Ensuring Accuracy of Dimen- sions in Centerless Grinding, S. S. VOLOSOV, G. B. TURBIN. Meas Techns 1960 n5 Jan 1961 p 379-81 2 figs 1 ref. Translated from Izmer Tekh n5 May 1960 p 7-9. Discusses limitations of self-adjusting systems of active automatic control and prerequisites to successful appli- cation. Automation Development — Machine Tool Trends, D. F. GALLOWAY. Machy Market n3140 Jan 19 1961 p 21-2. Example notes First State Ball Bearing Plant, Moscow, where automatic line comprises 150 machine tools, heat treatment furnaces, assembly presses, inspection equip- ment, and unit for greasing and packaging, all connected by handling devices ; problems in work handling, from machine to machine, with regard to feedback and numeri- cal control systems, and design of tool elements in relation to automatic control are considered. Abstract of paper before Instn Mech Engrs. An Automatic Electronic Coordinate Measuring Equip- ment for a Heaw Boring Machine, E. L. ABRAMZOM, G. L. GRIN, A. Y. PELIKS, S. S. PODLAZOV. Meas Techns 1960 n7 Feb 1961 p 579-83 6 figs. Translated from Izmer Tekh n7 July 1960 p 20-4. Equipment for measur- ing displacement coordinates, both vertical and horizontal, of heavy boring machine, by means of two circular induc- tive transducers, and reversible electronic counter which operates with decatrons. Automatic Control of Dimensional Accuracy in Internal Grinding, H. CH'ANGKEN. Meas Techns 1960 n8 Apr 1961 p 235-8 3 figs 2 refs. Translated from Izmer Tekh n9 Sept 1960 p 7-10. Describes method of measuring under optimum conditions by which it is almost possible to eliminate completely the effect of allowance variations on the accuracy of the ground ring diameters. It is pos- sible to grind details without subsequent precision grinding. Staveley Group Research Department, P. A. SIDDERS. Machy (London) v98 n2534 June 7 1961 p 1309-12. Three main sections are concerned with mechanical engineering, control systems, and electronics ; examples of work given include studies dealing with hydrostatic nut and lead- screw system for traversing machine tool slide, research connected with stiffness of hydrostatic slides, use of Pers- pex models of machine tools to predict dynamic behavior of design, investigating hydraulic drives for machine tool feed systems, and tape-controlled contour milling machine. Ferrodynamic Transducers for Automatic Monitoring and Controlling Devices, M. D. GAFANOVICH. Meas Techns 1961 n2 Oct 1961 pTOO-4 3 figs 4 refs. Translated from Izmer Tekh n2 Feb 1961 p 8-12. Transducer de- veloped for angle of rotation into appropriate voltage, on basis of which new improved telemetering system has been designed and several computing circuits developed ; advantages of system, including better linear relationship between output emf and angle of rotation, etc. Developments in Moire Fringe Measurement Systems, A. T. SHEPHERD. Machy (London) v99 n2562 Dec 10 1961 p 1424-6. Machine tool control system is described which gives digital subdivision of Vmth of pitch and could be extended to %oth of pitch without use of carrier ; with 1000-line/in. grating system affords digit size of 50 or 100/un, which would meet all normal engineering require- ments including jig borer applications ; principle of operation. Success of TV on Open-Side Machine Leads to Use of Digital Read-Out, S. C. BROWN. Machy (N.Y.) v68 n7 Mar 1962 p 89-91. Examples of machining jobs done at Waterbury Farrel Foundry & Machine Co. by television read-out on Ingersoll open-side milling, boring, and drilling machine whose movable column provides 22 ft of longitudinal and 6 ft of cross travel, with 5 ft of boring-bar feed ; 78- by 78- by 24-ft split-table, planer type milling machine, by employing Norden multiple-axis measuring system with digital read-out, eliminates guess- work as factor in setting machine positions. Automatically Controlled Machine Tools, C. A. SPARKES. Chartered Mech Engr v9 n6 June 1962 p 298-305 40 refs. Review considers automatic features of machine tools in 3 broad groups ; single-purpose unit is often highly auto- mated ; in various combinations, it is used for mass pro- duction ; modern universal center lathes, milling and planing machines, drillers and grinders are used for sev- eral types of operation but, to keep cost down, automatic features are kept to minimum ; third range of tools, often high in capital cost, incorporate features intended to reduce to minimum cost of components produced. Wide-Range Pneumatic Instrument for Automatic Check- ing of Dimensions (during Machining) , E. I. PED'. Meas Techns 1961 nl2 June 1962 p 949-51 3 figs. Translated from Izmer Tekh nl2 Dec 1961 p 12-4. Presents experi- mental and theoretical investigation of a new pneumatic measuring system having wide measuring limits applied for automatic checking of the dimensional parameters of components during machining. Digital Techniques in Precision Dimensional Measure- ment, R. J. MARMORSTONE. Automatic Control vl7 nl July 1962 p 32^. Review of electromechanical shaft po- sition encoders with sliding contacts: typical encoder applications for measurement and control in machine tool industry and for general laboratory use. Some Performance Limiting Features of Machine Tool Control System, A. COWLEY. Int J Mach Tool Design & Res v2 n4 Oct-Dec 1962 p 379-92. Simplified linear considerations, giving reasonable indication of system response, are discussed ; effects of principal nonlinearities within servo loop considered ; describing function is useful tool for dealing with single nonlinearities and will usually provide results with accuracies better than 50% ; if effect of several nonlinearities acting simultaneously is to be predicted, then use of analog computer may be necessary and is certainly desirable. Automatic Position-Setting, Aircraft Prod v24 nlO Oct 1962 p 350-8. GSP-Matic machine, installed at works of Sperry Gyroscope Co, Ltd, is highly ingenious and un- orthodox example of numerically controlled machining systems ; developed from jig-borer, it has two spindles and is fitted with automatic tool changing system ; one spindle is for heavy duty machining, other high speed spindle for lighter work ; all machine functions, including tool chang- ing, are programmed on 35-mm film. Computerless Programming vs Simple Control System and Simple Computer, R. CLEGG. ASTME Creative Mfg Seminars-Tech Paper SP63-42 Dec 1962 5 p. What nu- merical programmer must do to produce tapes required : features of computer routine ; computerless programming is considered desirable at start of numerical control ; after using variety of numerically controlled equipment, com- puter may become useful by simplifyinng programming for all numerically controlled machines; therefore, ques- tion is really computerless programming versus computer programming. New Photo-Optical, Random-Access Memory, W. RENOLD. Soc Photographic Instrumentation Engrs J vl n2 Dec 1962-Jan 1963 p 44-8. New concept for high capacity rapid access and readout photo-optical data stor- age system, combining recent advances in precision film movement with extreme accelerations, new optical-elec- tronic scanning methods, and digital positioning tech- 263 771-846 O— 66 niques developed for automatic machine tool control; integration of elements into system is described; imme- diate and potential capabilities are discussed; diagrams are included. Ferranti Mk. IV Continuous Path Phase Control System, D. F. WALKER. Int J Machine Tool Design & Res v3 nl Jan-Mar 1963 p 61-73. Background of Mk. IV system which was developed to supersede original continuous path tape control unit and to exploit benefits to be gained from use of transistors in place of thermionic valves ; measuring system described; block diagram of complete control system is shown along with some control wave- forms: design features; continuous path system was de- signed to automate small quanity production work where conventional mass production techniques are not applica- ble for economic reasons; applications indicated. Numerical Control of Machine Tools, D. F. WALKER. J Instn Elec Engrs v9 Feb 1963 p 61-5. Discussion of nu- merical control as system particularly suitable for small quantity production ; error checking and correcting, and measuring systems ; future trends. Pneumatic Contactless Instrument for Automatic Control in the Course of Machining, E. I. PED', A. V. FEDOTOV. Meas Techns 1962 n8 Feb 1963 p 639-40 3 figs 1 ref. Translated from Izmer Tekh n8 Aug 1962 p 16-7. De- scribes an automatic pneumatic instrument for produc- tion control which is equipped with a liquid manometer as an indicating device. Survey of Techniques Evolved for Measurement of Posi- tion in Numerically Controlled Machine Tools, R. BELL. Radio & Electronic Engr v25 n3 Mar 1963 p 207-24 64 refs. Techniques employed in numerical control of machine tools are reviewed ; they are classified into basic groupings of analog and digital, and then according to mode of operation of transducer ; inherent sources of error are discussed. Big Tables Ride N/C "Cushion" for Accurate Positioning. Iron Age vl91 nlO Mar 7 1963 p 140-1. Numerical posi- tioning control system guides table along horizontal and vertical planes ; it has already been applied to 30 ton Wiedemann press, where it positions large steel panels for turret punching; system designed by Cutler-Hammer, Long Island, N.Y., moves 2-ton table mass from "dead still" to speed of 600 ipm in only Vio sec ; it places work- piece under right punch with positioning accuracy of 0.006 in. ; punched tape controls all machine operations in automatic, or normal mode. Instrument for Automatic Control of Dimensions of Arti- cles with Discontinuous Surfaces, B. N. MARKOV, E. I. PED'. Meas Techns 1962 n9 Apr 1963 p 722-5 1 ref. Translated from Izmer Tekh n9 Sept 1962 p 9-11. Con- tactless pneumatic instrument with large measuring range developed by Moscow Machine Tool Inst for automatic control of parts during machining at low speeds. Magneto-Optic Positioning, R. J. MELTZER. IEEE Trans Indus Electronics vIE-10 nl May 1963 p 46-56 27 figs 4 refs. For accurate production of scales and grids it was necessary to develop device which would locate lines with precision better than 1/ain. ; system is described that ac- complishes this by forming image of line with polarized light, whose angle of polarization varies with position of line. Inside Mark Century Numerical Controls, J. T. EVANS, L. U. C. KELLING. Control Eng V10 n5 May 1963 p 112- 17. Design of Gen Elec Co positioning and contouring numerical control system that uses binary-coded-decimal computation throughout ; controls obtain high feed speeds (up to 500 in./min) with increments of 0.0001 in. ; absolute coordinates are used for positioning, and departure co- ordinates for contouring. Effect of Servomechanism Characteristics on Accuracy of Contouring Around Corner, H. E. VIGOUR. IEEE Trans on Applications & Indus v82 n66 May 1963 p 120-4. Servo- mechanism errors in 2-dimensional contouring system are analyzed to determine position error of tool center nego- tiating corner formed by 2 straight lines ; results establish feed rate which will permit specified tolerance on path error to be met; transient response information from analog computer tests is summarized in nomographic form to permit convenient consideration of maximum tool center path error during design of servomechanisms. Paper 62-250. Application of the Television Computing Technique in Automatic Control of Dimensions, V. S. VIKHMAN. Meas. Techns 1962 nil June 1963 p 904-8 6 figs. Translated from Izmer Tekh nil Nov 1962 p 9-14. Describes a system which amounts to the automation of known production control methods. Tests have shown that the system oper- ates with stability and very few adjustments during operation. Technological Requirements of Machine Tool Manufac- turing System, R. R. WEBER. Int Prod Eng Res Conf Proc Sept 9-12 1963 p 556-60. Published by ASME. De- sign, control, machining and part acceptance are con- sidered as necessary parts of fully integrated and auto- matic system ; role of numerical control in element of de- sign is discussed ; some problems in area of control are considered where applications can be made of current knowledge and where additional research is necessary to complete evolution of machine tool manufacturing system. Measurements and Control, V. Y. KNELLER. Meas Techns 1963 n3 Sept 1963 p 181^i 11 refs. Translated from Izmer Tekh n3 Mar 1963 p 1-4. Conclusions derived are that measurement and control (and correspondingly automatic measurement and automatic control) are dif- ferent processes distinguished by their objective and final results, and representing as a whole different forms of information transformation. The suggested definitions of measurement and control reflect these characteristics. Measurement can form part of an intermediate trans- formation in a control process. A clear conception of each of these processes, together with an understanding of their common features, will help to systematize the accumulated practical data, to understand the trends of development in automatic measurements and control, and to determine the tasks of further research. Television Methods of Controlling Dimensions, O. D. BYCHKOV. Meas Techns 1963 n5 Nov 1963 p 372-5 2 figs 21 refs. Translated from Izmer Tekh n5 May 1963 p 6-9. An article reviewing various methods. DIG, a Long-Travel Ultraprecise Absolute Reading Digital Linear Measuring Instrument. Bausch and Lomb, Rochester, N.Y. 1964 8 p 4 figs. See abstract under 1.2.1. The Use of Encoders in Machine Tool Control Systems, F. J. ROBINSON. Machy (London) vl04 n2668 Jan 1 1964 p 12-9 7 figs. Discusses types of control systems, methods of feedback, the Baldwin encoder, coding, and position control system using encoders. Measurement for Control, N. ANDERSON. Instrum Con- trol Syst (USA) v37 n8 Aug 1964 p 103-12. A review of the most common types of transducers that have an output suitable for use in control systems. 264 Controlling Workpiece Accuracy, R. TILLEN, NPL. Sept 1964 19 p 15 figs 24 refs in 2 parts. Part 1 is a review of known commercial and experimental techniques, including direct in-process measurement of diameter, in- direct in-process measurement, and comparison of direct and indirect in-process measurement. Part 2 is a first report on work at NPL on measurements during turning, including design considerations applied to NPL proto- type turning gage, experimental results obtained with such gage, and conclusions. Air and Electronic Gaging, J. J. DWYER, JR. Am Mach Special Rept n558 Oct 12 1964 16 p. Discusses the basics of air gaging; typical manual air-gaging applications; electronic gaging, automatic size control, gaging, and sorting. 12.4. Grinding Continuous Reading Grinder Caliper, H. K. SPENCER. Am Mach v25 Oct 5 1911 p636-8 6 figs. An amplifying gage of which the table of a rotary surface grinder is the work support. The rotary work table carries the pieces, which are being ground, alternately under the wheel and the measuring contact, so that each piece is measured after evey pass under the wheel. Die Grundlagen des Schleifens (Principles of Grinding), C. KRUG. VDI Zeit v71 Aug 6 1927 p 1109-16 36 figs. Classification of types of grinding, from rough to finest ; physics and technology of grinding process studied with aid of microscope ; structure and design of grinding wheel ; analytic and experimental study of details of grinding ; list of technical problems requiring study. Precision Surface Grinding, E. C. LARKE, F. C. SMITH. Machy (London) v31 Dec 8 22 29 1927 Jan 26 Feb 2 23 1928 p 308-12 391-4 422-3 545-7 579-81 673-5 48 figs ; also v32 Apr 26 May 31 June 7 1928 p 105-7, 265-7 294-5 25 figs. Precision surface grinding dependent upon skill of operator, accuracy of machine, and correct composition of grinding wheel ; fundamental rules governing choice of wheels ; grades of wheels ; form of wheels ; mounting of wheels ; hollowing and cornering ; wheel speeds ; feeds, preparation for lapping; swiveling angle plate; magnetic chucks ; producing accurate angles on wheels. Precision Cylindrical Grinding, R. E. W. HARRISON. Machine-Shop Prac (ASME Trans) v51 n24 Sept-Dec 1929 p 133-7 8 figs. Process of evolution through which preci- sion cylindrical grinding has passed during last eight years ; production dependent upon horsepower capacity of tool ; consequently its structure has been strengthened ; work handled on 54ip. machines in 1921, today being pro- duced in proportionately reduced time on 20-hp. machines ; still considerable work to be done ; comparative methods of metal removal ; production possibilities on controlled center-type machine. Alignment Tolerances on Precision Grinding Machines. Machy (London) v35 n890 Oct 31 1929 p 141-2 7 figs. Description of range of special alignment test developed by Churchill Machine Tool Co., Manchester, for all classes of precision grinding machines ; method of checking per- pendicularity of wheelhead slideway vee; cheeking align- ment of table as it travels along ways ; checking alignment of wheelhead spindles with bed slideways in both verti- cal and horizontal directions ; tolerances met on Churchill Cincinnati grinding machines. Technique of Size Control in Precision Grinding Opera- tions, R. E. W. HARRISON. ASME Advance Paper meet- ing Oct 3 1932 16 p 2 supp plates ; Am Mach v76 Oct 12 1932 p 1065-7 ; Iron Age vl30 Oct 13 1932 p 570-1 16 18 20; Machy (London) v41 Oct 6 1932 p 11-4 Oct p 37-9; Abrasive Indus vl3 Nov 1932 p 13-5 and Dec p 14-7 v!4 Jan 1933 p 15-7 22; Western Machy & Steel World v24 n2 Jan 1933 p 10-7; Indus Standardization v3 nl2 Dec 1932 p 299-305 and v4 nl Jan 1933 p 10-7. Use of limit system as major key to cheap manufacture ; functions of precision grinding machine and design factors which make for ease of size control. Profile Grinding Machine for Tools and Gages, O. P. VAN STEEWEN. Machy (N.Y.) v39 n6 Feb 1933 p 411-3. Operating characteristics of grinding machines developed by Loewe Gesfuerel of Berlin, Germany, with particular regard to accuracy obtained by pnofile-copying system using pantograph with ratio of 50 to 1. Electric Sizing in Grinding, A. V. MERSHON. Mech Wld v93 n2414 Apr 7 1933 p 335-6. Automatic sizing control developed by Gen Elec Co., Schenectady, which has been adopted by sections of American machine-tool industry ; single electric gage head has pair of coils which are used to produce deflection on indicating instrument while work- piece is being ground to size. Precision Profile-Grinding Machine. Eng vl39 n3601 Jan 18 1935 p 58-9 supp plate. Machine made by Loewe Gesfuerel, Berlin, it is claimed, reduces time required to form complicated profile on tool or gage to fraction of that required by usual methods; principle is that of em- ploying pantograph with tracing point on its long arm and microscope, with cross lines in its field, on its short one. Measurement During Machining and Automatic Sizing, H. C. TOWN. Eng vl39 n3603 3606 Feb 1 1935 p 107-8 and Feb 22 p 189-90. Feb. 1 : Details of automatic measuring device introduced few years ago by H. W. Kearns and Co, known as Insulater dial traverse indicator; with increas- ing accuracy demanded, Kearns now prefer to fit vernier scales on high precision Chesterman rules accurate to within 0.0005 in. in 4 ft. of length. Feb 22: Pneumatic micrometer developed by Solex Ltd. Precision Grinding Machine for Small Cylindrical Parts. Eng vl40 n3627 July 19 1935 p 62-3. Machine made by Loewe-Gesfuerel A-G, Berlin, intended for work ranging from 0.02 in. to 1.18 in. in diam only ; proportioned and constructed that within these limits, very high degree of accuracy of 0.00039 in. in error can be consistently obtained. Five Theorems for a Mechanical Surfacer, C. DEVE. Rev Opt vl5 June-July p 201-14 and Aug 1936 p 241-57. A machine for grinding surfaces is described and its mech- anism provides means for realizing new parameters and gives uniform use for the optical manufacturer. The theory of the instrument is explained in a series of five theorems and their principal applications are set out. Extreme Precision is Required in Gage Grinding. Abra- sives vl8 Sept 1937 p 9. Illustrated description of a few of the grinding operations at tool making plant of Taft- Pierce Mfg. Co. giving the size, kind, and grade of grinding wheel, and its speed for grinding a typical thread gage. Size Controlling Device for Internal Grinding Machines. H. A. DUDGEON. Machy (London) v60 nl537 Mar 26 1942 p 238-9. Description of device having light control wheel, attached to spindle running freely in bearings, which is placed in position close to end of work piece so that periphery of grinding wheel touches periphery of control wheel exactly when grinding wheel is in position for finishing hole; contact between grinding and control 265 wheels causes latter to revolve, thus opening or closing electric circuits which perform pre-arranged function. How to Secure Fine Surfaces by Grinding, H. J. WILLS, H. J. INGRAM. Machy (N.T.) v50 n5 6 7 8 9 10 11 Jan 1944 p 173-5. Feb p 167-70, Mar p 211-13, Apr 159-60, May p 181-2, June p 173-5, July p 208-9 ; Machy (London) v64 nl640 Mar 16 1944 p 294-6, v65 nl661 1663 Aug 10 1944 pl49-52 Aug 24 p 210-2. Jan : Balancing grinding wheels ; conditions responsible for chatter marks ; methods and equipment employed to balance wheels ; arbors equipped with balancing weights. Feb : Functions of coolants used in grinding; properties of different types of coolants and method for securing their most effective use. Mar : Fun- damentals of lapping. Apr : Machine lapping operations. May : Details of lapping operations in tool room. June : Production lapping of ground internal and external cylin- drical surfaces. July : Lapping operations as applied to production of gears and worms. Accurate Grinding Depends Upon Correct Location of Surfaces, S. H. NEADY. Am Maeh v88 n21 Oct 21 1944 p 110-12. Difficulty in securing correct lateral dimensions or correct relationship on ground parts is frequently due to incorrect use of multiple locating points; article gives specific case examples and illustrations showing methods of locating surfaces correctly. Surface Grinder Attachment Generates Involute Gears. Iron Age vl70 July 31 1952 p 87 1 fig. Describes a new universal involute gear generator for attachment on sur- face grinders. Only standard grinding wheels are re- quired. A wheel dressing unit is part of the attachment. Basic Gear Grinding Methods Compared, D. W. BOT- STIBER. Iron Age vl70 Aug 7 1952 p 118-21 6 figs. Grinding can correct gear tooth form and spacing errors. It is particularly useful after hardening. Each of the three basic methods — form, line, and point grinding, has advantages and limitations. Hardened and ground gears can make transmissions 50 percent lighter, 40 percent smaller, and cheaper than unground gears of equal capacity. How to Calculate Exact Wheel Profiles for Form Grinding Helical-Gear Teeth, O. SAARI. Am Mach v98 nl9 Sept 13 1954 p 172-5 3 figs 3 refs. In form-grinding helical gear teeth the exact wheel profile is not reproduced anywhere on the work. The article shows how the correct wheel profile and its radius of curvature at. any point can be calculated by an exact mathematical method. Formulas are derived for computing the coordinates, pressure angle, and radius of curvature of the cutter form. A numerical example shows how to use the computed data in establish- ing the settings of the radius-dressing fixture. Grinding Round Within Millionths, R. LEGRAND. Am Mach/Metalworking Mfg vl06 n26 Dec 24 1962 p 51-3 5 figs. New Highs in grinding accuracy — grinding round within ten millionths on a revolving spindle headstock — are now possible with the hydrostatic bearing, a develop- ment which has been around since 1907, but which has come into its own as a metalworking tool relatively re- cently. Hydrostatic bearings, which support the head- stock spindle by floating it on opposed pads of high-pres- sure oil, attain extremely high grinding accuracy through counter-balancing of oil pressures. The slightest off-axis movement of the spindle builds up pressure in one pocket and reduces it in the opposed pocket. This fact buildup of force limits the off-axis movement of the spindle to millionths of an inch. That is why, with the hydrostatic bearings, it is possible to produce OD, ID and face di- mensions that are round, concentric and square within plus or minus 10 millionths — or even less. At the moment, such superfine grinding is more or less limited to manu- facture of missile servos, gyroscopes, gimbals, gages and the like. Here the idea is to attain the correct geometry and an ultrasmooth finish to closer limits and at a lower cost through the use of hydrostatic bearings. But by now enough field experience has been racked up with these bearings that their future potential in the fine grinding field can be evaluated. Automatic Instrument for Combined Grinding, A. V. VYSOTSKII. Meas Techns 1962 nil June 1963 p 909-11 2 figs 2 refs. Translated from Izmer Tekh nil Nov 1962 p 14-5. Embodies a differential pneumatic pressure gage, one branch of which measures the diameter of a shaft dur- ing machining while the other branch is connected to a device for measuring the diameter of a hole to which the shaft is to be matched. 12.5. Lapping Laps and Lapping, W. A. KNIGHT, A. A. CASE. Trans ASME v37 June 1915 p 297-338. An investigation of the cutting properties of abrasives when used with different laps and different lubricants. Comment, Aug 1915 p 976. Accurate Lapping, L. J. VORHEES. Am Mach v53 Aug 5 1920 p 263-5 3 figs. Instructions for gage lapping and for making laps. Material for laps, work speeds, lapping screw threads, plain plugs, and flat surfaces. Modern Lapping Practice. Machy (N.Y.) v27 Nov 1920 p 209-17 19 figs; Machy (London) vl7 Nov 4 1920 p 129- 37 19 figs. Developments in lapping practice, including abrasives used in lap-charging methods, lapping thread gages, snap gages, measuring wires, flat surfaces, ring gages, die-casting dies and T-slots. Hand and Machine-Lapped Surfaces as Seen through a Microscope. Machy (N.Y.) v28 Apr 1922 p 638-9 6 figs. Illustrated study by Pratt and Whitney Co. of the char- acteristics of different surfaces, as obtained by various methods of lapping. Machining and Lapping Very Deep Holes, J. B. ROSE. Mech Engr v44 Dec 1922 p 807-12. Discussion of shop operations in the forming of very accurate and highly finished cylindrical holes. Precision Lapping, W. E. HOKE. Machy (N.Y.) v31 Apr 1925 p 593-6 1 fig; Machy (London) v26 1925 p 4. Lap- ping abrasives and methods, and use of double type of lap for plane parallel surfaces. Precise Cylindrical Lapping, P. M. MUELLER. Mech Eng v47 Sept 1925 p 701-4 11 figs; Machy (London) v27 1925 p 16 ; Am Mach v62 1925 p 749 and v63 1925 p 439. Method of production ; preparation before lapping ; prepa- ration of laps ; lobing ; measurement, international tests. See also abstract in Machy (N.Y.) v32 Sept 1925 p 60-2 3 figs. Moline Automatic Cylinder Lapping Machine. Machy (N.Y.) v33 Dec 1926 p 305-6 3 figs. Latest automobile- cylinder lapping machine developed by Moline Tool Co. with view to making operation as nearly automatic as possible. Maintaining Precision in Production Lapping, S. PLAYER. Machy (N.Y.) v36 May 1930 p 686-8 4 figs ; Iron Age vl25 Mar 27 1930 p 943 ; Abrasive Indus vll May 1930 p 23-6 4 figs ; Automotive Indus v63 Dec 20 1930 p 906-8 5 figs ; Machine Shop Practice (ASME Trans) v52 n24 Sept-Dec 1930 p 167-70 4 figs. Description of equipment and pro- cesses ; flat or cylindrical parts are lapped by machine to tolerance of 0.00002 in. ; 500 piston pins per hour being lapped ; limits of 0.0001 in. for straightness and round- 266 ness ; stock removed during roughing 0.0002 to 0.0004 in. ; for finishing from to 0.0002 in. over high limit of finished piece. Progression of Commercial Accuracy — Turning, Grinding, Lapping. Grits and Grinds v22 n2 Feb 1931 p 1-8 9 figs. Origin and development ; fields for use ; advantages ; methods. Zur Kenntnis des Schleif- und Polier-Vorganges ( Study of grinding and polishing process), L. HAMBURGER. Zeit Metallkunde v25 n2 Feb 1933 p 29-32 Mar p 58-62. At- tention is called to deceptive appearance of polished sur- face ; comparison of grinding and polishing processes ; deformations as result of polishing and grinding ; theoreti- cal principles of polishing ; factors influencing process ; change in properties of surface layers due to grinding and polishing. Bibliography. Production of Optical Flats. Machy (London) v56 nl454 Aug 22 1940 p 625-8 ; Eng vl50 n3905 Nov 15 1940 p385-6 and 390 supp plate. Methods employed at factory of Opti- cal Measuring Tools Ltd ; primarily, optical flats are de- signed for gaging differences too small to be detected by standard micrometer ; in practice it is possible to detect with ease differences of 0.00001 in. directly, or from 0.00001 in to 0.000005 in. by estimation ; preliminary opera- tions on quartz crystal ; finish grinding. Optical Flats by Mass Production. L. P. JACKSON. Iron Age vl48 n9 Aug 28 1941 p 42-4. Elimination of hand lap- ping operations in making optical flats has effected con- siderable savings in their production time and cost, thus making manufacture of these surface gages practical for general industrial production. Lapping Center Holes for Accurate Grinding. R. N. CLARK. Grits & Grinds v34 n6 June 1943 p 8-10. De- scription of lapping machine for grinding center holes, which handles work up to 36 in. long and 10 in. diam, with spindle speeds varying from 665 to 4300 rpm : machine operates similar to drill press, with work resting on vertically adjustable center, while spindle which carries lapping stone is brought down by hand lever ; entire mov- able spindle assembly is counterweighted to provide sensi- tivity to lapping pressure. Flatness and Parallelism in Quartz Plates, C. M. THURSTON. Bell Lab Rec v22 nlO 11 June 1944 p 435-9 July p 452-3. June : Description of lapping machine used for surfacing crystals. July : Design of hand lapper and outline of new technique which gives much improved results. Superfinishing by Lapping, F. M. BURT. Mill & Factory v36 n3 Mar 1945 p 96-100 306 310. In superfinishing measurements are made in millionths of inch ; incredibly fine tolerances of this magnitude are generally produced by precision lapping methods and measurements are made by light bands ; superfinishing processes as performed by company with experience in this field, are explained. Closer Dimensional Control, G. E. STEDMAN. Machine Tool Blue Book v42 nl Jan 1946 p 149-50 152 154 156. Developments in precision and dimensional control as ap- plied in manufacture of precision instruments and ma- chines ; detailed description of micrometer lapping ma- chines and precision thread lead finder developed and employed at N. A. Woodworth Co. Ferndale, Mich ; con- struction, operation, application and performance dis- cussed. How Russians Lap Carbides. Am Mach v90 n7 Mar 28 1946 p 138. Details of machine and methods developed for lapping brazing face surface of cemented carbide inserts for cutting tools ; machine operates on optical shop method principles and batch grinds inserts by oscillated motion of disks on eccentric driven swing frame ; machine con- struction and operation illustrated. Investigation of Lapping Process, F. EUGENE. Indus Diamond Rev v7 n75 76 Feb 1947 p 35-40, Mar p 67-71 ; Engrs' Digest (Am Ed) v4 n9 Sept 1947 p 403-8. Tests to determine: influence of period of testing; influence of hardness of metal tested ; comparison between abrasives ; influence of load and speed on abrasion ; abrasive prop- erties of lap in relation to time and usage ; wear of laps ; behavior of lap with reference to holding of abrasive ; com- parison between smooth and grooved laps. From Travaux et Memoirs du Laboratoire Central des Industries Mecani- ques 1945 p 9-33. Precision Lapping Centerless Method, P. L. SOMMER, JR. Tool Engr vl8 n3 Apr 1947 p 33-4 5 figs. Data concern- ing typical, complete unit cabinet type lapping machine, built by Size Control Co, Chicago ; simple but positive operating principle produces uniform precision finish to less than 2 mieroinches ; advantages of centerless over previously used ring lapping. New Lapping Technique is Economical, Accurate . . . In- creases Lapping Production by 55%, W. F. SCHLEICHER. Machine & Tool Blue Book v44 n8 Aug 1948 p 141-6. Features of process developed, by Crane Packing Co., Chi- cago, for superfinishing of faces of mechanical seals and closures, including design and operating details of Lap- master used in process ; machine eliminates grinding opera- tions between machining and lapping. Laeppen, die Grundlagen und ihre praktische Awendung (Lapping, the Fundamentals and their Practical Applica- tion), W. LAETZIG. Carl Hanser Verlag, Munich 1950 185 p illus, diagrs, charts, tables. Book deals with process of lapping all metallic materials with exception of cutting tools ; it covers lapping material and media, hand and machine lapping, lapping time and defects, kinematics of lapping and other allied aspects ; recommendations and examples are generally based on practical experiences and only in few cases on scientific research. Bibliography. Eng Soc Library, NY. Lapping Technique ; To Improve Image Quality of Elec- tron Microscope Lenses, F. A. HAMM. J App Phys vl2 n4 Apr 1950 p 271-8. Magnetic asymmetry or astigma- tism in objective lens is often due to imperfect machining, localized defects or impurities in iron, or grain anisotrop- ics ; lapping technique is described which effectively re- duces effect of imperfect machining or misalignment of components ; electron micrographs illustrating value of lapping procedure. Machine Lapping With Continuously Fed Free Abrasives, F. L. WHITE. Am Mach v95 nl2 June 11 1951 p 161-3. Important factors in machine lapping of flat surfaces to close tolerances for flatness and surface quality ; good re- sults obtained in short predetermined time controlled lap- ping cycles ; lapping machines arranged with wear rings providing continuous conditioning during lapping cycle ; pressure on work ; recommended abrasives ; stock removal rates indicated. Moderne Verfahren der meehanisehen Feinbearbeitung von Metallen (Modern methods for fine mechanical finishing of metals), H. H. FINKELNBURG. Metall v8 nll-12 June 1954 p 459-62. Honing and lapping : barrel grinding ; lapping with compressed air pistol ; immersion lapping. Machine for Lapping Centre Holes. Eng vl78 n4621 Aug 20 1954 p 249. Pillar mounted machine introduced by A. A. Jones and Shipman, designed for lapping centers, drilled in ends of shafts and other pieces, which have suffered slight distortion at time of cutting or by subse- quent hardening. 267 Ultrafinishing — New High-Precision Lapping Process, T. C. LEWIS, JR. ASME Trans v79 n7 Oct 1957 p 1699- 1706. Innovations which permit use of lapping for pro- duction of exceptionally smooth metal surfaces with pre- cise geometrical control ; technique includes necessary variations in velocity to permit lapping of soft homogene- ous and hard heterogeneous metals ; process can yield 0.3 to 0.5-microin. finish rms with overall geometry control equal to or better than any commercial finishing method. Finishing Surfaces by Vibration, R. C. HITCHCOCK, J. P. MORAN. Tool Engr v40 n4 Apr 1958 p 127-30. Pro- duction type vibratory lapping machines generate surface finishes as smooth as three ' microin. ; flatness is held to within three helium light bands ; productivity is high as compared to manual lapping; application of new tech- nique to bronze and stainless steel rings for mechanical shaft seals described. Whitworth Was Only Partly Right, R. J. RAHN. Am Mach vl03 n8 Apr 20 1959 p 112-13. 119 yr old three- plate matching system of Sir Joseph Whitworth for pro- ducing flat surfaces considered incomplete; how this established method, if followed literally, might easily pro- duce sections of spirals instead of flats; best modern method is to check with ten-millionths indicator. Investigating the Efficiency of Plane-Parallel Lapping of Gauges, A. M. VEDMIDSKII. Meas Techns 1961 n9 Feb 1962 p 642-4 1 fig 1 ref. Based on experimental data an empirical formula is developed giving the mean amount of metal removed per unit in plane-parallel mechanical lapping of gage blocks. However, at the beginning of lap- ping a more intensive removal of metal occurs. Plastic-Fabric Lapping Discs for Diamond Compounds. S African Min & Eng J v73 n3602 Feb 16 1962 p 367. Self- adhesive chemico-textile polishing disk, known as Hypro- cel, introduced as improved vehicle for diamond and other abrasive compounds used in lapping or polishing of soft, hard and very hard materials ; introduction represents major advance over other lapping cloths; Hyprocel is foam/fabric material composed of more than 50% chem- icals ; it is said to have excellent abrasive and lubricant retaining power. Centerless Lapping Smooths Its Wrinkles, R. G. PIERCE. Grinding & Finishing v8 n3 Mar 1962 p 42-4. Recent de- velopments which helped to improve Centerless Lapper; it can provide finish of 0.5 /t in. rms and tolerances down to 0.000005 in. ; recommended abrasives for centerless lap- ping ; 7 tips for improving quality of lapped work. Preliminary Study of Lapping Process, G. A. ALLAN, K. H. SUTHERLAND. Prod Engr v41 n4 Apr 1962 p 195- 202. Experiments on flat lapping carried out on 4 work- piece materials ; 60/40 brass, fully heat-treated aluminum alloy HE 30 WP, and two annealed carbon steels EN 9 and EN 24b were tested in order to ascertain effect of load on workpiece and speed of lap on stock removal rate and surface finish of workpiece; hardness of materials was obtained in order to see if this value correlated with any of results ; 36 in. Lapmaster machine was used for tests. Contribution Relating to Metallographic Study of Dis- turbed Metal Caused by Abrasion and Polishing, R. H. ATKINSON. Plating v49 n5 May 1962 p 485-9. Study of surface of brass, steel, nickel and palladium, polished with abrasives such as diamond, chromic oxide, alumina and rouge has revealed presence, hitherto unsuspected, of characteristic lines of very small "dots" which were found to be tears: formation of tears can be avoided by hand polishing; dark field illumination, which is particularly advantageous for detection of polishing tears with optical microscope, also enables much clearer pictures to be ob- tained of microstructures produced in disturbed metal by abrasion. Machining to 0.0000005 in. Steel vl53 n2 July 8 1963 p 58. Inside diameters are machined to half millionth surface finish at Taylor Devices, North Tonawanda, N.Y. » job in question concerns finishing cylindrical parts for liquid springs to be used in space programs of General Dy- namics/Astronautics ; after honing and polishing operar tions critical, 2 stage lapping process on specially designed machine is carried out with patented, thin Teflon lap covered with diamond particles ; lap, moving linearly, ex- pands uniformly from hydrostatic pressure within, to pro- vide surface finish of 0.0000005 in. Fine Art of Flat Lapping, C. STEAD. Am Mach/ Metalworking Mfg vl07 nl6 Aug 5 1963 p 78-80. Rec- ommendations for obtaining maximum results in flat lapping on semiautomatic machine; importance of close control over such variables as size, shape, weight and re- quired surface finish is emphasized. 12.6. Manufacture of Precision Measuring Tools and Components 12.6.1. General The Manufacture of Standard Thread Measuring Wires, F. R. DANIELS. Mach (N.Y.) v25 Mar 1919 p 606-7 4 figs. Table of values used for determining error in thread angle by the three-wire system. Also describes method of manufacture used by B. Seaboldt Corp. Gage Design and Gage-Making, E. OBERG, F. D. JONES. Industrial Press, N.Y. 1920 310 p 235 figs. Contents : De- veloping a gaging system ; snap and plug gages ; contour or profile gages ; flush-pin, sliding-bar, and hole gages : thread gages and their production ; making Whitworth thread gages ; grinding and lapping thread gages ; lead and diameter measurements on thread gages ; microscopic measuring machines for testing accuracy of contour and thread gages ; projection method of testing gage threads ; general gage-making practice. Making the Almond Micrometer, E. VIALL. Am Mach v53 nl4 Sept 30 1920 p 605-11 24 figs. Illustrates the mechanical processes of making the parts and discusses the extreme care and workmanship required. Accurate Tool Work, C. L. GOODRICH, F. A. STANLEY. McGraw-Hill Book Co., Inc. N.Y. 1923 29 chapters 300 p 327 figs. Also pub. as Tool and Gage Work. 1922. Con- tains chapters on making : master plates, accurate tapers, accurate index dials, thread gages, plug and ring gages, flat gages, and accurate squares. Manufacturing a Precision Tool, E. SHELDON. Am Mach v59 n25 Dec 20 1923 p 903-7 12 figs. Describes manufacture of micrometer caliper, including preparatory operations on frames and sleeve as one piece, threading the main and adjusting nuts, rigid inspection methods. Der Laeppvorgang bei der Herstellung von Messwerkzeu- gen (The Lapping Process in the Manufacture of Measur- ing Tools), C. BUETTNER. Werkstattstechnik v25 Mar 1931 p 113-6. Fundamental relations of various factors in lapping necessary for obtaining measuring surfaces of high quality ; relationship between tool and workpiece with particular regard to action of abrasive and lubricant. Balls for Bearings Are Last Word in Precision, H. T. MORTON. Metal Progr v35 n2 Feb 1939 p 149-55. His- torical review of evolution of present day ball bearing, tracing materials used, lowered tolerances in last 25 yr 268 for balls 2 in. and under, improvement of ball surfaces, and various stages in production of 3 in. steel balls for Grade I ball bearings. Manufacture of Precision Measuring Tools, A. E. MOR- RISON. Machy (London) v60 nl531 Feb 12 1942 p 81-4. Notes on state of precision tool industry in England ; dis- cussion on manufacturing methods, tolerances required, inspection and checking of micrometers, try squares, straight edges, etc ; improvements in micrometer design. Mechanical Problems in Setting of Spirit Levels, F. GROVER. Instn Prod Engrs J v21 n3 Mar 1942 p 123-36. Author undertook investigation of problems involved in construction of levels in general, and attempted to evolve simple technique for setting instruments of special form described ; review of fundamental principles and their ap- plication to specific ease. Precision Hole Location, J. R. MOORE. The Moore Special Tool Co. 1946 448 p 309 figs. Discusses hole loca- tion and early practices relating thereto, development of the jig borer with accurate lead screws, jig boring prac- tices, hole, grinding, and interchangeability in toolmaking. Notes on Gauge Making and Measuring, Metrology Di- vision, NPL, His Majesty's Stationery Office, London 2d ed. May 1946 73 p 38 figs, 4 parts 2 appendices. Part 2 on gagemaking. Covers selection of steel, machining the blanks, hardening, stabilizing, grinding, and special work- shop methods. On Sharpening of Microtone Knives for Ultra-Thin Sec- tioning, J. HILLIER. Rev Sci Instrum v22 n3 Mar 1951 p 185-8. Conventional methods of sharpening involve ex- tensive grinding primarily for removal of large nicks but which serves additional purpose of fitting knife to sharp- ening means ; since large nicks rarely occur in ultra-thin microtomy, grinding would become unnecessary if fitting of knife to sharpening means could be made permanent: how this may be done. A Precision X-ray Diffraction Spectrometer Ring, D. C. BARNES, C. WAIN WRIGHT, NPL, Machy (London) v84 n2149 Jan 22 1954 p 189-92. 5 figs 1 ref. The rota- table member carries a scale divided into degree and half- degree intervals. The scale is subdivided by a graduated drum mounted on a worm drive-shaft. Overall accuracy of angular setting is ±20" at any position of the rotatable member throughout 360° The design and construction are described. Cam Design on a Visual Computer, W. HOFFMAN. Indus Mathematics v9 1958 p 21-6 4 figs. The problem to be solved is the determination of the master cam outline for the production of a cam having previously determined lift characteristics on a cam grinding attachment. Anwendungsmoeglichkeiten von Lagerungen hoher Prae- zision (Possible Applications for High Precision Bear- ings), H. BECKER. VDI Zeit vlOO n29 Oct 11 1958 p 1398-1405. Increased accuracy required of modern in- struments leads to new combinations of structural parts by designer ; some examples are discussed and illustrated, e.g., optical dividing head, micromanipulator, microtome for ultrafine sections, etc. Determination and Correlation of Fundamental Instru- ment Bearing Parameters, T. P. BARNARD. R. S. GUY- ETTE. Lubrication Eng vl6 n2 Feb 1960 p 61-8. Paper shows why measurement and evaluation of dimensional, geometrical and performance qualities of miniature in- strument ball bearings requires use of ultra-precise in- struments ; development of Running Torque Tester, torque analyzer, and roundness comparator ; use of supporting instrumentation in determination and correlation of bear- ing, geometry, retainer, and surface finish analysis; dirt and lubrication analysis. The Effect of Mandrel Eccentricity on the Accuracy of Edge Cams, A. V. RUMYANTSEV. Meas Techns 1960 n5 Jan 1961 p 384-7 3 figs 6 refs. Translated from Izmer Tekh n5 May 1960 p 11-4. Present a mathematical analy- sis which shows that the effect of mandrel eccentricity on the accuracy of machining the working surface of a conoid amounts to a considerable and unavoidable quantity which must be taken into account when the cams are made. High-Speed Master Cams Generated Mechanically, R. E. CHENEY. Machy (N.Y.) v68 n2 Oct 1961 p 93-9, 148. Description of three-phase program by IBM Endicott, NY Development. Lab, to investigate and implement cam de- sign and cutting techniques ; new short run procedure en- ables hardened master cams for data processing machines to be generated and finished to radial accuracies of four decimal places ; computers provide design capabilities for establishing as many control points as needed to obtain necessary four-place accuracy in cam master model ; pro- cedure adopted as standard method for cutting master cams. Manufacture of Integral Ball Bearing Raceways, H. H. SHERRILL, Jr. Western Elec Engr v7 n4 Oct 1963 p 31-5. Method is presented for precision grinding and lapping in manufacture of bearing raceways for Nike Hercules guid- ance gyroscopes, to obtain design advantages of integral ball bearings ; roundness checking instrument and elec- tronic vibration analyzer used for precision grinding are described, along with lapping and grinding process, and evaluation of raceway curvature, geometry and waviness. Spheres Turned to Millionths. Iron Age vl92 nl6 Oct 17 1963 p 90-1 ; Am Mach/Metalworking Mfg vl07 nl8 Sept 2 1963 p 80-1. Machine developed by Brown & Sharpe especially for customer in atomic energy field, produces spheres up to 18 in. in diam within roundness tolerance of plus or minus 25 millionths; surface finish is very smooth ; spheres are sized with part-to-part repeatability of 0.0001 in. ; hydrostatic bearings used permit accurate positioning of workpiece and cutting tool and provide very stiff support for machine elements while in motion ; machine is reliable and very fast, turning out finished sphere in few hours. High-Accuracy Screws. Production Technology vl n8 Nov 1963 p 296-304. Procedures used in manufacture of recirculating ball-screws by Rotax Ltd for use in air- craft undercarriage mechanisms, and in machine-tools where low power servo motor drives for numerical con- trol and high resolution positioning are essential; assembly comprises shaft with semicircular helical groove, nut of corresponding threadform and steel balls; deflector plates in nuts, located between each complete revolution of threadform cause free rolling balls at end of turn to return to start of thread, thereby providing recirculating path for each row of threadform in nut ; thread whirling, hardening and thread grinding opera- tions applied ; equipment used and method of inspection. Unusual-Precision Bearings, H. HANAU, L. BURG- MEIER. Machine Design v36 n5 Feb 27 1964 p 148-53. Ball bearing systems are being produced that maintain erratic angular deviation within 1 arc sec and predictable angular deviation within 1.5 arc sec; however, specifica- tions of airborne guidance devices and optical systems demand limiting these deviations to less than 0.1 and 1.0 arc sec, respectively ; new production and assembly tech- niques for such highest precision bearings are discussed. New Instrument for Generating Angles to High Accuracy over 5-deg. Range, L. W. NICKOLS. Machy (Lond) vl04 n2677 Mar 4 1964 p 554-8. To overcome limitations of instrument, described previously, new instrument utiliz- ing same principle was developed at National Physical Laboratory, which enables angles up to 5° to be set out in increments of few seconds of arc ; diagram of kine- matic pivot arrangement for small-angle generator is 269 shown ; effect of errors on accuracy of angular measure- ment ; performance tests on instrument ; simplified method of calculating values of x required to set out angle a. Making of Spacers for Fabry-Perot Etalons, F. M. PHELPS III. J Opt Soc Am v55 n3 Mar 1965 p 293-5. The Fabry-Perot etalon is a versatile device but it is not widely used because of the high cost of its components if purchased from a commercial supplier. The author has developed a method of making spacers of excellent quality for a large diameter (60 mm) etalon for less than 10% of the typical price quoted by specialty houses which make them to order. While the spacers described here were made for use with the finest quality flats obtainable, the fact that 25.4 mm diam, 1/20 wavelength, optical flats are available for less than $100.00 per pair, means that a Fabry-Perot etalon is now within the reach of even the most impecunious physics department. Such an etalon can always be up-graded by purchasing better- quality flats ; no additional work on the spacers would be required. 12.6.2. Scales and Gratings See also subsection 4.1. Automatic Circular Dividing Engine, W. R. STAMPER, E. R. HALL. Phys Rev v3 Apr 1910 p 492-505. Illustrated description of the apparatus and of the method of calibra- tion employed. Precision in Instrument Making. Am Mach v33-2 July 7 1910 p 25-8. Illustrates and describes methods of extreme accuracy in measurement and division used in the manu- facture of standard scientific instruments. Building a Machine which Splits Millionths, D. M. LID- DELL. Am Mach v40 June 4 1914 p 969-73. A detailed description of the methods of making the screw, straight ways, and divided head of the Rowland dividing engine, with its maximum allowable error of two-millionths of an inch. The Circular Dividing Engine of Edward Troughton, 1793, D. BAXANDALL. Opt Soc Trans v25 1923-4 p 135-9. History of development and description of construction. Bibliography, 8 refs from 1768 to 1923. Ruling 15000 Lines per Inch, F. A. STANLEY. Am Mach v60 1924 p 161-6. Prepared by committee whose chair- man was Dr. Ames. A description of the dividing engines designed by Prof Rowland. Physical Papers of Rowland collected by Johns Hopkins Univ p 691. 3 machines, no. of teeth in the ratchet such that they rule 14,438, 15,020, and 20,000 lines in an inch. The 3 machines are kept in the sub-basement of the Physical Laboratory of Johns Hopkins University. Untersuchungen an einer Kreisteilmaschine (Investiga- tions of a Circular Dividing Machine), L. FRITZ. Zeit Instrumkde v46 June 1926 p 289-320 11 figs. Describes dividing machine of Geodetic Institute of Technical High School at Hannover ; illumination, microscopes, axial ro- tation, formation of rosettes, improvement in diameter, systematic and accidental errors. Accurate Graduating in Mount Wilson Shop, J. HOME- WOOD. Machy (NY) v34 Mar 1928 p 540-1 1 fig. Ma- chine for ruling diffraction gratings having 15,240 equi- distant lines per inch ; how diamond graduating tool is held and traversed ; obtaining indexing movement of 1/15,- 240 in. ; cross-slide which floats in mercury ; special thrust bearings and other constructional features. A Machine That Rules Fourteen Thousand Lines per Inch, E. F. BARKER. Michigan Technie v41 Mar 1928 p 17-8 25 2 figs. Machine to rule optical gratings; dis- tances marked off by parallel grooves of certain selected shape and depth with error of less than one millionth of inch ; machine resembles ordinary shaper ; two carriages ; tests of butt bearing and of screw thread ; optical tests of gratings ; preparation of diamond ruling points ; experi- mental gratings adapted for measurement of spectra. The Rowland Ruling Machine. Mech Eng v50 Apr 1928 p 294-8 3 figs. Details regarding mechanism and working of this historic precision dividing engine devised for en- graving lines of diffraction gratings; machine can be compared structurally to simple reciprocating steam en- gine ; it has flywheel, two-bearing crankshaft, connecting rod, crosshead, and slide which correspond in location to piston ; both technique of making mirrors and design of ruling machines have been somewhat modified and im- proved of late. The Manufacture of Steel Measuring Tape, F. W. HOBBS. Metal Indus (N.Y.) v26 Sept 1928 p 399-400. Manufac- ture of steel measuring tape is transfer and etching proc- ess, and consists briefly in filling etched surface of standard plate with acid-resisting paste, transferring it to etching tissue, and thence to blank steel line after which line is immersed in acid bath which eats away exposed parts having figures and lines in relief ; detailed descrip- tion of equipment and process is given. Graduating Machine for Special Rules and Gages, R. B. LOVELAND. Am Mach v73 Nov 20 1930 p 822 2 figs Hand-operated graduating machine and its operation. Machine for Dividing Scales of Varying Increment, B. M. DAVIES. J Sci Instrum vlO nlO Oct 1933 p 314-8. Di- viding machine incorporating special device for dividing thermometer and other scales of unequal increment; em- ploys flexible metal strip which can be set in given curve according to calibration of thermometer; curve of strip adjusts exact position of dividing tool in relation to work ; details of operation ; typical scale is shown. Machines for Ruling Diffraction Gratings. W. STONE, J Sci Instrum vl4 1937 p 309-11. The design of a type of machine is described which will reduce to a minimum the displacement of the lines being ruled, due to changes of temperature of the machine and of the plate on which the rulings are being made. Some suggestions for im- provements in the design and construction of machines for ruling diffraction gratings were made by the author in an earlier paper. Further improvements, particularly as re- gards expansion of the parts due to changes of tempera- ture, are suggested. Grayson Micro-Ruling Machine, W. STONE. J Sci In- strum vl4 Jan 1937 p 8-14. The principles involved in the design of micro-ruling machines are stated and it is shown how these principles were applied by Grayson in the design and construction of the machine which he made and used in ruling test plates with as many as 120,- 000 lines to the inch. The machine is described in detail. Rapid Calibration and Correction of Comparator Screws and Photographic Production of Scales, G. R. HARRISON. Rev Sci Instrum v9 Jan 1938 p 15-8. An automatic re- cording and computing comparator has been adapted to the rapid construction of uniform and non-uniform scales on glass by photography. With such a scale, the record- ing attachment of the comparator can be used to determine the correction curve for a screw in a few minutes. A three dimensional correcting cam may then be shaped to correct the errors found, and fairly cheap screws can thus be made to serve for precision measurements. Details of a method of mounting the screw and the comparator car- riage so as to reduce friction are given. Dividing and Ruling Scales, R. P. ABRAHAMS. J Sci Instrum vl6 July 1939 p 205-9. A general outline is given of modern methods of producing ruled scales, either singly 270 or iu quantity, on metal, glass, wood, or celluloid. The important elements of a dividing machine are discussed to- gether with the provisions necessary to reduce or com- pensate for errors. Reference is also made to those scales, reproduced on glass by photographic means which are now commonly employed as graticules in optical instruments. Graticule Ruling in Australia, M. SHAW. Instn Mech Engrs Proc vl60 n2 1949 p 145-52 (discussion) 152-3. Production of graticules or reticles for range finders, predictors, gun sights, telescopes, etc. under conditions prevailing in Dominion ; methods used in reproducing pat- tern, particularly ruling and etching process ; design of high precision machines which were made for ruling glass disks preparatory to etching pattern into glass ; machine accuracy tests. The Graduation of Precision Circles, B. L. PAGE, NBS. Surveying and Mapping vl3 n2 Apr-June 1953 p 149-61. See abstract in subsection 6.4. The Production of Accurate Linear Scales by Means of the Merton Nut, L. A. SAYCE. J. Sci Instrum v32 nl Jan 1955 p 11-2. A dividing engine is described for making linear scales of unusual accuracy. The scale is engraved photographically upon a plate carried by a Merton integrating nut riding upon a cylinder bearing a very fine screw thread. The cylinder is carried by bearings in which it is restrained from longitudinal move- ment by applying the principle of the Merton nut to a "thread" of zero lead. Interferometric Control of Grating Ruling with Continu- ous Carriage Advance, G. R. HARRISON, G. W. STROKE. J Opt Soc Am v45 n2 Feb 1955 p 112-21 10 figs 4 refs. See abstract in subsection 2.4.2. On Preparing Plastic Copies of Diffraction Gratings ; Ex- tension to Merton-NPL Process, G. D. DEW. J Sci Instrum v33 n9 Sept 1956 p 348-53. Process whereby num- ber of glass based plastic copies may be prepared from gelatine replica grating; these copies, considerably more stable than gelatine replicas, may be employed as transmis- sion gratings or aluminized and used by reflection ; by using plate glass blanks it is possible to reduce production costs while obtaining optical quality almost indistinguish- able from that of parent replica. Ruling of Large Diffraction Gratings with Interferometric Control, G. R. HARRISON, N. STURGIS, S. C. BAKER, G. W. STROKE. J Opt Soc Am v47 nl Jan 1957 p 15- 22 12 figs 14 refs. Describes mechanical features by which high accuracy has been attained. Precision Circular Scales. Nat Eng Lab. East Kilbride, Scotland June 1958 2 p. Extension of the moire fringe technique to automatic angular control has shown the requirement for circular scales having very large num- bers of lines. Automatic machine installed is capable of ruling scales accurate to 1 sec of arc. Controlled Ruling of Diffraction Gratings, G. R. HAR- RISON. Am Phil Soc Proc vl02 n5 Oct 20 1958 p 483-91. How, by using light waves to control diamond tool while it engraves grooves on aluminum coated mirror to pro- duce diffraction grating, quality of resulting grating can be improved and, if desired, its size increased ; half dozen gratings of high quality, 10 in. in ruled width, have been produced on such engine; resolving power of several of these gratings is found to equal that theoretically expected, in all orders up to and including highest obtainable with visible light. Interferometrically Controlled Ruling of Ten-inch Dif- fraction Gratings, G. R. HARRISON, N. STUYGIS, S. P. DAVIS, Y. YAMADA. J Opt Soc Am v49 n3 Mar 1959 p 205-11 10 figs 14 refs. Seven plane gratings of high quality, having ruled widths of more than 10 in., have been produced on the MIT servo controlled ruling engine, moni- tored with interference fringes. Discusses wavefront shapes, ghost and satellite intensities, etc. Attainment of High-Resolution Gratings by Ruling under Interferometrie Control, G. W. STROKE. J Opt Soc Am v51 nl2 Dec 1961 p 1321-39 83 refs. Theory of grating im- provements necessary for reduction of spectral-line im- perfections in gratings made on MIT ruling engine ; im- provements made in interferometric control of grating ruling give better performance by factor of 4 to 9 over 10-in. gratings described by G. R. Harrison and G. W. Stroke ; precision replicas permit high-resolution spec- trometer studies. Multi-section Gratings for Linear Measurement, G. D. DEW, NPL J Sci Instrum v39 1962 p 141-4 6 figs 2 refs. Describes recent improvements in the techniques of pre- paring multi-sectional gratings for moire-fringe measur- ing application. The system enables adjacent sections to be phased with accuracy of 5-10 £dn. and is applicable to gratings of the finest pitch employed in this work. A method of evaluating the phasing errors at the junctions is also described. Graticules and Pine Scales : Their Production and Appli- cation in Modern Measuring Systems, E. BOVEY. J Sci Instrum (GB) v39 n8 Aug 1962 p 405-13. See abstract under subsection 5.1. Ruling, Testing and Use of Optical Gratings for High- Resolution Spectroscopy, G. W. STROKE. Progress in Optics v2 North-Holland Publishing Co, Amsterdam, 1963 p 1-72 115 refs. Quality of gratings required for high-resolution spectroscopy, and means for obtaining such gratings by ruling under interferometric control are discussed ; highnresolution grating spectrometers and spectrographs are described ; contemporary methods for obtaining plastic replicas of gratings are briefly examined ; further improvements in quality and blaze of diffraction gratings, as well as in speed of ruling, are being made using electron microscopy and other control methods. Some New Advances in Grating Ruling, Replication, and Testing, R. F. JARRELL and G. W. STROKE. App Optics (USA) v3 nil Nov 1964 p 1251-62. A report on some significant recent advances in the art of grating rul- ing, blazing, replication, and testing, with a more detailed description of the construction and performance of a newly completed interferometrically controlled ruling engine re- cently put into operation. Ruling Engine with Hydraulic Drive, W. R. HORSFIELD. App Optics ( U'S A ) v4 n2 Feb 1965 p 189-94. The carriage of a ruling engine is driven by a hydraulic system servo- controlled by an optical interferometer, so that the posi- tion of the carriage i9 determined in terms of the wave- length of light. The arrangement is free from the errors of the conventional lead-screw system and is far cheaper to construct. A Method for Making Very Accurate Line Patterns for Photographic Reproduction, U. PICK. J Sci Instrum (GB) v42 n2 Feb 1965 p 120-1. A method is described for cutting a parallel line pattern in very thin metal films. The width of the cut lines is constant to less than 4X10" 4 cm and the edge definition is better than 2X10"* cm. Photographic negatives of similar accuracy can be produced by contact printing from the cut film. 12.6.3. Worms and Power Screws, Including Lead Screws (Leading Screws, Guide Screws [Leitspindeln], and Feed Screws) On a Practical Solution of the Perfect Screw Problem, W. A. ROGERS. Trans ASME v5 Paper nl46 1885 44p vl2 Paper n446 p 725-8. Discusses three classes of errors to 271 which screws are subject; a survey of the accuracy that had been attained ; and a new method of cutting screws. Das Frasen von Schraubengewinden (The Milling of Screw Threads), E. STUEBLER. Zeit fur Mathematik und Physik v57 1909 p 271-9 2 figs. Develops the geo- metric theory of producing a screw thread of a given form by means of a milling cutter. Screw, H. A. ROWLAND. Encyclopedia Britanniea 11th ed v24 1911 p 477-82 10 figs. With reference to lead screws the article contains sections on testing screws, errors of screws, and mounting of screws. Describes Rowland's machine for ruling gratings. Refers to Holtz- apffel's "Turning and Mechanical Manipulation" for early history of manufacture of screws. Cutter Shapes for Milled and Ground Threads, E. WILD- HABER. Am Mach v60 nl8 May 1, 1924 p 645-9 4 figs 1 ref. Presents an analysis of the relationships between the cutter and the thread which is important for worms and long-lead screws. Presents table of formulas for curvature radii for various threads and cutters. Cutting a Lead-screw of Unusual Accuracy, WM. GAERT- NER. Machy (N.Y.) v31 June 1925 p 808-10 5 figs. Methods used in producing precision screw about 4 ft. long with lead accurate within 0.00004 in. in entire length. Die analytische Berechnung des Gewinde-Drehstahlprofils fur steilgangige Schrauben und Schnecken mit geradem Achsenschnitt (The Analytical Calculation of the Thread Lathe Tool for Long-Lead Screws and Worms with Straight-Line Axial Section), W. F. VOGEL. Werk- stattstechnik v27 nl4 July 15, 1933 p 275-9. Classical equations proved to be only approximate; data on exact profile equations ; results of analysis ; relation between principal dimensions of thread and of cutting profile. Analytische Berechnung des Fingerfraserproflls fur steil- gangige Schrauben und Schnecken mit geradem Achsen- schnitt (The Analytical Calculation of End-Mill Profile for Long-Lead Screws and Worms having Straight-Line Axial Section), W. F. VOGEL. Zeit VDI v78 n5 Feb 3 1934 p 156-8 and discussion Oct 20 p 1222; Betrieb vl3 n9/10 May 1934 p 252 2 figs 3 refs. Error indicated in usual method for graphical determination of profile and correct method pointed out ; exemplification. Konstruction eines Erasers der eine gegebene Gegen- flanke erzeught (Construction of a Milling Cutter which Generates a Given Counterflank) O. BAIER. Zeit fur angew Mathematik und Mechanik vl4 n3 Aug 1934 p 248- 50 4 figs. Presents the principle of construction and a practical explanation of the construction ; also the proce- dure of the construction of the milling cutter by an example. Der Geradflanken-Drehstahl fiir steilgangige Schrauben und Schnecken mit geradem Achsenschnitt (The Straight- sided Lathe Tool for Long-Lead Screws and Worms with Straight Line Axial Section ) , W. F. VOGEL. Werkstatts- technik und Werksleiter v29 n6 Mar 15 1935 p 121-6 n7 Apr 1 p 135-40. Practical mathematical analysis for de- sign and making of tools ; limits of application. Gesetze und Berechnung der Mutterdrehstahle und Schlagmesser fiir steilgangige Schrauben und Schnecken mit geradem Achsenschnitt (Rules and Calculation of Internal Lathe Tool and Fly Cutter for Long-Lead Screws and Worms with Straight-Line Axial Section), W. F. VOGEL. Werkstattstechnik und Werksleiter v29 n20 Oct 15 1935 p 399-400. Theoretical design analysis and ex- emplification. Berechnung der Schneidflanken von Gewindedrehstahlen fur steilgangige Schrauben und Schnecken mit geradem Achsenschnitt (Calculation of the Cutting Flanks of Thread Lathe Tools for Long-Lead Screws and Worms of Straight Line Axial Section), W. F. VOGEL. Zeit VDI v79 n45 Nov 9 1935 p 1370-2 7 figs 7 refs. Consolidated report. Discusses lathe tools and impact tools with crooked cutting flanks ; the plane straight-sided tool ; the cross tool. Gewindedrehstahle und Schlagmesser fiir Schnecken und steilgangige Schrauben mit geradem Achsenschnitt. Er- mittlung und Verlauf der Schneidflanken. ( Thread Lathe Tools and Fly Cutters for Worms and Long-Lead Screws with Sraight Line Axial Section. Calculation and Analy- sis of the Shape of Cutting Edges), W. F. VOGEL. Ma- schinenbau — Der Betrieb vl5 nl/2 Jan 1936 p 27-30 13 figs 11 refs. Consolidated summary of the author's four pertinent papers. Se abstracts above, in 1933 and 1935. On Cutting and Hobbing Worms and Gears, D. W. DUD- LEY, H. PORITSKY. ASME Trans (J Appl Mechanics) vlO n3 Sept 1943 p A139-46, 197-201. Two problems are treated in this paper: (1) given the shape of a milling cutter tooth or of a hob tooth, to find out what is the re- sulting shape of worm or gear surface; (2) given the desired shape of a worm or gear tooth, what shape of mill- ing or hobbing tooth will produce it. Discusses four common types of worms : straight-sided axial section ; that produced by cutter or grinding wheel of straight-sided axial section; straight-sided normal section; involute helicoidal worm. Grinding Lead Screws, J. R. MOORE. Iron Age vl53 n22 June 1 1944 p 42-6 June 8 p 66-70. Description of elabo- rate techniques worked out by Moore Special Tool Co, Bridgeport, Conn, over period of years to achieve ultimate in accuracy in manufacture of micrometer screws for small jig borer ; highlights of method is use of electronic thermo- stat to maintain temperature of coolant and hence work at constant differential with respect to master lead screw of thread grinder; unusual methods of checking product are illustrated. Interferometric Calibration of Precision Screws and Con- trol of Ruling Engines, G. R. HARRISON, J. E. ARCHER. J Opt Soc Am v41 n8 Aug 1951 p 495-503 12 figs 14 refs. A new device is described with which screws of any length can be calibrated rapidly for both periodic and cumulative errors in terms of interference fringes. It can also be used to plot correction cams to remove fixed errors of translation or rotation, and to monitor the operation of an engine while ruling diffraction gratings or scales, cor- recting by automatic feedback differences between the actual carriage position and its proper position as shown by an optical interference field. This so-called "Commen- surator," whose name arises from its function of over- coming the incommensurability of the wavelength of the light used for calibration and the lead of a screw, consists principally of a screw drive system, eight-figure dials, and a generator, geared together in ratios that can be con- trolled to one part in 10 8 . Fringes produced by a Michelson interferometer mounted on the ruling engine (or having one mirror moved by the nut of the screw being calibrated) are changed photoelectrically to a wave train that measures translation to within 0.1 microinch. A second wave train of almost identical average frequency is produced by the Commensurator generator to measure screw rotation, and the two trains are continuously compared by means of a phase-sensitive amplifier and motor to within 1/100 cycle or fringe. Any error in carriage translation appears as a lag or lead which produces a torque in the motor until synchronism is re-established by a relative shift of the two wave trains, and thus makes possible automatic plotting of the screw error curve on a moving chart. Precision Screw Thread Corrector Lathe. Eng vl96 n5099 Oct 16 1953 p 489-90 ; Engr vl76 n4578 Oct 23 1953 p 524-5. Essential element for accurate operation of gear hobbing 272 machines is hob slide feed screw ; new high precision lathe for finishing of such screws as developed by Craven Brothers (Manchester) ; on this machine screw thread can be accurately measured in position after cutting and corrector mechanism can be directly adjusted to pre- cision gage readings as required. Craven Precision Screw Thread Corrector Lathe. Machy (London) v83 n2142 Dec 4 1953 p 1111-3. Lathe especially constructed for correcting gear hobbing machine hob slide feed screws, after they have first been cut by normal methods ; special measuring head mounted on top of tool post carries single stylus point and spigot type dial gage reading to 0.00005 in. Method of Recording the Pitch Errors of Screw Cutting Lathes. F. H. ROLT, NPL. Eng Dimensional Metrology, Proc of Symposium held at NPL, 2 vols, Her Majesty's Stationery Office (London) 1955. Paper nl9 p 323-8 3 figs. Describes equipment by which lathes can be tested in the works and an autographic record obtained showing the complete periodic and progressive errors over any length of traverse required. Discussion. Special Lathe at the National Physical Laboratory for Cutting and Forming Fine-Pitch Screw Threads, V. W. STANLEY, NPL. Eng Dimensional Metrology Symposium held at NPL. 2 vols, Her Majesty's Stationery Office (Lon- don) 1955. Paper n20 p 329-45 10 figs 3 refs. A high precision lathe is described capable of producing fine- pitch screws ranging from about 100 to 30,000 threads per inch. Reference is made to the application of these fine screws to the production of diffraction gratings for use in spectrochemical analysis and for measurement of linear displacement. Precision Lead-Screws Ground from Solid, M. C. SU- LANDER, W. F. SPIERLING. Machy (N.Y.) v62 n9 May 1956 p 146-9; Machy (London) v89 n2285 Aug 31 1956 p 505-6. Lead screws produced by Precision Thread & Gear Corp, Chicago, have variation in thread pitch diameter not exceeding 0.0002 in., and max lead error between any two vees at 1-in. intervals of 0.0003 in. ; importance of material selection, with good results obtained with Sparta, Universal Cyclops air hardening tool steel ; ultra-precise thread grinding operations described ; continuous inspec- tion of threads. 10,000 Threads to Inch, J. F. BELL. Am Mach vlOO nl6 July 30 1956 p 112-3. Modification of 50 yr old Rivett lathe at Johns Hopkins University has made it possible to make very accurate screws of 10,000 threads to inch ; thread is used as diffraction grating and is also of value for very accurate measurement of lineal displacement through relatively large distances ; methods of making screw. Mechanical Engineering Research Laboratory : Work of the Mechanisms, Engineering Metrology and Noise Control Division, C. TIMMS, Nat. Eng. Lab. Trans Instn Engrs and Shipbuilders in Scotland 1958 p 317-68. On p 334 is described and illustrated the master-screw correcting lathe recently transferred from NPL, which has a history dat- ing back to 1900. Screws to 10 ft. in length may now be corrected. Reference is made to "Standard Leading Screws for Screw-Cutting Lathes" 1905 ( Stationery Office, London ) . A Comparison between Different Tooth Forms on Ground Worm Gears, G. ZEISE. Klingelnberg News, W. Ferd. Klingelnberg Sonne, Remscheid Dec 1961 5 p 5 figs. Tooth- forms are designated in DIN 3975 as A, N, and E in which the generatrix of the toothflank is a straight line and as K when the straight line generatrix is on the tool itself. The paper shows the difference of the various profiles, and particularly the results obtained in relation to grinding wheel parameters. Finishing Worn Profiles on Universal Thread-Grinding Machine, B. SMITH. Machy (London) vl02 n2621 Feb 6 1963 p 304-8. Setup for fly-cutting teeth in worm wheel on hobbing machine; description of Matrix generating dresser for forming wheel on universal thread grinding machine ; Matrix dresser eliminates need for time-con- suming calculations and greatly facilitates dressing re- quired form ; example of calculating, producing and checking involute helicoid worm ; grinding fly-cutter for machining worm-wheel teeth ; development of dressers. See also H. KALUZKA subsection 9.2, 1963, p. 205. 12.6.4. Screw Thread Gages Making Thread Gages, A. L. MONRAD. Machy (N.Y.) vl4 Feb 1908 p 387. A thorough description of the manu- facture of thread gages ; tables of ball diameters to be used in determining angle of thread for V, USS, Briggs Standard, and Whitworth threads. The Production of Screw Thread Gages, W. RICHARDS. Mech Wld v59 1915 p 134-5 146 158-9. Methods of turn- ing on lathe ; measurement by three-wire method. The Manufacture of Screw Gages, J. E. SEARS, NPL. Eng vl03 Feb 9 1917 p 137. Various developments and refinements in the measuring of screw threads at NPL. Producing British Screw Gages, I. W. CHUBB. Am Mach v46 nl4 Apr 5 1917 p 593-4 3 figs. Gives brief description of screw thread plug and ring gages, methods of manu- facture, accuracy, composition of material, and method of hardening. Measurement of pitch diameter. Making Precision Thread Gages, E. A. SUVERKROP. Am Mach v47 Aug 16 1917 p 265. Describes manufacture. Comment by J. BOLKOVAC, v47 Nov 1917 p 938. The Manufacture of Hardened Thread Gages, G. DOORAKKERS. Eng vl24 n3222 Sept 28 1917 Oct 5 12 26 Nov 2 p 263 290 308 354 390. Gives details of manu- facture of master tool, thread cutting tool, checks for thread plug gages, laps. Making Whitworth Thread Gages, W. D. WOODWORTH. H. W. BENDER. Machy (N.Y.) v24 n6 Feb 1918 p 483-93 17 figs. Reviews practice of a successful manufacturer. Making Whitworth Thread Gages. Machy (London) vll Mar 14 1918 p 645-9, Mar 21 p 676-81. Elements of Whit- worth thread ; machining gage blanks ; preliminary anneal- ing process ; rough machining thread ; carburizing ; finish- machining ; hardening ; advantages of grinding thread be- fore lapping ; special grinding machine ; use of wires for measuring pitch diameter ; measuring core diameter ; heat treatment to prevent future distortion ; finish grinding operations ; timing lapping periods ; lead and angle check- ing gage. Gage Making in a Shell Plant, F. D. JONES. Machy (London) vl3 Sept 21 1918 p 197-202. Practice used for gaging of 75 mm shell ; materials used for thread gages ; thread gage cutting, grinding, and lapping ; testing ac- curacy of thread gages. Making Thread Gages, T. H. FENNER. Can Machy v20 Nov 7 1918 p 529-32 7 figs. Description of plant and methods of a Canadian firm. Present Practice in Thread Gage Making, F. O. WELLS. Trans ASME v40 paper nl666 1918 p 809-25 ; Am Mach v50 Jan 23 1919 p 153-8. Manufacturing difficulties ; lead errors in lathes ; approved methods of thread lapping, grinding, and testing ; gage tolerances. Advance of Thread Gage Making during the War. C. B. COLE. Machy (N.Y.) v25 Aug 1919 p 1153-t. Practices used during the war in thread gage making ; difficulties 273 experienced in cutting Whitworth threads ; choice of ma- terial ; annealing and pack-hardening ; laps ; checking ring gages using four check plugs. Thread Gage Standards, J. E. COLLINS, Machy (N.Y.) v26 Jan 1920 p 427. A complete system of thread plug and ring gages ; tolerances and their application, three-wire method of measurement, effects of heat treatment, lapping, and shadow projection method of measuring threads. Making Whitworth Thread Gages, C. E. ALLEN. Machy (N.Y.) v26 Aug 1920 p 1157-60 5 figs; Machy (London) vl4 July 1919 p 504. Method which utilizes disintegration of grinding wheel during grinding operation to produce final thread form. Hardening Screw Gages with Least Distortion in Pitch, W. J. LINEHAM. Am Mech v53 Sept 1920 p 547 ; Mech Wld v67 May 7 1920 p 291, May 14 p 307, May 28 p 339; Engr vl29 Apr 30 1920 p 443. Report of the procedure used at Goldsmith's College, London, to give least distor- tion. Discusses cutting, measurement, and heat treatment. The Manufacture of Hardened Screw Gages. Engr v!30 Sept 24 1920 p 310-1 5 figs. Manufacturing process fol- lowed at plant of Coventry Gauge & Tool Co., Coventry, England. The Manufacture of British Association Screw-Thread Gauges, T. F. DAVEY. J Inst Mech Engrs Apr 1921 p 191-6. Design, methods, and apparatus used in measure- ment, compensation and correction for errors in lathe, cut- ting tools, lapping, and heat treatment. Some Notes on Hardening Various Screw Gauges, F. A. LIVERMORE. Can Machy v28 July 13 1922 p 26-7. Re- sults of experimental work ; effort to obtain process that will eliminate warpage and change of shape; methods of heat treating and quenching ; expansion and contraction. Heat Treatment of Screw Gauges. Eng Prod v5 Aug 10 1922 p 138. Resume of experimental work conducted over period of nine months with view to determining best con- ditions for production of hardened screw gages to satisfy stringent tests of NPL. Special Apparatus for Tapering Thread, W. O. RUSSEL. Am Mach v60 Mar 1924 p 480. Description of apparatus used in place of taper attachment for cutting taper thread gages. Die Herstellungsgenauigkeit der Gewindelehren und ihre messtechnisehe Erfiillung (The Production Accuracy of Thread Gages and their Metrological Performance), G. BERNDT. Werkstattstechnik v22 n5 Mar 1 1928 p 131-6 5 figs. Describes special microscopes, gages, and measur- ing devices; methods used in making thread gages in accordance with German DIN standards. Nitriding Oil Tool Gages, F. W. CURTIS. Am Mach v70 n22 May 30 1929 p 863^4 5 figs. Description of nitriding process for large thread gages which eliminates difficult grinding operation ; and produces hard surface free from scale; tool joint made by Doheny Stone Drill Co. is dis- cussed ; case hardening by nitriding process can be done by small shop with inexpensive equipment. Tools for Hartometer Production, C. R. RANNEY. Am Mach v71 n25 Dec 19 1929 p 1001-2 6 figs. Discussion of how problems of aligning multiple starting points for threads of different pitch and diameter in Hartometer screw-thread gage are solved. Herstellung und Priifung von Normal-Gewindelehren (Manufacture and Inspection of Standard Thread Gages), O. KESSLER. Werkzeugmaschine v38 Jan 1934 p 3-6. Detailed description of machines, instruments, and methods used. Illustration of special microscope. Typical Operations on Ford Gages, C. O. HERB. Machy (N.Y.)'v43 July 1937 p 706; Machy (London) v50 Sept 16 1937 p 749. Grinding and thread-lapping accurate thread gages and methods of cheeking and measurement. Plating of gages. Aus der Fertigung von Gewindedorn und Lehrringen (On the Manufacture of Thread Plug and Ring Gages), F. MATTHEES. Werkstattstechnik v33 May 1939 p 262. Discussion of the methods with particular reference to lapping. 12.6.5. Other Gages See also subsection 3.1. Making Spherical End Gages, C. W. WRIGHT. Am Mach v26 Aug 13 1903 p 1148-9. Illustrates and describes in- ventions of the writer for grinding spherical end gages and a lapping rig for gages. The Making of a Knife Edge Square, T. MILLER. Machy (N.Y.) vl7 Mar 1911 p 519 5 figs. Detailed description with line drawings. Gage Making and Lapping. Machy's (N.Y.) Reference Book No. 64. Principles of gage making, the manufacture of gages, lapping flat work and gages, the rotary lap, miscellaneous lapping. The Manufacture of Gages at the L. C. C. Paddington Technical Institute, A. G. COOKE, W. J. GOW, W. G. TUNICLIFFE. Proc Inst Mech Engrs Jan Feb Mar 1917 p 45-108 ; Eng vl03 Jan 26 1917 p 89-91 5 figs ; Mech Wld v61 Jan 26 1917 p 46 ; Feb 2 p 57-8. Discusses work of Institute on standardization of Gages. Discusses accuracy and the tolerances on limit gages, position gages, screw gages. Discusses instruments devised there for measuring pitch and diameters of screw gages and an optical ap- paratus by which screw cutting tools could be shaped and the sections of screw threads examined. Gives results of some of tests in form of curves ; the optical apparatus consisted of a light source giving a parallel beam of light freed from heat rays by passage through saturated solu- tion of alum, a rigid optical adjustable bench carrying tool or gage and projecting lenses, a screen at a distance of about 16 feet. In final projection of screw thread in sil- houette a careful examination for symmetry is made. Magnification up to 400 diameters was obtained. Discus- sion which followed paper took up more in detail such points as pitch errors in lathe, the optical apparatus used, lenses used for magnification, method of lapping (much in detail) the importance of an accurate lead screw, materi- als, methods of hardening quenching and annealing of gages, the alum bath used, sequence of operations in man- ufacture of case-hardened mild-steel gages, method of inspection of gage, pitch measurement, etc. Grinding Accurate Profile Gages by Means of Master Plates, H. M. DARLING. Am Mach v50 Jan 16 1919 p 105-6 3 figs. Description of operation. Making Some Diflicult Duplicate Gages, E. A. DIXIE. Am Mach v50 Jan 23 1919 p 162. Describes method of making a special taper plug gage. Discussion by A. MOSES on p 706. Manufacture of Hoke Precision Gages at the Bureau of Standards, H. L. VAN KEUREN. Am Mach v50 Apr 3 1919 p 625-30 6 figs ; Mech Eng v41 Mar 1919 p 289-90. Gage blocks are being produced at the Bureau with an accuracy limit of a few millionths of an inch. Apparatus used in testing flatness and parallelism to one millionth of an inch. Development of process for their commercial manufacture has taken place within period of six months. Special reference is made to light-wave interference method for determining accuracy. Angular Plug-Gage Making, H. PUSEP. Am Mach v50 Apr 3 1919 p 635-40 15 figs. Lays emphasis on elimination 274 of errors in preliminary operation, in order to prevent their accumulation and the appearance of serious defects which will be difficult to eliminate in later operations. How Precision Gage Blocks are Made, F. D. JONES. Machy (N.Y.) v26 Apr 1920 p 697-708 27 figs; Machy (London) vl6 June 3 1920 p 253-63 27 figs. Practice of Pratt & Whitney Co., Hartford, Conn. Generating Precision Tools, W. E. HOKE. Machy (N.Y.) v31 Feb 1925 p 421-5 7 figs; Machy (London) v25 1925 p 613. Fundamental or natural methods of obtaining pre- cision in toolmaking, gagemaking, etc. by application of generating principle. Lapping Micrometers, H. L. VAN KEUREN. Am Mach v64 June 3 1926 p 871. Describes procedure for recondi- tioning micrometer calipers to high degree of accuracy. Manufacture of Wickman Gages. Machy (London) v33 Nov 29 Dec 27 1928 p 257-62 397^02 24 figs. Methods employed by Coventry Gauge and Tool Co. Ltd, in manu- facture of adjustable limit plain and thread snap gages. Wickman gage details ; operations on frame ; drilling holes for anvils ; seasoning process ; sizing anvil holes ; opera- tions on anvil ; hobbing threads ; grinding operation by which finished form of thread is generated; checking finished anvils ; method of assembly ; testa for alignment of teeth as between two opposing anvils. Der Laeppvorgang bei der Herstellung von Messwerk- zeugen (Lapping Procedure in Manufacture of Gages). C. BUETTNER. Werkstattstechnik v25 n5 Mar 1 1931 p 113-6 10 figs. Fundamental relations of various factors in lapping necessary for obtaining measuring surfaces of high quality ; relationship between tool and work piece with particular regard to action of abrasive and lubricant. Anleitung zur Herstellung einer Praezisions-Raehenleh- ren-Schleifmaschine (Design of Special Grinding Machines for Precision Grinding of External Gages), O. LICH. Maschinen Konstrukteur v65 Mar 5 1932 p 29-31. Production of Dial Indicators. Machy (London) v41 Oct 6 1932 p 6-9. Machining operations and equipment used by T. and F. Mercer, St. Albans, in manufacture of dial indicators giving readings up to 0.0001 in. Heat Treatment of Gage Steel, F. A. W. LIVERMORE. Mech Wld v92 Oct 21 1932 p 381-3. Ideal conditions would be realized if it were possible to transmit simul- taneously to each molecule of steel given amount of heat in given time ; in efforts to approach as nearly as possible this ideal, certain phenomena in connection with mass occur;. in heat treatment of steel for gages, these alterna- tions are of great importance ; results obtained ; construc- tion of special furnace. How to Make Accurate Multi-Spline Gage, W. C. BETZ. Machy (N.Y.) v40 nl Sept 1933 p 22-3; Machy (London) v43 nll03 Nov 30 1933 p 245-6. Difficulties in obtaining precision spacing of blade slots are overcome by simple and ingenious method ; simple ring gage used for precision spacing; equipment used for making final inspection of slots in gage body. Facts to Know in Gage Grinding, H. J. CHAMBERLAND. Abrasive Indus vl7 n4 Apr 1936 p 8-10. Form of physical adjustment which steel must undergo, between heat treat- ing and finish grind, which is known as seasoning period ; procedure to be followed ; gages ground to size. Typical Operations in Making Ford Gages, C. O. HERB. Machy (N.Y.) v43 nil July 1937 p 706-8; Machy (Lon- don) v50 nl301 Sept 16 1937 p 749-51. Commentary on some of grinding and thread lapping operations carried out in gage plant of Ford Motor Co. Extreme Precision is Demanded in Gage Grinding. Abra- sives vl8 n9 Sept 1937 p 9-11 62-3. Brief illustrated de- scription of few of grinding operations carried out at toolmaking plant of Taft-Peirce Manufacturing Co. Woon- socket, R.I. Production of Dial Gauges. Machy (London) v74 nl896 Feb 22 1949 p 227-32. Methods employed by British Indi- cators, Ltd. St. Albans, for making "John Bull" gages; punching, boring and plating ; machining operations are few ; production of gear train components ; assembly. Zur Frage des Feinschleifens und Laeppens von Lehren (Fine Grinding and Lapping of Gages), O. RICHTER. Werkstatt und Betrieb v82 n5 May 1949 p 160-1. Con- clusions based on replies to circular letter sent to gage manufacturing firms ; problems discussed include : accu- racy of gages, their uses, costs, and manufacturing problems. How Gage Blocks Are Made, R. GIERLICH. Am Mach v94 nl Jan 9 1950 p 85-9. Importance of surface finish ; wear on gage block surfaces ; manufacture of gage blocks ; lapping procedure and importance of interchanging blocks during lapping; inspection of finished gages including calibrating for exact size and inspection for flatness. Producing Gage-Blocks To "Millionths", R. A. GIERLICH. Machy (N.Y.) v59 n6 Feb 1953 p 147-56 ; Machy (London) v83 n2121 July 10 1953 p 59-67. Techniques employed in Savage, Minn, plant of Continental Machines, Inc. for manufacturing DoAll gage blocks ; 131 sizes of gage blocks, ranging from 0.010 to 20 in. in length produced; grinding, heating and inspection operations; lapping of gage blocks. Lapping Anvils of Micrometer Calipers, H. M. BUCK. Machy (London) v88 n2251 Jan 6 1956 p 14-5. Descrip- tion of apparatus and techniques which were applied suc- cessfully for generating accurately flat and parallel measuring faces on micrometer calipers ; method involves first rectification of measuring face of micrometer spindle, after which anvil face is lapped in fixture. "C.E.J." + "B. & S." = Precision Gaging. Machy (N.Y.) v64 n8 Apr 1958 p 132-5. Manufacture of "Jo" (after Carl Edward Johansson) gage blocks at Brown & Sharpe Mfg Co, Providence, R.I. ; details of making "Thrift" blocks which is new class of blocks produced to better than Class B accuracy ; lapping operations indicated. Gage Inspection in Millionths — Not Guesswork, G. ASH- MEAD. Machy (N.Y.) v70 n5 Jan 1964 p 104-6. Del- tronic Corp, Costa Mesa, Calif manufactures Class "X" cylindrical plug gages exclusively in over 6000 sizes ; with each plug gage certificate is supplied which uncondition- ally guarantees that gage is within size tolerance of plus 0.000,040 in. minus 0.000,000 in. and that it has sur- face finish of approximately one /tin ; manufacturing methods described and illustrated. 275 Addendum to Section 12. 12.6.2. Scales and Gratings, Manufacture of Preliminary Notice of the Results Accomplished in the Manufacture and Theory of Gratings for Optical Purposes, H. A. ROWLAND. Phil Mag ser5 vl3 1882 p 469-74. Re- fers to previous work of Rutherford in making gratings. Describes progress in making a highly accurate screw ; the ruling of 160,000 lines on a surface or 29,000 per inch, and the making of concave gratings. See LOEWEN, pll9. See TAYLOR pl66, and ZEISS, pi 66. 12.6.5. Other Gages, Manufacture of See KNOYLE, pl63, on manufacture of combination angle gages. Addendum to Section 2 (continued from page 90) flection within a plane-parallel plate, by means of which interferences can be investigated for much larger path differences than previously. Green rays from a mercury lamp pass into a glass plate 6 cm thick through a slit in the opaque silvering which covers the face of the plate. The opposite face is half-silvered, and the rays which emerge pass into a telescope focused at infinity. A movable shutter at the eyepiece can cut off the rays in suc- cession, and the change observed on cutting off the ninth reflected ray shows that the latter is still in a condition to interfere. The corresponding path-difference is 2.600,000 wavelengths, — a limit which could be extended by the use of a thicker plate. Uber cine Kadmiumamalgamlampe aus Quartz ( Regarding a Cadmium Amalgam Lamp of Quartz), O. LUMMER, E. GEHRKE. Zeits InstrumKde v24 n 10 Oct 1904 p 296-8 6 refs. Lamp produces eight strong visible Cd and Hg lines from 644 to 436/i/i. Construction is described. 2.4.1. Length and Diameter Measurements — General Methode pour Mesurer en Longueurs d'Onde de Petites Epaisseurs (Methods of Measuring Small Thicknesses in Wavelengths), J. M. De LEPINAY. Ann Chim Phys ser6 vlO 1887 p 68-85. The method adopted was based on the use of Talbot fringes, the advantages of which were set forth by Mascart. Presents numerical data ; corrections for temperature and pressure ; description of apparatus ; preliminary experiments and calculations ; conclusion. Mesures Optiques D'Etalons D'Epaisseurs (Measurement of the Thickness of Optical Standards), J. M. De LEPINAY. Ann Chim Phys ser7 v5 May-Aug 1895 p 210- 55 10 figs. Contents : measurement of index ; measure- ment of thickness ; determination of the equal-thickness curves. 2.4.2. Fringe Count Interferometers and Dilatometers Measuring Device Emploving Light Interference Fringes, E. ROOT III. U.S. Patent 2 604 004 July 22 1952 8p 20 refs. Provides an apparatus for making absolute meas- urement of an article of any size by an actual count of the succession of interference fringes. Reversible Interference Fringe Counter with a Small Measurement Range, L. Ya. KVASKOV. Meas Techns n8 Mar 1965 p 675-8 4 figs 3 refs. Translated from Izmer Tekh n8 p 16-9 Aug 1964. Describes a Michelson inter- ferometer, photocells, and an electronic unit consisting of a photo multiplier, a dc two-channel amplifier, a reversing stage, and a counter. The apparatus has a range of 50 fringes and a precision of one interference fringe. 2.4.4. Interference Comparators New Interferometer for Measuring Block Gauges. V. P. GOLUBKOVA, V. P. KORONKEVICH, E. I. FINKEL' SHTEIN. Meas Techns n8 Mar 1965 p 672-4 3 figs 4 refs. Translated from Izmer Tekh n8 p 14-6 Aug 1964. Describes a new interference comparator for measuring the lengths of gage blocks from 3 to 100 mm without wringing them to auxiliary surfaces. 2.4.5. Measurement of Long Lengths (by Interferometry) Sur les Phenomene des Interferences entre deux Rayons de Lumiere dans le cas de Grandes Differences de Marche (Regarding the Phenomenon of Interference of Two Rays of Light in the Case of a Large Path Difference), H. FIZEAU, L. FOUCATJLT, CR Acad Sci v21 1845 p 1155- 8; Ann de Chim Phys ser3 v26 1849 p 138-48, v30 1850 p 146-59. Discussess interferences produced by an array of mirrors, by reflection on thin plates, and by means of double refraction. 2.4.6. Measurement of Line Standards (by Interferometry) Automatisches Vermessen und Protokollieren von Pra- zisionmasstaben durch fotoelektrisches Interferometer und fotoelektrisches Mikroskop (Automatic Measurement and Programming of Precision Measurement Standards by Means of the Photoelectric Interferometer and Photo- electric Microscope), F. HOCK, K. HEINECKE. Maschinemarkt v71 n37 May 7 1965 p 27-37 25 figs 14 refs. Describes apparatus for fast, completely automatic length measurements of line standard intervals in rela- tion to the wavelength definition of the meter, millimeter graduations are calibrated to 0.1m as the result of many years of development work. Graduation lines are scanned photoelectrically by an oscillating light beam, and a punched tape is used for recording. 276 AUTHOR INDEX Note. References showing names of firms or organizations, but not naming authors, are indexed in italics. Subsection/Year Page AA Gage Co 6.3/1958 163 Abadzhi, K 7.1/1961 180 Abbe 1.1/1940 7 1.2.1/1963 10 2.2.1/1964 48 2.3.7/1964 68 Abbott, E. J 1.7/1936 36 Abeles, F 11.3/1950 250 11.3/1953 251 11.3/1954 251 Abrahams, R. P 12.6.2/1939 270 Abramzom, E. L 12.3/1961 263 Abrikosova, I. I 1.7/1957 38 Acker, G. H 10.3/1927 238 Ackerl, F 6.4/1926 165 Acquista, N 2.3.1/1952 57 Acton, F. J 8.2/1943 195 Adadurova, M. A L 4.3/1960 123 Adam, N. K 1.7/1941 36 Adams, A.R 5.2.4/1963 141 Adams, H 12.1/1943 258 Adams, J. R 2.1/1956 43 2.3.1/1956 58 2.3.4/1956 64 Adams, K. B 2.3.4/1950 64 Adderley, E. E 3.1/1943 93 Afanas'eva, V. A 2.4.4/1961 83 Agar, A. W 11.3/1957 252 Ahearn, J 6.1/1947 154 Airborne Instruments Lab. Div 2.4.5/1964 86 Airy, G. B 1.5/1846 40 Aitchison, P. M 2.2.5/1950 54 Akhmatov, A. S 3.1/1961 93 Aksyuk, Y. F 3.6.2/1960 113 Albert, M. P 11.1/1962 246 Albrecht, S 1.3.4/1920 26 5.2.3/1936 138 Alciati, C. J 6.2/1955 158 Aldis, A. C. W 8.1/1911 189 G. H. Alexander Mach., Ltd 2.4.1/1939 70 Alexander, W 5.2.2/1951 135 Alford, L. P 7.1/1911 175 Aliab'ev, D. V 1.3.3/1959 25 Alig and Baumgartel 1.2.3/1930 13 Allan, E. R 1.2.1/1957 8 Allan, G. A 12.5/1962 268 Allen, C. E 12.6.4/1920 274 AUer, W. F 3.4/1944 101 5.2.1/1952 132 Allsopp, H. F 1.4/1958 29 Alpar, G 6.7/1964 171 Alquist, H 7.3/1936 181 Altmann, F. G 10.1.2/1932 215 10.3/1932 239 Alvan Mfg. Co 3.6.4/1912 115 American Gear Manufacturers Association 10.1 .1/1945 213 10.1.1/1947 213 10.1.1/1955 214 10.1.1/1956 214 10.1.1/1958 215 10.1.1/1959 215 10.1.1/1962 215 10.1.3.4/1962 221 10.1.4/1962 228 10.2.2/1956 231 10.2.2/1964 232 Subsection! Year Page American Grinder Co 10.2.1/1923 229 American Instrument Co 6.2/1948 158 American Society of Mechanical Engineers 1.2.1/1963 10 3.6.1/1958 110 American Society for Testing and Materials 3.3/1961 100 American Standards Association 10.1.1/1946 213 10.1.1/1950 213 10.0.1/1954 214 10.1.1/1955 214 10.1.1/1956 214 10.1.1/1958 214 10.1.1/1960 215 10.1.1/1962 215 10.1.3.4/1956 221 10.1.3.4/1960 221 10.2.4/1956 233 10.2.4/1960 233 American Tool Works 12.2/1924 .259 Ames 3.3/1929 98 3.5/1930 106 3.6.4/1930 115 Ames, J. S 2.3.1/1897 90 Ammco 7.4/1930 185 Anders, O. U 11.3/1956 252 Anderson, G. M 1.3.2/1962 21 Anderson, J. S 3.4/1923 101 Anderson, M. E 9.1/1909 197 Anderson, N 12.3/1964 264 Anderson, N. A 5.2.3/1956 139 Anderton, P 1.2.2/1964 13 Andrade, E. N. da C 1.7/1953 37 Andrae, W. C 1.1/1930 1 Andrejev, E. M 1.2.3/1961 14 Andress, J. E 12.1/1937 257 Andrew, K. L 2.4.3/1964 81 Andrews, H. I 3.2/1947 95 Andrews, J. P 1.5/1931 32 7.3/1928 181 Andrushevich, Y. M 12.2/1961 260 Angles, J. W 1.1/1919 1 Angus, H. T 5.6/1955 147 Antal, J. J 11.3/1952 251 Aoki, S 3.5/1963 108 10.1.1/1960 240 Apitz, G 10.3/1943 239 Appleby, A. N 5.6/1945 147 7.4/1958 185 Archer, J. E 9.1/1951 201 10.6.3/1951 272 Archer, R. J 11.2/1962 248 Arecchi, F. T 2.4.5/1964 86 Aregger, A 6.4/1921 165 Armand, G 1.7/1964 39 Armstrong, L. D 5.4/1955 145 Armstrong, W. E 4.4/1958 126 Armstrong, Whitworth & Co 3.5/1918 105 Army Tank Automotive Center 10.2.2/1962 232 Arnulf, A 6.1/1929 153 8.1/1928 190 Aronson, M. H 5.2.2/1953 136 Arregger, C. E 3.1/1945 93 3.2/1945 95 Arrow Tool Co 9.2/1919 202 Arthur Knapp Eng. Corp 9.1/1919 198 Arutvunov, V. O 1.1/1961 4 277 SubsectionlYear Page Asanov, V. V 1.3.2/1965 40 Ashby, H. F 1.4/1961 30 Ashmead, G 12.6.5/1964 275 Aspinwall, D. M 1.3.3/1960 25 Astin, A. V 1.1/1961 4 Astrop, A. W 3.5/1961 108 4.4/1961 127 Atkins, H. F 3.6.4/1911 115 Atkins, W. F 3.2/1964 116 3.3/1957 99 9.1/1964 202 Atkinson, M. P 2.5/1959 88 Atkinson, R. H 12.5/1962 268 Attwood, C 10.1.3.1/1947 218 Atwell 6.2/1915 157 7.3/1915 181 Aubertin, A 6.3/1936 162 Austen, A. E. W 1.3.3/1946 23 Automation Gages 8.2/1962 196 Averbach, B. L 4.3/1951 173 Avery, D. G 2.2.5/1950 54 11.1/1949 242 Avril, J 5.2.2/1956 136 Axman, B 1.1/1961 4 Ayre, V. E 3.4/1920 101 9.3/1921 206 Azim, K. A 11.1/1963 246 11.3/1963 254 B Bacon, R. H 1.3.3/1953 23 Baeckstroem, A 5.2.2/1934 133 Baeckstroem, H 1.3.1/1930 17 1.3.4/1933 27 Baier, O 12.6.3/1934 272 Bainbridge, N. W 1.4/1963 30 Baird, D. C 1.1/1962 4 1.2.2/1961 12 Baird, K. M ....2.1/1957 43 2.3.1/1960 59 2.3.1/1963 59 2.3.2/1958 62 2.3.3/1959 62 2.3.3/1962 63 2.3.3/1963 63 2.3.4/1956 64 2.3.4/1957 64 2.3.4/1959 65 2.3.7/1963 68 2.4.1/1958 71 2.4.3/1954 79 2.4.6/1961 87 2.4.6/1963 87 4.1/1961 119 Baivel, L. P 5.2.2/1964 138 Baker, D 3.6.4/1916 115 5.7/1959 150 6.6/1916 169 Baker, E. B 3.5/1951 107 5.2.2/1951 135 Baker, H . 3.5/1922 105 BakerfH. D 1.4/1953 28 Baker, H. W 3.6.4/1958 116 Baker, J. B 1.2.2/1962 12 Baker, K. E 1.3.4/1949 27 3.6.3/1949 114 Baker, L. R 2.2.3/1953 50 6.2/1961 160 Baker, M. I 6.1/1964 156 Baker, N. H 1.4/1953 28 Baker, S. C 12.6.2/1957 271 Baker, W. C 8.1/1915 189 Baker, W. H 5.1/1945 130 Bakos, J 5.1/1961 131 Baldwin, R. R 6.2/1964 162 Ballik, E. A 2.3.7/1963 68 Subsection/Year Page I Balsara, E. M 11.3/1957 Banfield, A. C 8.2/1919 Banhart, A 10.1.4/1962 Banwell, I 9.3/1914 Barakat, N 2.2.1/1963 2.2.5/1963 6.5/1949 11.1/1963 11.3/1963 Barany, N 5.4/1959 6.1/1958 6.1/1960 6.5/1960 Barash, M i 10.1 .4/1959 Barber-Colman 10.1.2/1954 Barber, C. R 1.4/1954 Barber, D. L. A 2.5/1959 Barer, R 4.4/1960 Barford, J 2.4.2/1963 5.2.2/1963 Barger, R. L 2.3.3/1961 2.3.6/1958 65, 66 2.3.6/1960 66 Barinberg, A. D 6.1/1960 Barker, A. J 1.2.3/1964 Barker, E. F 12.6.2/1928 Barker, G. H 1.3.2/1938 Barker, S. G 8.1/1930 Barlow, B. L 6.2/1963 7.3/1963 Barnard, G. P 6.1/1945 Barnard, T. P 12.6.1/1960 Barnes, C 3.3/1950 Barnes, D. C 2.4.1/1953 3.5/1954 6.7/1950 12.6.1/1954 Barnes, J. H 12.1/1928 Barnes, W. P 1.6/1963 Barnet, E. J 6.2/1957 Barnett, C 3.5/1954 Barr, G 3.4/1923 Barrell, H 1.1/1957 1.1/1965 1.2.2/1959 1.2.2/1962 2.1/1948 2.1/1951 2.1/1954 2.2.4/1951 2.2.5/1929 2.2.5/1951 2.3.1/1932 2.3.1/1947 2.3.2/1933 2.3.2/1944 2.3.3/1957 2.3.4/1951 2.4.5/1950 3.1/1927 3.3/1927 6.1/1947 6.3/1947 7.1/1948 7.1/1950 Barret, P 5.4/1956 Bartholdy, M 3.3/1927 3.3/1929 Bartley, A. J 6.1/1956 Barus, C 2.2.3/1918 2.4.2/1919 2.5/1900 6.5/1919 Barwell, F. T 1.7/1953 Barz, E 5.2.3/1938 Bastien, P 1.7/1946 252 193 228 206 48 55 167 246 254 145 155 155 168 227 216 29 88 127 77 136 63 155 15 270 20 190 161 184 154 269 99 70 107 171 269 257 35 159 107 101 4 6 12 12 42 43 43 52 54 54 57 57 60 60 62 64 84 92 97 154 163 177 177 145 97 98 155 50 73 87 167 37 138 37 278 Subsection/Year Page Batarchukova, N. R 2.1/1963 44 2.3.2/1942 60 2.3.2/1956 60 2.3.3/1963 63 2.4.5/1963 85, 86 2.4.6/1963 87 Batchelor, L. E 6.2/1960 160 Batemen, J. B 11.1/1954 243 Bates, W.J 7.3/1947 182 Bath, J 3.4/1921 101 John Bath & Co 3.6.2/1921 111 9.1/1917 198 Baty, J. E 9.1/1928 199 Bauer and Schaurte 3.4/1939 101 Bauerle, K. E 9.3/1938 212 10.1.3.4/1938 220 Bausch and Lomb 1.2.1/1964 10 1.2.3/1926 13 3.3/1930 98 4.4/1926 125 6.4/1930 166 8.2/1922 194 8.4/1923 194 12.3/1964 264 Baxandall, D 6.4/1923 165 12.6.2/1923 270 Bayle, F 1.2.2/1923 10 Beals, L. S. Jr 4.1/1951 118 Beam, A. S 9.3/1962 212 10.1.3.1/1962 219 10.2.1/1962 230 10.2.4/1962 234 10.3/1954 239 Bean, H. S 8.2/1919 193 Bearce, H. W 1.2.2/1926 10 1.2.2/1932 11 Beardsley, R 10.1.4/1935 224 Bechtold, M. F 11.1/1947 241 Beck, G 5.2.2/1958 137 Becker, E 3.6.2/1924 112 Becker, G. C 4.4/1946 126 Becker, H 4.1/1951 118 12.6.1/1958 269 Becker, L 3.5/1928 106 Becker, P. W 2.3.7/1962 67 Becker, S. E 2.3.7/1962 67 Beers, Y 1.3.3/1957 24 Behar, M. F 1.1/1951 3 Behrens, D. J 3.4/1941 101 Beilby, G 1.7/1959 38 Belanger, J. Y 11.3/1952 251 Bell, J. F 12.6.3/1956 273 Bell, R 12.3/1963 264 Belyi, M. I .3.3/1963 100 5.2.2/1963 137 Bender, H .6.1/1951 154 Bender, H. W 12.6.4/1918 273 Benedict, R. P 1.3.1/1961 18 1.3.1/1964 19 1.4/1954 29 1.4/1961 30 Benedikt, E. T 1.3.2/1949 20 Benford, R. L 6.1/1962 156 Benjamin, P 11.1/1956 243 11.1/1958 245 Bennett, F. D 2.2.3/1951 50 2.2.3/1952 50 Bennett, G. T 5.1/1905 129 Bennett, J. M 2.4.4/1959 83 4.4/1961 127 9.2/1961 204 Benoit, J. R 2.3.1/1913 56 2.3.2/1895 59 2.4.1/1934 70 3.2/1902 94 4.1/1895 117 4.1/1900 117 4.2/1883 121 Subsection/Year Benoit, R. Bensimon, R__ Benson, J. M. Bentley, G. P. Bentley, H Bergere, J Bergmann, H. Berkeley Berlin, G. S. Berndt, G._. Bernhardson, R_ Bernolak, K Berring, H Bessel, F. W. . . _._2.2.2 2.2.2 2.3.2 2.4.2 2.4.2 .-.5.2.5 1.4 5.1 ...3.6.2 ..10.2.1 10.2.6 10.1.3.4 10.1.4 10.2.4 7.1 .. .5.2.1 1.1 1.2.1 1.2.1 1.2.1 1.2.1 1.3.1 1.3.2 1.4 1.5 1.5 1.5 2.4.1 2.4.4 2.4.4 3.4 3.5 3.5 3.6.1 3.6.1 3.6.2 3.6.2 3.6.2 3.6.4 5.1 5.1 5.2.3 5.2.3 5.2.4 6.1 6.2 6.3 6.6 6.8 7.2 7.2 8.1 9.1 9.1 9.1 9.1 9.1 9.1 9.1 9.3 9.3 9.3 9.3 9.3 9.3 9.3 10.1.2 10.1.4 10.2.5 12.6.4 6.6 5.4 4.2 4.1 4.2 6.4 6.4 /1897 /1898 /1907 /1897 /1898 /1937 /1962 /1939 /1926 /1949 /1947 /1961 /1959 /1961 /1915 /1961 /1925 /1932 /1941 /1952 /1954 /1925 /1922 /1921 /1922 /1928 /1938 /1924 /1921 /1924 /1941 /1921 /1932 /1934 /1935 /1921 /1922 /1932 /1953 /1929 /1930 /1921 /1932 /1932 /1953 /1928 /1927 /1961 /1958 /1927 /1928 /1958 /1922 /1929 /1930 /1932 /1933 /1936 /1952 /1931 /1932 /1935 /1937 /1939 /1940 /1942 /1938 /1937 /1925 /1928 /1917 /1953 /1954 /1839 /1826 /1822 /1844 Page 48 90 59 72 73 141 30 130 112 230 237 221 227 233 175 132 1 7 7 17 20 28 32 32 32 69 82 82 101 105 106 110 110 112 112 113 115 129 129 138 138 140 154 157 162 170 173 180 180 192 198 199 199 199 199 200 201 208 208 208 208 209 209 209 216 224 234 274 169 144 122 128 120 164 164 77^-846 O — 66 279 Subsection /Year Page Bethel-Player 3.5/1924 106 6.7/1924 171 Betz, W 11.2/1905 247 Betz. W. C 6.6/1918 169 12.6.5/1933 275 Beuret, P 8.2/1921 193-4 Bhalla, M. S 2.4.2/1959 76 Bialy, A. El 11.1/1963 246 11:3/1963 254 Bielefeld, J 12.2/1960 260 Bigg, P. H 1.2.2/1964 13 Bingham-Powell, H. J 9.1/1917 198 Bikermann, J. J 1.7/1949 37 Billings, J. H 9.3/1917 206 Binder, R. C 1.3.3/1955 24 Biondi, M. A 2.4.3/1956 80 Biot, A 7.1/1932 176 8.1/1929 190 8.1/1931 190 8.1/1953 191 Birch, A. J 1.3.4/1948 27 Bircher, F. A 10.2.6/1947 237 Birdsall, F. W 6.3/1944 163 Birdsall, G. W 10.2.2/1945 231 Birge, R. T 1.3.3/1934 22 Birkebak, R. G 1.7/1964 39 Birks, L. S 11.3/1946 250 Birtwistle, J. K 11.3/1963 255 Biryukov, G. S 7.4/1964 187 Biryukov, L. I 2.4.5/1962 85 Bjerhammar, A 1.2.4/1960 16 Bjornberg, S. O 10.1.4/1923 223 10.1.4/1938 224 Black, A 1.2.2/1947 11 Blackburn, D. H 2.4.1/1961 71 Blaise, J 2.4.3/1958 80 Blake, D. V 6.7/1950 171 Bland, J. R 1.2.1/1938 40 Blank, J. M 2.3.4/1950 64 Blaschke, A 4.4/1907 124 Blet, G 2.3.4/1942 63 Block, W 1.1/1925 1 1.2.1/1930 6 1.3.1/1924 17 3.5/1924 106 5.4/1922 143 6.7/1930 171 Blodgett, K. B 11.1/1941 241 Blomstrom, L. C 6.6/1916 169 Blumova, V 8.1/1956 191 Board of Trade, Westminister 9.2/1901 202 Bochmann, G 9.1/1932 199 Bochmann, H 1.5/1927 32 9.1/1932 199 9.3/1927 207 9.3/1929 208 Bock, E 9.1/1930 199 Bock, R 10.1.4/1937 224 Bodart, E 1.2.1/1961 9 Bodner, C. H 10.2.1/1947 229 Boeckel, F. W 9.1/1945 200 Boehm, K 10.1.4/1959 227 Boella, C 10.2.2/1912 230 Boerdijk, A. H 6.1/1955 155 11.3/1963 254 Bogros, A 2.2.1/1937 45 Boguslavskii, M. G 1.3.2/1964 40 1.4/1964 31 Boguslawski, M 3.2/1956 96 Bohle, F 10.1.4/1955 226 10.2.2/1952 231 10.2.2/1957 231 Boisvert, M 5.2.2/1949 135 5.2.2/1950 135 Bokin, M. N 10.2.2/1960 231 Bolbrinker, E 10.2.1/1939 229 Boldin, L. A 7.4/1959 186 Subsection/Year Page Boldrini, M 1.3.3/1946 22 Bolf, J 6.2/1963 162 Bolkovac, J 12.6.4/1917 273 Bolotov, B. E 7.3/1961 183 Bonanomi, J 2.3.1/1962 59 Bond, G. M 3.1/1884 103 3.1/1886 91 3.5/1884 91 Bond, W. L 11.1/1956 244 Bond, W. N 5.2.4/1928 140 5.2.4/1929 140 Bonetti, A 1.4/1958 29 Bonnell, D. G. R 5.2.4/1950 140 Bonsdorff, J ■. 6.7/1908 170 Boonshaft, J. C 1.3.2/1953 20 Booth, S. F 1.1/1961 4 Bopp, F. H 7.3/1926 181 Bordewijk, J. L 1.1/1947 2 Borie, B. P 11.3/1961 253 Born, M 1.5/1946 32 Borneman, C. H 3.1/1938 92 Bornemann, W 5.4/1939 144 Boss, L 6.4/(1900) 164 Bostock, F. J 10.3/1913 238 Boston, O. W 5.1/1945 130 Botstiber, D. W 12.4/1952 266 Bottcher, K 3.1/1928 92 Bottema, M 2.2.1/1958 47 2.2.1/1960 47 2.3.1/1960 59 Bottomley, S. C 3.2/1959 96 4.1/1959 119 Bouasse, H 6.4/1917 165 Boulet, J. H 3.6.4/1907 114 Bousquet, P 11.3/1965 255 Bovey, E 5.1/1962 131 12.6.2/1962 271 Bowden, F. P 1.7/1953 37 Bowen, H. W 1.2.1/1938 7 Bowker, A. H 1.3.3/1959 24 Bouzitat, J 1.5/1951 33 Boyd, H. S 2.2.2/1922 49 2.4.1/1920 69 2.4.1/1922 69 2.4.3/1922 78 7.1/1920 175 Boyer, J 1.1/1921 1 Bracey, R. J 6.2/1943 157 Bradsell, R. H 1.2.4/1961 16 1.2.4/1964 16 2.4.5/1962 86 Bradshaw, E 5.2.2/1944 134 Brangaccio, D. J 2.3.7/1962 67 Branin, F. H. Jr 2.4.2/1953 74 Braune, G 3.4/1962 103 Braybon, J. E. H 2.1/1950 42 Brdicka, M 11.2/1947 247 11.2/1948 247 Breazeale, E. N 5.7/1958 150 Bredin, H. W 1.2.3/1961 14 Breene, R. G. Jr 2.3.1/1957 58 Breithaupt, W 3.1/1913 91 Brewer, W. B 1.4/1965 31 Bricout, P. A 5.2.2/1949 135 5.2.2/1950 135 Briggs, C. A 1.5/1918 31 Bright, R. J 2.4.3/1949 79 Brillouin, M 6.5/1903 167 British Indicators, Ltd 12.6.5/1949 275 British Standards Institution 1.2.2/1962 12 3.2/1961 96 3.3/1939 98 3.3/1942 98 3.4/1941 101 3.6.2/1938 113 3.6.2/1950 113 3.6.3/1940 114 4.1/1964 120 280 Subsection/Year Page British Standards Institution — Continued 5.2.3/1939 139 5.2.3/1940 139 5.3/1964 143 6.4/1951 166 6.6/1959 170 6.7/1941 171 7.4/1964 187 9.3/1964 212 10.1.1/1937 213 10.1.1/1940 213 10.1.1/1949 213 10.1.1/1951 214 10.1.1/1952 214 10.1.1/1958 214 10.1.1/1963 215 10.2.2/1963 232 Brittan, K. W 6.2/1960 159 Broch, O. J 3.1/1890 91 4.2/1886 121 Brockman, R. H 2.4.1/1962 72 2.4.2/1962 77 6.2/1949 158 Brooker, A 9.1/1917 197 Brookes, A. J. C 3.1/1924 92 Brooks, D. E 2.3.1/1954 57 Brossel, J 7.3/1946 181 Broussaud, G 1.2.4/1956 16 2.4.5/1956 84 Brousseau, H. E 9.1/1964 202 Brouwer, F 5.2.1/1963 132 12.3/1957 262 Brower, E. O 8.1/1921 189 Brower, F 3.5/1957 108 Brown, A. F. C 2.4.2/1958 75 Brown, C. C 4.2/1883 121 Brown, E. B 5.2.2/1951 135 6.2/1955 159 6.2/1956 159 Brown, F. P 12.2/1957 259 Brown, F. W. Ill 2.4.2/1948 74 Brown, J. H 2.5/1955 88 Brown, P 10.3/1913 238 Brown, R. W 3.5/1927 106 Brown, S. C 12.3/1962 263 Brown and Sharpe Mfg. Company 3.6.1/1909 109 3.6.2/1900 110 3.6.2/1907 111 3.6.2/1927 112 3.6.2/1928 112 3.6.2/1932 113 3.6.3/1928 114 12.6.1/1963 269 12.6.5/1958 275 David Brown and Sons, Ltd 10.1.4/1944 225 10.2.1/1932 229 10.2.6/1944 237 David Brown Tool Co 10.1.4/1955 226 10.3/1947 239 Browning, F. E 10.1.4/1948 225 Bruce, C. F 2.1/1954 43 2.2.1/1962 48 2.2.2/1953 49 2.2.3/1955 50-1 2.2.3/1957 51 2.3.1/1956 57, 58 2.3.1/1961 59 2.3.2/1961 61 2.3.3/1962 63 2.4.5/1956 84 3.1/1956 93 3.6.4/1949 115 6.5/1950 167 6.5/1952 168 Bruce, R. A 9.2/1904 202 Brunnow, F 6.4/1865 164 Bruno, M. S 10.2.2/1963 232 Subseetion/Year Page Bruns, H 6.4/1892 164 6.4/1912 165 Brutti, C 1.6/1962 35 Bryan, J. B 1.4/1965 31 Bryant, C. D 5.1/1962 131 Bryant, E. J 3.5/1917 105 6.6/1917 169 Brzhezinskii, M. L 2.4.6/1963 87 Bubert, J 5.7/1947 148 Buck, H. M 12.6.5/1956 275 Buckingham, E 3.6.1/1928 109 9.3/1938 208 9.3/1945 209 10.1.2/1928 215 10.1.2/1935 215 10.1.2/1949 216 10.1.3.1/1928 217 10.1.3.1/1935 217 10.1.4/1927 223 10.2.6/1921 235 10.3/1960 239 Budgett, H. M 3.1/1911 91 Budnick, A 9.1/1949 201 10.1.1/1955 214 10.1.1/1960 240 10.1.4/1959 227 10.2.6/1948 237 Buettner, C 5.4/1935 144 12.2/1936 259 12.6.1/1931 268 12.6.5/1931 275 Buisson, H 2.2.5/1908 54 2.3.1/1908 56 2.3.1/1912 56 2.3.1/1913 56 2.4.1/1902 69 Buman, H 5.4/1938 144 Bunch, J. M 6.2/1958 159 Biinnagel, R 7.1/1956 178 7.3/1956 183 Bunt, B. P 11.3/1961 253 Burch, J. M 2.5/1963 89 Burge, E. J 11.3/1951 250 Burger, K 9.1/1953 201 10.1.4/1944 225 10.2.2/1940 231 10.2.2/1942 231 10.2.6/1937 236 10.2.6/1938 236 Burgess, E 6.1/1959 155 Burgess, G. K 1.2.1/1924 6 1.2.1/1928 6 1.4/1928 28 Burgmeier, L 12.6.1/1964 269 Burguburu, P 1.1/1932 39 Burley, G. W 3.4/1913 101 3.6.2/1912 111 3.6.4/1911 115 10.2.6/1913 235 Burlingame, L. D 3.6.1/1914 109 3.6.2/1915 111 Burkhart, L. E 2.3.4/1949 63 Burmistrow, F 2.5/1936 87 Burns, K 2.3.4/1950 64 Burt, F. M 12.5/1945 265 Burtin, R 11.3/1960 253 Burton, A. E 4.3/1902 122 Busch, A. E 1.2.4/1963 16 Busch, T 1.2.1/1964 10 3.6.1/1965 110 Butler, C. T 6.4/1953 166 6.6/1953 169 10.2.5/1953 234 Butrick, F. M. Jr 9.2/1951 204 9.2/1953 204 281 Subsection/Year Page Buttner, C 5.4/1935 144 9.1/1922 198 Buza, J. A 2.4.2/1960 76 Bychkov, O. D 12.3/1963 264 C Cabrera, N 2.2.1/1941 45 2.4.5/1951 84 4.2/1944 122 Cadwell, J. H 1.3.3/1950 23 Callame, J 3.5/1923 105 Camargo, M. C 1.3.3/1956 24 Cambridge Scientific Instrument Co 4.4/1903 124 5.1/1931 129 9.1/1904 197 9.1/1918 198 Cameron, A 1.7/1949 37 Cameron, C 2.4.2/1963 77 Cameron, J. M 1.3.1/1960 18 Campbell, N 1.3.3/1920 22 Campbell, N. R 1.1/1928 1 Canac, F 1.7/1937 36 Canada, Topographical Surveys __4. 3/1921 123 6.4/1923 165 Candee, Allan H 9.3/1928 207 10.1.2/1959 216 10.1.2/1961 216 10.1.3.1/1961 218 10.1.3.4/1928 220 10.2.4/1928 233 10.2.6/1928 236 Candler, A 2.1/1951 42 Candler, A. C 2.2.1/1946 45 Canfield, W. G 7.4/1958 185 Cantelo, W 9.3/1903 205 9.3/1907 205 Canzek, L 8.2/1964 196 Carbone, P. E 7.1/1959 179 7.4/1958 185-6 Carey, M. C 2.5/1965 90 Carl, R 5.2.5/1959 142 Carlstedt, R. L 1.6/1963 35 Carman, P. D 7.1/1955 178 Carmichael, C. M 1.4/1959 29 Carson, P. A 4.3/1911 173 Carson, R. W 3.3/1947 99 3.5/1932 106 3.5/1941 107 5.2.2/1931 133 5.2.2/1936 133 5.7/1937 148 Carter, B. C 5.2.2/1944 134 Cartwright, B. W 10.2.4/1952 233 Cartwright, R 7.1/1940 176 Case, A. A 12.5/1915 266 Casey, J. P., Jr 2.5/1952 88 Cassignol, C 2.3.4/1963 65 Cau, M 2.1/1937 41 Cave, E. F 2.1/1955 43 Caville 6.4/ 1 893 164 Ceely, F. F 1.2.4/1960 16 Cerni, R 1.3.2/1961 21 1.3.2/1962 21 Cerni, R. H 1.1/1962 4 Chabbal, R 2.4.3/1958 80 Chalmers, S. D 7.3/1917 181 Chalvet, M 1.1/1950 3 Chaman, V. S 6.1/1961 156 Chamberland, H. J 3.1/1950 93 12.6.5/1936 275 Chambers, R. G 1.7/1953 37 Chaney, L 1.7/1954 38 Ch'angken, H 12.3/1961 263 Ch'ao-tseng, L 3.1/1961 93 Chao-wang, H 2.3.1/1943 57 Chapin, W. C 1.5/1918 31 Chapanis, A 5.3/1955 143 Chapman, W. A. J 10.2.6/1930 236 Subsection/Year Page Chappell, A. W 10.2.4/1914 232 Chappell, F. A 8.1/1952 191 Chappie, M. A 1.7/1957 38 Charbal, R 2.4.3/1958 80 Charman, W. N 1.3.4/1963 27 Chekhonadskii, N. A 1.3.2/1963 22 1.3.3/1959 25 Chen, H. S. C 8.1/1954 191 Ch'en, S 2.3.1/1957 58 2.3.2/1958 61 Cheneveau, C 3.5/1923 105 Cheney, R. E 12.6.1/1961 269 Cherna, J. C 7.4/1956 185 Cherry, R L 5.2.2/1947 135 Chescoe, D 11.3/1962 254 Chesley, W. L 9.3/1937 208 10.2.4/1937 233 Chesterman-Sogenique 3.6.3/1964 1 14 Chicherova, A. S 6.8/1960 173 Childs, W. H. J 2.4.3/1926 78 Chitayat, A. K 2.4.2/1964 78 Chittleburgh, R 3.4/1954 102 Chiverton, H. A 3.6.2/1955 113 Chree, C 1.5/1901 31 Christoff, P 5.7/1951 149 Christoph, W. P 1.2.3/1958 14 Chubb, I. W 12.6.4/1917 273 Churchill Machine Tool Co 12.4/1929 265 Churchman, C. W 1.1/1959 4 Cichon, J 4.1/1960 119 Ciddor, P. E 2.2.5/1960 55 Clark, J. A 1.4/1955 29 Clark, J. S 4.1/1951 118 4.2/1956 122 4.3/1950 123 4.3/1951 123 4.4/1956 126 Clarke, K. A 9.1/1948 200 Clark, R. N 12.5/1943 267 Clay, R. S 5.2.3/1940 139 Clay, W. E. R 1.7/1945 36 Clayton, D 1.7/1945 36 Clegg, R 12.3/1962 263 Closson, H. T 4.2/1958 122 9.2/1958 204 Clunie, D. M 2.4.5/1964 86 Clusius, K 1.2.1/1963 40 Coales, J. F 1.1/1956 3 5.1/1956 130 Coats Machine Tool Co 9.2/1918 203 Cobb, E. T 3.2/1938 95 Cochet, C 1.4/1918 28 Cochin, L 1.3.3/1963 26 Cocks, M 1.7/1954 37 Coffman, M. C 3.1/1938 92 Cohen, M 4.3/1951 173 Cole, C. B 12.6.4/1919 273 Colebourne, R 1.2.1/1956 8 Collart, K. S 1.7/1957 38 Collet, E 2.4.3/1953 79 Collett, C. T 3.4/1950 102 Collier, J. G 11.3/1964 255 Collins, J. D 5.6/1963 148 Collins, J. E 12.6.4/1920 274 Combs, J. F 11.1/1962 246 Compain, L 1.2.1/1952 8 10.1.2/1952 216 12.2/1938 259 Compudex Enq. Co 10.2.5/1946 234 Comrie, L. J.' 10.1.3/1962 217 Conaty, A. L 3.6.1/1919 109 Condon, E. U 5.2.1/1949 132 Conners, E. R 9.2/1908 202 Connes, P 2.4.3/1958 80 Connolly, T. F 4.4/1920 124 6.7/1923 170 Conrad, E. E 11.1/1964 247 Constans, M 2.4.1/1961 71 282 Subsection/Year Page H. H. Controls 6.2/1961 160 Cook, A. H 1.1/1957 4 1.2.2/1957 12 2.2.1/1957 47 2.2.1/1962 48 2.2.5/1959 55 2.4.3/1959 80 4.1/1953 119 4.2/1956 122 4.4/1956 126 6.1/1954 154 6.3/1954 163 Cook, H. D 2.3.7/1964 68 2.4.2/1961 77 2.4.6/1961 87 4.1/1961 119 Cooke, A. G 12.6.5/1917 274 Cooke, Troughton and Simms 4.4/1942 126 6.2/1962 161 8.2/1935 194 Cornelius, J 5.2.2/1945 134 Cornelius, J. R 9.3/1932 208 Cornell, S 10.1.4/1944 225 Corner, W. C 5.2.2/1954 136 Corson, A. J 5.2.1/1948 132 Cos, A 5.4/1948 144 Cotton, A 2.2.1/1911 45 Cotton, P 2.2.5/1945 54 Couling, S. A 10.1.4/1956 226 Courtel, R 1.7/1963 39 Courtney-Pratt, J. S 11.1/1952 243 Coventry Gauge & Tool Company 3.4/1957 102 3.6.1/1949 110 6.6/1958 170 7.1/1950 177 10.1.4/1950 225 12.6.4/1920 274 12.6.5/1928 275 Cowee, R. L 10.1.4/1956 226 Cowell, P. H 6.4/1901 164 Cowley, A 12.3/1962 263 Cowlin, W. H 10.1.3.4/1920 220 10.2.6/1920 235 Cox, A. J 4.4/1907 124 Cox, R. J 3.5/1942 107 5.2.2/1942 134 Crain, C. M 2.2.4/1950 52 Craven Brothers 12.6.3/1953 272-3 Crede, C. E 1.6/1961 34 Crompton Parkinson, Ltd 5.7/1962 150 Culmann, P 2.3.2/1902 59 Culshaw, W 2.1/1950 42 2.1/1960 44 Cumberland, N 10.3/1942 239 Cuninghame, W. A. F 6.4/1950 167 6.4/1952 168 Cunningham, H 1.5/1962 33 10.1.3.6/1962 222 Cuny, B 7.1/1948 182 Curry, C 5.2.2/1947 135 Curtis, F. W 12.6.4/1929 274 Curtis, H. E 3.6.3/1909 114 Curtis, H. J 5.4/1931 144 Cutkosky, R. D 1.1/1961 4 5.2.2/1961 137 Cutler- Hammer 12.3/1963 264 Czerski, Z 8.1/1956 192 Czygan, W 6.2/1957 159 D Dacus, E. N 5.7/1958 150 Daeves, K 1.3.4/1930 27 Dallas, D. B 1.2.2/1962 12 Damm, T 3.6.1/1931 109 Damski, A. M 12.1/1962 258 Daniels, F. R 1.2.1/1923 6 12.6.1/1919 268 Subsection/Year Danielson, W. E 4.2 9.2 Danilevich, F. M 4.4 5.2.2 Danilyuk, P. M 10^4 10.2.4 10.3 10.3 Dannehower, G. L 12.1 Dantu, P 2.5 Darling, H. M : 12.6.5 Darmody, W. J 1.3.1 1.3.1 7.4 Darwin, C 1.1 1.1 Dauber, J 2. 1 Dauphinee, T. M 5.2.4 Davey, T. F 12.6.4 Davies, B. M 12.6.2 Davies, E. E._ 10.2.6 Davies, H. J 12.1 Davis, E. P 6.6 Davis, R. H 11.3 Davis, R. J 4.4 Davis, S. P 12.6.2 Davis, W. O 5.1 Davison, C. St. C 1.2.2 Davydov, B. S 2.1 Dawney, W. H 9.3 10.1.2 Dawson, G. W 3.6.2 Dayton, R. W 5.2.2 De, M 2.2.1 De Baufre, W. L 3.5 de Bruin, T. L 2.3.3 2.3.3 de Bruin, W 1q.2 10.1.4 Deby, H. L 10.3 10.3 de Gramont, A 6.7 de Jong, A. N 6.2 De Juhasz, K. J 5.2.4 Delavignette, P 11.3 5.2.5 2.4.1 2.4.1 2.4.1 2.4.1 2.4.3 de Leiris, H. de Lepinay, J. M. 1958 1958 1963 1963 1961 1962 1958 1960 1964 1962 1919 1956 1962 1958 1944 1945 1943 1955 1921 1933 1941 1935 1917 1951 1958 1959 1955 1957 1963 l'.)4'.> 1948 1946 1946 1956 1916 1921 1931 1955 1957 1962 1963 1928 1963 1940 1963 1937 1887 1895 1899 1902 68 1899 1948 1953 1961 1962 Delhomme, F 4.1 Deloffre, G 5.2.2 Delyunov, N. F 1.2.1 3.2 De Mallemann, R 1L2/1944 Deming, W. E 1.3.3/1934 Denisov, F. P 11.3/1963 Denisov, P. V 3.1/1959 Denis-Papin, M 1.1/1946 Denton, P 5.4/1952 Desch, C. H 1.7/1946 de Senneville, C 1.7/1946 Des vignes, F 2.3. 1/1 949 Detroit 9.2/1931 Deutschen Normenaussehuss 1.1 /l 962 5.1/1962 5.6/1949 5.6/1950 Deve\ C 6.1/1941 6.2/1941 12.4/1936 de Veer, J. D 6.2/1961 7.1/1961 Deverall, G. V 2.4.3/1953 Devienne, M 11 .3/1951 de Villemeur, Y 5.6/1962 14 Page 122 204 127 138 233 234 239 239 258 89 274 18 18 185-6 2 2 42 140 274 270 237 257 169 251 126 271 130 11 44 210 216 113 134 46 105 61 61 158 226 240 240 171 161 140 254 141 276 276 68 69 ' 78 118 136 9 96 247 22 254 93 2 144 37 37 57 203 ► 5 131 147 147 153 157 265 160 179 79 251 8 283 Subsection/Year Page DeVos. L 10.2.1/1962 230 Dew, G. D 2.4.1/1964 72 2.5/1962 89 12.6.2/1956 271 12.6.2/1962 271 Dexter, A. M., Jr 11.1/1959 245 Dicke, R. H 2.3.1/1957 58 Dickson, J. H 5.1/1953 130 Diederichs, H 1.1/1930 1 Dieffenbach, A. P 7.1/1954 178 Diettrich, G 3.2/1958 96 9.1/1939 200 Dimmer, G 1.5/1920 31 Dixie, E. A 12.6.5/1919 274 Dixon, H. D 1.4/1960 30 Djurle, E 1.2.3/1958 14 Dmitriev, I. S 11.3/1959 253 The Do All Co 1.2.1/1953 8 7.1/1953 177 Dobrowolski, J. A 3.3/1957 99 4.4/1957 126 Dobson, G. M. B 8.1/1911 189 Doekes, J. G 6.2/1955 158 Doi, V 2.4.6/1962 87 Dolgushev, A. N 3.6.2/1959 113 Dolinskii, E. F 1.3.2/1959 21 Donald, G. W 12.2/1960 260 Donaldson, W. K 11.1/1947 241 Doorakkers, G 12.6.4/1917 273 Dorey, S. F 10.1.4/1947 225 Dornenburg, G 2.2.5/1951 54 Dornhofer, R 12.2/1963 261 Dorsey, E 1.3.1/1953 17 Dort, S. T 10.2.4/1914 232 Douglas, R 4.4/1932 125 Douglas, R. W 2.5/1952 88 Dovey, D. M 1.7/1953 37 Dowell, J. H 1.5/1926 32 2.4.1/1960 71 2.4.4/1960 83 4.4/1926 125 5.6/1932 146 Dowling, J. J 5.2.2/1920 151 Draper, C. S 1.1/1953 3 5.1/1939 130 Dratz, H. R 5.4/1942 144 Draudin, A. T 10.2.1/1960 230 Dress, K 7.4/1940 185 Dreyer, C. F 5.7/1930 148 Dreyhaupt, W 10.1.4/1962 228 12.1/1962 258 Drinkwater, J. W 9.1/1943 200 9.1/1944 200 9.1/1946 200 9.2/1942 203 Drude, P 2.2.5/1893 53 2.2.5/1894 53 11.1/1893 241 11.2/1889 247 Dubinovskii, A. M 4.4/1964 128 du Bois, H 2.1/1911 41 Dubrovskii, G. B 2.3.2/1956 60 Duckert, P 3.6.2/1924 112 Dudgeon, H. A 12.4/1942 265 Dudley, D. W 10.1.2/1954 216 10.1.2/1962 216 10.1.3.1/1962 218, 219 10.1.3.4/1962 221 10.2.1/1947 229 12.6.3/1943 272 Duffieux, M 7.1/1932 176 Duffieux, P. M 2.2.1/1939 45 Dufour, C 2.2.1/1948 45 2.3.1/1946 57 2.4.3/1946 78 2.4.3/1950 79 Subsection/Year Dugit, M 6.1/1920 Diihmke, M 2.4.2/1957 2.4.4/1957 2.4.5/1957 2.4.5/1961 3.6.4/1962 7.2/1959 11.1/1953 11.1/1962 12.3/1957 Dukhopel, I. I 7.3/1956 7.3/1961 Dumanois 5.2.5/1937 Dumontet, P • 11.3/1957 Dunaev, B. B 1.3.1/1963 Dunin-Barkovskii, I. V 1.3.3/1960 12.1/1964 Dupeyrat, R 2.4.3/1957 DuPont Eng. Dept 12.2/1961 Dupuy, O 2.4.1/1962 Duquesne, M 1.3.3/1963 Durand, W. F 7.4/1899 Durasova, Y. A 11.1/1963 Durbin, E. J 1.3.3/1959 Durfee, W. C 3.6.2/1906 Duston, F. C 10.2.5/1929 Dwyer, J. J. Jr 12.3/1964 Dymott, E. R 3.4/1948 Dyson, J 3.3/1959 5.4/1959 5.4/1961 6.2/1960 6.2/1961 6.2/1964 7.3/1955 10.1.4/1955 11.1/1953 11.1/1958 11.1/1963 Dziobek 4.2/1903 E East, F. G 10.1.1/1954 Eastman, F. S 5.7/1935 Eastman Kodak Co 10.2.2/(1953) Eastmen, H 1.2.1/1963 3.1/1963 Eastwood, E 1 .3.4/1948 Eaton, G. M 10.2.4/1926 10.2.6/1925 Ebbeni, J 2.5/1964 Eberhardt, E 3.3/1951 Eckert, E. R. G 1.7/1964 Eckerkunst, W 1.2.1/1964 Eddington, A. S 1.3.3/1933 Edensor, K 9.1/1960 Edlen, B 2.2.4/1953 Edmundson, D 5.2.2/1949 Edush, V. Y 5.2.2/1963 Efimov, A. A 6.4/1960 Efremov, I. P 2.2.2/1960 Efremov, Y. P 2.2.3/1960 2.3.3/1960 2.3.3/1963 Efros, I. E 7.4/1964 Egen, P. N. C 4.2/1827 Egudkin, A. S 2.4.4/1963 Egy, W. L 6.2/1955 Ehrenburg, W 1.3.3/1958 Ehrenhaft, F 1.3.2/1937 Eichler, F 5.1/1932 Eidinov, V. Y 5.2.3/1962 6.1/1963 Einsporn, E 1.5/1929 7.1/1950 Einthoven, W 1.6/1895 Eisele, F 12.2/1961 Page 153 75 82 84 85 116 181 243 246 262 182 186 141 252 19 25 258 80 260 72 26 185 246 25 110 234 265 102 100 145 145 159 160 162 182 226 243 244 246 121 214 148 231 9 94 27 232 235 90 99 39 10 22 202 52 135 137 166 49 51 62 63 187 120 83 159 24 20 130 139 156 32 177 34 260 284 Subsection/Year Page Eisenhart, C 1.3.1/1953 17 1.3.1/1962 18 1.3.3/1952 23 1.3.3/1962 25 1.3.3/1963 26 1.3.3/1964 26 Eisner, R. L 2.4.2/1958 75 Eitelman, H. K 12.1/1959 258 Elberty, R. S 5.2.5/1948 141 El Bialy, A 11.3/1963 254 Elkins, E 6.8/1940 172 Ellingham, B 3.3/1959 100 Elliott, A 5.1/1953 130 Elliott, A. J 7.1/1949 177 Elliott, K. W. T 5.4/1957 145 Elliott, R. M 2.4.3/1940 78 Emara, S. H 2.3.4/1961 65 Embleton, T. F. W 2.1/1955 43 Emde, F 8.1/1938 190 Emel'yanov, A. P 6.6/1963 170 Emerson, C 5.4/1949 144 Emerson, W. B 2.4.1/1950 70 7.1/1952 177 Encinas, J 11.1/1963 246 Endo, O 9.1/1961 201 Engelhard, E 1.2.2/1961 12 2.1/1957 43 2.3.1/1959 58 2.3.1/1960 58 2.3.3/1954 62 2.3.3/1959 62 2.3.3/1960 62 2.4.5/1959 85 Entin, L. P 1.3.2/1959 21 Eppenstein, O 1.2.1/1925 6 9.1/1924 199 9.3/1922 206 Erdoekuerti, Z 2.2. 1/1963 48 2.2.3/1963 51, 52 2.4.3/1964 81 Erdokuri, Z 5.1/1961 131 Erickson, E. C 9.1/1937 200 Erickson, K. E 2.2.4/1962 53 2.4.5/1962 85 Esclangon, F 2.1/1937 41 Essen, L 1.2.2/1957 11 1.2.2/1959 12 2.2.4/1953 52 Esserman, N. A 3.1/1943 93 Estabrook, M 10.2.2/1923 230 Estey, M. E 7.4/1948 185 Eugene, F 12.5/1947 267 Evans, J. C 1.1/1946 2 1.2.3/1962 15 3.3/1957 99 5.2.5/1951 141 5.2.5/1956 142 5.2.5/1957 142 5.2.5/1964 143 6.1/1961 155 6.1/1964 156 Evans, J. T 12.3/1963 264 Evans, U. R 1.7/1953 37 Eversole, W. G 4.4/1941 125 Evich, E. M 3.6.4/1962 116 Ewald, W 3.6.4/1926 115 Ewell, M. D 3.6.2/1907 110 Ewles, J 5.2.2/1947 135 F Fabish, E. F 10.1.4/1963 228 Fabry, C 2.1/1897 41 2.1/1899 41 2.2.5/1908 54 2.3.1/1900 56 2.3.1/1908 56 2.3.1/1912 56 2.3.1/1913 56 Subsection/ Year Page Fabry, C. — Continued 2.3.2/1907 59 2.3.2/1934 60 2.4.1/1899 68 2.4.3/1899 78 2.4.3/1901 78 2.4.4/1898 81 2.4.5/1899 84 Fainerman, I. D 1.3.4/1963 27 Fairchild Aircraft Div 1.2.3/1952 14 3.2/1952 96 Fairey Aviation Co 5.6/1951 147 Fairfield, D. J 1.2.3/1963 15 Fano, U 1.1/1950 3 Farago, F 7.4/1964 187 8.1/1964 193 Farrar, W. A ,_ 3.6.2/1907 111 Fath, J. M 11.2/1964 249 Fastie, W. G 2.3.1/1958 58 Fateeva, L. N 11.3/1959 259 Faust, R. C 2.2.1/1955 46 Fawssett, E 3.4/1943 101 Fayet, G 6.4/1907 164 6.4/1910 164 Fayolle, P 5.2.2/1947 134 Federal Products Co 3.3/1923 97 Federov, A. V 12.3/1963 264 Federov, G. V 11.3/1957 252 Fedotov, A. V 5.2.2/1965 151 12.3/1963 264 Fedukin, V. A 10.1.4/1962 228 Feibelman, W. A 11.1/1956 244 Feklistov, E. M 6.4/1961 167 Fellows Gear Shaper Company 10.1.2/1957 216 10.1.4/1932 224 10.2.1/1943 229 12.3/1935 262 Fennell, K 9.3/1916 206 Fenner, T. H 12.6.4/1918 273 Ferguson, J 7.3/1964 184 Fergusson, P 1.5/1957 33 Ferranti Ltd 1.2.3/1963 15 Ferris, C. D 1.1/1962 5 1.3.4/1962 27 Feuersanger, A. E 11.1/1963 246 Field, J. C 2.3.5/1960 65 Field, R. H 1.2.1/1951 8 3.3/1947 99 6.8/1947 172 Field, T. H 4.1/1939 118 Fields, T. H 1.2.3/1960 14 Fieseler, A 10.3/1935 239 Figatner, A. M 12.2/1963 261 Finch, G. I 1.7/1945 36 5.6/1950 147 Finch, J. M 3.5/1943 107 Findlay, V. R 2.2.2/1953 49 Findley, R. W 1.2.3/1960 14 Fink, G. A 2.4.2/1933 73 Finkelnburg, H. H 12.5/1954 267 Finkel'shtein, E.I 2.4.4/1965 276 4.4/1961 127 6.4/1960 166 10.2.5/1959 234 Finckelstein, L 1.1/1963 5 Thos. Firth & John Brown 9.1/1946 200 Fischer, L. A 1.1/1925 1 1.2.1/1915 6 4.1/1898 117 4.1/1906 117 8.2/1920 193 Fischer, W 3.6.4/1962 116 Fisher, A 9.3/1922 206 10.2.6/1922 235 10.3/1922 238 10.3/1923 207 Fizeau, H 2.4.2/1866 72 2.4.5/1845 276 285 Flanders, R. E 10.1.4 Fleischmann, R 2.2.5 11.3 Fletcher, A 1 0. 1 .3 Fleury, P 6.2 Fochs, P. D 11.3 Folds, W. H 10.2.4 Foley, G. M 5.2.2 5.2.2 Fok, M. V 2.2.\ Fomicheva, M. K 8.1 Fomina, O. P 7.3 Forestier, M 7.1 Forshaw, J. R 5.2.2 Forster, G 6.4 Fortney 9.3 Forsyth, G. H 10.1.4 F ortuna-W erke Spezialmaschinenfabrik A-G 5.2.3 Forward, E. A 8.1 Foster, C. E 5.5 Foster, J 3.6.2 Foster, L. E 1.1 Foucault, L 2.4.5 Fox, A. G 2.3.7 2.3.7 Fox, G. W 2.4.2 Fraichet, L 1.3.1 9 3 Francis, V 10.1.4 10.3 Frankel, A. B 6.6 Franklin, C. H. H 5.1 Frankzenburg, W 6.2 7.3 Fraunthal, A. H 7.4, Fred, M 2.3.1 Fredericks, P. A 9.3 Freeman, D. H 4.4 Freise, H 6.2 Frieden, B. R 11.3 Friedman, H 11.3 Frisch, O. R 4.4 Fritz, L 6.4 12.6.2 Froboese, E 5.2.2 Frolov, F. P 9.2 Fromherz, H 11.1 Frommer, J. C 5.2.2 Froome, K. D 1.2.4 Fr uedenstein, F 10.1.4 Fry, T. C 11.2 Fujiki, Y 11.3 Fujil, C 12.1 Fu j i wara, S 6.2 Fukuda, Y 12.2 Fullmer, I. H 1.2.1 1.2.1 1.4 3.2 Fultz, A. R 6!2 8 2 Funnell, H. M 9.3 Furey, M. J 1.7 Furse, J. E 8.2 Subsection/Year Page 1922 223 1951 1951 1962 1947 1950 1924 1945 1946 1953 1963 1959 1962 1944 1913 1918 1947 1931 1919 1930 1948 1962 1845 1961 1963 1933 1929 1928 1952 1952 1960 1946 1938 1938 1923 1958 1922 1964 1948 1964 1946 1960 1928 1926 1939 1961 1929 1943 1961 1958 1927 1959 1938 1962 1963 1935 1960 1960 1959 1949 1954 1918 1963 1962 G Gabriel, G 4.2/1823 Gadzuk, B 11.1/1959 Gaertner, W 12.6.3/1925 Gafanovich, G. Y 10.2.1/1961 Gafanovich, M. D 12.3/1961 Galassini, A 3.6.2/1903 Gale, B 7.1/1962 Gale, H. G 2.1/1901 Gallagher, D. R 3.4/1919 54 250 217 157 250 232 134 134 46 192 183 180 134 165 206 225 138 189 146 113 4 276 66 67 73 17 207 226 239 170 130 157 181 185 58 207 128 158 255 250 127 165 270 133 204 241 134 16 227 247 253 257 161 261 7 9 30 96 158 195 206 39 196 120 245 272 230 263 110 180 41 101 Subsection/Year Page Gallo, P. M 10.2.4/1925 232 Galloway, D. F 12.2/1955 259 12.2/1961 260 12.3/1961 263 Gardner, G. F 1.1/1948 2 Gardner, I. C 1.3.2/1955 21 2.1/1955 43 2.3.1/1955 57 2.4.1/1957 71 2.4.5/1960 85 Garner, W. R 5.3/1949 143 Garrett, P. L 6.4/1964 167 Gary, M 4.3/1956 123 9.1/1953 201 9.3/1955 210 9.3/1956 210 10.2.1/1957 230 10.2.4/1956 233 12.1/1956 258 Gaskill, D. M 6.2.2/1955 136 Gates, J. W 2.2.3/1956 51 7.4/1960 186 8.1/1954 191 Gates, T. S 10.1.4/1955 226 Gauss, H. E 8.1/1934 190 Gay, P 1.7/1953 37 11.3/1951 251 Gear Grinding Co 10.2.1/1933 229 Geary, P. J 5.7/1954 149 5.7/1958 150 5.7/1960 150 Geballe, R 5.7/1958 150 Gebhard, J. W 5.3/1949 143 Gee, A. E 11.3/1949 250 Geer, R. L 1.1/1946 2 Gehlhoff, G 6.2/1922 157 Gehrke, E 1.6/1931 34 1.6/1932 34 2.2.1/1902 44 2.3.1/1902 90 2.3.1/1904 276 2.3.1/1906 56 Geiger, F. E. Jr 2.4.3/1949 78 General Electric Co 5.2.2/1931 133 Georgi, G 3.6.4/1962 116 11.1/1953 243 Gerasimov, F. M 2.5/1961 88 2.5/1963 89 Gerchikov, A. M 12.2/1962 260 Gerhardt, U 11.1/1958 245 Gerlach, W 1.1/1937 2 1.3.1/1937 17 Germansky, B 1.3.3/1933 22 Gershman, G 6.8/1960 173 Gertsbakh 1.3.2/1962 22 Giacomo, P 2.4.3/1952 79 Gibbs, D. F 1.4/1958 29 Gidel, A. Y 1.3.2/1960 21 Gielessen, J 4.4/1962 127 Gierlich, R. A 3.1/1962 94 12.6.5/1950 275 12.6.5/1953 275 Gieseler, E. A 4.1/1888 177 Giesler, H 9.2/1959 204 Giessbart, R 8.1/1938 190 Gigas, E 2.4.6/1934 86 Gilet, P. M 1.3.3/1953 23 10.1.4/1951 226 Gill, D 4.2/1889 121 6.4/1888 164 Gillilland, K. E 2.3.7/1964 68 Gilson, J. R 8.1/1963 192 Gini, E. C 12.2/1962 260 Gladilina, T. S 1.2.3/1961 14 Glazebrook, R 1.2.1/1923 6 3.1/1920 92 Glazebrook, R. T 1.1/1919 286 Subsection/Year Page Gleason Works 10.2.2/1930 231 10.2.6/1926 235 10.3/1927 238 10.3/1928 238 10.3/1930 238 Glennan, T. K 1.1/1961 4 Glover, J. H 9.3/1961 210 10.2.4/1961 233 Glover, L. E 2.4.1/1951 70 Godfrey, C 4.1/1959 119 Godfrey, G 3.2/1959 96 Godfrey, J. R 7.1/1926 176 Godfrey, W 3.3/1957 99 4.4/1957 126 Goetze, S 5.7/1962 150 Gogate, D. V 2.3.2/1938 60 Gogava, L. A 7.1/1965 188 Goldberg, J. L 2.2.1/1963 48 2.4.1/1962 72 2.4.2/1962 77 4.4/1964 128 Goldberg, M 7.4/1960 186 Goldes, L 6.6/1963 170 6.8/1964 173 Goldsborough, J. P 6.2/1693 162 Gollnow, H 4.4/1962 127 Golod, S. D 3.3/1965 116 Goloul'nikov, E. M 6.1/1961 156 Golubkova, V. P 2.4.4/1965 276 7.2/1961 181 7.2/1962 181 7.2/1965 188 Goncharskii, L. A 5.2.2/1952 135 5.2.2/1955 136 Gondik, S. L 4.4/1963 127 7.4/1963 187 Gonnessiat 6.4/1 907 1 64 Good, C. H 1.7/1954 38 1.7/1959 38 Goode, B 7.4/1956 185 Goodeve, T. M 3.5/1877 103 Goodier, A 3.6.4/1959 116 Goodman, J 1.5/1923 32 Goodman, L. E 1.5/1962 33 Goodrich, C. L 12.6.1/1923 268 Goodwin, H. M 1.3.1/1913 17 1.3.1/1920 40 Gootschau, C. M 4.4/1925 124 Gopel, F 1.2.1/1926 39 1.4/1912 28 2.4.4/1919 82 3.3/1914 97 3.3/1920 97 3.5/1910 104 3.5/1917 105 6.1/1926 153 6.4/1926 165 9.1/1920 198 9.1/1929 199 9.1/1929 199 9.1/1930 199 10.2.6/1913 235 Gorbacheva, V. V 6.1/1963 156 6.2/1963 . 161 7.3/1963 184 Gordon, E. I 2.4.3/1963 81 Gothel, E 5.2.5/1947 141 Gough, V. E 8.2/1953 195 Gould and Eberhart 10.2.2/1922 230 Gould, G 2.3.7/1963 67 Goulder 2.4.3/ 1962 81 10.1.4/1964 228 10.2.2/1964 232 10.3/1961 239 Gouzil, J 1.1/1961 4 Govorkov, V. G 5.4/1959 145 Subsection/Year Gow, W. J 12.6.5/1917 Gradenwitz, A 3.6.4/1910 Gran, G 1 .2.3/1958 Grand, P 1.4/1952 1.4/1955 Graneek, M 5.2.5/1951 Grant, G. B 10.1.2/1958 Graux, L 1.4/1927 Gray, A. W 1.2.1/1919 4.4/1914 Gray, J. B 6.6/1919 Grayson, H 1.2.1/1940 Green, A. E 1.5/1951 Green, C. J 8.1/1963 Green, D. R 1.1/1962 Green, R. E 9.2/1962 12.2/1964 Green, S. E 2.4.3/1930 Green, T. M 11.1/1955 Greenfield Tap & Die Corp 9.1/1917 Greenland, K. M 1.1/1956 11.3/1953 Greeye, J. W 10.2.1/1962 Gregor, H 10. 1.4/ 1936 Grether, W. F 5.3/1948 Gribben, W 4.3/1896 Greiss, E. C 8.2/1918 Griffin, P. M 2.3.4/1949 Griffiths, R. B 2.3.1/1957 Griggs, H. J 1.7/1945 Grigor'ev, I. A 3.4/1956 Grim, E. D 5.4/1962 Grimod, Y 2.4.2/1955 Grin, G. L 12.3/1961 Grodzinski, P 12.2/1952 Grohe, W 1.2.1/1960 Groocock, W. G 6.6/1916 Groosfield, K 1.2.4/ 1952 Gross, F. L 7.1/1959 Groth, W 3. 1/ 1 948 Grover, F 12.6.1/1942 Grozinskaya, Z. P 7.4/1961 7.4/1963 Grudzinski, R 2.3.7/1963 Gruenberg, I. J 10.2.4/1934 Grunberg, L 7.1/1961 Gruneisen, E 2.4.2/1907 GSP-Malic 1 2.3/1 962 Guenther, A. H 2.3.1/1957 Guenther, N 8.2/1939 9.3/1934 9.3/1939 Guild, J 2.2.1/1920 2.5/1956 2.5/1960 5.2.4/1924 8.1/1919 8.1/1920 Guillaume, C. E 1.1/1921 1.4/1928 2.3.2/1895 3.1/1918 3.2/1902 3.2/1913 4.1/1895 4.1/1921 4.2/1886 4.2/1889 4.2/1907 4.3/1903 Guillaume, H 6.3/1956 Gulbransen, E. A 1.7/1946 Gumenyuk, V. S 2.4.3/1961 Gunn, A. F 11.1/1946 Gunn, R 3.5/1940 5.2.2/1939 Page 274 114 14 28 29 141 216 28 6 124 169 7 33 192 5 204 261 78 243 197 3 251 230 224 143 122 193 63 58 36 102 146 75 263 259 9 169 15 179 93 269 186 187 68 233 179 73 263 58 194 208 209 45 139 189 189 1 28 59 91,92 94 94 117 117 121 121 121 128 163 37 80 241 107 133 287 Subsection/Year Page Gtinther, N 8.2/1939 194 9.3/1939 209 Gunther, C. O 8.1/1930 190 Gupta, S. C 1.6/1962 35 Gurney, C 1.7/1953 37 Gurney, J. P 12.2/1961 260 Gustafsson, G 3.5/1948 107 Gustafsson, O 7.4/1960 186 Gustyr', L. Y 6.4/1961 167 8.2/1962 196 9.1/1963 202 Gutzwiller, J. E 10.1.1/1960 215 Guyette, R. S . 12.6.1/1960 269 H Haake, H 9.3/1962 211 Haas, H 5.2.4/1958 140 5.3/1958 143 Haas, L 3.6.4/1909 114 Habell, K. J 5.4/1948 144 6.2/1960 159 8.1/1954 191 Haber, H 2.4.3/1949 79 Hadlev, L. N 11.1/1955 243 Haertel, A 9.1/1929 199 Hagee, G. R 11.3/1965 255 Hagen, W 10.1.4/1955 226 Halis, F. W 10.1.3.4/1951 220 10.2.4/1951 233 Hall, C. E 9.3/1962 212 10.2.4/1962 234 Hall, E. R 12.6.2/1910 270 Hall, G. A., Jr 1.1/1961 4 Hall, J. A 3.6.1/1929 109 Hall, R. G. N 2.5/1961 88 3.5/1960 108 7.3/1961 183 Halle, G 8.1/1902 189 Hallert, B. P 4.4/1963 127 Halliday, J. S 11.3/1962 254 Halpern, C 1.4/1961 30 1.4/1963 30 Halsey, F. A 3.6.1/1909 109 Hamburger, L 12.5/1933 267 Hameed, A. S 7.1/1959 179 Hamilton, D. T 3.5/1916 105 9.1/1917 197 10.1.4/1917 222 10.1.4/1932 224 10.1.4/1935 224 10.1.4/1941 224 Hamm, F. A 12.5/1950 267 Hammond, R . 1.6/1959 34 Hamon, J 2.2.3/1951 50 2.3.3/1957 62 2.3.4/1957 65 2.4.1/1956 71 2.4.5/1954 84 Hamy, M 2.3.2/1897 59 2.4.2/1898 72 Hanau, H 12.6.1/1964 269 Handel, S 2.5/1963 89 Handley, R 1.4/1954 29 Haneman, G. C 3.6.2/1919 111 Hanes, G. R 2.2.1/1959 47 2.2.1/1963 48 Hanley, D. S 1.6/1960 34 Hanold, J. I 6.2/1958 159 Hansen, G 2.2.3/1958 51 Hansen, J. R 6.6/1957 169 Hansen, P. A 4.2/1879 120 3.6.1/1921 109 Hanson, B. M. W 9.1/1923 198 Hanson, M 11.2/1948 248 Hanson-Whitney 3.5/1925 106 Hanysz, E. A 11.3/1958 252 Hara, K ..2.4.2/1959 76 Subsection/Year Hard, C. G 5.2.5/1949 Hariharan, P 2.4.1/1959 2.4.2/1959 2.4.3/1961 2.4.4/1960 2.4.4/1961 2.4.5/1959 6.5/1959 6.5/1961 7.3/1961 11.1/1960 Hariharan, S .7.1/1959 Haringx, V. J. A .1.5/1949 1.6/1949 Harkness, Wm. .1.1/1 887 Harle, G. A 2.2.1/1955 Harrick, N. J.. ..11.3/1962 Harries, R .3.6.1/1944 Harrington, J. A. 1.3.2/1954 Harris, C. M 1.6/1961 Harris, F. K ...1.1/1961 5.2.2/1961 Harris, N. L 2.3.1/1950 2.3.3/1950 Harrison, E. R ...3.2/1963 3.5/1963 Harrison, G. R .2.3.1/1946 2.4.2/1955 9.1/1951 12.6.2/1938 12.6.2/1955 12.6.2/1957 12.6.2/1958 12.6.3/1951 Harrison, P. W 1.3.1/1961 1.3.1/1962 1.3.1/1963 3.2/1953 3.2/1955 3.4/1959 3.4/1960 6.2/1954 7.3/1960 8.1/1956 8.2/1962 9.1/1953 9.1/1961 9.3/1961 Harrison, R. E. W 1.7/1936 12.4/1929 12.4/1932 Harrison, W. H 9.3/1952 Harrisson, E. R 3.2/1963 3 5/1963 Harrold, B. P 6.1/1948 6.1/1953 Hart, K. H 1.2.2/1961 2.2.2/1960 2.3.1/1963 2.3.4/1956 2.4.6/1963 Harting, H 2.3.5/1907 Hartman, R. E 11.1/1954 Hartman, R. S 11.1/1954 Hartmann, J 1.1/1947 Hartmann, L 3.5/1895 Hartness, J 8.2/1919 Hartridge, H 1.3.4/1923 Hartschen, H 10.1.4/1957 Harzer, P 6.4/1914 Hathaway, C. M 5.2.2/1937 Hauer, F 6.4/1936 Hauseler, E 2.5/1965 Haven, C. E__ ...6.3/1953 Hawrylak, H 12.2/1962 Hayes, J. W 10.2.6/1930 Hayford, J. F 4.3/1902 288 Subsection/Year Page Hayward, H. N 5.1/1940 130 Hazi, T 7.4/1962 186 Head, J. W 1.1/1953 3 12.3/1948 262 Heavens, 0. S 1.7/1957 38 2.1/1950 42 11.1/1951 242 11.1/1958 245 Hefft, K 2.4.3/1963 81 Dr. Johannes Heidenhain 2.5/1963 89 4.1/1963 120 5.4/1964 146 6.4/1963 167 Heil, H. G 1.5/1918 31 Heinecke, K 2.4.6/1965 276 Heinemann, E 8.1/1952 191 Heinold, L. O. Jr 3.4/1962 103 12.3/1956 262 Heinssen, H 10.2.6/1933 236 Heinz, A 5.2.2/1935 133 Heisen, A 11.1/1958 245 Heldt, P. M 3.6.4/1934 115 10.3/1923 238 Heller, W 11.3/1948 250 Hellmich, H. K 10.1.1/1960 240 Helmert, F. R 6.4/1907 164 Hemscheidt, H 12.1/1937 257 Henderson, G 2.2.5/1964 56 Henderson, G. A 5.2.4/1963 141 Hennert 4.2/1758 120 Hennig, M 11.1/1956 243 Henrici, E. O 6.4/1923 165 6.7/1918 170 Henry, J. M 9.3/1922 206 Herb, C. O 12.6.4/1937 274 12.6.5/1937 275 Alfred Herbert, Ltd 1.2.3/1920 13 4.4/1918 124 9.1/1920 197, 198 10.2.6/1921 235 Herington, E. F 1.4/1954 29 Herkt, K 12.2/1959 260 Hermann, K. L 10.1.4/1922 223 Herriott, D. R 2.3.7/1962 67 7.1/1961 180 Hertz, H 1.5/1896 31 Hessen, V. B 3.2/1953 96 Heughebaert, D 5.4/1958 145 Heughebaert, J 5.4/1958 145 Heuvelink, H. J 6.4/1913 165 Hewitt, G. F 11.3/1964 255 Heyde, G 6.4/1929 165 Hiatt, H. D 5.1/1945 130 Hidiegan, M. E 10.2.2/1909 230 Hidnert, P 4.3/1953 123 Hiersig, H. M 10.3/1948 239 Hight, E. K 9.1/1941 200 Hildebrand, K 6.2/1961 160 Hildebrand, S 5.7/1956 149 Adam Hilger Ltd 2.4.1/1924 69 2.4.1/1942 70 6.1/1944 154 6.2/1944 157 8.2/1941 194 Hilger and Watts, Ltd 2.4.1/1947 70 2.4.1/1951 70 2.4.4/1939 82 6.2/1948 158 6.2/1949 158 7.2/1944 180 8.2/1951 195 8.2/1953 195 12.2/1964 261-2 Hill, B. R 12.1/1936 257 SubstdionlYear Page Hill, R. M ..2.2.1/1962 48 2.3.1/1961 59 2.3.2/1961 61 2.3.3/1962 63 2.4.3/1963 81 Hill, W. J.. 1.3.1/1959 18 Hillier, J 12.6.1/1951 269 Hillman, M. H 5.6/1955 147 Hindes, J. W 12.2/1930 259 Hinkle, R. T 12.1/1947 258 Hire, M. de La 6.7/1897 170 Hirsch, P. B 1.7/1953 37 11.3/1951 251 Hirsl, P ..1.2.3/1961 14 Hisakado, T 1.7/1964 39 Hitchcock, R. C 8.1/1934 190 12.5/1958 268 Hoadley, H. O. 5.2.4/1949 140 Hobbs, F. W 12.6.2/1928 270 Hock, F 2.4.5/1961 85 2.4.6/1965 276 Hodsman, G. F 8.1/1952 191 Hoefter 10.2.6/1961 237 Hoersch, V. A 1.5/1930 32 Hoffman, G. R 11.3/1963 255 Hoffman, W_._ 12.6.1/1958 269 Hoffrogge, Ch 2.2.2/1954 49 2.4.5/1957 84 2.4.6/1956 86 2.4.6/1961 87 4.1/1955 119 4.1/1961 119 4.3/1955 123 4.3/1958 123 5.6/1961 147 Hofmann, W 5.1/1932 130 Hogland Eng. and Mfg. Co 10.1.3.1/1954 218 Hohenner, H ..6.4/1910 165 Hoitz, H ..6.4/1959 166 Hoke, W. E 12.5/1925 266 12.6.5/1925 275 Holden, J .2.2.1/1949 46 Holecek, K 8.2/1942 195 Hollis, W. W ...2.4.4/1957 83 Holman, S. W -1.3.1/1887 17 1.3.1/1901 40 6.1/1898 153 Holmes, P 3.2/1963 97 3.5/1963 108 Holmes, W. G._ 8.1/1921 189 Holroyd, L. V 2.1/1955 43 Holt, W. L 3.5/1933 106 Holtwijk, T__ 1.2.3/1960 14 Homewood, J 12.6.2/1928 270 E. H. Hones, Ltd... 3.6.2/1946 113 Hopkins, H. H 2.2.1/1957 47 Hopper, J. W ..12.3/1958 262 Hopper, V. D 7.1/1946 176 7.1/1947 176 Hori, S 1.2.3/1959 14 Home, R ..1.4/1962 30 Horner, F 5.1/1937 130 Horner, J .3.6.1/1905 108 Horsfield, W. R 12.6.2/1965 271 Horton, J. W .1.2.2/1952 11 Horton, W. L 1.1/1962 5 Hoshina, N 9.1/1961 201 Hoskins, M 8.1/1959 192 Hoskins, M. S 2.1/1956 43 Hosmer, G. L 6.4/1930 165 Hough 6.4/1904 164 Hough, J 1.3.1/1951 17 Houghton, J. L ..8.1/1941 190 Houston, P. L ...3.6.4/1922 115 5.2.3/1922 138 Houston, W. V ..2.3.5/1927 65 Howard, J. E ...3.5/1893 104 289 Subsection I Year Page Howden, P. F 1.3.3/1962 25 Howell, E. A 5.5/1951 146 Howlett, L. E 1.2.2/1961 12 2.3.3/1963 63 Hoyt, A 2.4.2/1936 73 Hrdlicka, J 8.1/1956 191 Hsu, B. S 7.3/1962 184 Hsueh, C. W 2.3.2/1946 60 Hubbard, D 11.1/1948 241 Hubbell, C. A 3.6.2/1920 111 Huber 1.3.3/1936 22 Hudson, F. C 1.7/1922 36 Hudson, W. S 10.2.4/1918 232 Huetz, J 5.2.2/1953 136 Huff 2.3.1/1897 90 Hughes, H. A 1.3.1/1946 17 Hughes, J. C 3.4/1950 102 Hugo, S. W 7.1/1956 178 7.1/1961 179 Hiihn, H 1.4/1959 29 Humbert, B 3.3/1947 99 Hume, K.J 1.2.1/1950 7 1.2.1/1956 8 6.1/1949 154 Hume, K. S 6.2/1955 158 Humphreys, C. J 2.3.3/1929 60 2.3.3/1930 60 2.3.3/1931 60 2.3.1/1934 57 Humphreys, H 7.3/1925 181 Humphreys, W. J 2.3.1/1897 90 Hunt, G. H 5.2.2/1954 136 Hunt, I. A 3.6.4/1949 115 Hunt, R. W. G 5.4/1946 144 Hunter, J. J 1.4/1962 30 Hunter, M. C 5.5/1944 146 Hunter, P. H 1.4/1959 29 5.2.2/1946 134 Huntoon, R. D 1.1/1950 3 1.1/1965 39 2.4.2/1954 75 Hunzinger, J. J 2.1/1957 44 2.4.4/1955 82 Hupe, K 3.2/1941 95 Hurtt, L 1.2.4/1964 17 Hwang, H 1.4/1963 30 Hylar, J 5.6/1954 147 I Ichikawa, M 9.2/1964 205 Ickert, J 1.3.1/1955 17 Ido, M .-.7.4/1962 186 Idrac, J 5.1/1960 130 Ignatenko, V. V 1.6/1963 34 Iizuka, K 3.6.4/1962 116 Ikeda, I 2.4.2/1958 76 Her, W. T. Jr 9.3/1917 206 Illinois Tool Works 9.2/1934 203 9.2/1935 203 10.1.4/1928 223 10.1.4/1954 226 10.2.2/1952 231 10.2.6/1934 236 Imahori, K .11.2/1953 248 Imaizumi, M 2.3.2/1928 59 2.4.5/1929 84 Imbusch, G. F 2.4.5/1963 86 Indian Government 3.2/1915 95 Industrial Press 9.4/1964 212 10.1.3.2/1964 219 10.1.3.4/1964 221 Ingelstam, E 2.2.3/1958 51 Ingram, H. J 12.4/1944 266 Institute of Metals 1.7/1953 37 International Bureau of Weights and and Measures 2.4.5/1961 85 4.1/1889 117 International Business Machines 1.2.l/l952 8 Subsection I Year Page International Comm. on Weights and Measures 1.2.2/1963 13 International Organization for Standardization 10.1.1/1953 214 10.1.1/1957 214 10.1.1/1961 215 Irland, J 11.1/1963 246 Isa, S 9.2/1963 205 Isakower, R 1.3.3/1963 26 Isard, J. O 2.5/1952 88 Isebeck, K 1.4/1964 31 Ishikawa, J 10.1.4/1962 228 Iudin, S. P 5.2.5/1960 142 Ivanov, Y, V _■ 10.1.4/1963 228 Ivantsov, A. I 1.3.2/1965 40 Ives, F. E 4.4/1902 123 Ives, H. E 11.2/1927 247 Izotov, S. I 7.2/1963 181 J Jackson, C. V 2.3.2/1936 60 Jackson, D. A 2.4.3/1949 79 2.4.3/1963 81 Jackson, L. C 11.3/1951 250 Jackson, L. P 12.5/1941 267 Jacobs, S. F 2.4.3/1962 81 Jacoby, H 4.2/1895 121 4.2/1896 121 Jacquinot, P 2.2.1/1948 45 Jaeger, J. J 10.1.3.2/1959 220 Jaffe, H 2.4.1/1950 70 Jaffe, J. H 2.2.1/1956 46 2.4.1/1950 70 2.4.3/1951 79 James, P. R 5.2.2/1961 137 Jansson, A 9.2/1946 204 Jarrell, R. F 12.6.2/1964 271 Jaseja, T. S 2.3.7/1963 67 Javan, A 2.3.7/1963 67 Jeans, L. E 10.1.4/1948 225 Jeffcott, H. H 9.3/1907 205 Jeffery, E. E 12.3/1952 262 Jeffree, J. H 5.4/1932 144 Jeffreys, H 1.3.3/1932 22 Jenkins, I 1.7/1953 37 Jennings, W. O 3.4/1948 102 7.1/1947 177 Jensen, H 8.1/1950 191 8.1/1954 191 Jewell, R. G 4.2/1935 122 Jimbo, Y 1.6/1962 35 Jobst, C 5.6/1947 147 Johansen, F. C 1.7/1945 36 Johansson, C. E 1.2.2/1933 11 C. E. Johansson, Ltd 5.2.3/1953 139 5.2.3/1954 139 5.2.3/1958 139 6.3/1919 162 Johansson, L. P 2.2.3/1958 51 Johnson, J 1.1/1948 2 Johnson, K. L 5.6/1959 147 Johnson, K. W 1.6/1962 34 Johnson, L. J 3.2/1906 94 Johnson, L. O. C 3.1/1952 93 4.1/1951 118 4.3/1951 123 Johnson, S. G 9.1/1957 201 Johnson, S. J 9.3/1957 211 Johnsrud, A. L 11.2/1927 247 John-Sons 9.2/1924 203 Johnstone-Taylor, F 10.1.4/1924 223 A. A. Jones and Shipman 12.5/1954 267 Jones, A. B 1.5/1946 32 Jones, A. G 1.2.3/1959 14 Jones, D. E 1.5/1896 31 E. H. Jones, Ltd 3.5/1943 107 6.1/1943 154 290 Subsection/Year Page Jones, F. D 3.1/1922 92 8.2/1918 193 12.6.1/1920 268 12.6.4/1918 273 12.6.5/1920 275 Jones, R. V 1.5/1961 33 5.1/1962 131 5.2.4/1951 140 5.2.4/1959 140 5.2.4/1961 140 5.4/1956 145 5.6/1961 147 5.7/1951 148 5.7/1955 149 5.7/1956 149 5.7/1959 151 5.7/1962 150 Jones, T. E 3.4/1948 102 Jordon, W 6.4/1923 165 Jotzoff, A 3.2/1940 95 Joyce, A. H 5.2.5/1958 142 Judge, A. W 1.1.1/1957 8 Judson, L. V 1.2.2/1956 11 1.2.2/1959 40 1.2.2/1960 12 4.1/1960 119 4.2/1934 121 4.2/1960 122 4.3/1926 123 4.3/1927 123 4.3/1960 123 6.4/1927 165 Julius, W. H 1.6/1895 34 Juran, J. M 1.3.4/1935 27 Jurek, B 8.1/1948 190, 191 8.2/1954 195 Juricic, H 6.2/1959 159 K Kaatz, K 3.2/1958 96 Kabatov, N. F 10.3/1962 240 Kadikov, G. M 1.2.3/1961 14 Kahl, G. D 2.2.3/1952 50 Kainer, G. B 1.4/1963 31 3.4/1965 116 .52.3/1962 139 Kaiser, F 6.4/1870 164 Kaiser, H 1.3.3/1936 22 Kaluzka, H 9.2/1963 204 Kamada, A 1.4/1952 28 Kamilov, I. K 2.4.2/1962 77 Kammerer, O. F 11.3/1958 252 Kaneko, T 2.3.2/1958 62 2.3.4/1958 65 Kanevskii, Y. P 2.2.3/1960 51 Kann, G 12.1/1949 258 Kans, N. F 1.4/1958 29 Kantor, K 2.2.1/1963 48 2.2.3/1963 51,52 2.4.5/1961 85 5.1/1961 131 Karelin, N. M 8.1/1962 192 12.2/1960 260 Karolus, A 1.2.4/1960 16 Karovic, K 6.2/1963 162 Karpasheva, A. N 1.3.3/1960 25 Kartacheff, A. I 2.4.3/1935 78 Kartaschoff, P 2.3.6/1962 66 Kartashev, A. I 1.3.2/1962 21 2.3.2/1942 60 2.4.5/1960 85 2.4.5/1963 85 2.4.6/1963 87 Kartashova, A. N 3.6.4/1963 116 Kartcher, H. S 6.8/1927 172 Kashirin, V. B 5.5/1961 150 Kasper, R. H .3.6.1/1921 109 SubsectionlYear Page Kastler, A 2.3.7/1962 66 Kater, H 1.3.2/1830 40 Kath, H 2.2.5/1897 53 Katsman, F. M 9.2/1963 205 Kaufman, V 2.3.4/1962 65 2.3.6/1959 66 Kautsky, F 8.1/1948 190 Kavalerov, G. I 1.1/1963 5 12.1/1962 258 Kaverkin, I. Y 1.1/1963 5 Kavle 10.2.1/1920 228 Kawamura, C 9.2/1963 205 Kayak, L. K ■ 1.3.2/1963 22 1.3.2/1964 40 2.4.1/1961 71 3.2/1956 96 4.4/1960 127 Kaye, G. W. C 3.1/1911 91 Kayser, H 2.3.2/1904 59 Keane, C. B 6.21(1948) 158 Keating, D. T 11.3/1958 252 Keck, K 10. 1.1/1960 240 Kedrov, S. S 1.6/1962 35 Keil, E 2.4.1/1908 69 Keinath, G 1.2.1/1958 9 1.3.2/1935 20 4.1/1934 117 5.2.1/1932 131 Kelling, L. U. C 12.3/1963 264 Kellner, H 4.4/1923 124 Kelly, J. C 11.1/1958 245 Kennedy, C. W 1.2.1/1962 9 1.3.2/1958 21 Kennedy, J. T 6.1/1962 156 Kern, R 2.4.3/1963 81 Kern, W. F 1.2.1/1938 40 Kerns, D. M 2.1/1960 44 Kessler, K. G 2.3.3/1961 63 2.3.4/1950 64 2.3.6/1958 66 2.3.6/1960 66 Kessler, O 12.6.4/1934 274 Khairov, A. A 9.1/1961 202 Khalebskii, N. T 9.3/1963 212 Khamsavi, A 11.1/1947 241 Khanna, B. N 2.2.4/1962 53 Khomazyuk, V. G 2.2.2/1960 49 Kickman, L 8.1/1959 192 Kiehne, H. 3.6.2/1919 111 Kienzle, O 1.2.1/1954 8 1.7/1937 36 3.6.2/1920 111 6.8/1922 172 10.1.1/1949 213 Kimble, R 2.5/1963 89 3.2/1963 97 Kinder, W 2.2.3/1958 51 2.4.5/1962 85 2.4.5/1963 86 2.4.6/1963 87 King, A. A 10.1.4/1948 225 King, H. M 5.2.3/1962 139 King, L. E 8.2/1921 193 King, R. J 6.1/1961 156 King, R. P 6.7/1903 170 Kinzel, A. B 1.1/1961 4 Kirby, R. K 4.3/1953 123 Kirchner, W 3.4/1962 103 Kirchhofer, K. F 3.1/1942 93 Kirichenko, A. P 2.1/1962 44 2.1/1963 44 2.4.1/1962 72 2.4.5/1963 85, 86 2.4.6/1963 87 Kirillova, T. S 9.2/1963 205 Kirk, D. B .5.2.5/(1945) 141 Kirkham, E. E 10.1.3.2/1959 220 291 Subsection/Year Page Kirkpatrick, P 1.3.4/1922 26 Kirner, J 7.4/1922 185 Kissam, P 1.2.4/1949 15 1.2.4/1962 16 6.2/1963 161 Klapper, E 1.2.2/1929 10 1.2.2/1930 11 Klawe, C. H 1.2.1/1945 7 Klebanov, M. K 12.2/1961 260 Kleintov, N. A 4.4/1960 127 Klemm, W. F 1.7/1945 36 Kline, J. E - 1.7/1935 36 12.3/1947 262 W. Ferd. Klingelnberg Sohne 10.2.1/1956 230 Klucher, T. M 2.3.7/1963 67 Kluwe, P 10.1.4/1940 224 1.1/1963 5 Arthur Knapp Engr. Corp 9.1/1919 198 Knedel, W 9.1/1935 200 9.3/1935 208 Kneller, V. Y 12.3/1963 264 Kniehahn, W 5.1/1928 129 Knight, W. A 6.1/1908 153 12.5/1915 266 Knott, R. D 2.3.3/1951 61 Knowles, T. R 10.2.5/1956 234 10.2.5/1957 234 Knoyle, C. H 2.4.4/1926 82 6.3/1950 163 Koana, Z 2.1/1951 43 Kobler, H 2.4.3/1963 81 Kobold, H 6.4/1914 165 Koch, W 4.1/1945 118 4.2/1945 122 Henry Koch & Son 3.6.4/1908 114 Kochenov, M. I 6.1/1961 156 Koehler, H 6.2/(1963) 162 Koehler, O. E 9.3/1938 208 Koehler, W. F 2.2.2/1958 49 2.2.5/1953 55 Koenig, E. H 2.4.4/1959 83 6.2/1964 162 Koenig, F 4.4/1944 126 Koenigsberger, F 12.2/1963 261 Koester, C. J 2.2.5/1958 55 2.2.5/1960 55 Kogan, G. I 10.1.4/1960 227 Kogelnik, H 2.3.7/1962 67 Kohn, J. P 1.3.1/1962 18 Kolomiitsov, Y. V 2.4.4/1963 83 7.3/1956 182 7.3/1959 183 Kolomitsova, T. S 2.4.2/1960 76 Kolpakov, D. I 8.1/1963 193 Kondo, Y 2.4.1/1961 71 Konejung, A 1.3.3/1933 22 Konig, F 2.2.2/1928 49 Kon'kova, E. M 3.5/1965 151 Kono, T 2.4.6/1962 87 Koop, H. A 9.2/1962 204 10.1.4/1962 228 Koppelman, G 2.4.3/1961 81 2.4.3/1963 81 7.3/1961 183 11.1/1956 243 11.3/1960 253 Kornhauser, M 1.5/1951 33 Koroleva, A. N 2.4.2/1963 77 Koronkevich, V. P 2.4.2/1960 77 2.4.4/1961 83 2.4.4/1965 276 7.2/1961 181 7.2/1962 181 7.2/1965 188 8.2/1962 196 9.1/1963 202 Korotkov, V. P 12.3/1960 262 Korwien, H 1.2.1/(1950) 7 Subsection/Year Page Korsunskii, M. I 5.2.2/1964 134 Koster, G. F 2.3.7/1962 67 Kosters, W 2.3.2/1935 60 2.4.1/1922 69 2.4.1/1926 69 2.4.4/1925 82 2.4.5/1938 84 3.1/1912 91 3.5/1908 104 3.5/1923 105 4.4/1913 124 Kostich, B. E 1.2.4/1960 10 1.2.4/1965 40 5.2.2/1962 137 Kostin, V. E 4.4/1960 126 Kostrov, B. D 5.2.5/1960 142 Kotsyubinskii, O. Y 12.2/1962 260 Kottas, H 5.2.2/1935 133 Kouno, T 2.4.6/1964 87 Kozma, A 1.5/1962 33 10.1.3.6/1962 222 Kragel'skii, I. V 7.7.1/1965 188 Krasnoperov, N. K 5.4/1961 145 Krause, G 2.2.1/1916 45 Krause, H 2.4.3/1963 81 Krebs, K 2.4.3/1961 81 7.3/1961 183 11.1/1956 243 Kreis, E 9.1/1925 199 Kremen', Z. I 3.1/1963 94 Kress, K 1.2.1/1942 7 Kreusler, H 2.4.1/1932 70 Krug, C 12.4/1927 265 Krug, W 6.4/1938 166 7.3/1956 182 Kruger, J 11.2/1964 249 Krumme, W 10.1.1/1960 240 Krupp, N. Y 1.3.1/1963 19 Kruszynski, M 1.3.3/1957 24 Kubadek, L 6.2/1963 162 Kudinov, V. A 12.2/1962 260 Kuebler, K. H 9.1/1952 201 Kuehni, H. P 5.2.2/1942 134 Kugler, C 8.1/1926 189 9 3/1931 208 Kuhlmann-Wilsdorf, D 5.2!3/1954 139 5.7/1954 149 Kuhn, H 2.1/1951 42 2.4.3/1949 79 2.4.3/1950 79 Kuhne, C 6.4/1960 167 Kuhne, K 7.1/1958 178 Kuhne, P 3.2/1937 95 Kuhnen, F 3.2/1913 95 Kumagai, I — 9.2/1963 205 Kuokkanen, P. E 5.2.2/1934 133 Kupriyanov, V. M 11.2/1963 249 Kuptsov, I. A 3.4/1960 103 Kurochkin, A. P 5.2.5/1962 142 5.2.5/1963 142 Kurrein, M 3.6.4/1922 115 10.1.4/1923 223 Kurtz, H. F .4.4/1925 125 5.4/1925 144 8.2/1938 194 Kutay, A 3.3/1933 98 Kvaskov, L. Ya 2.4.2/1965 276 L Laborde, A .3.6.3/1946 114 4.2/1946 122 Laessker, F 9.2/1939 203 Laetzig, W 12.5/1950 267 Lafay, A .2.4.4/1901 81 Lagunov, A. S— 5.2.2/1964 138 Lakshminarayanan, S 1.2.2/1955 11 LaMarre, D. 2.4.1/1956 71 292 Subsection/Year Page Landwekr, R 2.2.2/1956 49 2.2.3/1958 51 2.2.3/1959 51 7.1/1949 177 7.1/1958 178-9 7.3/1959 183 7.3/1962 184 7.4/1958 185 8.2/1958 196 8.2/1959 196 Langer, R. E 1.1/1959 39 Lapujoulade, J 1.7/1964 39 Larke, E. C 12.4/1927 265 Larrnor Eng. Co 9.3/1945 209 Larson, K 11.1/1954 243 Lasnier 1.7/1945 36 LaTourrette, J 2.3.7/1963 67 Laurent, P. A 9.3/1929 207-8 Lawrence, T. R 2.3.7/1963 67 Lawson, J. L J 2.3.4/1936 63 Lea, F. C 1.2.1/1946 7 Le Bourhis, C. A 9.1/1953 201 Lede, W 1.3.3/1948 23 Lee, A. J 9.2/1917 202 Lee, E. S 5.2.2/1937 133 Lee, J. W 6.8/1951 172 9.3/1947 210 Lees-Bradner Co 9.2/1934 203 10.1.4/1934 224 10.2.1/1923 229 Lees, E. J 10.2.6/1903 235 Lees, S 1.1/1953 3 Legallais, V 1 5.2.2/1947 135 Legay, F 2.2.4/1956 52 Legrand, C 11.3/1948 250 LeGrand, R 6.2/1958 159 12.1/1962 258 12.4/1962 266 Lehmann, H 2.4.2/1936 73 Lehmann, R 1.2.1/1940 7 1.2.1/1956 8 1.7/1957 38 9.1/1932 199 Leibfried, G 5.2.3/1950 139 Leighton, R. B 8.2/1956 196 Leinweber, P 1.2.1/1954 8 1.3.1/1964 19 1.3.2/1964 22 1.7/1944 36 2.4.2/1960 76 2.4.4/1963 83 3.2/1944 95 10.1.3.1/1954 218 Leman, A 3.5/1913 104 4.2/1906 121 Lement, B. S 4.3/1951 173 Lenkova, G. A r 6.2/1964 162 Lennuier, R 2.3.4/1963 65 Lepper, E 3.3/1959 100 5.4/1959 145 Leslie, R. T__ 1.3.1/1963 19 1.3.3/1947 23 1.3.3/1954 23 3.1/1963 94 4.1/1963 119 4.2/1963 122 5.4/1955 145 Leslie, W. H. P 2.5/1962 89 10.2.5/1961 234 Lethersich, W 1.5/1944 32 Levesque, G. N 7.3/1953 182 Levin, B. M 6.1/1952 154 Levina, Z. M 5.6/1962 148 Lewis, A 6.1/1959 155 6.5/1959 168 Lewis, C. R 1.7/1950 37 1.7/1952 37 SubtedionlYear Page Lewis, E. A 2.5/1952 88 Lewis, H. B 2.4.6/1924 86 6.6/1917 169 Lewis, R. E__ 1.2.3/1950 13 3.6.3/1950 114 Lewis, T. C. Jr 12.5/1957 268 Li, T 2.3.7/1961 66 2.3.7/1963 67 Lich, O 12.6.5/1932 275 Lichtenauer, G 10.2.2/1963 232 Liddell, D. M___, 12.6.2/1914 270 Lieberman, G. J 1.3.3/1959 24 Liebhafsky, H. A 11.3/1956 251 Liem, S. II 6.2/1961 160 7.3/1961 183 Lieneweg, F 1.4/1952 28 Liggett, J. V 1.2.3/1962 15 Lily, J. C 5.2.2/1947 135 Limming, E. A 9.3/1922 206, 207 9.3/1923 207 9.3/1924 207 9.3/1928 207 9.3/1929 207 10.3/1922 238 Lindberg, P. J 11.1/1957 244 Lindholm, A. C 3.6.1/1910 109 Lindley, D. V 1.3.3/1946 23 Lindner, W 12.1/1954 258 Linebrink, O. L 1.1/1961 4 Lineham, W. J 12.6.4/1920 274 Linge, J. R 2.5/1957 88 Linnik, V. P 7.1/1942 176 9.1/1960 202 Linsley, H. E 3.6.1/1951 110 Lion, K. S 5.2.1/1956 132 Lippmann, G 6.2/1902 157 Lisitsa, M. P 11.3/1959 252 Littlefield, T. A 2.3.3/1946 61 Litvin, F. L 9.3/1950 210 Livermore, F. A 12.6.4/1922 274 12.6.5/1932 275 Lloyd, H 6.5/1950 167 Lloyd, W. A 8.2/1948 195 Lobe, F 10.1.4/1960 227 Lobell, D 3.5/1958 108 Lobov, S. I 11.3/1963 255 Lochte-Holtgreven, W 2.4.4/1957 83 Lodge, A 1.1/1895 39 Loewe Gesfiirel 12.4/1935 265 Loewen, E. G 1.2.1/1958 9 4.1/1963 119 6.2/1963 161, 163 7.3/1963 183 Loewy 6.4/1906 164 Lofton, R. E 4.4/1932 125 Logacheva, L. N 6.5/1959 168 Lohmann, A 2.3.1/1962 59 2.5/1959 88 Lohse, O 4.4/1910 124 Lokhmatov, A. I 6.2/1964 162 London, F. H 2.3.7/1964 68 Longwell, J 2.3.4/1950 64 Lopovok, T. S ...7.3/1961 183 7.4/1963 187 8.1/1963 197 Lorents, E. V 8.1/1962 192 Lorentzen, I 4.2/1893 121 4.2/1894 121 Lotmar, W 4.4/1962 127 Louckes, F. I. Jr 4.4/1956 126 Love, R. J 1.7/1953 37 Loveland, R. B 12.6.2/1930 270 Lovins, G. H 2.2.1/1964 48 Lowczynski, L 1.2.1/1952 8 Lowe 3.6.4/1914 115 293 SubseciionlYear Page Loxham, J 1.2.1/1962 9 10.2.6/1958 237 12.2/1963 261 Ludemann, K 3.6.3/1929 114 4.1/1922 117 5.5/1931 146 6.7/1928 171 Luders, G 1.1/1951 3 Ludovici, B. F 2.3.7/1962 67 Luers, G. A 10.2.6/1924 235 Lufkin Rule Co 3.6.2/1930 112 Lukacs, E 1.2.4/1951 15 Lukens, H. R. Jr 11.3/1962 254 Lukin, I. V 2.4.5/1962 85 Lummer, O - 2.2.1/1902 44 2.3.1/1902 90 2.3.1/1904 276 7.2/1884 188 Lur'e, B. G 12.2/1962 261 Lush, A. J 5.5/1931 146 Lynch, E. E 5.2.1/1948 132 M Maag Gear Wheel Co 10.1.2/1963 216 10.1.3.1/1963 219 10.1.3.5/1963 222 10.1.3.6/1963 222 10.1.4/1928 223 10.2.1/1926 229 Maag, M 3.4/1952 102 Mabboux, G 6.7/1928 171 Macabrey, C 10.1.4/1947 225 MacDonald, D. K. C 1.3.4/1948 27 MacGahan, P 5.7/1944 148 MacGeorge, W. D 5.2.2/1950 135 Mach, L 6.7/1894 170 Machabey, A 1.2.1/1959 40 Machine Shop Equipment, Ltd 9.1/1946 200 Macinante, J. A 1.6/1963 35 Maclndoe, R. C 5.7/1959 150 Mack, J. E 5.4/1942 144 Mackay, D. M 1.3.3/1958 24 Mackensen, O 7.1/1926 176 MacLachlan, D. F. A 6.7/1962 171 Maevskii, V. M 11.3/1959 252 Magor, L. S 12.2/1963 261 Magyar, G 2.3.7/1963 68 Mah'lmeister, R 7.4/1958 185-6 Mailey, G. C 4.4/1941 125 Maitre, J 6.1/1921 153 Makishima, S 2.1/1951 43 Male, D 11.3/1952 251 11.3/1963 254 11.3/1964 255 Mandel, J 1.3.3/1946 22 1.3.3/1954 24 1.3.3/1962 26 Mandel, L 2.3.7/1963 68 Manke, H. R 6.1/1961 156 Mansfield, D. L 6.1/1962 156 Mansour, T. M 11.3/1963 254 Manzotti, M 5.2.1/1956 132 Mapes, C. W 10.3/1920 238 Marcotte, E 2.4.4/1928 82 Marshal, A 2.4.1/1962 72 6.2/1961 160 Marek, W. J 4.2/1879 120 Mark, A 10.1.4/1964 228 Markov, B. N 12.3/1963 264 Markov, N. N 1.4/1963 31 5.2.3/1962 139 10.1.4/1960 227 10.1.4/1963 228 Markov, P. U 3.4/1962 103 Maries, D 5.6/1955 147 Marmorstone, R.J 12.3/1962 263 Marrinan, H. J 2.2.1/1955 46 Subsection/Year Page Marriner, R 7.1/1947 177 7.1/1948 177 Marriner, R. S 8.1/1953 191 9.3/1958 211 Marsh, D. M 5.7/1962 150 Marsh, M. C 3.5/1929 106 Martin, J 4.1/1948 118 Martin, L. D 9.3/1958 211 10.1.1/1958 215 10.1.4/1948 225 10.2.2/1949 231 10.2.2/1950 231 10.2.2/1964 232 10.2.6/1953 237 Martin, P 1.2.1/1964 10 4.1/1960 119 Martin, W. C 2.3.5/1960 65 Martynov, A. D. 5.2.1/1960 132 Marzetta, A 4.1/1961 119 Marzetta, L. A 2.4.2/1961 77 2.4.6/1961 87 Mason, G. W .1.2.3/1964 15 Mason, W. P 5.2.2/1957 136 Masui, T___ 2.3.3/1957 62 2.3.4/1957 65 Masuda, T_ 12.2/1963 261 Mateos, M 1.2.2/1963 13 Mathews, G. G 2.4.2/1963 77 Matsumoto, T 12.2/1963 261 Matthees, F 12.6.4/1939 274 Matthew, J. A ___3.3/1932 98 Matthews, G. G 2.4.2/1963 77 Matthews, J. W 5.2.2/1929 133 Mattuck, R. D._ 11.1/1956 244 11.2/1957 248 Matveev, V. V ..5.2.1/1962 132 7.4/1960 186 8.1/1963 193 Maudet, L 3.1/1912 91 3.1/1927 92 4.1/1944 118 Maurer, H 1.2.2/1935 11 4.1/1937 118 6.1/1935 153 Maurice, D. M 5.2.2/1954 136 Maxwell Motor Corp 10.1.4/1926 223 Mayer, A. E 7.4/1932 185 Mazur, M 1.3.3/1957 24 Mazurenko, I. V 10.2.6/1962 237 McArdell, W 6.6/1916 169 McCain, G. L 10.2.4/1946 233 McCallum, W. B 1.3.1/1965 19 McCaw, G. T 6.4/1909 164 McClure, E. R 1.4/1965 31 McCombie, C. W 1.1/1953 3 McConnell, D 1.7/1945 36 McCrackin, F. L 11.2/1963 248 McCubbin, T. K. Jr... 2.2.4/1958 52 McCutchen, C. W 7.3/1964 184 McDermott, J. V 7.1/1964 180 McDowell, C. H 10.1.4/1964 228 Mcllraith, A. H__._ 2.5/1963 90 2 5/1964 90 Mcllwraith, C. G 5.7/1958 150 McKee, S. A 1.5/1947 33 McKay, W ...1.1/1953 3 McKeown, P. A. 2.3.3/1960 62 McKewen, G. E 1.5/1962 40 McKinley, W. A 1.2.2/1960 12 McNally, F. A 11.1/1953 243 McNally, J. R., Jr .2.3.4/1949 63 2.4.3/1956 80 McNamara, J. E 11.3/1962 254 McNicholas, H. J 5.4/1931 144 McNish, A. G 1.1/1958 4 1.1/1963 5 1.1/1965 39 294 Subtedion/Year Page McNish A. G. — Continued 1.2.2/1959 12 1.3.1/1960 18 2.3.7/1964 68 McPharlin, L. M 1.7/1927 36 Meadows, J. J 9.3/1946 210 Medhurst, C. W 7.3/1951 182 Medyantseva, L. L 6.1/1963 156 6.2/1963 161 7.3/1963 184 Meggers, W. F 2.2.4/1918 52 2.3.1/1921 56 2.3.1/1934 57 2.3.1/1942 57 2.3.3/1929 61 2.3.3/1931 61 2.3.4/1948 63 2.3.4/1949 63 2.3.4/1950 63, 64 2.3.4/1951 64 Mehdahl, A 10.1.4/1942 225 Meili, J 5.7/1962 150 Meinke, W. W 11.3/1956 252 Meissner, K. W 2.3.6/1958 65 2.3.6/1959 66 2.4.2/1929 73 2.4.3/1942 78 2.4.3/1953 79 Meister, G 1.2.1/1963 9 4.1/1960 119 Mellor, H 6.8/1940 172 Melson, E. W 2.1/1935 41 Meltzer, R. J 4.1/1963 119 4.4/1963 127 12.3/1963 264 Mendenhall, T. C 1.2.2/1892 10 Mennesson, M 5.2.5/1932 141 Menschick, W 11.1/1929 241 Menzel, B 2.2.1/1952 46 11.1/1952 242 Menzel, E 11.1/1957 244 T. and F. Mercer 12.6.5/1932 275 Mergol'd, M. M 6.4/1960 166 Merriam, R 7.1/1955 178 Merrill, P. W 2.3.5/1917 65 Merritt, H. E 9.3/1922 207 9.3/1923 207 9.3/1924 207 10.1.1/1956 214 10.1.2/1955 216 10.1.3.1/1946 218 10.1.4/1923 223 10.2.4/1923 232 Mershon, A. V 5.2.2/1929 133 5.2.2/1932 133 12.4/1933 265 Mertens, F. P 11.2/1963 249 Merz, L 5.5/1950 146 Meslin, G 2.4.4/1904 82 Mesnager 2 .4 .4/1 904 82 Metsik, M. S 11.2/1963 249 Metz, A 1.1/1950 3 3.3/1961 100 4.4/1954 126 5.1/1950 130 6.2/1954 158 8.1/1939 190 Meurers, J 1.3.3/1948 23 Meyding, L 1.3.2/1958 21 6.5/1962 168 10.1.4/1959 227 Meyer-Arendt, J. R 2.5/1963 89 6.5/1963 168 Meyer, F., Jr 7.4/1958 185 9.1/1920 198 Meyerson, M. R 3.1/1960 93 3.1/1961 93 3.1/1964 94 Subtection/Year Page Michalec, G. W 10.1.4/1956 226 Michalet, G 3.6.4/1949 115 Michelson, A. A 2.3.1/1888 56 2.3.1/1894 56 2.3.1/1903 56 2.3.2/1895 59 4.4/1924 124 5.4/1924 143 6.5/1890 173 Michigan Tool Co 9.2/1931 203 Middleton, S. P 6.1/1961 156 8.1/1954 191 Mielenz, K. D 2.3.7/1964 68 2.4.1/1964 72 Mielich, R 5.3/1936 143 Mikhailova, M. G .5.4/1963 146 Mikryukov, V. E 2.4.2/1962 77 Miller, D. C 1.2.1/1903 6 5.2.4/1909 139 Miller, D. R 3.6.4/1922 115 5.2.3/1922 138 Miller, F. J 3.5/1892 103 Miller, H. W 9.3/1919 206 Miller, J. C. P 10.1.3/1962 217 Miller, J. M 6.2/1963 161 Miller, J. R. Ill 1.3.1/1961 18 1.3.1/1964 19 1.3.2/1964 20 Miller, L 1.2.1/1962 9 Miller, T 12.6.5/1911 274 Milner, S. R 7.1/1908 175 Minaire, C 6.8/1955 172 6.8/1958 173 7.1/1957 178 7.1/1958 179 8.1/1949 191 Miner, E. D 2.5/1963 89 6.5/1963 168 Mirau, A 7.3/1951 182 12.1/1953 258 Mirkin, M. S 1.3.3/1960 25 Misener, A. D 1.4/1959 29 Mitchell, C. A 3.6.1/1930 109 Mitchell, R. F 7.1/1952 177 Mitra, S. S 2.2.1/1958 47 11.3/1962 254 Mitrovich, V. P 8.1/1963 192 Miwa, S 12.2/1963 261 Miyasato, I 2.3.3/1958 62 2.3.4/1958 65 Miyazaki, K .8.1/1958 192 Moen, W. K 1.4/1960 29 Moffat, R. J 1.4/1961 30 Moffit, G. W 8.1/1919 189 Mohamed, A. A. A. ...11.1/1963 246 11.3/1963 254 Mohler 2.3.1/1897 90 Mohorovicic, S 8.1/1954 191 Mokhov, A. V 8.1/1959 192 Mokhtar, S 2.2.1/1963 48 2.2.5/1963 55 Moles, A 1.1/1953 3 Moline Tool Co 12.5/1926 266 Molle, R 5.2.5/1950 141 Mollenauer, L. F 2.4.5/1963 86 Mollet, P 1.1/1960 4 2.2.1/1960 47 Molstead, O 2.5/1964 90 Monarch Tool Co 10.1.4/1941 244 10.2.2/1941 231 Monch, G. C 11.1/1951 242 11.1/1952 242 11.1/1955 243 Moncrieff, D 10.L4/1946 225 Monrad, A. L 3.6.2/1903 110 3.6.2/1904 110 9.3/1908 205 12.6.4/1908 273 771-846 O — 66- -20 295 Subsection/Year Montgomery, D. J 1.1/1954 Montilla, J 9.2/1963 Moody, J. C 1.2.1/1963 1.3.1/1963 1.4/1957 1.4/1960 6.1/1963 6.2/1955 6.2/1958 7.1/1953 7.1/1955 Moon, C 3.1/1933 3.5/1925 Moore, C. B 5.2.5/1945 Moore, J. R 12.6.1/1946 12.6.3/1944 Moore Special Tool Co 1.2.3/1960 Moos, H. W 2.4.5/1963 Morais, C 2.5/1958 Moran, J. P 12.5/1958 Moreau, H 4.2/1944 Moreau, T 6.2/1948 7.3/1948 Moret, H 3.4/1962 Morey, F. C 3.4/1950 Morgan, I. G 3.3/1955 3.3/1962 3.3/1963 3.4/1959 3.4/1960 5.2.5/1956 5.2.5/1964 Morin, J. O 5.2.1/1960 Morimura, M 1.3.3/1958 Morita, N 1.2.3/1959 Morita, Y 12.2/1963 Morley, E. W 2.3.1/1888 Morokuma, T 2.3.7/1963 2.3.7/1964 2.4.2/1962 Morrelli, D. A 3.5/1942 Morrison, A. E 12.6.1/1942 Morrow, J 2.4.2/1905 Mortonand, F. G 8.2/1953 Morton, G. F 3.4/1954 Morton, H. T 12.6.1/1939 Moses, A 12.6.5/1919 Mosman, A. T 4.1/1893 Mossoux, R 1.2.1/1961 Mottu, A 1.2.1/1947 1.3.2/1949 4.4/1964 Mueller, F 3.5/1939 Mueller, P. M 12.5/1925 Mueller, R 1.6/1929 Mugridge, E. G. V 2.4.3/1962 5.2.1/1962 Miihlig, F 4.3/1949 6.4/1933 Muirhead, D. P 8.2/1925 Muller, J. M 3.4/1964 Minister, C 7.2/1932 Murase, Z 9.3/1962 Murdock, G. J 3.5/1909 3.6.2/1909 Murray, D 5.2.2/1959 Murray, T. P 11.2/1962 Murrell, K. F. H 5.3/1963 5.4/1963 Murty, M. V. R, K 2.1/1964 2.4.2/1960 7.1/1962 Musk, A. W 3.1/1949 N Nabiev, M. A 5.2.2/1962 Nagaoka, H 2.2.1/1915 2.4.3/1917 Page 3 205 10 19 29 29 156 159 159 177 178 92 106 141 269 272 14 86 88 268 122 158 182 103 102 99 100 100 102 103 142 143 132 24 14 261 56 67 68 77 107 269 73 195 102 268 274 128 9 7 20 128 107 266 34 81 132 123 166 194 103 180 211 104 111 137 248 143 146 44 76 180 93 137 45 78 Subsection/Year Page Nagata, R 7.4/1962 186 Naik, Y. G 11.3/1957 252 Nakada, T 1.2.1/1964 10 12.2/1963 261 Nakata, T 10.1.4/1939 224 Nalle, D. H 1.4/1963 30 Nassal', V. I 5.2.2/1963 138 National Broach and Machine Co 10.1.2/1964 216 12.1/1950 258 National Bureau of Standards 1 .1/1961 4 1.1/1963 5 1.2.1/1912 6 1.3.3/1954 24 2.1/1957 43 2.2.2/1961 50 2.3.4/1951 64 2.4.2/1963 73 2.4.4/1957 82 2.4.4/1958 83 2.5/1963 90 3.1/1945 93 3.4/1960 103 4.1/1927 117 4.2/1927 121 6.3/1953 163 6.8/1920 172 7.2/1958 181 8.1/1919 189 8.2/1921 193 9.1/1919 198 9.1/1923 198 9.3/1923 207 9.3/1957 211 9.4/1957 212 National Cash Register Co 8.1/1927 189 National-Cleveland 9.2/1931 203 10.2.1/1926 229 10.2.1/1930 229 National Engineering Laboratory, G. B 1.6/1963 35 12.6.2/1958 271 National Physical Laboratory, G. B 1.1/1946 2 1.1/1951 3 1.1/1952 3 1.3.1/1953 17 1.3.1/1962 19 2.1/1960 44 2.4.1/1922 69 3.1/1920 92 3.5/1925 106 3.5/(1955) 108 4.1/1906 117 5.2.4/1920 139 5.7/1956 149 6.7/1919 170 8.2/1917 193 8.2/1918 193 8.2/1920 193 9.1/1920 198 9.1/1922 198 9.1/1951 201 9.2/1906 202 9.3/1916 206 9.4/1951 212 10.1.4/1923 223 12.6.1/1946 269 National Screw Thread Commission 9.1/1929 199 Natrella, M. G 1.3.3/1963 26 Neady, S. H... 12.4/1944 266 Nefflen, K. F 2.3.7/1963 67 2.4.5/1960 85 Nelson, L. M 7.4/1962 186 Nemirovskii, A. S 4.2/1961 122 Neumann, F. E 4.2/1879 120 Newall Engineering Co 3.5/1903 104 3.5/1906 104 3.5/1937 107 296 Subsection/Year Page Newbound, K. B 2.2.4/1949 52 New Departure Engineering Data 10.1.3.6/1946 222 Newman, S. B 3.6.2/1952 113 Ney, W. R 3.1/1960 93 3.1/1961 93 Nezhurin, I. P 9.3/1961 211 9.3/1963 212 10.2.4/1961 233 Nichterlain, P 8.2/1937 194 Nicolau, P 1.1/1936 2 1.7/1937 36 5.2.5/1937 141 Nickols, L. W 1.2.2/1955 11 1.3.1/1962 18 1.3.1/1963 19 1.3.2/1961 21 1.5/1961 33 3.2/1956 96 3.3/1955 99 3.5/1955 108 5.1/1957 130 5.7/1951 149 6.4/1962 167 6.6/1962 170 9.1/1957 201 9.2/1960 204 9.3/1957 211 12.1/1964 258 12.6.1/1964 269 Nidey, R. A 6.1/1958 155 Nieberding, 3.3/1961 100 5.2.5/1942 141 5.2.5/1957 142 5.2.5/1960 142 7.1/1961 179 Nielsen, R. J 4.2/1958 122 9.2/1958 204 Niepel, H 5.2.5/1946 141 Nigge, K. E 1.2.4/1963 16 Nikiforov, V. V 5.2.2/1963 138 Nikitin, B. D 7.3/1957 183 Nikitin, V. A 3.3/1965 116 4.4/1963 127 5.2.2/1963 138 5.2.4/1963 141 Nikolaev, V. I 6.1/1960 155 6.6/1960 170 Nikolaev, V. S 11.3/1959 253 Nishijima, Y 2.5/1963 89 Nishimura, G 1.6/1962 35 Niu, H 2.3.3/1958 62 2.3.4/1958 65 Noble, P. J. W 6.2/1964 162 Noch, R 1.3.3/1959 24 1.4/1959 29 6.1/1962 156 6.4/1961 167 7.4/1959 186 10.1.1/1956 214 10.1.4/1962 228 10.2.2/1961 232 10.2.2/1964 232 10.2.5/1961 234 Noldeke, G 2.4.3/1963 81 Noltingk, B. E 5.2.1/1960 132 5.2.2/1955 136 5.2.2/1959 137 Nomarski, G 2.2.5/1954 55 Norbury, J 5.2.2/1958 137 Nordon, P 1.4/1963 30 Norris, M. H 8.1/1930 190 Noskin, A. P 5.2.5/1963 142 Nourse, F 1.7/1945 36 Nourse, J. H 8.1/1965 193 Novikova, I. V 2.4.2/1960 76 Novitskii, P. V 1.3.3/1963 26 Nuttall Gear Works 10.1.4/1941 224 O Subsection/Year Oakley, T. R 12.2/1955 Oakley, T. R. J 1.3.2/1961 1.5/1961 Obata, J 5.2.2/1931 Oberg, E 3.6. 1/ 1928 9.2/1908 12.6.1/1920 Oberman, Y. I 12.2/1962 Obetz, S. W 2.4.2/1953 Ockenden, F. E. J 8.2/1939 8.2/1954 O'Donnell, T. J 2.1/1960 2.4.1/1960 Offner, F. F 3.6.4/1954 Ogawa, M 9.3/ 195 1 Ogden, H 2.5/1962 Ohmura, H 10.1.4/1962 Okamoto, Y 1.2.3/1959 Okun', I. Y 5.2.5/1963 Oldenbourg, R 1.1/1932 1.2.1/1932 Oldfield, R 10.2.6/1940 Olson, C. G 10.1.4/1921 10.2.1/1953 Omar, M 7.1/1953 8.2/1952 Omel'chenko, A. I 8.1/1959 9.1/1960 Omer, G. C, Jr 2.3.4/1936 Omptimeter 3.3/1940 Onions, W. J 3.3/1959 Oppenheim, U 2.2.1/1956 Optical Measuring Tools Ltd 12.5/1940 Orshanskii, D. L 1.3.2/1962 Osanov, B. A 5.2.2/1960 Osetinskii, G. M 11.3/1959 Oshchepkov, P. K 5.2.2/1960 Oshima, K 2.1/1951 Osmick, H. R 6.2/1958 6.2/1963 Oster, G 2.5/1963 2.5/1964 Osterberg, H 2.4.1/1956 Ostrander, H 12.2/1956 Oswald, R 12.2/1959 Ota, K 2.4.2/1959 Otryashenkov, Y. M 6.4/1960 Otterman, J 5.1/1959 Outin, J 5.2.5/1937 Oxley, A. J 4.4/1960 Oxley, P 10. 1.4/1959 P Paananen, R 2.3.7/1962 Packard, W. B 1.3.3/1963 Page, B. L 2.4.4/1925 4.1/1955 4.2/1934 6.4/1953 7.1/1925 12.6.2/1953 Paigne, J 1.7/1964 Paillette, M 2.3.7/1963 Palatnik, L. S , 11.3/1957 Palei, M. A 7.4/1962 Palmer, A. deF 1.1/1912 Palmer, D. A 2.5/1960 Pampel, H 9.1/1929 Pandeya, D. C 11.1/1958 Paoli, A. R 6.2/1956 Papp, G 11.1/1959 Papworth, Ltd 6.1/1943 Parker, E. R 1.7/1944 Parkes, D. H 2.4.1/1963 Parkes, R 10.2.6/1939 Parkhurst, D. L 6.7/1957 Parkinson, A. C 9.3/1949 10.1.2/1948 Page 259 21 33 151 109 202 268 260 74 194 195 44 71 115 210 89 228 14 142 2 7 237 222 229 177 195 192 202 63 98 100 46 267 21 136 253 137 43 159 161 89 90 71 259 260 76 166 130 141 127 227 67 2fi 82 119 121 166 175 271 39 68 25 186 1 88 199 245 159 245 154 36 72 236 171 210 216 297 Subsection/Year Parkinson and Sons 10.2.2/1912 10.3/1912 Parks, J. R 1.3.4/1947 Parkson 10.2.2/1934 Parnet, A 5.2.2/1947 Parratt, L. G 1.3.3/1961 Parsons, R. T 9.3/1961 10.1.3.1/1962 Parsons, S. A. J 1.2.1/1960 Partovi, F 11.2/1962 Passaglia, E 11.2/1963 11.2/1964 Pastukhov, I. M 8.1/1963 Paton Hawksley Electronics 2.5/1960 Paul, M • 1.2.1/1955 1.2.3/1955 Pearce, D. C. K 5.6/1959 Pearse, D. J 1.4/1955 Pearse, W. H 5.5/1948 Pearson, H. A 9.3/1919 9.3/1920 Pearson, J. W 1.4/1965 Peck, E. R 2.1/1948 2.2.1/1948 2.2.1/1955 2.2.1/1957 2.2.4/1958 2.2.4/1962 2.3.1/1949 2.4.2/1953 2.4.2/1955 6.5/1949 Ped', E. I 12.3/1962 12.3/1963 Pefhanv, J 5.2.5/1961 Pehland, H 1 1.3/1960 Pelander, C. E 12.2/1957 Pelika, A. Y 6.1/1961 Peliks, A. Y 12.3/1961 Pelphrey, H 10. 1.4/1942 10.1.4/1947 Pelzer, H 1 . 3.3/ 1 946 Pen'kov, V. V 7.4/1964 Penn, R. G 3.6.4/1959 Penndorf , R_ 2.2.4/1957 Pennie, A. M 11,3/1952 Pennington, E. W 1.3.2/1944 4.4/1940 7.1/1958 7.4/1958 Pennington, W. A 3.1/1964 Penselin, S 2.4.3/1955 Pepper, P. M 4.2/1961 Perard, A 1.2.2/1956 1.4/1927 1.4/1928 2.2.2/1920 2.2.2/1922 2.2.2/1947 2.3.2/1934 2.3.3/1932 2.3.4/1950 2.4.1/1912 2.4.1/1920 2.4.1/1922 2.4.1/1930 2.4.1/1934 2.4.1/1944 2.4.2/1932 2.4.4/1921 3.1/1912 3.1/1927 3.2/1913 4.1/1923 4.1/1939 4.1/1941 4.1/1944 4.1/1952 Page 230 238 27 231 134 25 211 219 9 248 248 249 192 14 147 29 146 206 206 31 42 46 46 47 52 53 57 74 75 167 263 264 142 253 259 156 263 224 225 23 187 116 52 251 20 125 178 185 94 79 122 11 28 28 49 1!) 49 60 (il (14 69 69 69 70 70 70 73 82 91 92 94 17 Subsection/Year Page Pe>ard, A. — Continued 4.2/1917 121 5.4/1923 143 Peres, N. J. C 9.3/1950 210 10.1.4/1954 226 10.1.4/1959 227 10.2.4/1950 233 Perevertaev, V. D 11.2/1963 249 Perfect, D. S 5.2.3/1944 139 6.7/1928 171 7.2/1948 180 Perkins, F. C ■_ 5.2.3/1918 138 Pernet, J 3.2/1900 94 Pernet, M.J _' 4.1/1884 117 Pernetta, C 5.3/1957 143 Perot, A 2.1/1897 41 2.1/1899 41 2.2.5/1906 54 2.3.1/1900 56 3.2.1/1913 56 2.3.2/1907 59 2.4.1/1899 68 2.4.3/1899 78 2.4.3/1901 78 2.4.4/1898 81 2.4.5/1899 84 Perrier, A 6.1/1936 153 Perrigo, O. E 3.5/1908 104 Perrin, E 6.2/1947 157 Perrot, M 2.2.5/1945 54 11.3/1957 252 Peters, C. G 2.2.2/1922 49 2.2.4/1918 52 2.4.1/1920 69 2.4.1/1922 69 2.4.1/1950 70 2.4.2/1919 73 2.4.3/1922 78 2.4.4/1925 82 2.4.6/1924 86 7.1/1920 175 7.1/1925 175 Peters, J 2.4.2/1953 74 10.1.3.1/1937 218 10.1.3.1/1951 218 12.2/1963 261 Peters, O 12.2/1951 259 Petavel, J 4.1/1960 119 Pettavel, J 4.4/1960 126 4.4/1964 128 Pettitt, C 9.3/1923 207 Pfleiderer, N 5.2.3/1924 138 Phelps, F. M. Ill 12.6.1/1965 270 Philbert, M 7.1/1958 179 Phillips, H. W. L 1.7/1953 37 Philpot, A. J 5.2.1/1948 131 Physical Society of London 1.1/1919 1 Picca, R 2.4.3/1946 78 Piccord, A 1.2.2/1947 11 Picht, J 8.1/1953 191 8.1/1954 191 Pick, U 12.6.2/1965 271 Pierce, R. G 12.5/1962 268 Pierre, E 5.2.2/1953 136 Pietzsch, H 2.2.2/1928 49 Piggott, M. R 2.5/1965 90 Pippard, A. B 1.7/1953 37 Pisharoty, P. R 1.5/1940 32 Pitter Gage & Precision Tool Co., Ltd 3.2/1923 95 3.2/1944 95 3.5/1944 107 3.6.1/1944 110 Plagnol 1.7/1945 36 Plainevaux, J. E 4.4/1954 126 5.7/1953 149 5.7/1956 149 Planer, G. V 6.7/1962 171 Player, S 12.5/1930 266 298 Pleasse, II 3.5 Plessner 11.1 Pliskin, W. A 11.1 Plourde, A. J 1.3.1 Plumb, R. C 11.2 Plvler, E. K 2.3.1 Pocklington, H. C 2.2.1 Podlazov, S. S 12.3 Poett, H. H 6.2 Pohl, R. W 2.2.1 Polacek, M 12.2, Polidor, E. C 8.2, 8.2, 8 2 Polk, L 1.3!2 Polkova, A. Z 3.1 Pollard, A. F. C 5.1 5.1 5.2.3 5.6 Pollok, J 2.5 Polster, H. D 11.3, Ponce, A 2.5, Poole, S. P 2.4.1 2.4.4, 3.3 Popp, H. P 5!l Poppa, H 2.5 Popov, G. S 2.3.3 Popov, M. I 1.2.3 Poritsky, H 12.6.3 Pose, R 1 .2.2 Post, D 2.2.1 Potter, J. A :6.1 10.3 PoweU, E. F 3.4, Powell, R. W 1.7 Powers, R. A 12.3 Pratt & Whitney Co 1.2.3 3.1 3.3 3.3 3.4, 3.5 6.4, 6.7 10.2.6 12.5 Precision Grinding, Ltd 1.2.3 Preger, E 1.5 Prescott, J 1.5 Presto Machine Works 6.6 Preston, J. S 2.1 Pribylev, A. A 7.1 Priest, I. G 2.4.2 Primak, W 2.2.1 Proschan, F 1.3.3 Pruliere, A. C 1.1 9.1 Pucalka, V _11.3 Pulfrich, C 2.2.1 2.2.2 2.4.4 4.4 Purman, H. V 3.6.4 Purvis, R. D _ 3.6.1 5.6 Pusep, H 12.6.5 Pusep, H. F 3.6.2 Putschbach, R . 1.2.3 Puttock, M. J 2.2.2 2.4.1 2.4.1 2.4.5 3.4 7.1 7.4 Pyle, L 3.6.2 Subsection/Year Page Q SubtectionlYear Page 1959 108 Quentin, J 5.2.2/1960 137 1946 241 Quincke, G 6.4/1873 164 1964 247 11.1/1866 241 1963 19 R 1963 249 Rabhin, A. L 12.2/1961 260 1952 57 Rabinovich, V. I 1.1/1963 6 1902 44 Rabinowitz, P 2.3.7/1963 67 1961 263 2.4.3/1962 81 1956 159 Radford, G. S 1.3.1/1921 17 1960 47 Raentsch, K 1.2.1/1963 10 1963 261 3.5/1947 107 1947 195 6.1/1952 154 1951 195 Rahn, R. J 7.1/1953 177 1962 196 7.1/1954 178 1960 21 7.1/1959 179 1960 93 7.1/1960 179 1922 129 12.5/1959 268 1928 129 Ramsauer, C 1.1/1936 2 1938 138 Ramsay, B. P 2.2.1/1934 45 1934 146 2.2.1/1941 45 1965 90 Ramsay, J. V 2.4.3/1962 81 1949 250 5.2.1/1962 132 1961 89 Randall, K. C 1.7/1953 37 1960 71 Rang, O 2.5/1959 88 1960 83 Rank, D. H 2.2.4/1954 52 1962 100 2.2.4/1958 52 1962 131 2.3.1/1957 58 1959 88 6.1/1946 154 1963 63 8.1/1946 190 1961 14 Rankin, B 6.1/1954 154 1943 272 Rankin, R. L 3.1/1919 92 1961 14 3.6.1/1919 109 1958 47 4.4/1919 124 1930 153 7.1/1919 175 1931 239 8.1/1919 189 1954 102 Rank Taylor Hobson 7.4/1963 187 1957 38 Ranney, C. R 12.6.4/1929 274 1937 262 Rannie, J. L 6.4/1930 165 1963 15 Ransford, G.-D 1.3.3/1951 23 1886 91 Rantsch, K 1.2.1/1963 10 1922 97 3.3/1959 100 1932 98 3.5/1947 107 1944 101 3.5/1959 108 1927 105 4.2/1960 122 1958 166 5.4/1941 144 1923 170 5.4/1949 144 1922 235 5.4/1959 145 1922 266 Rao, I. R 6.1/1947 154 1955 14 Rao, K. N 2.4.3/1963 81 1927 32 Rao, K. V. K 11.3/1960 253 1924 32 Rao, P. S 11.3/1957 252 1918 169 Rao, S. V. S 6.1/1947 154 1951 43 Rao, V. V. L 1.2.2/1955 1 1 1965 188 Rasmussen, E. K 7.1/1945 176 1920 73 Rasmussen, R. E. H 7.3/1953 182 1958 47 Rassow, J 11.2/1962 248 1953 23 Rassudova, G. N 2.5/1961 88 1947 2 2.5/1963 89 1948 200 Ratoosh, P 1.1/1959 4 1959 252 Rausch, R. H 6.6/1924 169 1898 44 10.1.4/1922 223 1898 48 Rawling, R. E 10.1.3.4/1952 220 1898 81 Rayleigh, Lord 2.3.1/1906 56 1907 124 2.3.5/1908 65 1912 115 2.4.3/1906 78 1963 110 3.1/1936 92 1963 148 7.1/1893 175 1919 274 Razuvaev, A. N 9.1/1963 202 1918 111 Reading, O. S 1.2.4/1953 15 1951 14 3.2/1953 96 1962 50 Reason, R. E 1.7/1945 36 1953 70 1.7/1951 37 1965 72 7.4/1959 186 1950 84 Redepenning, W 5.2.2/1943 134 1948 102 Reeb, O 1.2.2/1954 11 1950 177 1.2.2/1955 11 1948 185 Reed Small Tool Works 3.6.2/1922 112 1919 111 Regel, V. R 5.4/1959 145 299 Subsection/Year Page Regler, F 11.3/1948 250 Reid, N. E 8.1/1964- 193 Reilley, G. C 10.1.4/1925 223 Reimer, J 10.2.6/1944 237 Reindl, J 9.3/1919 206 9.4/1919 212 Reisch, S 5.2i2/1931 133 5.2.2/1936 133 Remade, G. A 6.6/1916 169 Renaudin 10.2.6/1936 236 Renault, M 2.4.1/1962 72 Renet, C 5.2.5/1963 142 Renold, W 12.3/1963 263 Revesz, A. G 11.2/1964 249 Rey, J. R 1.3.3/1960 25 Reznik, Z 8.1/1960 192 Richard, G 3.6.1/1906 108 Richards, J. C. S 5.2.4/1959 140 5.7/1959 151 Richards, W 6.8/1946 172 6.8/1947 172 9.3/1918 206 9.3/1928 207 9.3/1929 207 12.6.4/1915 273 Richardson, D 2.4.6/1957 86 Richardson, H 1.3.3/1960 25 Richardson, H. M 2.2.5/1959 55 2.4.3/1959 80 Richardson, J. M 2.1/1960 44 Richardson, S. C 1.1/1961 4 Richter, O 12.6.5/1949 275 Rickenmann, A 9.1/1931 199 9.3/1931 208 Rickwood, G. E 5.2.1/1963 132 Ridge, W. G 8.2/1962 196 Riekher, R 11.1/1958 245 Rienitz, J 2.2.1/1951 46 2.2.1/1961 48 Rieth 6.7/1887 170 Rigby, S 5.2.2/1960 137 Rigden, J. D 2.4.3/1963 81 Righi, A 5.2.1/1897 131 Rights, H. T 9.2/1944 204 Rigrod, W. W 2.3.7/1962 67 2.3.7/1963 67 Rimrott, U 7.4/1960 186 Ring, W. A 10.1.4/1949 225 Ritchie, J 2.4.2/1957 75 Ritter, H. J 4.4/1964 128 Ritter, R 10.1.2/1950 216 Ritzow, G 5.4/1938 144 Rivers, J. H 12.2/1947 259 Rivot, P. M 1.1/1963 5 1.3.1/1963 19 Robbin, M. A 5.2.3/1932 138 Robbrecht, G. G 2.4.3/1962 81 Roberts, H. C 5.2.2/1944 134 5.2.2/1945 134 Robertson, H. M 11.3/1962 254 Robida, L 1.7/1945 36 Robinson, F. J 12.3/1964 264 Robinson, I. R 1.7/1953 37 Robinson, S. L 3.4/1953 102 Robinson, T. R 6.4/1835 164 Robson, R. S 3.6.4/1959 116 Rock, N. H 2.4.5/1964 86 Rockefeller, J. W. Jr 5.7/1936 148 5.7/1951 149 Rockwell, H 6.2/1948 158 Rodgers, J. M 11.3/1962 254 Roehler, R 5.1/1962 131 Roesler, F. L 7.3/1962 184 Rogers, G. L 2.5/1959 88 Rogers, M. D 4.4/1962 127 8.1/1963 193 Subsection/Year Page Rogers, W. A.. 1.2.2/1879 49 3.1/1886 91 4.2/1893 121 12.6.3/1885 271 Rohlin, J 6.5/1963 168 Rohmann, H 5.2.2/1920 133 Roig, J 2.2.1/1938 45 2.4.3/1953 79 5.2.2/1953 136 Rokhman, D. E 3.4/1960 103 Rolt, F. H 1.2.1/1929 6 1.2.1/1937 7 1.2.1/1952 8 2.1/1957 43 2.2.5/1929 54 2.4.1/1955 70 2.4.4/1926 82 3.1/1927 92 3.1/1938 92 3.2/1959 96 5.1/1929 129 6.4/1937 166 9.1/1938 200 9.2/1938 203 9.2/1951 204 10.2.5/1937 234 12.6.3/1955 273 Romanova, M. F 2.1/1957 43 2.3.2/1942 60 2.3.2/1957 61 Romerskirch, W 10.1.4/1961 228 10.2.1/1959 230 Ronan, H. R 10.2.5/1962 234 Ronchi, V 2.2.1/1964 48 2.5/1958 88 Root, E., Ill 2.4.2/1952 276 Rose, J. B 12.5/1922 266 Rosenberg, H 3.6.2/1902 110 Rosenfeld, G. H 1.2.3/1963 15 Rosenhauer, K 8.1/1956 192 8.1/1957 192 Rosenhead, L 10.1.3/1962 217 Ross, G. S . 1.4/1960 30 Ross, I. M 5.2.2/1956 136 Ross, R.J 10.2.5/1958 234 Rosson, J. W 6.1/1962 156 Rostovykh, A. Y 5.2.5/1963 143 Rotax, Ltd 12.6.1/1963 269 Rothen, A 11.2/1945 247 11.2/1948 248 11.2/1957 248 Rothrock, B. D 2.2.1/1963 48 11.2/1963 248 Rotzoll, E 12.2/1939 259 Rouard, P 11.3/1965 255 Rowell, H. S 8.1/1924 189 Rowell, W. S 6.8/1930 172 9.1/1918 198 9.3/1918 206 9.3/1932 208 Rowland... 12.6.2/1928 270 Rowland, H. A ...12.6.2/1882 275 12.6.3/1911 272 Rowley, W. R. C 2.3.7/1963 68 Rozenberg, E. I 1.2.1/1961 9 3.2/1962 96 7.4/1964 187 Rubin, L. G 1.4/1964 30 Rubinov, A. D 7.4/1959 186 Riicker 4.2/1882 120 Rudberg, F 4.2/1837 120 Ruffino, G 2.4.2/1957 75 2.4.2/1960 76 Rugg, K. E 5.2.5/1958 142 Ruggaber, W 1.3.2/1948 20 Ruhle, H ..1.3.4/1938 27 Rumiantsev, A. V 6.8/1959 173 300 Subsection/Year Page Rummert, H 4.3/1958 123 Rumyantsev, A. P 11.3/1959 253 Rumyantsev, A. V 12.6.1/1961 269 Runge, I 3.3/1928 97 Russel, W. O 12.6.4/1924 274 Russell, A. M 1.3.3/1956 24 Russell, H. N 2.1/1921 41 Russell, H. W 1.1/1961 4 Ryaskov, V. L 7.4/1960 186 Rybak, E. N 11.1/1963 246 Ryder, E. A 1.4/1953 28 Ryffel, H. H 10.3/1960 239 Rynders, G. F 11.1/1948 241 S Saari, O 10.3/1956 239 12.4/1954 266 Sachs, H. K 1.6/1964 35 Sachs, S 1.4/1963 30 Sadowski, A 12.2/1964 261 SaegmuUer, G. N 6.7/1922 170 Safonov, L. N 6.1/1962 156 Sagaspe, P 1.3.3/1937 22 Saha, M. N 2.3.1/1917 56 Saker, E. W 5.2.2/1956 136 Saksena, G. D 2.2.4/1958 52 Sakurai, T 7.1/1949 177 Sakurai, Y 2.4.2/1958 75 2.4.2/1959 76 2.4.5/1963 86 2.4.6/1960 86 2.4.6/1961 87 4.1/1961 119 5.2.2/1951 135 Samal, E 5.7/1959 150 Samuels, L. E 1.7/1959 38 1.7/1961 38 Sanborn, G. H 10.2.2/1945 231 Sanders, J. V 1.7/1959 38 Sanford, A. C 7.4/1952 185 Sanford, B. P 11.1/1958 245 Santer, L 3.4/1948 102 Sappet, C. L 1.1/1963 5 Sasaki, N 1.4/1952 28 Satserdotov, P. A 1.4/1964 31 Satterthwaite, I. H. R 2.4.2/1963 77 Sauer, R. L 11.1/1958 245 Saunders, J. B 1.2.4/1963 76 2.1/1957 43 2.1/1963 44 2.2.1/1957 47 2.2.2/1960 50 2.4.2/1939 74 2.4.2/1944 74 2.4.2/1945 74 2.4.4/1960 83 2.4.5/1960 85 6.1/1961 156 6.2/1961 160 6.2/1963 162 7.1/1951 177 7.1/1954 177 7.1/1959 179 7.1/1964 180 7.2/1958 180, 181 7.3/1951 182 7.3/1961 183 7.3/1962 184 Saurer 10.3/1921 238 10.3/1922 238 Savenkova, M. V 11.3/1959 253 Sawabe, M 9.1/1961 201 Sawin, N. N 1.7/1937 36 3.2/1944 95 3.2/1947 95 SubtedionlYear Page Sayce, L. A 12.6.2/1955 271 Saylor, C. P 3.3/1965 116 Schaffer, R. R 8.1/1963 193 Schawlow, A. L 2.4.5/1963 86 Scheidegger, R 11.3/1962 254 Schendell, G 4.4/1950 126 Schepler, H. C 8.1/1944 190 Schermer, E. B 11.1/1963 246 Scherr, G 3.5/1928 106 Geo. Scherr Co 3.4/1932 101 10.1.4/1932 223 Schiebel, A 10.1.2/1930 215 Schilling, F -. 2.4.5/1957 84 Schimz, K 1.3.4/1930 27 Schleicher, W. F 12.5/1948 267 Schlesinger, F 9.2/1917 202 Schlesinger, G 1.7/1951 37 5.2.3/1939 139 12.2/1942 259 Schlueter, D. J 2.2.4/1958 52 Schlink, F. J 1.1/1924 1 1.3.2/1918 19 5.2.3/1919 138 Schlippe, O 12.2/1935 259 Schloss, F 1.6/1961 34 Schmerwitz, G 1.7/1933 36 Schmidt, H 1.3.1/1942 17 1.3.2/1943 20 1.3.3/1942 22 3.2/1928 95 3.2/1942 95 3.2/1958 96 3.3/1928 97 8.1/1928 189 Schmidt, H. W 3.2/1956 96 Schmidt, K 6.1/1953 154 Schmidt, W 1.7/1957 38 Schneider, A. W 12.2/1935 259 Schneider, D. B 1.3.1/1963 19 1.3.4/1962 27 Schneider, E. J 7.4/1958 185-6 Schoeffler, F 1.4/1943 28 Schoen, A. L 11.3/1951 251 Schoenbacher, K 5.2.2/1939 133 Scholetzer 5.7/1937 148 Schonrock, O 1.5/1929 32 7.1/1905 187 7.1/1939 176 Schopper, H 11.1/1951 242 11.1/1956 243 11.3/1951 250 Schorsch, H .3.4/1940 101 3.5/1959 108 9.1/1935 200 Schott, G. H 1.5/1896 31 Schreiber, O 6.4/1886 164 Schroder, R. P 1.3.2/1922 19 3.1/1922 92 3.2/1939 95 3.6.2/1920 111 Schulthess, E 10.1.4/1958 227 Schultz, H 6.2/1956 159 Schultz, T 2.4.3/1962 81 Schulz, G 2.2.1/1954 46 2.2.3/1954 50 2.4.1/1956 71 11.1/1956 243 Schulz, H 1.3.4/1920 26 2.2.1/1922 45 5.1/1929 129 6.2/1956 159 8.1/1952 191 Schulz, L. G 2.2.5/1951 54 2.4.3/1950 79 11.1/1950 242 11.1/1951 242 Schulze, B 3.3/1931 98 Schulze, M. T 2.4.2/1936 73 301 Subsection/Year Page Schulze, R 3.5/1951 107 6.2/1963 161 Schumacher, B. W 11.3/1962 254 Schuster, A 2.2.1/1924 45 Schwartz, J 5.2.2/1948 135 Schweitzer, W. G 2.3.6/1958 66 Schwinger, J 1.1/1959 4 Schwink, C 11.3/1960 253 Scoles, C. A 7.4/1960 186 7.4/1963 187 10.2.5/1955 234 Scott, D 7.1/1961 179 Scott, G. D 11.1/1958 245 Scott, L. W 6.2/1947 157 Scott, R. A 11.1/1946 241 Searle, G. F. C 8.1/1911 189 Sears, J. E. Jr 1.2.1/1924 6 1.3.2/1926 20 2.3.1/1932 57 2.3.2/1933 60 2.3.2/1934 60 2.3.2/1935 60 2.4.1/1923 69 2.4.1/1927 69 4.4/1941 125 12.6.4/1917 273 Sedoric, J 6.2/1955 158 Segeletz, R 7.1/1956 178 Seidensticker, F. W 6.3/1908 162 Seliger, W 12.2/1964 262 Sen, D 2.4.1/1959 71 2.4.2/1959 76 2.4.3/1961 80 2.4.4/1960 83 2.4.4/1961 83 2.4.5/1959 85 6.5/1959 168 6.5/1961 168 7.3/1961 184 11.1/1960 246 Sen, P 11.3/1957 252 Sergeev, N. V 9.1/1963 202 Series, G. W 2.3.5/1960 65 Server, F 3.6.2/1917 111 Severn, G. M 3.4/1959 102 3.4/1960 103 Sewig, R 4.1/1936 118 Shaevich, A. B 1.3.1/1963 19 Shannon, J. F 5.2.2/1944 134 Sharova, E. E 6.3/1961 163 Sharp, C. H 11.3/1900 249 Sharp, G. H 1.2.1/1956 8 Sharp, K. W. B 8.1/1954 191 Shaw, F. W 7.4/1932 185 9.3/1928 207 10.1.3.1/1930 217 10.1.4/1931 223 10.2.6/1930 236 10.2.6/1931 236 10.2.6/1935 236 10.2.6/1939 237 10.2.6/1940 237 Shaw, H 7.4/1931 185 7.4/1932 185 Shaw, M 12.6.2/1949 271 Shaw, P. E 3.1/1911 91 3.5/1903 104 3.5/1905 104 3.5/1906 104 3.5/1912 104 3.5/1913 104 3.6.2/1904 110 5.2.2/1900 132 7.1/1912 175 9.1/1919 198 Shchipacheva, N. M 3.2/1964 97 Shchukin, L. D 3.6.3/1962 114 Subsection/Year Shearer, J. N 2.2.4/1954 2.3.1/1957 The Sheffield Corp l!2!3/1964 9.2/1918 Sheldon, E 3.6.2/1921 10.2.6/1923 12.6.1/1923 Shelley, C. P. B 3.5/1877 Shenbrot, I. M 1.3.3/1964 Shenfield, S 6.1/1961 Shepard, C. D 4.3/1932 Shepherd A. T 2.5/1963 12.3/1961 Sherrill, H. H _• 12.6.1/1963 Shevchuk, S. A 12.2/1962 Shewhart, W. A 1.3.1/1926 Shewring, D 5.2.2/1958 Shield, A. H 6.6/1915 Shield, R. T 1.5/1951 Shilova, E. A 9.2/1963 Shimizu, K 2.4.6/1962 2.4.6/1964 Shipilevskii, B. A 7.4/1963 Shishido, K 7.1/1949 Shishkov, V. A 12.1/1960 Shklyarevskii, I. N 2.2.5/1956 11.1/1958 Shlyandin, V. M 5.1/1962 Shlyaposhnikov, B. M 3.5/1965 Shokhtin, A. P 6.7/1963 Shor, G. I 11.3/1963 Shost'in, N. A _. 1.1/1963 Shtein, V. G 5.2.1/1960 Shuckburgh, G 6.4/1793 Shultz, T 2.4.3/1962 Shvets, A. D 5.7/1961 Shvets, V. F 11.1/1963 Siadbei, G 6.7/1932 Sichirollo, A. E 1.4/1958 Sidders, P. A 3.6.3/1962 12.3/1961 Sidjak, N 11.1/1951 Sieker, K. H 5.2.4/1932 Sigma Instrument Co 3.3/1943 3.3/1946 3.3/1950 6.1/1943 12.3/1949 Sillitto, G. P 1.3.3/1948 Silvagi, J 9.3/1958 10.1.4/1952 10.2.1/1949 10.2.4/1949 10.2.4/1955 10.3/1952 Sim, P.J 3.1/1959 Simeon, F 2.2.1/1924 Simkin, G. S 1.3.3/1959 1.3.3/1960 1.3.3/1962 2.4.5/1962 7.3/1959 10.2.1/1961 Simmons, A. T. F 6.5/1920 Simnad, M. T 1.7/1953 Simon, H 2.4.1/1928 3.3/1929 4.1/1928 Simonenko, G. L 7.2/1962 Simonet, J 6.5/1950 9.2/1959 9.3/1958 Sine Line 9.2/1942 Siprikov, I. V 5.2.2/1960 Sittner, W. R 2.3.1/1949 6.5/1949 Skidan, V. V 2.4i4/1961 Skinner, N. P 6.6/1946 302 Skvortsov, B. N 5.2.2 Slater, P. N 3.3 4.4 Slatis, H . 4.4 Slevogt, H 2.2.1 Slocomb, J. T 3.6.2 q C O Sluis, K. L. V 2^2 2.4 3 Smirnov, V. V 1.2.3 Smir'nova, E. P 3.2 5.2.4 Smirnova, L. I 6.3 Smith, B 12.6.3 Smith, C. F 2.3.1 2.4.1 3.5 7.2 8.2 8.2 9.1 Smith, D. S 2.3.1 2.3.3 2.3.3 2.3.3 2.3.4 2.3.4 2.4.1 2.4.2 2.4.2 Smith, F. C 1V4 Smith, W 2.4.2 Smith, W. M 6.2 Smits, F. M 11.1 Smoluchowski, R 1.7 Soci&tiGenevoised' Instrumentsde Physique . 1.2.3 1.2.3 1.2.3 3.2 3.3 3.3 3.3 3.4 3.5 3.5 3.5 4.1 4.4 4.4, 4.4 4.4 5.2.3 6.4 6.7 8.2 8.2 9.2 9.3 10.1.4 10.1.4 10.2.6 Soderberg, E. F 6.1 Sodha, M. S 2.2.1 2.4.3 Soffel, A. R L3!3 Sokolov, S. S 1.1 Sokolov, S. Y 5.4 Sokolsky, H _ _ 12.1 Sola, M. C 3.1 Solov'ev, A. I 1.2.1 Somervaille, L. J 5.2.1 Sommer, A 9.1 Sommer, P. L., Jr 12.5 Sona, A 2.4.5 Sorber, G. E 1.3.2 Sosnovskii, V. I 6.2 Souder, W 3.6.2 8.1 Subsection/Year Page 1960 137 1957 1957 1958 1954 1901 1915 1956 1956 1961 1962 1963 1961 1963 1926 1933 1927 1932 1926 1931 1935 1963 1958 1959 1962 1957 1959 1933 1959 1960 1927 1954 1963 1956 1944 1928 1930 1963 1914 1923 1930 1931 1927 1914 1920 1939 1950 1924 1926 1928 1931 1930 1930 1924 1949 1962 1927 1938 1924 1928 1933 1961 1958 1953 1959 1963 1953 1962 1964 1963 1954 1929 1947 1964 1960 1964 1952 1920 99 126 126 46 110 111 60 80 14 96 141 163 273 56 70 106 180 194 194 200 59 62 62 63 64 65 70 76 77 265 75 161 244 36 L3 13 15 95 97 98 98 101 104 105 107 118 124 125 125 125 138 165 170 195 196 203 208 223 223 236 156 47 79 25 5 145 258 94 9 132 199 267 86 21 162 113 189 SvJitectionlYear Souers, R. C 3.6.4/1954 Souler, R. A 12.3/1957 Soulet, M 2.4.3/1958 Spaeth, W 1.1/1949 Spannuth, J 6.4/1913 Sparkes, C. A 12.3/1962 Sparks, C. J 11.3/1961 Spear, P 1.7/1953 Spear, W. E 5.2.4/1963 Speen, G. B 5.5/1964 Spence, J 10.1.4/1964 Spencer, H. K 12.4/1911 Spencer, J 1.3.2/1961 5.3/1961 Spencer-Smith, J. L 1.3.3/1937 Sperry Gyroscope Co 12.3/1962 Spierlingi W. F 12.6.3/1956 Spies, R 12.3/1938 Spikowski, R. J 7.4/1964 Spitzer, W. G 11.1/1961 Spotts, M. F 10.1.3.1/1962 Spring, K. H 1.3.3/1950 Squire, A. M 6.7/1962 Stabe, H 5.7/1939 Stabel, J. M 9.3/1904 Stacey, D. S 6.1/1958 Stadthagen, H 1.3.1/1911 Stamper, W. R 12.6.2/1910 Stang, A. H 3.5/1935 Stanley, F. A 3.6.1/1907 4.4/1907 4.4/1908 12.6.1/1923 12.6.2/1924 Stanley, R. W 2A3/1964 Stanley Rule & Level Plant 3.6.1/1932 Stanley, V. W 1.2.1/1956 2.5/1961 3.5/1960 4.1/1951 12.6.3/1955 Stanton, T. E 10.3/1920 Stark, R. M 2.4.6/1957 Starling, S. G 6.7/1922 L. S. Starrett Co 3.6.2/1928 3.6.2/1931 3.6.2/1932 6.7/1930 Statz, H 2.3.7/1962 Stead, C 4.4/1963 12.5/1963 Stearn, J. L 1.3.3/1960 Stecher, M 2.5/1964 Stedman, G. E 12.5/1946 Steel, W. H 2.2.1/1962 Steele, H. B 9.2/1917 Stegner, C. B 5.7/1962 Steinberg, H. L 11.2/1963 Steiner, K 4.4/ 1962 Steinle, A 3.4/1923 4.4/1926 10.1.4/1924 Steiskal, F 5.2.2/1950 Stejskal, F 5.2.2/1950 Stepanek, K 10.1.4/1963 Stephens, R. B 2.3.7/1964 Stephens, R. W. B 1.7/1957 Stern, B. J 11.1/1963 Steudel, A 2.4.3/1955 2.4.3/1957 2.4.3/1963 Stevens, F. L 1.2.1/1943 Stewart, B 4.2/1882 Stewart, J. J 9.3/1912 Stiehler, R. D 1.3.3/1954 Paqt 115 262 80 2 165 263 253 37 141 146 228 265 21 143 22 263 273 262 187 246 218 23 171 148 205 155 17 270 106 109 124 124 268 270 81 109 108 118 273 238 86 170 112 112 112 171 67 128 268 25 90 267 48 202 150 248 127 101 125 223 135 135 228 68 38 246 79 SO SI 7 120 206 24 303 Subsection I Year Page Stille, U 1.1/1957 39 1.1/1959 14 1.2.2/1955 11 1.2.2/1959 12 Stiller, B 4.4/1956 126 Stimson, G. H 9.1/1958 201 Stimson, H. F 1.4/1962 30 Stocker, W. M 9.2/1958 204 Stolar, G 5.7/1962 150 Stolow, N 5.2.5/1955 142 11.3/1956 252 Stone, N. W. B 1.1/1957 4 Stone, W 12.6.2/1937 270 Storey, C 1.5/1960 33 Storey, J. E 3.5/1905 104 3.5/1906 104 Strakun, G. I 6.3/1961 163 Strang, A. G 1.7/1957 38 6.3/1953 163 Stratton, S. W 4.3/1916 122 Street, C. C 3.4/1941 101 Stribeck, R 1.5/1901 31 1.5/1907 31 Stroh, H 6.8/1925 172 Stroke, G. W , 2.2.1/1957 47 2.4.2/1953 74 2.4.2/1955 75 2.4.2/1957 75 2.4.2/1958 75 6.2/1961 160-1 6.5/1961 168 12.6.2/1955 271 12.6.2/1957 271 12.6.2/1961 271 12.6.2/1963 271 12.6.2/1964 271 Stromberg, R. R 11.2/1963 248 11.2/1964 249 Struve, W 6.4/1838 164 Stryker, J. D 3.6.4/1907 114 Stuebler, E 12.6.3/1909 272 Stukin, E. D 11.3/1963 254 Stulla-Goetz, J 1.2.2/1961 12 2.4.1/1932 70 Stumpp, E 7.4/1941 185 Sturgis, N 12.6.2/1957 271 12.6.2/1959 271 Sturkey, L 2.2.1/1941 45 2.4.3/1940 78 Sugg, R. E 6.5/1957 168 Suhner, F 11.2/1944 274 Sukigara, S 9.1/1961 201 Sulander, M. C 12.6.3/1956 273 Sully, J. R 5.4/1960 145 Sutherland, K. H 12.5/1962 268 Suverkrop, E. A 12.6.4/1917 273 Suvorov, A. I 3.6.2/1962 113 Svensson, K. F 2.2.4/1960 53 Swain, E 1.7/1945 36 Sweet, J. E 3.5/1906 104 6.3/1908 162 Sweetman, L. R 3.5/1935 106 Swift, E. A 6.8/1926 172 Swindells, J. F 1.4/1965 31 Sykes 10.2.6/1921 235 10.2.6/1930 236 Sykes, A. O 1.6/1960 34 T Tabor, D 1.7/1953 37 Taft-Peirce Mfg. Co 12.4/1937 265 12.6.5/1937 275 Tagg, G. F 5.5/1951 146 Taits, B. A 10.1.4/1960 227 12.3/1960 262 Takahashi, S 2.4.2/1959 76 Takeo, M 2.3.1/1957 58 Subteetion/Year Page Tako, T 2.3.2/1960 61 2.3.3/1958 62 2.3.4/1958 65 2.3.4/1960 65 Tanaka; S 11.3/1933 249 Tandler, W. S 10.1.4/1954 226 Tanenbaum, M 11.1/1961 246 Tangerman, E.J 3.4/1949 102 Tanner, H. D 12.1/1928 257 Tarasov, K. I 2.4.3/1956 79 Tarczy-Hornoch, A 6.7/1964 171 Taylerson, C. O 1.2.3/1962 15 1.3.2/1954 20 3.4/1953 102 6.1/1961 155 6.1/1964 156 6.3/1947 163 6.3/1948 163 6.4/1937 166 10.2.5/1937 234 Taylor Devices 12.5/1963 268 Taylor, E. W 6.4/1943 166 Taylor, H. E 10.2.6/1913 235 Taylor, J. B 8.2/1916 193 Taylor, J. E 6.2/1963 161 Taylor, M. H 5.4/1941 144 Taylor, M. J 2.3.7/1963 68 Taylor, Taylor and Hobson 4.4/1942 125 7.4/1952 185 8.2/1942 194 8.2/1954 195 Taylor, W. G. A 2.1/1957 44 2.2.1/1957 47 Taylor, W. T 9.3/1943 209 10.2.4/1945 233 Teasdale-Buckell, P 2.2.5/1951 54 Tebble, R. S 11.3/1962 254 Templin, R. L 3.5/1921 105 3.5/1928 106 Tennant, R. M 7.3/1953 182 Terpstra, J 2.4.2/1955 75 Teplova, Y. A 11.3/1959 253 Terrana, E 6.1/1952 154 Terrien, J 1.1/1963 5 1.1/1965 5 1.2.2/1962 12 2.2.1/1941 45 2.2.1/1958 47 2.2.3/1959 50 2.2.4/1965 53 2.2.5/1954 55 2.3.3/1957 62 2.3.3/1958 62 2.3.3/1959 62 2.3.3/1960 62 2.3.4/1950 64 2.3.4/1957 65 2.3.4/1958 65 2.3.5/1960 65 2.4.1/1956 71 2.4.2/1959 76 2.4.4/1952 82 2.4.5/1954 84 2.4.6/1954 86 6.2/1948 158 7.3/1948 182 Tesa, Ltd 3.4/1953 102 3.6.2/1952 113 3.6.3/1951 114 Tetens, O 6.4/1914 165 Theocaris, P. S 2.5/1962 89 11.1/1963 246 Theroux, P.. 11.2/1963 249 Theime, B ...3.6.2/1912 111 Thiesen, M 4.2/1879 120 Thomander, V. S. 5.7/1959 150 Thomas, A. E 3.4/1948 102 Thomas, D. E... .7.1/1915 175 304 Subied ion/Year Page Thomas, H. A 2.4.2/1928 73 5.2.2/1923 151 Thomas, H. R 1.5/1930 32 Thomas, P. A 4.3/1919 122 Thompson, A 12.1/1940 257 Thompson, I. M. G 6.1/1961 156 Thomson, A. G 4.1/1953 118 Thomson, J 5.2.2/1957 136 Thornton, B. S 2.2.1/1955 46 2.2.3/1957 51 2.2.5/1959 55 3.1/1956 93 Thorpe, T. E 4.2/1882 120 Thrasher, L. W 1.3.3/1955 24 Thuesen, H. G 10.2.4/1925 232 Thulin, A 2.3.4/1955 64 Thurston, C. M 12.5/1944 267 Thurston, R. N 5.2.2/1957 136 Thwaite, E. G 1.3.1/1963 19 3.1/1963 94 4.1/1963 119 4.2/1963 122 4.4/1964 128 Tienstra, J. M 1.3.3/1948 23 Tiffany, H. E 5.6/1963 148 TiUen, R 12.3/1964 265 Tillen, R.J 6.2/1963 162 Tilton, L. W 2.2.4/1934 52 2.2.4/1935 52 6.4/1929 165 7.1/1945 176 Timken Roller Bearing Co. Timms, C 1.7/1945 36 8.2/1964 196 10.1.4/1947 225 10.1.4/1948 225 10.1.4/1950 225 10.1.4/1954 226 10.1.4/1958 227 10.2.5/1955 235 12.2/1949 259 12.6.3/1958 273 Timofeeva, A. A 5.7/1958 150 Tinaut, D 2.2.2/1964 50 Titsch, J 3.6.1/1944 110 Tittmann, O. H 4.1/1893 128 Tlusty, J 12.2/1963 261 Tobias, S. A 12.2/1961 260 12.2/1962 260 Todd, H. A. C 1.3.3/1937 22 Todd, T 3.5/1925 106 Toernebohm, H 1.2.1/1939 7 1.7/1937 36 Tolansky, S 1.3.4/1960 27 1.7/1953 37 1.7/1957 38 1.7/1961 38 2.1/1950 42 2.2.1/1946 45 2.2.5/1950 54 2.4.2/1950 74 2.4.3/1943 78 7.1/1953 177 7.1/1963 180 8.2/1952 195 8.2/1954 196 11.1/1950 242 11.1/1951 242 Tolley, G 1.7/1949 37 Tolmon, F. R 3.3/1962 100 3.3/1963 100 3.4/1959 102 3.4/1960 103 3.5/1962 108 3.5/1963 108 5.6/1959 147 7.3/1959 183 8.2/1951 195 SubteetionlYear Page Tolstoj, N. S 1.2.3/1961 14 Tomascheck, R 5.7/1956 149 Tomaszewski, A 1.2.1/1952 8 3.6.1/1949 110 Tomkins, F. S 2.3.1/1958 58 Tomkins, J. A 5.1/1928 129 Tomlinson, G. A 3.3/1926 97 3.3/1927 97 5.2.2/1929 133 6.3/1940 163 8.2/1926 194 9.3/1926 207 9.3/1927 207 9.4/1926 212 Tomonaga, Y 2.4.4/1961 83 Toropin, S. I 4.4/1960 127 Tortosa, J 11.3/1957 252 Town, H. C , 1.2.1/1956 8 12.4/1935 265 Townes, C. H 2.3.7/1963 67 Towns, V 6.7/1926 171 Trautschold, R 10.1.3.4/1918 220 10.2.4/1918 232 Trbojevich, N 6.3/1938 163 12.1/1919 257 12.1/1923 257 Trimbath, S 9.3/1932 208 10.1.4/1931 223 10.1.4/1933 224 10.2.4/1930 233 10.2.4/1932 233 Troeger, H 5.7/1962 151 Trost, S 3.3/1961 100 7.1/1961 179 Trott, J. J 5.2.2/1952 136 Trotter, A. P 5.3/1916 143 Trowbridge, R. P 1.7/1950 37 Trulev, Y. I 2.4.2/1960 77 Truten', V. A 3.3/1963 100 Tsapenko, M. P 1.1/1962 6 1.1/1963 6 Tschirf, L 3.5/1942 107 6.8/1941 172 9.1/1939 200 Tseitlin, Y. M 5.7/1964 151 Tsidulko, F. V 5.2.5/1962 142 5.2.5/1963 142 Tslaf, M. Y 12.2/1961 260 Tsuboi, T 2.4.6/1962 87 2.4.6/1964 87 Tsukerman, V. A 11.3/1963 255 Tsukizoe, T 1.7/1964 39 Tucker, M. J 5.2.2/1952 136 Tucker, R. H 6.4/1895 164 Tuckerman, L. B 5.2.4/1923 139 Tunicliffe, W. G 12.6.5/1917 274 Tuplin, W. A 1.7/1945 36 7.1/1942 176 10.1.1/1948 213 10.1.1/1952 214 10.2.6/1959 237 10.3/1963 240 Turbin, G. B 12.3/1961 263 Turlan, C 3.6.3/1946 114 4.2/1946 122 Turnbull, L. G 7.2/1947 180 Turner, A 3.1/1938 92 3.4/1953 102 4.4/1941 125 9.1/1938 200 9.2/1938 203 Turner, J. A 11.3/1963 255 Turner, R 2.3.7/1963 68 Turrettini, F 5.2.2/1952 136 Turrettini, J 8.2/1953 195 Turrettini, M. F 5.1/1937 130 305 Subsection/Year Page Tuttle, C 5.4/1939 144 7.1/1940 176 Tuttle, L 1.1/1916 1 Tutton, A. E. H 2.3.1/1931 56 2.4.2/1898 73 2.4.2/1910 73 2 4 2/1923 73 Twogood, E. N 10!2!6/1930 236 Tyr, V. R 3.4/1960 103 U Uhink, W 6.4/1928 165 6.4/1932 166 Ullrich, R 2.4.4/1957 83 U.S. Army, Office of Chief of Ordnance 9. 1/1944 200 Utumi, H 1.2.3/1959 14 Uverskii, I. T 1.3.2/1959 21 V Vaganov, I. P 1.4/1963 30 3.2/1962 96 3.2/1963 97 Vaisala, Y 2.4.1/1927 69 2.4.5/1923 84 2.4.5/1930 84 Vale, L. B 3.6.2/1963 113 Valedinskii, A. S 5.7/1962 150 Valentine, A. L 9.1/1927 199 Vallot, J 1.1/1946 2 Van Acker, J. E 10.1.3.5/1954 222 10.2.6/1955 237 Van der Breeggen, J. C 5.2.2/1960 137 Vanderman, E. J 5.2.2/1951 135 Vanet, P 3.3/1919 97 Van Heel, A. C. S 6.2/1946 157 6.2/1949 158 6.2/1950 158 6.2/1960 160 6.2/1961 160 6.2/1962 161 7.1/1961 179 11.1/1958 244 11.1/1958 245 The Van Keuren Co 3.5/1932 106 7.1/1920 175 7.1/1955 178 10.1.3.4/1955 221 Van Keuren, H. L 2.4.4/1920 82 7.1/1920 175 8.2/1918 193 9.1/1918 198 9.3/1918 206 9.4/1948 212 12.6.5/1919 274 12.6.5/1926 275 Van Outryve, E 2.4.3/1962 81 Van Soest, J. L 1.1/1947 2 Van Steewen, O. P 5.4/1931 144 12.4/1933 265 Van West 10.2.6/1923 235 Vargady, L. O 2.5/1964 90 Varnum, E. C 9.3/1957 211 10.1.3.1/1962 219 Vasicek, A 11.2/1947 247 11.2/1957 248 Vasilenko, I. S 3.4/1960 103 Vasil'ev, V. G 1.1/1963 5 Vedder, E. H 12.3/1937 262 Vedmidskii, A. M 12.5/1962 268 Verhaeghe, J. L 2.4.3/1962 81 Verkhoturov, B. Y 3.4/1963 103 10.1.4/1963 228 Vernotte, P 1.3.3/1959 24 Vernotte, P. C. R 1.3.3/1946 23 Verschoffel, A 6.4/1916 165 Viall, E 12.6.1/1920 268 Vickers 9.2/1924 194 10.2.6/1922 235 Subsection/Year Page Vidal, J. M. T 1.4/1951 28 Vienot, J. C 2.4.1/1956 71 8.2/1956 196 Vieweg, R 1.2.2/1961 12 Vigman, B. A.. 1.3.1/1963 19 Vigness, I 1.6/1965 35 Vigour, H. E 12.3/1963 264 Vikhman, V. S 12.3/1963 264 Vinco Corp 10.2.5/1960 234 Visser, A 7.4/1960 186 Vittoz, B 2.2.1/1960 47 Vlahos, C. J 1.6/1962 35 Voeneky, G 9.3/1962 212 Vogel, W. F 9.3/1937 208 9.3/1945 208 9.3/1947 210 9.3/1955 210 9.3/1957 211 10.1.2/1933 215 10.1.2/1945 216 10.1.3.1/1936 217,218 10.1.3.1/1945 217,218 10.1.3.2/1943 219 10.1.3.2/1945 219 10.2.4/1937 233 10.2.6/1937 236 10.3/1933 239 12.6.3/1933 272 12.6.3/1934 272 12.6.3/1935 272 12.6.3/1936 272 Vogl, G 7.3/1958 183 Vogl, J. G 6.2/1947 157 7.1/1946 176 Vogt, W 1.5/1938 32 Voight, W 3.3/1954 99 Voigt, B 1.6/1931 34 1.6/1932 34 Voigt, W 3.3/1954 99 Volet, C 1.6/1952 34 2.4.5/1951 84 4.1/1939 118 4.1/1941 118 4.1/1942 118 4.1/1944 118 4.1/1948 118 4.1/1952 118 Volger, J 1.3.4/1948 27 Volkonskii, V. A 4.2/1961 122 Volkova, E. A 1.2.2/1963 13 Volosevich, F. P 3.2/1959 96 4.4/1960 127 6.4/1960 166 Volosin, Y. P 3.6.2/1960 113 Volosov, S. S 12.3/1961 263 Von Fragstein, C 11.3/1954 251 Von Geldern, O 6.7/1897 170 Von Hofe, C 5.4/1925 143 Von Keussler, V 9.1/1948 200 Von Weingraber, H 7.3/1960 183 8.1/1960 192 von Weiss, A 1.6/1956 34 Vook, R. W 11.3/1963 254 Vorhees, L. J 12.5/1920 266 Vorob'eva, T. S 12.2/1962 260 Vorontsov, B. N 3.6.1/1960 110 Vysotskii, A. V 7.4/1960 186 12.4/1963 266 W Wade, H. T 4.1/1906 117 Wadsworth, F. L. O 6.4/1894 164 Wagner, E 10.1.4/1956 226 Wagner, G. H 4.4/1941 125 Wahl, A. M 5.7/1939 148 Wahrlich, G. V 2.3.2/1942 60 Wainwright 12.6.1/1954 269 Wait, E. V 7.1/1941 176 306 Subsection/Year Page Waite, B. C. Jr 5.2.2/1929 133 Waldersee, J 1.6/1963 35 Walker, D. F 12.3/1963 264 Walker, H 10.1.1/1952 214 10.2.2/1941 231 10.2.6/1926 235 Walker, J 2.2.3/1898 50 Waller, M. D 1.5/1940 32 Walter, L 3.3/1958 99 Walther, A 11.1/1958 245 Wanach, B 6.7/1926 171 Warers, D. V 10.2.2/1922 230 Warlich, G. V 2.3.2/1942 60 Warman, W. A 10.2.5/1902 234 Warner, R. M. Jr 11.3/1962 254 Warren, G. W 2.4.2/1928 73 Warrington, D. H 11.3/1962 254 Washburn, E. W 1.5/1925 32 Washer, F. E 6.2/1946 157 6.2/1947 157 Wasserman, M 2.5/1964 90 Watanabe, N 2.3.2/1928 59 2.4.5/1929 84 Waterman, A. T 1.1/1961 4 Waters, D. V 10.2.2/1922 230 Waters, W. C 10.1.4/1961 227 Watkin, E. L 2.4.2/1905 73 Watkins, A 3.6.1/1919 109 Watson, A 5.2.4/1950 140 Watson, G. S 1.3.3/1953 23 Watson, J. H. L 11.3/1948 250 Wattebot, L 5.2.5/1937 141 E. R. Watts & Son 3.1/1945 93 6.2/1947 157-8 6.7/1925 171 Watts, G. W 6.4/1923 165 Weaver, C 2.2.5/1964 56 11.1/1956 243 11.1/1958 245 Weaver, F. D 1.3.2/1950 20 1.3.2/1954 20 Webber, G 2.1/1953 43 Webber Optical Polygons 6.3/1959 163 Weber, A. H 11.3/1952 251 Weber, A. P 2.3.3/1928 61 Weber, K. H 10.1.4/1956 226 10.2.1/1964 230 Weber, L 6.1/1908 153 Weber, P. W 2.3.7/1964 68 Weber, R. R 12.3/1963 264 Webster, R. A 5.2.2/1931 133 Weicholdt, W 3.6.2/1902 110 3.6.4/1902 114 Weidenhammer, F 5.3/1963 143 WeiU, R 12.2/1963 261 Weiner, B. L 1.2.2/1961 12 Weinhold, H 10.1.4/1960 227 Weinstein, W 3.3/1957 99 4.4/1957 126 Weir, J. B 5.2.3/1962 139 Weisman, D 12.1/1964 258 Weiss, A 2.4.2/1954 75 Weiss, H 1.3.3/1962 25 Welford, W. T 4.4/1960 126 Wells, F. O 12.6.4/1919 273 Wendeln, D. E 1.2.1/1963 10 Werner, A 9.1/1932 199 Fritz Werner 3.5/1932 106 Wernicke, W 2.2.5/1894 53 11.1/1878 241 11.1/1894 241 Wescott, B. B 9.1/1937 200 West and Dodge Co 9.2/1918 202 West, J 2.4.2/1959 76 Westfall, F. O 2.3.4/1950 63 Westinghouse Machine Co 3.2/1904 94 Westmeyer, H 11.1/1960 245 Subsection/Year Page Weston, S 6.7/1926 171 Wetzel, K. E 12.2/1963 261 Weyerer, H 2.2.2/1954 49 Weyl, R 11.3/1961 253 Wheeler, B 10.2.6/1927 235 Whibley, R. J 3.1/1920 92 3.5/1920 105 8.2/1920 193 Whiddington, R 5.2.2/1920 151 Whipple, R. S 5.1/1920 129 Whitaker, H 3.6.4/1931 115 White, C. E 1.6/1959 34 While Co 10.3/1913 238 White, F. L 12.5/1951 267 White, P. H 5.5/1931 146 Whitmarsh, W. L 3.6.1/1924 109 Whitney, C. A 7.4/1958 185-6 Whittemore, H. L 9.2/1911 202 Whitten, L. G 6.2/1964 162 7.4/1963 187 Whitworth, J 1.2.1/1858 6 1.2.1/1946 7 1.2.2/1857 10 7.1/1858 175 12.1/1840 257 Wick, C. H 1.2.3/1962 15 2.4.1/1962 72 Wickman 1.2.3/1920 13 3.5/1923 105 10.1.4/1924 223 10.2.6/1920 235 Wieckowski, J 1.6/1962 34 Wiegand, H 1.7/1958 38 Wiemer, A 1.7/1957 38 Wiener, O 11.1/1887 241 Wiens, J. H 2.3.4/1946 63 Wigan, E. R .10.2.1/1955 230 Wiggins, T. A 2.3.1/1957 58 Wight, K. C __.2.3.1/1951 57 Wilcox, R. H 3.6.1/1952 110 Wilde, H 9.2/1926 203 Wildhaber, E 7.3/1955 182 10.1.3.5/1923 222 10.2.6/1923 235 _ 10.3/1945 239 10.3/1946 239 12.6.3/1924 272 Wildhack, W. A 1.1/1961 4 5.2.5/1950 141 Wilharm, L. F 6.6/1949 169 Wilhelm, J 9.3/1933 208 Wilhelm, J. H 8.1/1918 189 Willey, E. J. B 1.1/1948 2 Williams, C. W 5.2.2/1952 136 Williams, D. C 1.5/1962 33 2.2.2/1962 50 3.1/1962 94 3.2/1962 97 Williams, F. R 9.1/1917 197 Williams, H. B 6.2/1946 157 Williams, M. H 3.2/1924 95 Williams, W. E 2.1/1930 41 2.1/1948 42 2.3.2/1938 60 Williamson, D. E 9.3/1946 210 Williamson, J. L._ 10.1.3.6/1949 222 10.1.3.6/1957 222 10.1.4/1925 223 10.1.4/1926 223 10.2.2/1957 231 Willoughby, A. B .2.4.2/1948 74 Wills, H. J 12.4/1944 266 Wilson, B. L 2.4.2/1944 74 Wilson, B. W 2.4.1/1950 70 Wilson, D. C 2.3.7/1963 68 2.3.7/1964 68 5.4/1957 145 307 Subsection/Year Page Wilson, J. H 7.1/1961 180 Wilson, L 7.1/1962 180 Wilson, M. D 10.2.4/1921 232 Wilson, R. N 8.1/1956 192 8.2/1956 196 Wilson, W. K _1. 7/1945 36 Wilson, W. M 10.1.4/1905 222 Winchester Repeating Arms Co 6.8/1928 172 Winder, G. E 6.5/1950 167 Winkler, O 1.4/1953 28 Winter, P. K 1.1/1962 5 Winterbottom, A. B 11.2/1946 247 11.2/1948 247 Wirrer, G 10.2.1/1920 228 Wise, J. F 2.3.2/1956 60 Wise, W. F 12.2/1935 259 Wittke, H 2.1/1948 42 Wittrick, W. H 5.7/1948 148 10.1.4/1947 225 Witzke, F. W 1.7/1961 38 3.6.2/(1959) 113 5.2.2/1960 137 7.4/1958 185-6 7.4/1962 186 Wizenz, L 1.3.1/1959 18 3.3/1959 99 3.3/1960 100 3.4/1960 103 Wobschall, D 5.2.2/1961 137 Wojtowicz, W. J 11.3/1948 250 Wolf, F 9.3/1952 210 Wolfe, K. J. B 1.7/1953 37 Wolfer, A 1.2.3/1907 13 Wolper, M 10.1.4/1948 225 Wolter, H 2.4.1/1956 70 11.3/1952 251 11.3/1957 252 Womack, J. D 6.2/1958 159 Wong, G. S. K 2.5/1964 90 Wood, B 10.1.4/1959 227 Wood, Mrs. J. G 8.2/1951 195 9.3/1958 211 Wood, J. K 3.5/1925 106 Woodman, L. E 1.3.3/1942 22 Woods, R. C 9.1/1941 200 Woods, R. W 1.4/1955 29 Woodson, R. A 6.5/1960 168 Woodward, R 6.4/1876 164 Woodward, R. S 4.1/1893 128 Woodward, R. W 6.1/1933 153 Woodworth, W. D 12.6.4/1918 273 Wootan, G. G 1.3.3/1963 26 Woran, H. P 2.2.5/1922 54 Work, R. N 2.4.2/1950 74 2.4.2/1951 74 Worthen, J 7.4/1958 185 Worthen, J. H 3.5/1962 108 Worthy, R. J 6.8/1923 172 Wouterlood, H.J 5.2.2/1960 137 Wright„C. D 6.6/1946 169 Wright, C. W 12.6.5/1903 274 Wright, F. E 6.2/1924 157 Wright, H. H 9.3/1918 206 Wright, H. T 9.2/1923 203 Wright, J. P 3.3/1954 99 10.2.5/1958 234 Wright, K. H. R 7.1/1961 179 Wright, P 11.3/1963 255 Wulff, J 1.7/1941 36 Wunsch, H. L 5.6/1962 147 5.7/1951 149 Wurzinger, M 2.4.5/1930 84 Wylie, K. F 11.3/1965 255 Wynn, N. R -... 5.2.5/1955 142 Y Subsection/Year Page Yakonovskii, S. V 9.2/1963 205 Yamada, Y 12.6.2/1959 271 Yamaguchi, J 5.2.2/1951 135 Yamamoto, A _ 9.2/1963 205 9.2/1964 205 Yamamoto, H .2.4.5/1963 86 Yamamoto, K 3.6.4/1962 116 6.1/1960 155 10.2.1/1959 230 Yamoto, S 9.2/1963 205 Yanus, R. I 1.3.3/1957 24 Yeh, L 1.6/1962 35 Yoder, P. R. Jr ■ 2.4.4/1957 83 Yokoyama, Y ..9.1/1960 201 Yoneyama, Y 11.2/1953 248 Yorgensen, P. L. L 3.6.2/1908 111 York, H. F 1.1/1961 4 Yoshida, T 2.4.2/1959 76 11.3/1959 253 Yoshitsugu, M... 3.4/1963 108 Youden, W. J 1.1/1962 4 1.3.1/1961 18 1.3.1/1962 19 1.3.2/1954 20 1.3.3/1953 23 1.3.3/1962 25 1.3.3/1962 26 1.3.4/1962 27 Young, A. W 1.2.1/1963 9 4.1/1963 119 6.1/1962 156 6.1/1963 156 6.2/1963 161 Young, C. A 10.2.6/1942 237 Young, I. R 1.2.3/1960 14 5.7/1956 149 6.1/1959 155 6.5/1959 168 Young, J. G 12.2/1930 259 Young, L 11.1/1958 244 Young, N. O 2.4.4/1956 82 Young, Thomas 2.2.1/1960 47 Young, T. R 1.2.1/1963 9 2.1/1957 43 2.2.1/1963 48 2.4.4/1957 82 3.1/1960 93 3.1/1961 93 11.2/1963 248 11.2/1964 249 Yribarren, R 5.2.5/1948 141 Z Zablonskii, K. I 5.2.2/1963 138 Zahorski, A 9.3/1939 209 10.2.4/1937 233 Zaininger, K. H 11.2/1964 249 Zamis, A. F 10.1.4/1947 225 Zarubin, A 1.2.3/1961 14 Zaslavskii, Y. S 11.3/1963 254 Zeise, G 12.6.3/1961 273 Zeitz, K. H 5.1/1962 131 Zelbstein, U 5.1/1960 131 Zeiss, Jena 3.3/1924 97 3.3/1928 97 3.3/1930 98 3.4/1926 101 3.5/1949 107 3.5/1956 108 3.6.1/1925 109 4.4/1925 124 4.4/1927 125 4.4/1930 125 4.4/1931 125 4.4/1938 125 5.1/1931 129 308 Subsection/Year Page Zeiss, Jena — Continued Carl Zeiss, Oberkochen 6.2/1934 157 6.4/1946 166 7.1/1925 176 7.3/1934 181 8.2/1926 194 9.1/1925 199 9.1/1929 199 9.2/1926 203 10.1.4/1932 223 10.2.1/1927 229 10.2.5/1926 234 10.2.6/1923 235 10.3/1932 239 . 2.4.5/1961 85 10.1.3.2/1957 219 SvJjgection/Year Page Zemany, P. D 11.3/1956 251 Zernike, F 2.1/1957 44 Zhuravlev, N. M 9.2/1960 204 Ziegenhals, E 12.2/1933 259 Zieher, G 3.4/1937 101 10.1.4/1937 224 10.1.4/1959 227 10.2.2/1952 231 Zissis, G. J 2.4.3/1953 79 Zobel, T 2.1/1937 42 Zollner, H 9.3/1939 209 10.2.4/1939 233 Zorll, U 11.1/1952 243 Zuehlke, A. A 1.3.2/1962 21 Zwerling, C 2.5/1964 90 309 THE NATIONAL BUREAU OF STANDARDS The National Bureau of Standards is a principal focal point in the Federal Government for assur- ing maximum application of the physical and engineering sciences to the advancement of technology in industry and commerce. Its responsibilities include development and maintenance of the national standards of measurement, and the provisions of means for making measurements consistent with those standards; determination of physical constants and properties of materials; development of methods for testing materials, mechanisms, and structures, and making such tests as may be neces- sary, particularly for government agencies; cooperation in the establishment of standard practices for incorporation in codes and specifications; advisory service to government agencies on scientific and technical problems; invention and development of devices to serve special needs of the Government; assistance to industry, business, and consumers in the development and acceptance of commercial standards and simplified trade practice recommendations; administration of programs in cooperation with United States business groups and standards organizations for the development of international standards of practice; and maintenance of a clearinghouse for the collection and dissemination of scientific, technical, and engineering information. The scope of the Bureau's activities is suggested in the following listing of its three Institutes and their organizational units. Institute for Basic Standards. Applied Mathematics. Electricity. Metrology. Mechanics. Heat. Atomic Physics. Physical Chemistry. Laboratory Astrophysics.* Radiation Physics. Radio Standards Laboratory:* Radio Standards Physics and Radio Standards Engineering. Office of Standard Reference Data. Institute for Materials Research. Analytical Chemistry. Polymers. Metallurgy. Inorganic Materials. Reactor Radiations. Cryogenics.* Materials Evaluation Laboratory. Office of Standard Reference Materials. Institute for Applied Technology. Building Research. Information Technology. Perform- ance Test Development. Electronic Instrumentation. Textile and Apparel Technology Center. Technical Analysis. Office of Weights and Measures. Office of Engineering Standards. Office of Invention and Innovation. Office of Technical Resources. Clearinghouse for Federal Scientific and Technical Information.** •Located at Boulder, Colorado 80301. "Located at 5285 Port Royal Road, Springfield, Virginia 22151. U.S. GOVERNMENT PRINTING OFFICE: 1966 O — 771-846 u PENN STATE UNIVERSITY LIBRARIES "illllilllllllllllW