DEPARTMENT OF COMMERCE CIRCULAR OP THE BUREAU OF STANDARDS S. W. STRATTON, DIRECTOR No. 43 JEWELERS' AND SILVERSMITHS' WEIGHTS AND MEASURES (2d Edition) A revised and enlarged edition of Bureau of Standards Circular No. 43 (1st edition), issued November 1, 1913 entitled "The Metric Carat" JANUARY 24, 1921 PRICE, 10 CENTS Sold only by the Superintendent of Documents, Government Printing Office Washington, D. C. WASHINGTON GOVERNMENT PRINTING OFFICE 1921 DEPARTMENT OF COMMERCE CIRCULAR OF THE BUREAU OF STANDARDS S. W. STRATTON. DIRECTOR No. 43 JEWELERS' AND SILVERSMITHS' WEIGHTS AND MEASURES (2d Edition) A revised and enlarged edition of Bureau of Standards Circular No. 43 (1st edition), issued November 1, 1913 entitled "The Metric Carat" JANUARY 24, 1921 PRICE, 10 CENTS Sold only by the Superintendent of Documents, Government Printing Office Washington, D. C. WASHINGTON GOVERNMENT PRINTING OFFICE 1921 JEWELERS' AND SILVERSMITHS' WEIGHTS AND MEASURES 1 CONTENTS Page I. Introduction 6 1. Adoption of the new metric carat 6 2. Proposed adoption of the metric system 6 II. The metric system 7 i. Description 7 (a) Legal status * 7 (6) General outline 7 (c) Fundamental relationships 9 (d) Spelling and abbreviations of units 10 (e) Special ways to use the tables 10 a. Definitions of units 1 1 (a) Length n (b) Area n (c) Volume 12 (d) Capacity 13 (e) Mass 14 3. Length conversion tables 15 Table i. Inches into millimeters (values, i to 9; see also Table 6, p. 16); millimeters into inches (values, i to 9; see also Table 7, p. 18) 15 Table 2. Inches into centimeters; centimeters into inches. . 15 Table 3. Feet into meters; meters into feet 15 Table 4. Yards into meters; meters into yards 15 Table 5. Decimal and metric equivalents of common (binary) fractions of an inch 15 Table 6. Inches into millimeters (values, o.ooo to 0.999, and i to 20; see also Table i, p. 15) 16 Table 7. Millimeters into inches (values, o.oo to 9.99; see also Table i, p. 15) 18 4. Tab 1 es of area 20 Table 8. Square inches into square centimeters; square centimeters into square inches 20 Table 9. Square feet into square meters; square meters into square feet 20 Table 10. Square yards into square meters; square meters into square yards 20 5. Tables of volume 20 Table n. Cubic inches into cubic centimeters; cubic centimeters into cubic inches 20 Table 12. Cubic feet into cubic meters; cubic meters into cubic feet 20 Table 13. Cubic yards into cubic meters; cubic meters into cubic yards 20 Table 14. Cubic inches into liters; liters into cubic inches. . 20 Table 15. Cubic feet into liters; liters into cubic feet 20 1 Prepared by A. F. Beal, Associate Physicist, Bureau of Standards. Circular of the Bureau of Standards II. The Metric System Continued. Page 6. Tables of capacity 21 Table 16. Minims into milliliters; milliliters into minims. . 21 Table 17. U. S. fluid drams into milliliters; milliliters into U. S. fluid drams 21 Table 18. Fractions of fluid drams and fluid ounces into . milliliters 21 Table 19. U. S. fluid ounces into milliliters 21 Table 20. Milliliters into U. S. fluid ounces 21 Table 21. U. S. liquid pints into liters; liters into U. S. liquid pints 21 Table 22. U. S. liquid quarts into liters; liters into U. S. liquid quarts 21 Table 23. U. S. gallons into liters; liters into U. S. gallons. . 21 Table 24. British Impeial gallons into liters; liters iinto British Imperial gallons 21 Table 25. U. S. gallons into British Imperial gallons; British Imperial gallons into U. S. gallons 21 7. Tables of mass (weight) 22 Table 26. Grains into grams (values, i to 9; see also Table 32, p. 23); grams into grains (values, i to 9; see also Table 33.P-23) 22 Table 27. Pennyweights into grams (values, i to 9; see also Table 34, p. 24); grams into pennyweights (values, i to 9; see also Table 35, p. 24) 22 Table 28. Troy ounces into grams (values, i to 9; see also Table 36, p. 25); grams into troy ounces (values, i to 9; see also Table 37. p. 25) 22 Table 29. Avoirdupois ounces into grams 22 Table 30. Avoirdupois pounds into kilograms (values, i to 9; see also Table 38, p. 26); kilograms into avoirdupois pounds (values, i to 9; see also Table 39, p. 26) 22 Table 31. Short tons into metric tons; metric tons into short tons 22 Table 32. Grains into grams (values, o to too) 23 Table 33. Grams into grains (values, o to 100) 23 Table 34. Pennyweights into grams (values, o.oo to i.oo; also o to too) 24 Table 35. Grams into pennyweights (values, o to 100) 24 Table 36. Troy ounces into grams (values, o.oo to i.oo; also o to 100) 25 Table 37. Grams into troy ounces (values, o to 100) 25 Table 38. Avoirdupois pounds into kilograms (values, o to 100) 26 Table 39. Kilograms into avoirdupois pounds (values, o to 100) 26 III. The metric carat 27 1. Definition 27 2. Conversion tables 27 Table 40. Fractions of old carat into new metric carat 28 Table 41 .Old carats into new metric carats 29 Jewelers' Weights and Measures 5 Page IV. Gages (wire and drill) 29 i. Existing practice in gaging materials 29 a. Wire gages 30 (a) American wire gage 30 (6) Steel wire gage 30 (c) Stubs' steel wire gage 30 (d) Birmingham wire gage 31 (e) Standard wire gage 31 (/) Old English or London gage 31 3. Twist drill and steel wire gages 31 4. Tables of gage sizes (inches and millimeters) 32 Table 42. Douzieme caliper 32 Table 43 . Tabular comparison of wire gages 33 Table 44. Equivalents of lettered sizes, for drills and Stubs' steel wire gage 34 Table 45. Numbered sizes, i to 60, for drills and Stubs' steel wire gage 34 Table 46. Numbered sizes, 60 to 80, for drills and Stubs' steel wire gage 35 Table 47. Index to numbered sizes, 60 to 80, drills, etc. ... 35 V. Watch glasses 35 1 . Gage sizes for watch glasses 35 2. Reasons for adoption of metric gage sizes 36 3 . Specimen labels 36 4. Influence of watchcase design 37 5. Conversion tables 37 Table 48. Diameter of watch glasses; conversion of Lignes (i6ths) into tenth-millimeters 37 Table 49. Height of watch glasses 37 VI. Sizes of watches 38 Table 50. Watch sizes 38 VII. Ring sizes 39 1. Original standard 39 2. Introduction of errors 39 3. Many similar standards 39 4. Confusion also in use of gage 40 5. Outline of the problem 40 VIII. Miscellaneous tables 41 Table 51. Decimal equivalents of gold karats 41 Table 52 . Densities of various metals 41 Table 53. Melting points of various metals 41 Table 54. Conversion of centigrade temperatures (C) into Fahren- heit temperatures (F) 42 Table 55. Conversion of Fahrenheit temperatures (F) into centi- grade temperatures (C) 42 i. Approximate temperatures by color 43 Index 45 6 Circular of the Bureau of Standards I. INTRODUCTION 1. ADOPTION OF THE NEW METRIC CARAT The carat weights in use previous to July i, 1913, in different countries had differed greatly, scarcely any two of the important countries having the same standard. Even within the United States there was not agreement in the standard used, the various makers of weights using slightly different standards. This led to considerable confusion in the weighing of gems, and was the more serious because of the great value of the article. Beginning July i, 1913, the international metric carat of 200 milligrams as the unit of weight for diamonds and other precious stones was put into commercial use in the United States by practi- cally all the dealers in gems and precious stones through the efforts of a committee representing all the principal firms handling gems. On the same date the Treasury Department of the United States Government also began the use of this unit in the customs service for the levying of import duties on precious stones, and the Bureau of Standards recognized this unit for purposes of certifi- cation of all carat weights submitted to the Bureau for test. The movement for the adoption of a uniform, decimally divided standard was a decided step forward and therefore has met w r ith success. The new metric carat of 200 milligrams is universally used in the United States and has been officially adopted by Belgium, Bulgaria, Denmark, England, France, Germany, Holland, Italy, Japan, Norway, Portugal, Roumania, Spain, Sweden, and Switzer- land. The Bureau of Standards in 1913 prepared tables for con- verting "old" carats to new metric carats, and vice versa, and published them as Circular No. 43. These tables were of great aid at the time to the transition from the old unit of about 205.3 **&- ligrams and binary fractions to the new unit and decimal fractions. 2. PROPOSED ADOPTION OF THE METRIC SYSTEM The inconvenience and inefficient use of the present system of pennyweights and grains as opposed to the benefits derived from the use of the new metric decimally divided carat has become so pronounced that the Bureau was invited to prepare a practical working outline of the metric system that would suit the needs of the jewelry trade and allied industries. The purpose of this is to make it easily possible for jewelers and silversmiths to substitute the gram for the dual unit of pennyweights and grains 2 and also to use the metric system in all of their work. a It is desirable to note in this connection that all medical prescriptions of the U. S. Army must be expressed in metric units, not in grains. Jewelers' Weights and Measures The Bureau therefore is publishing this circular giving tables of the relations between the customary units and the correspond- ing ones of the metric system. There is also given information that is of interest to other branches of the jewelry trade, such as the comparative table for the diameters corresponding to the sizes of watches. With this edition, the material on the metric carat has been revised, and, because of the large amount of new material which has been added to the publication, the title has been changed. II. THE METRIC SYSTEM 1. DESCRIPTION (a) LEGAL STATUS The metric system was rendered legal for all transactions in the United States by an act of Congress, approved July 28, 1866, and is now legal or obligatory in all commercial countries. Many industries in the United States are using it. In Europe, and also in many other parts of the world, more measurements are made in metric terms than in any other system. The metric system must be understood by those who deal intelligently with their customers in the metric countries. (b) GENERAL OUTLINE The meter for measuring length, the liter for measuring capacity, and the gram for weight form the basis of the metric system. These units, together with the multiples and subdivisions given in the following table, 3 are sufficient for practical purposes and are recognized in all countries. Correct English spelling Standard abbre- viations 10 millimeters= 1 centimeter 10 mm= 1 cm Length 100 centimeters^ 1 meter 1000 meters 1 kilometer 100cm =lm 1000m -1km Capacity.... Weight 1000 milliliters = 1 liter 1000 milligrams = 1 gram 1000 grams =1 kilogram 1000ml =11 1000 mg =lg 1000 g =lkg 1000 kilograms = 1 metric ton 1000kg =lt * Additional units, multiples, and subdivisions, which may be needed occasionally, are given later under 'Definitions of Units," pp. n to 14. Tables giving the interrelation of units of measurement may be found in Bureau Circular No. 47. oo E CD = 10 3 tfd w EH W grH H H UQ Circular of the Bureau of Standards Complete metric tables are formed by combining the words " METER," " LITER," and "GRAM" with the six numerical pre- fixes as in the following tables : IO 03 'j | S 1 fr C. Prefixes Meaning mill!- = one-thousandth centi- = one-hundredth dCCi- = one-tenth Unit -one deka- - ten ~1O~ .01 ml kilo- = one thousand "meter" fa length "liter" for ca- /or The metric unit of length for jewelers and silversmiths is the millimeter, or one-thousandth of a meter; the milli- meter is the size of the smallest space shown in Fig. i . It is also very nearly the diameter of a No. 18 wire of American (Brown & Sharpe) wire gage. For very small values of length, such as the thick- ness of the plating on an electroplated article, it is convenient to use the " micron, " which is one-thousandth of a millimeter. The smallest subdivision on the head of a micrometer with a milli- meter screw usually is o.oi millimeter, or 10 microns. In working material to a given dimension within a quarter of a thousandth of an inch, the accuracy ob- tained is 6 microns. An inch equals almost exactly 25.4 millimeters. The liter is the standard unit of capac- ity and is divided into a thousand equal parts called milliliters. For ordinary purposes, the liter 4 is equivalent to a 4 There is a minute distinction between the liter and 1000 cubic centimeters which is used only in work of extreme precision. See " Fundamental Relationship," page 9 . Jewelers' Weights and Measures 9 cubic measure 10 centimeters on each edge, or 1000 cubic centi- meters. A liter is a trifle larger than a U. S. liquid quart. The gram is the unit of mass (or weight) ; 1000 grams make a kilogram. The kilogram is exactly the mass of a liter of water when at the temperature of 4 C (39.2 F). The gram is fre- quently subdivided into 1000 parts called milligrams. For a small article (less than i gram) the weight usually is expressed in milligrams. A piece of platinum wire one-half inch long and American (B. & S.) wire gage No. 30 weighs about 14 milligrams; if of copper wire it weighs about 6 milligrams. A one-half carat dia- mond weighs exactly 100 milligrams. For large weighings, or in expressing the sum of several weighings, it is convenient to use the gram even up to about 10 ooo grams, or 10 kilograms, thus avoiding the change from one unit to another. In the metric system a quantity is always expressed in terms of only one unit. The gram equals about 15.4 grains, and the kilogram is about 2.2 avoirdupois pounds. A change to a larger or smaller metric measure of length, area, volume, capacity, or weight is effected by merely multi- plying or dividing by 10 or a multiple of 10. This enables those who use the metric system to make accurate mental and written calculations with a rapidity which would otherwise be impossible. (c) FUNDAMENTAL RELATIONSHIPS The tables in this circular have been prepared to aid in changing values from one system of weights and measures to another. The U. S. units are referred to except when otherwise indicated. The tables have been based upon the following equivalents: 39.37 United States inches =i meter i United States gallon =231 cubic inches i liter =1000.027 cubic centimeters i United States avoirdupois pound=o. 4535924277 kilogram The values in most of the tables have been expressed with the accuracy usually required at the bench. In some cases, however, many figures are given for use in connection with precise work. Equivalents, such as those in the tables given on pages 15, 20, 21, and 22, should be used only to the required degree of accuracy. For example, in Table 2, page 15, it is stated that 4 inches are equal to 10.16002 centimeters. This may be rounded off, giving 4 inches equal to 10.2 centimeters, or, if less accuracy is desired, the approximate value of 10 centimeters may be used. 16340 21 2 io Circular of the Bureau of Standards (d) SPELLING AND ABBREVIATION OF UNITS The spelling of the names of metric units is that given in the law of July 28, 1866, legalizing the metric system in the United States. The following principles of abbreviation have been adopted by the Bureau in conformity with international agreement. 1. The period is omitted after the abbreviations of the metric units, while it is used after those of the customary system. 2. The same abbreviation is used for both singular and plural. 3. Unless all of the text is printed in capital letters, only small letters are used for abbreviations (except in the case of A. for acre, where the use of the capital letter is general) . 4. The exponents " 2 " and " 3 " following abbreviations of units of length, are used to signify area and volume, respectively, in the case of the metric units instead of the longer prefixes " sq. " and "cu. " In conformity with this principle the abbreviation for cubic centimeter is "cm 3 " in preference to any other usual practice. (e) SPECIAL WAYS TO USE THE TABLES When the tables do not give the equivalent of any desired quantity directly and completely, the equivalent can usually be obtained without the necessity of making a multiplication. This is done by using quantities from different parts of the same table or from several tables, making a shift of decimal points if necessary, and merely adding the results. For example: 1. Convert 27.3 millimeters into inches. (Refer to Table i, P- I5-) 2 mm=o. 07874 inch, hence 20.0 mm=o. 7874 inch 7.omm= . 27559 inch 3 mm= .11811 inch, hence .3 mm= .01181 inch 27.3 mm=i. 0748 inches 2. Convert 1.0748 inches into millimeters. (Refer to Table i, P- 15.) i inch = 2 5- 4 mm 7 inches=i77. 8 mm, hence o. 07 inch = i. 778 mm 4 inches=ioi. 6 mm, hence .004 inch = . 102 mm 8 inches=203- 2 mm, hence . 0008 inch = . 020 mm i. 0748 inches=27. 300 mm 3. Convert 253 pennyweights 13.5 grains into grams. 200 pennyweights (Table 34, p. 24) =311. 035 g 53 pennyweights (Table 34, p. 24) = 82. 424 g 13 grains (Table 32, p. 23) = . 842 g 5 grains=o.324 g, hence 0.5 grain = . 032 g 253 pennyweights 13.5 grains = 394. 333 g Jewelers' Weights and Measures 1 1 2. DEFINITIONS OF UNITS (a) LENGTH Fundamental Units A METER (m) is a unit of length equivalent to the distance between the defining lines on the international proto- type meter at the International Bureau of Weights and Measures when this standard is at the temperature of melting ice (o C). A YARD (yd.) is a unit of length equivalent to $$4$ of a meter. Multiples and Submultiples i kilometer (km) = 1000 meters. i hectometer (hm) = 100 meters. i dekameter (dkm) = 10 meters. i decimeter (dm) =0.1 meter. i centimeter (cm) =0.01 meter. i millimeter (mm) =0.001 meter = 0.1 centimeter. i micron (M) =0.000001 meter = 0.001 millimeter. i millimicron (m/x) =0.000000001 meter =0.00 1 micron. i foot (ft.) -=K yard=if^ meter. i inch (in.) =& yard = -rV foot = -sVW meter. i link (li.) =0.22 yard = 7. 92 inches. i rod (rd.) =5^2 yards = i6 l / 2 feet. i chain (ch.) =22 yards = 100 links = 66 feet = 4 rods. i furlong (fur.) = 220 yards = 40 rods = 10 chains. i statute mile (mi.) = 1 760 yards = 5280 feet = 320 rods. i hand = 4 inches. i point (printers') = -fa inch (approximately) . i point (silversmiths') =TiiW inch. i mil=o.ooi inch. i fathom = 6 feet. i span = 9 inches = yi fathom. i nautical mile United States = 6080. 20 feet = 1.151 553 statute miles = 1853.2 49 meters, i geographical mile (b) AREA Fundamental Units A SQUARE METER (m 2 ) is a unit of area equivalent to the area of a square the sides of which are i meter. A SQUARE YARD (sq. yd.) is a unit of area equivalent to the area of a square the sides of which are i yard. 12 Circular of the Bureau of Standards Multiples and Submultiples i square kilometer (km 2 ) = i ooo ooo square meters. i hectare (ha), or square hectometer (hm 2 ) = 10 ooo square meters. i are (a), or square dekameter (dkm 2 ) = 100 square meters, i Centare (ca) = i square meter. i square decimeter (dm 2 ) =0.01 square meter, i square centimeter (cm 2 ) =0.0001 square meter. i square millimeter (mm 2 ) =0.000001 square meter =0.01 square centimeter. i square foot (sq. ft.) = square yard. i square inch (sq. in.) =TTFF square yard = -rir square foot, i square link (sq. li.) =0.0484 square yard = 62. 7264 square inches, i square rod (sq. rd.) =30.25 square yards = 272. 25 square feet = 62 5 square links. i square chain (sq. ch.) =484 square yards = 16 square rods = 100 ooo square links, i acre (A.) =4840 square yards = 1 60 square rods = io square chains, i square mile (sq. mi.) =3 097 600 square yards = 640 acres. (c) VOLUME Fundamental Units A CUBIC METER (m 3 ) is a unit of volume equivalent to a cube the edges of which are i meter. A CUBIC YARD (cu. yd.) is a unit of volume equivalent to a cube the edges of which are i yard. Multiples and Submultiples i cubic kilometer (km 3 ) = i ooo ooo ooo cubic meters. i cubic hectometer (hm 3 ) = i ooo ooo cubic meters. i cubic dekameter (dkm 3 ) = 1000 cubic meters. i stere (s) = i cubic meter. i cubic decimeter (dm 3 ) =0.001 cubic meter. i cubic centimeter (cm 3 ) =0.000001 cubic meter = 0.00 1 cubic decimeter, i cubic millimeter (mm 3 ) =0.000000001 cubic meter = o.ooi cubic centimeter. i cubic foot (cu. ft.) =TT cubic yard, i cubic inch (cu. in.) = 46656 cubic yard = T ^ cubic foot, i board foot = 144 cubic inches = -rV cubic foot, i cord (cd.) =128 cubic feet. Jewelers' Weights and Measures 13 (d) CAPACITY Fundamental Units A LITER (1) is a unit of capacity equivalent to the volume occupied by the mass of i kilogram of pure water at its maximum density (at a temperature of 4 C, prac- tically) and under the standard atmospheric pressure (of 760 mm). It is equivalent in volume to 1.000027 cubic decimeters. A GALLON (gal.) is a unit of capacity equivalent to the vol- ume of 231 cubic inches. It is used for the measure- ment of liquid commodities only. A BUSHEL (bu.) is a unit of capacity equivalent to the volume of 2150.42 cubic inches. It is used in the measurement of dry commodities only. 5 Multiples and Submultiples i hectoliter (hi) = i oo liters. i dekaliter (dkl) = 10 liters. i deciliter (dl) =0.1 liter. i centiliter (cl) =0.01 liter. i milliliter (ml) =0.001 liter = 1.000027 cubic centimeters. i liquid quart (liq. qt.) =>^ gallon = 5 7. 75 cubic inches. i liquid pint (liq. pt.) =>i gallon = K liquid quart = 2 8. 8 75 cubic inches. i gill (gi.) = -fa gallon = K liquid pint = 7.21 875 cubic inches. i fluid ounce (fl. oz.) =TTF gallon = ^ liquid pint. i fluid dram (fl. dr.) =y& fluid ounce = T^r liquid pint. i minim (min. or ^l) =-$ fluid dram = TSTF fluid ounce. i firkin = 9 gallons. i peck (pk.) =% bushel = 53 7. 605 cubic inches. i dry quart (dry qt.) = -fa bushel = l /i peck = 6 7. 20062 5 cubic inches. i dry pint (dry pt.) = -fa bushel = % dry quart = 33.6003 1 25 cubic inches. i barrel (for fruit, vegetables, and other dry commodi- ties) 6 =705 6 cubic inches = 105 dry quarts. 6 The above bushel is the so-called stricken or struck bushel. Many dry commodities are sold by heaped bushel, which is generally specified in the State laws to be the usual stricken bushel measure "duly heaped in the form of a cone as high as the article will admit " or '' heaped as high as may be without special effort or design. " The heaped bushel was originally intended to be 25 per cent greater than the stricken bushel. ' As fixed by United States statute, approved Mar. 4, 1915- 14 Circular of the Bureau of Standards (e) MASS Fundamental Units A KILOGRAM (kg) is a unit of mass equivalent to the mass of the international prototype kilogram at the Interna- tional Bureau of Weights and Measures. An AVOIRDUPOIS POUND (lb. av.) is a unit of mass equivalent to 0.4535924277 kilogram. A GRAM (g) is a unit of mass equivalent to one-thousandth of the mass of the international prototype kilogram at the International Bureau of Weights and Measures. A TROY POUND (lb. t.) is a unit of mass equivalent to %i%% of that of the avoirdupois pound. Multiples and Submultiples i metric ton (t) = 1000 kilograms. i hectogram (hg) =100 grams =0.1 kilogram. i dekagram (dkg) =10 grams = 0.01 kilogram. i decigram (dg) =0.1 gram. i centigram (eg) =0.01 gram. i milligram (mg) =0.001 gram. i avoirdupois ounce (oz. av.) = -rV avoirdupois pound. i avoirdupois dram (dr. av.) =-zir avoirdupois pound = iV avoirdupois ounce. i grain (gr.)=T^nr avoirdupois pound = i$fc avoirdupois ounce = -5-7*5-0- troy pound. i apothecaries' pound (lb. ap.) = i troy pound =TOTT avoir- dupois pound. i apothecaries' or troy ounce (oz. ap., or 3, or oz. t.) =iV troy pound = 7 4 o 8 oo avoirdupois pound = 480 grains. i apothecaries' dram (dr. ap. or 5) = TS apothecaries' pound = ]/% apothecaries' ounce = 60 grains. i pennyweight (dwt.) =-fa troy ounce = 24 grains. i apothecaries' scruple (s. ap. or 9)=X apothecaries' dram = 20 grains. i metric carat (c) =200 milligrams = 0.2 gram. i short hundredweight (sh. cwt.) = 100 avoirdupois pounds. i long hundredweight (1. cwt.) =112 avoirdupois pounds. i short ton = 2000 avoirdupois pounds. i long ton = 2240 avoirdupois pounds. Jewelers 1 Weights and Measures 3. LENGTH CONVERSION TABLES LABILE/ 1 LABLE, Z lA.t5.Ut, J 1AJD.L.& 4 **- JSS. **~ SS Feet Meters Yards Meters 1 = 25.4001 2 - 50.8001 3 = 76.2002 4 =101.6002 1 = 2.54001 3 = 5.08001 3 = 7.62002 4 =10.16002 1 =0.304801 2 = .609601 3 = .914402 4 =1.219202 1 =0.914402 2 =1. 828804 3 =2.743205 4 =3.657607 5 =127.0003 =152.4003 7 =177.8004 8 =203.2004. 9 =228.6005 5 =12.70003 6 =15.24003 7 =17.78004 8' =20.32004 9 =22.86005 5 =1.524003 6 =1. 828804 7 =2.133604 8 =2.438405 9 =2.743205 5 =4.572009 6 =5.486411 7 =6.400813 8 =7.315215 9 =8.229616 0. 03937= 1 . 07874= 2 . 11811= 3 . 15748= 4 0. 3937= 1 . 7874= 2 1. 1811= 3 1. 5748= 4 3. 28083= 1 6. 56167= 2 9. 84250= 3 13. 12333= 4 1. 093611= 1 2. 187222= 2 3. 280833= 3 4. 374444= 4 . 19685= 5 . 23622= 6 . 27559= 7 . 31496= 8 . 35433= 9 1. 9685= 5 2. 3622= 6 2. 7559= 7 3. 1496= 8 3. 5433= 9 16. 40417= 5 19. 68500= 6 22. 96583= 7 26. 24667= 8 29. 52750= 9 5. 468056= 5 6. 561667= 6 7. 655278= 7 8. 748889= 8 9. 842500= 9 a See also extended Tables 6 and 7. TABLE 5. Decimal and Metric Equivalents of Common (Binary) Fractions of an Inch Fraction's of inch Equivalent in millimeters Fractions of inch Equivalent in millimeters Eighths and quarters Decimal Sixty-fourths Decimal y* 0.125 3.175 1 0. 015625 0.397 .250 6.350 3 . 046875 1.191 ^ .375 9.525 5 . 078125 1.984 % .500 12.700 7 . 109375 2.778 9 . 140625 3.572 y* .625 15. 875 y* .750 19. 050 11 . 171875 4.366 H .875 22. 225 13 . 203125 5. 159 15 . 234375 5 953 Sixteenths: 17 19 265625 '. 296875 6.747 7.541 1 3 5 7 .0625 .1875 .3125 .4375 1.588 4.763 7.938 11. 113 21 23 25 27 . 328125 .359375 .390625 . 421875 8.334 9.128 9.922 10. 716 9 .5625 14. 288 29 . 453125 11.509 11 13 .6875 .8125 .9375 17.463 20.638 23. 813 31 33 35 . 484375 . 515625 . 546875 12. 303 13.097 13. 891 Thirty-seconds: 37 39 . 578125 .609375 14. 684 15. 478 1 . 03125 .794 41 .640625 16. 272 3 .09375 2.381 43 . 671875 17.066 5 . 15625 3.969 45 . 703125 17. 859 7 . 21875 5.556 47 . 734375 18. 653 9 . 28125 7.144 49 . 765625 19. 447 11 . 34375 8.731 51 . 796875 20. 241 13 .40625 10. 319 53 . 828125 21.034 15 . 46875 11.906 55 .859375 21. 828 17 . 53125 13.494 57 .890625 22. 622 19 . 59375 15. 081 59 . 921875 23. 416 21 . 65625 16. 669 61 . 953125 24.209 23 . 71875 18. 256 63 . 984375 25.003 25 . 78125 19.844 27 .84375 21.431 29 .90625 23. 019 31 . 96875 24.606 16 if Circular of the Bureau of Standards OTHIMCO-* invor-ooav KSSS8 SSKKS ddddd ddddd m 5SSSSS3 00 i-l CO VO OO *-H CO \O CTi i-H -. 22 22222 222222 2222222^ 222^222 222222 22222 222222 222222 i d 8o2 2^2^! iiniftuSxn irJinuSioirJ !KKS 2g Hillilli2^sS o xn\ot>.ooo^ O^evjco-*- 10^01 RSSRK SSSSS S?I 22222 22222 22222 22222 222'22 2222'2 222 dd ddddd ddddd ddddd f-ssss Illll 15^55 5??33 !3S> ( <5 a 1 iii8 sssss sssss sss; ododododoo ododododod 00000000=0 oo oo oo oo od od=dododod =0000000=0 od=dod=dod in'uiininin inui^invn ininuiinin inS>nin viSuiin o >ovdvdvb>o H - 1 i! >j fsi csj (si eg N rg mt^orgin ooocomoo cococomco cocococom coco 510 00 < CO VO 00 ^H CO ID 00 --4 (O VO 00 rr^-min minvoiovo vot^S?*S cococomco comcococo co'cocococo 2ii sSHSS S^SSS S! o 10 ^-< vo co oo co at Tf-atmovo ^Hvorgc^co oo co av ^* o movo^nt^ rgr*.coaov cj\^t-oinrH vo^nt^cgoo co oo -4- CM QiMinS-o fjinKorg inSocoui ooocomoo ocomoov-, co vo oo -c co vooo <35 oo ^ TT vo CT> n 3- vo eh -H 90S< OOOO*H 1-4 ^H ^H pg eg rg eg co co co co ^- -^- ^- * in m in m vo vovovoc~i>. t^t^oooooo OOOVO\OVCT> o o o o *-* ^H -i -H eg c ^e*aco^ invptooov o^egco-^- invot^oOCT* o^egco-*- mvoc^ooov o^eqco-* mvot^ooa* o ^H eg co <* in vo r^ oo av 88Sl 8l88i SSoSS SSSSS SSSSS SSSSS 88888 88888 SSSSS SSSSS ' ' " iisi :i SSSSS SSSSS ???? :?:?$?! Jewelers 1 Weights and Measures SSo-22 25 S I 5 3S'S'5'3 SSSSS S'SS'SS SSSSS SSSSS 5555S ' 2 2S3J m-ir^ooa\ o^ntMco-^ m \o r*. oo o^ OI-H<^< vSJSSlSvS SvoSioio ic i v vD S ^O^I 8ESSS gSoSS Tr^^rr^ T^^^TfV ^ ,f V * n= * ^ . So sss: gnKRS KSKSS SSSS3S SSI S^RS KSKSS |SS Ipjpj (vjpjfvicjrj rJNtvitviivi rg^'tsirj(vj (vi^c-itsirj 1-1 *M co * m\Dt^.ooa> o --H c^ ro -^- ui vo r-* oo o\ o ^H fM co - u-\or^ooo^ o ^H rvi co -^- invor-oocTN o *-* S o *- *- c ooooo ooooo ooooo SoooS ooooo oooSo ooooo ooooo ooooo ooooo in K 8 in SS3SS 16340 21 3 17 inches=431. 80 mm 18 inches=457. 20 mm 19 inches=482. 60 mm 20inches=508.00mm 330. 20 355. 60 381. 00 406. 40 in in in in 60 mm 00 mm 40mm 80mm inches= inches= inches= inches= ISI liil Illl 1 inch = 25. 40 mm 2inches= 50.80mm 3inches= 76.20mm 4 hiches= 101. 60 mm 18 Circular of the Bureau of Standards SooSS ooooS o rn ^H ,-* < SSSS! SS2S 00 CO 00 00 00 0) 00 CO CO 00 00 CO CO C icgoacgcg r3 f^ co c^ c^j M c J.S II i-icq-* invot^-oocri o *-< <^a co * ir>\ot^coch 0000 00000 ^^-H^-i^^ ^H^^,-,^ *-* i>- co co co co co co ro <3 co -^ ^ ^ -* TJ- -fl- rf- TJ- - II a I I! d ' ' sssss S HiH iiisS IISs 5 VO >O VO ^d^^^vd U3U3VOVOVO Islll sSSS inu-vo t- t oo oo 22 222^^ 22 2 S S o * s 2 1 o 8SSSS SSSSS 2^ SSSS? 5?^? fOCOC ooooo ooooo 2^223 22S22 SNNNN SQSSrSS SS wmmcom 5 5 5 ? 5 d ' 8SS8S SSg 22222 22S2 5S5S SSSSS SSSSS SSSSS SSSSS SSS8S SSSSS 2^22S 22^22 SS ?5: sssss sssss 1\O O r!- 00 ^ ft is iilii il SSSSS loo oooSo ooooo g2222 rtrt ^, rt ^, ^, >oo 08000 oooSo ooooo ooooo oc r*. r*. i>. r-- t-^ t^ i>. i>- o- r- *> t-. t-- t Jewelers' Weights and Measures SSSSS gKK S?S SSSSS 52SS5S8 SSS 3SSS ^SSS K^KSS SSSSS SS5SS g^KKS ^gfcSS SSSS3S odododod ododododod 0606000000 ododododod eoodcdodcd oo 06060606 0606060606 060606 oocooooooo III SSSSS SS5SS gSS?2?: KSKSS SSSS3S 1111 SS3SS SSSSS gSKKS SSRSR SSSS3S gigi 1111 <*> in vo SS53 SSSSS 22S S8SSI jsss sssl 288 S3888 SSSS5 SSSSS SS5SS SSSSS KSKSS SSSS3S SSK iuSuSuS vnuSuiuiuS SSKSS gSSSS SSSSS Issil llsl SSS8S SSSsSS 1111 a\ o i-< *M o^H<*0(OTt- u^i^t^ooo\ O^HP^OO-* m*oc~coc> O^-*^MT- tnvor^ooov OT-HMCOTJ- uiinmvoio m*n*nmw) vo vo *o xo *> vo ^ o ^ o t^ c^ t^ t^ t^ c^ t^ t^ t^ t^ oo oo oo oo oo cotofocom mcorioito m m m m m mmmmm m m m m m mmmmm mmmmm mmminm mmmmm mmmmm l lissl sssss iisss iiisl llsSl ssSSS 22SS .a.s.a.a SSES invor-oo o ^H fM eo Th ir vo t^ oo o> O ^ \o t^. oo en o i- 6= 3. 70 1^= A= 5.54 2 - J4= 7.39 1 = 29.57 3 = 59.15 3 =88.72 4 =118.29 0. 0338= 1 . 0676= 3 . 1014= 3 . 1353= 4 6 = .308 6 = .370 7 = .431 8 = .493 9 = .554 5 = 18. 48 6 =22.18 7 =25.88 8 =29.57 9 =33.27 314= A= 9-24 3 = H-11.09 3^= A- 12. 94 4 = >4=14. 79 4H= A=16.63 5 =147.86 6 =177.44 7 =207.01 8 =236.58 9 =266.16 . 1691= 5 . 2029= 6 . 2367= 7 . 2705= 8 . 3043= 9 16. 23= 1 32. 46= 48. 69= 3 64.92= 4 0. 271= 1 .541= a .812= 3 1. 082= 4 5 = 5^=18.48 5K= H=20.33 6 = %=22.18 6J^= $=24. 03 1O =295.73 11 =325.30 13 =354.87 13 =384.45 .3381= 10 . 6763= 30 1. 0144= 3O 1. 3526= 40 81. 16= 5 97. 39= 6 113. 62= 7 129. 85= 8 146. 08= 9 1. 353= 5 1. 623= 6 1. 894= 7 2. 164= 8 2. 435= 9 7 = ^=25.88 7H= #=27.72 8 =1 =29.57 14 =414.02 15 =443.59 16 =473.17 1. 6907= 5O 2. 0289= 60 2. 3670= 7O 2. 7052= 8O 3. 0433= 9O TABLE 21 TABLE 22 TABLE 23 TABLE 24 TABLE 25 U.S. liquid Liters pints U.S. liquid Liters quarts gallon's Liters British Imperial Liters gallons , British AS. '^s' 1 =0.473 3 = .946 3 =1.419 4 =1.893 1 =0.946 8 =1.893 3 =2.839 4 =3.785 1 = 3.785 8 = 7.571 3 =11.356 4 =15.141 1 =4.546 3 =9.092 3 = 13. 638 4 =18.184 1 =0.8327 a =1.6654 3 =2.4980 4 =3.3307 5 =2.366 6 =2.839 7 =3.312 8 =3.785 9 =4.258 5 =4.732 6 =5.678 7 =6.624 8 =7.571 9 =8.517 5 =18.927 6 =22.712 7 =26.497 8 =30. 283 9 =34.068 5 =22.730 6 =27.276 7 =31. 822 8 =36.368 9 =40.914 5 =4.1634 6 =4.9961 7 =5.8287 8 =6 6614 9 =7.4941 2. 113= 1 4. 227= 2 6. 340= 3 8. 454= 4 1. 057= 1 2. 113= 3 3. 170= 3 . 4. 227= 4 0. 2642= 1 . 5284= 3 . 7925= 3 1. 0567= 4 0. 2200= 1 . 4400= 3 . 6599= 3 . 8799= 4 1. 2009= 1 2. 4019= a 3. 6028= 3 4.8038= 4 10. 567= 5 12. 681= 6 14. 794= 7 16. 907= 8 19. 021= 9 5. 284= 5 6. 340= 6 7. 397= 7 8. 454= 8 9. 510= 9 1. 3209= 5 1. 5851= 6 1. 8492= 7 2. 1134= 8 2. 3776= 9 1. 0999= 5 1. 3199= 6 1. 5398= 7 1. 7598= 8 1. 9798= 9 6. 0047= 5 7. 2057= 6 8. 4066= 7 9. 6075= 8 10. 8085- 9 22 Circular of the Bureau of Standards 7. TABLES OF MASS (WEIGHT) TABLE 26 TABLE 27 TABLE 28 Grains Grains weK> Grams " ouncLc Grams * 1 =0.06480 2 = .12960 3 = . 19440 4 = .25920 1 = 1.55517 2 = 3.11035 3 = 4.66552 4 = 6.22070 1 = 31.10348 2 = 62.20696 3 = 93.31044 4 =124.41392 5 = .32399 6 = .38879 7 = .45359 8 = .51839 9 = .58319 5 = 7.77587 6 = 9.33104 7 =10.88622 8 =12.44139 9 = 13. 99657 5 =155.51740 6 =186.62088 7 =217.72437 8 =248.82785 9 =279.93133 15. 4324= 1 30. 8647= 3 46. 2971= 3 61. 7294= 4 0. 64301= 1 1. 28603= 3 1. 92904= 3 2. 57206= 4 0. 03215= 1 . 06430= 2 . 09645= 3 . 12860= 4 77. 1618= 5 92. 5941= 6 108. 0265= 7 123. 4589= 8 138. 8912= 9 3. 21507= 5 3. 85809= 6 4.50110= 7 5. 14412= 8 5. 78713= 9 . 16075= 5 . 19290= 6 . 22506= 7 . 25721= 8 . 28936= 9 a See also extended Tables 32 and 33. & See also extended Tables 34 and 35. c See also extended Tables 36 and 37. TABLE 29 TABLE 30 TABLE 31 Avoir- dupois Grams Avoir- dupois Grams Avoir- dupois Grams Avoir- dupois Grams Avoir- KUo _ n Short Metric ounces ounces ounces ounces pounds gr < 4 =113.398 i 8 =226.796 12 =340.194 1 =0.45359 1 =0.90718 M= 7. 087 4^=120.485 81-4=233.884 12^4=347.282 2 = .90718 2 =1.81437 14= 14.175 4)4=127.573 8^=240.971 12U=354.369 3 =1.36078 3 =2.72155 %= 21.262 4%= 134. 660 8%= 248. 058 12%= 361. 456 4 =1.81437 4 =3.62874 1 = 28.350 5 =141.748 9 =255.146 13 =368.544 5 =2.26796 5 =4.53592 1)4= 35.437 \Yy= 42.524 514= 148. 835 5)4=155.922 9)4= 262. 233 9)4=269.321 13)4=375.631 6 =2.72155 7 =3.17515 6 =5.44311 7 =6.35029 194= 49.612 5%- 163. 010 9%= 276. 408 13%= 389! 806 8 =3.62874 8 =7.25748 . 9 =4.08233 9 =8.16466 2 = 56.699 6 =170.097 10 =283.495 14 =396.893 2J4= 63. 786 6)4=177. 185 10)4=290.583 14)4=403.981 2.20462= 1 1. 10231= 1 2)4= 70.874 6)4=184.272 10)4=297.670 14)4=411.068 ; 4.40924= 2 2. 20462- 8 2%= 77.961 6%= 191. 359 10%= 304. 757 14%= 418. 156 ' 6.61387= 3 3. 30693- 3 8. 81849= 4 4. 40924- 4 3 = 85.049 7 =198.447 11 =311.845 15 =425.243 3%= 92.136 7)4=205.534 11)4=318.932 15)4=432.330 11.02311= 5 5. 51156- 5 34= 99.223 3%= 106. 311 7%= 219. 709 11)4=326.020 11%= 333. 107 15)4=439.418 15%= 446. 505 16' =453.592 13. 22773= 6 15. 43236= 7 17. 63698= 8 6. 61387- 6 7. 71618= 7 8. 81849- 8 19. 84160- 9 9. 92080- 9 i See also extended Tables 38 and 39. Jewelers' Weights and Measures MASS GRAINS AND GRAMS 2 3 TABLE 32 TABLE 33 [1 grain= 0.06479892 gram [1 gram= 15.4323564 grains] Grains Grams Grains Grams Grams 1 Grains Grams Grains 0.000 55 3.564 0.00 55 848. 78 1 .065 56 3.629 1 15.43 56 864. 21 2 .130 57 3.694 2 30.86 57 879.64 3 .194 58 3.758 3 46.30 58 895.08 4 .259 59 3.823 4 61.73 59 910. 51 5 .324 60 3.888 5 77.16 60 925.94 6 61 3.953 6 92.59 61 941.37 7 !454 62 4.018 7 108. 03 62 956. 81 8 .518 63 4.082 8 123. 46 63 972. 24 9 .583 64 4.147 9 138. 89 64 987. 67 10 .648 65 4.212 10 154.32 65 1003. 10 11 .713 66 4.277 11 169. 76 66 1018. 54 12 .778 67 4.342 12 185. 19 67 1033. 97 13 .842 68 4.406 13 200.62 68 1049. 40 14 .907 69 4.471 14 216.05 69 1064.83 15 .972 70 4.536 15 231.49 70 1080. 26 16 1.037 71 4.601 16 246. 92 71 1095. 70 17 1.102 72 4.666 17 262. 35 72 1111. 13 18 1.166 73 4.730 18 277. 78 73 1126. 56 19 1.231 74 4.795 19 293.21 74 1141. 99 20 1.296 75 4.860 20 308. 65 75 1157. 43 21 1.361 76 4.925 21 324. 08 76 1172. 86 22 1.426 77 4.990 22 339. 51 77 1188.29 23 1.490 78 5.054 23 354.94 78 1203. 72 24 1.555 79 5.119 24 370. 38 79 1219. 16 25 1.620 80 5.184 25 385. 81 80 1234. 59 26 1.685 81 5.249 26 401. 24 81 1250. 02 27 1.750 82 5.314 27 416. 67 82 1265. 45 28 1.814 83 5.378 28 432. 11 83 1280. 89 29 1.879 84 5.443 29 447.54 84 1296. 32 30 1.944 85 5.508 30 462. 97 85 1311. 75 31 2.009 86 5.573 31 478. 40 86 1327. 18 32 2.074 87 5.638 32 493.84 87 1342. 62 33 2.138 88 5.702 33 509.27 88 1358. 05 34 2.203 89 5.767 34 524. 70 89 1373. 48 35 2.268 90 5.832 35 540. 13 90 1388. 91 36 2.333 91 5.897 36 555. 56 91 1404.34 37 2.398 92 5.962 37 571.00 92 1419. 78 38 2.462 93 6.C26 38 586. 43 93 1435. 21 39 2.527 94 6.091 39 601. 86 94 1450. 64 40 2.592 95 6.156 40 617.29 95 1466. 07 41 2.657 96 6.221 41 632. 73 96 1481. 51 42 2.722 97 6.285 42 648.16 97 1496. 94 43 2.786 98 6.350 43 663. 59 98 1512. 37 44 2.851 99 6.415 44 679. 02 99 1527. 80 45 2 916 100 6.480 45 694.46 100 1543. 24 46 47 48 49 2.981 3.046 3.110 3.175 200 300 400 500 12.960 19.440 25. 920 32.399 46 47 48 49 709.89 725. 32 740.75 756. 19 200 300 400 500 3086. 47 4629. 71 6172. 94 7716. 18 50 51 52 53 54 3.240 3.305 3.370 3.434 3.499 600 700 800 900 1000 38.879 45. 359 5&319 64.799 50 51 52 53 54 771. 62 787. 05 802.48 817.91 833.35 600 700 800 900 1000 9259. 41 10802. 65 12345. 89 13889. 12 15432. 36 24 Circular of the Bureau of Standards MASS PENNYWEIGHTS AND GRAMS TABLE 34 TABLE 35 [1 pennyweight= 1.55517404 grams] [1 gram= 0.64301485 pennyweight] 5SK o SB' Grams 55B ""- wligWs Grams * 558 <* 5S 0. 00 0. 000 0. 55 0. 855 0.000 55 85. 535 0.000 55 35. 366 . 01 . 016 . 56 . 871 1 1. 555 56 87. 090 1 .643 56 36. 009 . 02 . 031 . 57 . 886 2 3. 110 57 88. 645 2 1. 286 57 36. 652 .03 .047 .58 .902 3 4. 666 58 90. 200 3 1. 929 58 37. 295 .04 .062 . 59 . 918 4 6. 221 59 91. 755 4 2. 572 59 37. 938 . 05 . 078 . 60 . 933 5 7. 776 60 93. 310 5 3. 215 60 38. 581 .06 .093 . 61 . 949 6 9. 331 61 94. 866 6 3. 858 61 39. 224 .07 .109 .62 .964 7 10. 886 62 96. 421 7 4. 501 62 39. 867 . 08 . 124 . 63 . 980 8 12. 441 63 97. 976 8 5.144 63 40. 510 . 09 . 140 .64 .995 9 13. 997 64 99. 531 9 5. 787 64 41. 153 . 10 . 156 . 65 1. Oil 10 15. 552 65 101. 086 10 6. 430 65 41. 796 . 11 . 171 . 66 1. 026 11 17. 107 66 102. 641 11 7. 073 66 42. 439 . 12 . 187 . 67 1. 042 12 18. 662 67 104. 197 12 7. 716 67 43. 082 . 13 . 202 . 68 1. 058 13 20. 217 68 105. 752 13 8.359 68 43. 725 . 14 . 218 .69 1.073 14 21. 772 69 107. 307 14 9. 002 69 44. 368 . 15 . 233 . 70 089 15 23. 328 70 108. 862 15 9. 645 70 45.011 . 16 . 249 . 71 104 16 24. 883 71 110. 417 16 10. 288 71 45. 654 .17 .264 . 72 120 17 26. 438 72 111.973 17 10. 931 72 46. 297 . 18 . 280 . 73 135 18 27. 993 73 113. 528 18 11. 574 73 46. 940 . 19 . 295 . 74 151 19 29. 548 74 115. 083 19 12. 217 74 47. 583 . 20 . 311 .75 166 20 31. 103 75 116. 638 20 12. 860 75 48. 226 . 21 . 327 . 76 182 21 32. 659 76 118. 193 21 13. 503 76 48. 869 . 22 . 342 . 77 197 22 34. 214 77 119. 748 22 14. 146 77 49. 512 . 23 . 358 . 78 213 23 35. 769 78 121. 304 23 14. 789 78 50. 155 . 24 . 373 . 79 . 229 24 37. 324 79 122. 859 24 15. 432 79 50. 798 . 25 . 389 .80 244 25 38. 879 80 124. 414 25 16. 075 80 51. 441 .26 .404 . 81 260 26 40. 435 81 125. 969 26 16. 718 81 52. 084 . 27 . 420 . 82 275 27 41. 990 82 127. 524 27 17. 361 82 52. 727 . 28 . 435 . 83 291 28 43. 545 83 129. 079 28 18. 004 83 53. 370 . 29 . 451 . 84 306 29 45. 100 84 130. 635 29 18. 647 84 54. 013 .30 .467 . 85 . 322 30 46. 655 85 132. 190 30 19. 290 85 54. 656 . 31 . 482 . 86 337 31 48. 210 86 133. 745 31 19. 933 86 55. 299 . 32 . 498 . 87 . 353 32 49. 766 87 135. 300 32 20. 576 87 55. 942 .33 .513 . 88 . 369 33 51. 321 88 136. 855 33 21. 219 88 56. 585 . 34 . 529 .89 .384 34 52. 876 89 138. 410 34 21. 863 89 57. 228 . 35 . 544 .90 .400 35 54. 431 90 139. 966 35 22. 506 90 57. 871 .36 .560 . 91 . 415 36 55. 986 91 141. 521 36 23. 149 91 58. 514 . 37 . 575 . 92 . 431 37 57. 541 92 143. 076 37 23. 792 92 59. 157 . 38 . 591 .93 .446 38 59. 097 93 144. 631 38 24. 435 93 59. 800 . 39 . 607 . 94 . 462 39 60. 652 94 146. 186 39 25. 078 94 60. 443 . 40 . 622 . 95 . 477 40 62. 207 95 147. 742 40 25. 721 95 61. 086 . 41 . 638 . 96 . 493 41 63. 762 96 149. 297 41 26. 364 96 61. 729 . 42 . 653 .97 .509 42 65. 317 97 150. 852 42 27. 007 97 62. 372 . 43 . 669 .98 .524 43 66. 872 98 152. 407 43 27. 650 98 63. 015 .44 .684 . 99 . 540 44 68. 428 99 153. 962 44 28. 293 99 63. 658 . 45 . 700 1.00 1.555 45 69. 983 100 155. 517 45 28. 936 100 64. 301 . 46 . 715 46 71. 538 200 311. 035 46 29. 579 200 128. 603 . 47 . 731 47 73. 093 300 466. 552 47 30. 222 300 192. 904 .48 .746 48 74. 648 400 622. 070 48 30. 865 400 257. 206 . 49 . 762 1 A 0.194 49 76. 204 500 777. 587 49 31. 508 500 321. 507 % .389 .50 .778 H .583 50 77. 759 600 933. 104 50 32. 151 600 385. 809 . 51 . 793 % .778 51 79. 314 700 1088. 622 51 32. 794 700 450.110 .52 .809 fi .972 52 80. 869 800 1244. 139 52 33. 437 800 514. 412 .53 .824 Y 4 1. 166 53 82. 424 900 1399. 657 53 34. 080 900 578. 713 .54 .840 H 1.361 54 83. 979 1000 1555. 174 54 34. 723 1000 643. 015 Jewelers' Weights and Measures MASS TROY OUNCES AND GRAMS TABLE 36 TABLE 37 [Itroy ounce= 31. 1034808 grams] [1 gram=0.03215074 troy ounce] ounc'e Grams ' ounc'e Grams ounces <*" ounces Grams G ' ams ounce's Grams ounc^ 0. 00 0. 000 .01 .311 . 02 . 622 . 03 . 933 . 04 1. 244 0. 55 17. 107 . 56 17. 418 . 57 17. 729 . 58 18. 040 . 59 18. 351 0. 000 1 31. 103 2 62. 207 3 93. 310 4 124. 414 55 1710. 691 56 174i: 795 57 1772. 898 58 1804. 002 59 1835. 105 0.0000 1 . 0322 2 .0643 3 .0965 4 . 1286 55 1. 7683 56 1. 8004 57 1. 8326 58 1. 8647 59 1. 8969 . 05 1. 555 . 06 1. 866 . 07 2. 177 . 08 2. 488 . 09 2. 799 . 60 18. 662 . 61 18. 973 . 62 19. 284 . 63 19. 595 . 64 19. 906 5 155. 517 6 186. 621 7 217. 724 8 248. 828 9 279. 931 60 1866. 209 61 1897. 312 62 1928. 416 63 1959. 519 64 1990.623 5 . 1608 6 . 1929 7 . 2251 8 . 2572 9 .2894 60 1.9290 61 1. 9612 62 1. 9933 63 2. 0255 64 2. 0576 . 10 3. 110 .11 3.421 . 12 3. 732 . 13 4. 043 . 14 4. 354 . 65 20. 217 .66 20.528 . 67 20. 839 . 68 21. 150 . 69 21. 461 10 311. 035 11 342. 138 12 373. 242 13 404. 345 14 435. 449 65 2021. 726 66 2052. 830 67 2083. 933 68 2115. 037 69 2146. 140 10 . 3215 11 . 3537 12 . 3858 13 . 4180 14 . 4501 65 2. 0898 66 2. 1219 67 2. 1541 68 2. 1863 69 2. 2184 . 15 4. 666 . 16 4. 977 . 17 5. 288 . 18 5. 599 . 19 5. 910 . 70 21. 772 . 71 22. 083 . 72 22. 395 . 73 22. 706 . 74 23. 017 15 466. 552 16 497. 656 17 528. 759 18 559. 863 19 590. 966 70 2177. 244 71 2208. 347 72 2239. 451 73 2270. 554 74 2301. 658 15 . 4823 16 . 5144 17 . 5466 18 . 5787 19 . 6109 70 2. 2506 71 2. 2827 72 2. 3149 73 2. 3470 74 2. 3792 . 20 6. 221 . 21 6. 532 . 22 6. 843 . 23 7. 154 . 24 7. 465 . 75 23. 328 . 76 23. 639 . 77 23. 950 . 78 24. 261 . 79 24. 572 20 622. 070 21 653. 173 22 684. 277 23 715. 380 24 746. 484 75 2332. 761 76 2363. 865 77 2394. 968 78 2426. 071 79 2457. 175 20 . 6430 21 . 6752 22 . 7073 23 . 7395 24 . 7716 75 2.4113 76 2. 4435 77 2. 4756 78 2. 5078 79 2. 5399 . 25 7. 776 . 26 8. 087 . 27 8. 398 . 28 8. 709 . 29 9. 020 . 80 24. 883 . 81 25. 194 . 82 25. 505 . 83 25. 816 . 84 26. 127 25 777. 587 26 808. 690 27 839. 794 28 870. 897 29 902. 001 80 2488. 278 81 2519. 382 82 2550. 485 83 2581. 589 84 2612. 692 25 . 8038 26 . 8359 27 . 8681 28 . 9002 29 . 9324 80 2. 5721 81 2. 6042 82 2. 6364 83 2. 6685 84 2. 7007 . 30 9. 331 . 31 9. 642 . 32 9. 953 . 33 10. 264 . 34 10. 575 . 85 26. 438 . 86 26. 749 . 87 27. 060 . 88 27. 371 . 89 27. 682 30 933. 104 31 964. 208 32 995. 311 33 1026. 415 34 1057. 518 85 2643. 796 86 2674. 899 87 2706. 003 88 2737. 106 89 2768. 210 30 .9645 31 . 9967 32 . 0288 33 . 0610 34 . 0931 85 2. 7328 86 2. 7650 87 2. 7971 88 2. 8293 89 2. 8614 . 35 10. 886 . 36 11. 197 . 37 11. 508 . 38 11. 819 . 39 12. 130 . 90 27. 993 . 91 28. 304 .92 28.615 . 93 28. 926 .94 29.237 35 1088. 622 36 1119. 725 37 1150. 829 38 1181. 932 39 1213. 036 90 2799. 313 91 2830. 417 92 2861. 520 93 2892. 624 94 2923. 727 35 . 1253 36 . 1574 37 . 1896 38 . 2217 39 . 2539 90 2. 8936 91 2. 9257 92 2. 9579 93 2. 9900 94 3. 0222 . 40 12. 441 . 41 12. 752 . 42 13. 063 . 43 13. 374 .44 13.686 . 95 29. 548 . 96 29. 859 . 97 30. 170 . 98 30. 481 .99 30.792 40 1244. 139 41 1275. 243 42 1306. 346 43 1337. 450 44 1368. 553 95 2954. 831 96 2985. 934 97 3017. 038 98 3048. 141 99 3079. 245 40 . 2860 41 . 3182 42 . 3503 43 . 3825 44 . 4146 95 3. 0543 96 3. 0865 97 3. 1186 98 3. 1508 99 3. 1829 . 45 13. 997 . 46 14. 308 . 47 14. 619 .48 14.930 . 49 15. 241 1. 00 31. 103 45 1399. 657 46 1430. 760 47 1461. 864 48 1492. 967 49 1524. 071 100 3110. 348 200 6220 696 300 9331. 044 400 12441. 392 500 15551. 740 45 1. 4468 46 1. 4789 47 1. 5111 48 1. 5432 49 1. 5754 100 3. 2151 200 6. 4301 300 9. 6452 400 12. 8603 500 16. 0754 . 50 15. 552 . 51 15. 863 . 52 16. 174 . 53 16. 485 .54 16. 796 50 1555. 174 51 1586. 278 52 1617. 381 53 1648. 484 54 1679. 588 600 18662. 088 700 21772. 437 800 24882. 785 900 27993. 133 1000 31103. 481 50 1. 6075 51 1. 6397 52 1. 6718 53 1. 7040 54 1. 7361 600 19. 2904 700 22. 5055 800 25. 7206 900 28. 9357 1000 32. 1507 26 Circular of the Bureau of Standards MASS POUNDS AND KILOGRAMS TABLE 38 TABLE 39 [1 avoirdupois pound= 0.45359 24277 kilogram] [1 kilogram=2.20462234 avoirdupois pounds] Avoir- Avoir- Avoir- Avoir- dupois pounds Kilograms dupois Kilograms pounds Kilograms " dupois pounds" Kilograms dupois pounds 0.0 55 24.9 0.0 55 121.3 1 .5 56 25.4 1 2.2 56 123.5 2 .9 57 25.9 2 4.4 57 125.7 3 1.4 58 26.3 6.6 58 127.9 4 .1.8 59 26.8 8.8 59 130.1 5 2.3 60 27.2 11.0 60 132.3 6 2.7 61 27.7 13.2 61 134.5 7 3.2 62 28.1 15.4 62 136.7 8 3.6 63 28.6 17.6 63 138.9 9 4.1 64 29.0 19.8 64 141.1 10 4.5 65 29.5 10 22.0 65 143.3 11 5.0 66 29.9 11 24.3 66 145.5 12 5.4 67 30.4 12 26.5 67 147.7 13 5.9 68 30.8 13 28.7 68 149.9 14 6.4 69 31.3 14 30.9 69 152.1 15 6.8 70 31.8 15 33.1 70 154.3 16 7.3 71 32.2 16 35.3 71 156.5 17 7.7 72 32.7 ir 37.5 72 158.7 18 8.2 73 33.1 18 39.7 73 160.9 19 8.6 74 33.6 19 41.9 74 163.1 20 9.1 75 34.0 20 44.1 75 165.3 21 9.5 76 34.5 21 46.3 76 167.6 22 10.0 77 34.9 22 48.5 77 169.8 23 10.4 78 35.4 23 50.7 78 172.0 24 10.9 79 35.8 24 52.9 79 174.2 25 11.3 80 36.3 25 55.1 80 176.4 26 11.8 81 36.7 26 57.3 81 178.6 27 12.2 82 37.2 27 59.5 82 180.8 28 12.7 83 37.6 28 61.7 83 183.0 29 13.2 84 38.1 29 63.9 84 185.2 30 13.6 85 38.6 30 66.1 85 187.4 31 14.1 86 39.0 31 68.3 86 189.6 32 14.5 87 39.5 32 70.5 87 191.8 33 15.0 88 39.9 33 72.8 88 194.0 34 15.4 40.4 34 75.0 89 196.2 35 15.9 90 40.8 35 77.2 90 198.4 36 16.3 91 41.3 36 79.4 91 200.6 37 16.8 92 41.7 37 81.6 92 202.8 38 17.2 93 42.2 38 83.8 93 205.0 39 17.7 94 42.6 39 86.0 94 207.2 40 18.1 95 43.1 40 88.2 95 209.4 41 18.6 96 43.5 41 90.4 96 211.6 42 19.1 97 44.0 42 92.6 97 213.8 43 19.5 98 44.5 43 94.8 98 216.1 44 20.0 99 44.9 44 97.0 99 218.3 45 20.4 100 45.4 45 99.2 100 220.5 46 20.9 200 90.7 46 101.4 200 440.9 47 21.3 300 136.1 47 103.6 300 661.4 48 21.8 400 181.4 48 105.8 400 881.8 49 22.2 500 226.8 49 108.0 500 1102.3 50 22.7 600 272.2 50 110.2 600 1322. 8 51 23.1 700 317.5 51 112.4 700 1543. 2 52 23.6 800 362.9 52 114.6 800 1763. 7 53 24.0 900 408.2 53 116.8 900 1984. 2 54 24. 5 1000 453.6 54 119.0 1000 2204. 6 1 For the conversion of avoirdupois ounces to grams see Table 29. Jewelers 1 Weights and Measures 27 III. THE METRIC CARAT 1. DEFINITION The carat which had been in use prior to July i, 1913, in the United States, while varying, has been nearer the value 205.3 m g than any other. This value has therefore been taken in making up the tables of equivalents given in this circular. The old carat has usually been subdivided on the binary system, the smallest subdivision used being usually one sixty-fourth of the carat. The equivalents in fractions of a carat in these tables are, therefore, given in sixty-fourths. One of the improvements introduced with the new carat of exactly 200 mg is the subdivision of it on the decimal system. The fractions of the new carat in these tables are accordingly given to hundredths of a carat. 2. CONVERSION TABLES Tables 40 and 41 are for the conversion of quantities in the old unit to the equivalent weight in terms of the new metric carat. Table 40 is used for the conversion of fractions of a carat, while Table 41 gives the equivalent of each unit or whole carat from i to 100 of the old system in terms of new metric carats and hun- dredths of a carat. If it is desired to convert whole carats and fractions of a carat of the old unit to the new, the two tables can be used in combination; that is, by adding the quantities obtained from each, thus: Suppose it is desired to obtain the equivalent of 28|i old carats in terms of the metric carats: From Table 40. . M old carats = o. 72 metric carats From Table 41 .. 28 old carats = 28. 74 metric carats Adding. . . 28|f old carats = 29. 46 metric carats. Or, if it is desired to convert a larger quantity involving several hundred or thousand carats, one uses the equivalents in the last column of Table 41 for each hundred and thousand of the old carats up to ten hundred and ten thousand thus, to convert 3225! old carats to metric carats: From Table 40. . f old carats = o. 77 metric carats From Table 41 .. 25 old carats = 25. 66 metric carats 200 old carats =- 205. 30 metric carats 3000 old carats = 3079. 50 metric carats Adding. . . 3225! old carats = 331 1 . 23 metric carats. 28 Circular of the Bureau of Standards TABLE 40. Equivalents of Fractions of the Old Carat Weight in New Decimal Metric Carats [Computed on the basis of 1 old carat = 205.3 mg; r metric carat=200 mg] Old carat New metric carats Old carat New metric carats 1/2's 1/4's 8ths leths 32ds 64ths 1 1 carat 1/2's 1/4's 8ths leths 32ds 64ths = 0.02 33 = 0.53 1 2 = .03 17 34 = .55 3 = .05 35 = .56 i 2 4 = .06 9 18 36 = .58 5 = .08 37 = .59 3 6 = .10 19 38 = .61 7 = .11 39 = .63 1 2 4 8 = .13 5 10 20 40 = .64 9 = .14 41 = .66 5 10 = .16 21 42 = .67 11 = .18 43 = .69 3 6 12 = .19 11 22 44 = .71 13 = .21 45 = .72 7 14 = .22 23 46 = .74 15 = .24 47 = .75 1 2 4 8 16 = .26 3 6 12 24 48 = .77 17 = .27 49 = .79 9 18 = .29 25 50 = .80 19 = .30 51 = .82 5 10 20 = .32 13 26 52 = .83 21 = .34 53 = .85 11 22 = .35 27 54 = .87 23 = .37 55 = .88 3 6 12 24 = .38 7 14 28 56 = .90 25 = .40 57 = .91 13 26 = .42 29 58 = .93 27 = .43 59 = .95 7 14 28 = .45 15 30 60 = .96 29 = .47 61 = .98 15 30 = .48 31 62 = .99 31 = .50 63 = 1.01 1 2 4 8 16 32 = .51 1 2 4 8 16 32 1 64 -1.03 Jewelers' Weights and Measures 29 TABLE 41. Equivalents of the Old Carats in New Decimal Metric Carats [Computed on the basis of 1 old carat= 205.3 mg; 1 new metric carat=200 mg] Old carats New metric carats Old carats New metric carats Old carats New metric carats Old carats New metric carats Old carats New metric carats 1 1.03 26 26.69 51 52.35 76 78.01 200 205.30 2 2.05 27 27.72 52 53.38 77 79.04 300 307.95 3.08 28 28.74 53 54.40 78 80.07 400 410.60 4.11 29 29.77 54 55.43 - 79 81.09 500 513. 25 5.13 30 30.80 55 56.46 80 82.12 600 615.90 6.16 31 31.82 56 57.48 81 83. 15 700 718. 55 7.19 32 32.85 57 58.51 82 84.17 800 821. 20 8.21 33 33.87 58 59.54 83 85.20 900 923. 85 9.24 34 34.90 59 60.56 84 86.23 1000 1026. 50 10 10.26 35 35.93 60 61.59 85 87.25 2000 2053. 00 11 11.29 36 36.95 61 62.62 86 88.28 3000 3079. 50 12 12.32 37 37.98 62 63.64 87 89.31 4000 4106.00 13 13.34 38 39.01 63 64.67 90.33 5000 5132. 50 14 14.37 39 40.03 64 65.70 89 91.36 6000 6159. 00 15 15.40 40 41.06 65 66.72 90 92.38 7000 7185. 50 16 16.42 41 42.09 66 67.75 91 93.41 8000 8212. 00 17 17.45 42 43.11 67 68.78 92 94.44 9000 9238. 50 18 18.48 43 44.14 68 69.80 93 95.46 10 000 10265. 00 19 19.50 44 45. 17 . 69 70.83 94 96.49 20 20.53 45 46.19 70 71.86 95 97.52 21 21.56 46 47.22 71 72.88 96 98.54 22 22.58 47 48.25 72 73.91 97 99.57 23 23.61 48 49.27 73 74.93 98 100.60 24 24.64 49 50.30 74 75.96 99 101. 62 25 25.66 50 51.32 75 76.99 100 102. 65 IV. GAGES 7 (WIRE AND DRILL) 1. EXISTING PRACTICE IN GAGING MATERIALS The sizes of materials were for many years indicated in commer- cial practice almost entirely by gage numbers. This practice was accompanied by considerable confusion because numerous gages were in use. In general, gage sizes are used much less now than formerly. 8 In so far as wire gages are now in use in the United States, the practice has been practically limited to the use of two gages. For iron plates, there is only one gage viz, the " U. S. standard." For drills there are two, with an additional one for drill rod and steel wire. Finally, there are some special gages, including several music wire gages. The trend of practice in the gaging of materials is increasingly toward the direct specification of the dimensions in decimal frac- tions of an inch or millimeter without the use of gage numbers. Numerous engineering societies have gone on record as in favor of the direct use of diameters. This is similar to the practice in Germany, France, and Italy, where sizes are specified directly by the diameter in millimeters. 7 This information about gages was gathered from the statements on the subject in the catalogues of manufacturers and in scientific literature, including B. S. Circular No. 31. 8 In an article written in 1887 (S. S. Wheeler, Elec. World, 10, p. 254; 1887), over 30 gages were described, 19 of which were wire gages. 30 Circular of the Bureau of Standards 2. WIRE GAGES 9 Among the wire gages that have survived, two are used exten- sively in this country, viz, the "American wire gage" (Brown & Sharpe) and the "Steel wire gage" (variously called the "Washburn & Moen," " Roebling," and "American Steel & Wire Co.'s"). Three other gages are still used to some extent, viz, the "Stubs' steel wire gage," the "Birmingham wire gage" (Stubs), and the "Old English wire gage" (London). In England one wire gage has been made legal and is in use generally, viz, the "Standard wire gage." The diameters corresponding to the gage number of five of the general wire gages mentioned are given in both inches and in millimeters in Table 43. (a) American wire gage The American wire gage is frequently called the " Brown & Sharpe gage." Its sizes are not utterly arbitrary and the differ- ences between successive diameters are more regular than those of other gages. It is the only wire gage now in use whose suc- cessive sizes are determined by a mathematical law. The law of geometrical progression on which the gage is based is that the ratio of any diameter to the next smaller is a constant number (i . 1 229322) . It is derived from the fundamental definition of the gage, which is that size No. 4-0 shall be 0.4600 inch in diameter, size No. 36 shall be 0.0050 inch in diameter, and 38 intermediary sizes or diameters shall be formed by geometrical progression. (b) Steel wire gage The "Steel wire gage" 10 with a number of its sizes expressed only to the nearest thousandth of an inch, has been known as the Roebling gage. It was originally established about the year 1830, and was named after the Washburn & Moen Manufac- turing Co. This company was later merged into the American Steel & Wire Co., which continued the use of the Washburn & Moen gage for steel wire, giving it the name "American Steel & Wire Co.'s gage." (c) Stubs' steel wire gage The Stubs' steel wire gage has a somewhat limited use for tool steel wire and drill rods. This gage should not be confused with the Birmingham wire gage, which is sometimes known as Stubs' 8 For a more complete discussion of wire gages, see B. S. Circular No. 31, Copper Wire Tables. 10 The name "Steel wire gage" was suggested by the Bureau of Standards in its correspondence with various companies, and it met with practically unanimous approval. It was necessary to decide upon a name for this gage, and the three names which have been used for it in the past were all open to the objec- tion that they were the names of particular companies. These companies have accepted the new name. The abbreviation of the name of the gage should be "Stl. W. G.," to distinguish it from "S. W. G.," the abbreviation for the (British) Standard wire gage. When it is necessary to distinguish the name of this gage from others which may be used for steel wire e. g., the (British) Standard wire gage it may be called the United States steel wire gage. Jewelers' Weights and Measures 31 iron wire gage. The diameters of its sizes are very nearly iden- tical with the diameters of the corresponding sizes of drill gages, as is shown in Tables 45, 46, and 47. (d) BIRMINGHAM WIRE GAGE Of the various wire gages which have remained in use but are now nearly obsolete, the one most frequently mentioned is the Bir- mingham. Its steps are quite irregular. Some of the later gages were based on the Birmingham, and by the repeated copying of old specifications its use has persisted to some extent, both in England and the United States. In the past this gage held certain departmental sanction in the United States Government, but this sanction was removed in 1914. (e) STANDARD WIRE GAGE The "Standard wire gage," otherwise known as the new British standard, the English legal standard, or the Imperial wire gage, is the legal standard of Great Britain for all wires, as fixed by order in Council, August 23, 1883. It was constructed by improving the Birmingham wire gage. (f) OLD ENGLISH OR LONDON GAGE The Old English or London gage, the sizes of which differ very little from those of the Birmingham gage, has had considerable use in the past for brass and copper wires, and is now used to some extent in the drawing of brass wire for weaving. It is nearly obsolete. 3. TWIST DRILL AND STEEL WIRE GAGES The confusion in the use of gages for twist drills, drill rod, and steel wire is a constant source of trouble. The differences between the diameters of the corresponding sizes of the various gages are very small, generally being less than 0.002 inch. In this field also, the manufacturers (of drills) are encouraging the direct use of diameters in place of specifying sizes by gage numbers. At the present time there are three gages in extensive use in this field. These are (i) the Stubs' steel wire gage, (2) the drill gage used by the Standard Tool Co., and (3) the drill gage used by various other leading manufacturers of twist drills. This latter gage is referred to in the tables which follow as "various manu- facturers " but in other publications it is sometimes referred to as ' ' manufacturers ' standard. ' ' All of these gages have 26 lettered sizes and 80 numbered sizes. The lettered sizes of all three gages are identical. (See Table 44.) For the numbered sizes, the Stubs' steel wire gage does not agree with either of the drill gages. For Nos. i to 60 (Table 45) the gage of the Standard Tool Co. agrees with the corresponding sizes Circular of the Bureau of Standards of the gage used by various other manufacturers; for sizes Nos. 61 to 80 (Tables 46 and 47) there are numerous, but small, differences. The Standard Tool Co. gage sizes were the original, which, for sizes 6 1 to 80, were changed by certain manufacturers. The old size numbers and diameters were retained by the Standard Tool Co., which, in turn, began to manufacture drills of the new diameters as determined by the modified gage numbers of the other manu- facturers, but assigned them gage sizes by inserting so-called half- sizes into their own gagt. The relationships between the diameters and the various gage sizes are shown in Table 47. 4. TABLES OF GAGE SIZES (INCHES AND MILLIMETERS) TABLE 42. DouziSme Caliper <* [Equivalent of each graduation on douzieme spring caliper.a l douzieme= 1/12 Hgne; 1 ligne= 2.2559 mm] Douziemes Inch. mm Douziemes Inch mm 0074 188 37 2738 6 956 2 .0148 .376 38 . 2812 7 144 3 0222 .564 39 .. 2886 7 332 4 .0296 .752 40 .2960 7.520 5 6 .0370 0444 .940 1 128 41 42 .3035 3109 7.708 7 896 7 .0518 1.316 43 .3183 8 084 8 0592 1 504 44 3257 8 272 9 0666 1 692 45 3331 8 460 10 0740 1 880 46 3405 8 648 11 0814 2 068 47 3479 8 836 1 ligne - 12 .0888 2.256 4 lignes=48 .3553 9.024 13 .0962 2.444 49 .3627 9.212 1036 2 632 50 3701 9 400 15 1110 2.820 51 .3775 9 sag 16 1184 3 008 52 3849 9 776 17 1258 3.196 53 .3923 9 964 18 1332 3 384 54 3997 10 152 19 .1406 3.572 55 .4071 10 340 20 21 .1480 1554 3.760 3 948 56 57 .4145 4219 10. 528 10 716 22 1628 4.136 58 .4293 10 904 23 1702 4 324 59 4367 11 092 2 lignes 24 1776 4 512 5 lignes= 60 4441 11 280 25 1850 4 700 61 . .4515 11 467 26 1924 4 888 62 4589 11 655 27 .1998 5.076 63 .4663 11.843 28 2072 5 264 64 4737 12 031 29 .2146 5.452 65 .4811 12. 219 30 31 .2220 2294 5.640 5 828 66 67 .4885 4959 12.407 12 595 32 .2368 2442 6.016 6 204 68 69 . .5033 5107 12.783 12 971 34 .2516 6 392 70 .5181 13 159 35 2590 6 580 71 .. 5255 13 347 3 lignes 36 2664 6 768 6 lignes 72 5329 13 535 <* This caliper must not be confused with the tenth-millimeter spring caliper, which is similar in appear- ance to the douzieme caliper. For the graduation equivalents of the gage, or caliper, referred to by the various names of screw, point, or dial gage, using the values of "points" as used by silversmiths, or quarter-thousandths of an inch, see the first column of Table 6. Jewelers' Weights and Measures TABLE 43. Tabular Comparison of Wire Gages 33 Gage No. American wire gage (Brown & Sharpe) Steel wire gage a Birmingham wire gage (Stubs') Stubs' steel wire gage (British) Standard wire gage Inch mm'' Inch mm Inch mm Inch mm Inch mm 7-0 0.4900 .4615 .4305 .3938 .3625 .3310 .3065 .2830 .2625 .2437 .2253 .2070 .1920 .1770 .1620 .1483 .1350 .1205 .1055 .0915 .0800 .0720 .0625 .0540 .0475 .0410 .0348 .0317 .0286 .0258 .0230 .0204 .0181 .0173 .0162 .0150 .0140 .0132 .0128 .0118 .0104 .0095 .0090 .0085 .0080 .0075 .0070 .0066 .0062 .0060 .0058 .0055 .0052 .0050 .0048 .0046 .0044 12.45 11.72 10.93 10.00 9.21 8.41 7.79 7.19 6.67 6.19 5.72 5.26 4.88 4.50 4.11 3.77 3.43 3.06 2.68 2.32 2.03 .829 .588 .372 .207 .041 .884 .805 .726 .655 .584 .518 .460 .439 .411 .381 .356 .335 .325 .300 .264 .241 .229 .216 .203 .191 .178 .168 .157 .152 .147 .140 .132 .127 .122 .117 .112 0.500 .464 .432 .400 .372 .348 .324 .300 .276 .252 .232 .212 .192 .176 .160 .144 .128 .116 .104 .092 .080 .072 .064 .056 .048 .040 .036 .032 .028 .024 .022 .020 .018 .0164 .0148 .0136 .0124 .0116 .0108 .0100 .0092 .0084 .0076 .0068 .0060 .0052 .0048 .0044 .0040 .0036 .0032 .0028 .0024 .0020 .0016 .0012 .0010 12.70 11.79 10.97 10.16 9.45 8.84 8.23 7.62 7.01 6.40 5.89 5.38 4.88 4.47 4.06 3.66 3.25 2.95 2.64 2.34 2.03 1.83 1.63 1.42 1.22 1.02 .91 .81 .71 .61 .56 .51 .46 .417 .376 .345 .315 .295 .274 .254 .234 .213 .193 .173 .152 .132 .122 .112 .102 .091 .081 .071 .061 .051 .041 .030 .025 6-0 5-0 4-0 3-0 0.4600 .4096 .3648 .3249 .2893 .2576 .2294 .2043 .1819 .1620 .1443 .1285 .1144 .1019 .0907 .0808 .0720 .0641 .0571 .0508 .0453 .0403 .0359 .0320 .0285 0253 .0226 .0201 .0179 .0159 .0142 .0126 .0113 .0100 .0089 .0080 .0071 .0063 .0056 .0050 .0045 .0040 .0035 .0031 .0028 .0025 .0022 .0020 .0018 .0016 .0014 .0012 .0011 .0010 11.68 10.40 9.27 8.25 7.35 6.54 5.83 5.19 4.621 4.115 3.665 3.264 2.906 2.588 2.305 2.053 1.828 1.628 1.450 1.291 1.150 1.024 .912 .812 .723 .644 .573 .511 .455 .405 .361 .321 .286 .255 .227 .202 .180 .160 .143 .127 .113 .101 .090 .080 .071 .063 .056 .050 .045 .040 .035 .032 .028 .025 0.454 .425 .380 .340 .300 .284 .259 .238 .220 .203 .180 .165 .148 .134 .120 .109 .095 .083 .072 .065 .058 .049 .042 .035 .032 .028 .025 .022 .020 .018 .016 .014 .013 .012 .010 .009 .008 .007 .005 .004 11.53 10.80 9.65 8.64 7.62 7.21 6.58 6.05 5.59 5.16 4.57 4.19 3.76 3.40 3.05 2.77 2.41 2.11 1.83 1.65 1.47 1.24 1.07 .889 .813 .711 .635 .559 .508 .457 .406 .356 .330 .305 .254 .229 .203 .178 .127 .102 2-0 2 0.227 .219 .212 .207 .204 .201 .199 .197 .194 .191 .188 .185 .182 .180 .178 .175 .172 .168 .164 .161 .157 .155 .153 .151 .148 .146 .143 .139 .134 .127 .120 .115 .112 .110 .108 .106 .103 .101 .099 .097 .095 .092 .088 .085 .081 .079 .077 .075 .072 .069 5.77 5.56 5.38 5.26 5.18 5.11 5.05 5.00 4.93 4.85 4.78 4.70 4.62 4.57 4.52 4.45 4.37 4.27 4.17 4.09 3.99 3.94 3.89 3.84 3.76 3.71 3.63 3.53 3.40 3.23 3.05 2.92 2.84 2.79 2.74 2.69 2.62 2.57 2.51 2.46 2.41 2.34 2.24 2.16 2.06 2.01 1.96 1.91 1.83 1.75 B.'.'.'.'.'. 9 10.. 11 12 13 14 15 16. ... 17 18 19 20 21 22 23.... 24 25.... 26 27 28 29 30.... 31 32 33 34 35. ... 36 37 38 40.... 41 ::::::::: 42 43 44 45 46 47 48 49 50 o The Steel wire gage is the same gage which has been known by the various names: "Washbum & Moen " "Roebling," and "American Steel & Wire Go's." Its abbreviation should be written 'Stl. W. G. to distinguish it from "S. W. G.," the usual abbreviation for the (Bntish) Standard wire gage. <> The millimeter diameters given for the American wire gage were obtained by multiplying by 25.4001 the mathematically correct values in inches before the latter were rounded off in the fourth decimal place as shown in the second column of the table. 34 Circular of the Bureau of Standards TABLE 44. Equivalents of Lettered Sizes for Drills and Stubs' Steel Wire Gage Letter Size of letter Letter Size of letter Letter Size of letter Inch mm Inch mm Inch mm Z.... Y x 0.413 .404 .397 .386 .377 .368 .358 .348 .339 .332 10.49 10.26 10.08 9.80 9.58 9.35 9.09 8.84 8.61 8.43 Sir.::::::::::::: N M L 0.323 .316 .302 .295 .290 .281 .277 .272 .266 .261 8.20 8.03 7.67 7.49 7.37 7.14 7.04 6.91 6.76 6.63 F.... E D C B A 0.257 .250 .246 .242 .238 .234 6.53 6.35 6.25 6.15 6.05 5.94 w.... V u K.... T T S R Q r::::::::::::::: H G TABLE 45. Numbered Sizes, 1 to 60, for Drills and Stubs' Steel Wire Gage Gage No. Stubs' steelwire gage Drill gage a Gage No. Stubs' steelwire gage Drill gage Inch mm Inch mm Inch mm Inch mm 1... 2 0.227 .219 .212 .207 .204 .201 .199 .197 .194 .191 .188 .185 .182 .180 ,178 .175 .172 .168 5.766 5.563 5.385 5.258 5.182 5. 105 5.055 5.004 4.928 4.851 4.775 4.699 4.623 4.572 4.521 4.445 4.369 4.267 0. 2280 .2210 .2130 .2090 .2055 .2040 .2010 .1990 .1960 .1935 .1910 .1890 .1850 .1820 .1800 .1770 .1730 .1695 5.791 5.613 5.410 5.309 5.220 5.182 5.105 5. 055 4.978 4.915 4.851 4.801 4.699 4.623 4.572 4.496 4.394 4.305 30... 31 32 0.127 .120 .115 .112 .110 .108 .106 .103 .101 .099 .097 .095 .092 .088 .085 .081 .079 .077 .075 .072 .069 .066 .063 .058 .055 .050 .045 .042 .041 .040 .039 3.226 3.048 2.921 2.845 2.794 2.743 2.692 2.616 2.565 2.515 2.464 2.413 2.337 2.235 2.159 2.057 2.007 1.956 1.905 1.829 1.753 1.676 1.600 1.473 1.397 1.270 1.143 1.067 1.041 1.016 0.991 0. 1285 .1200 .1160 .1130 .1110 .1100 .1065 .1040 .1015 .0995 .0980 .0960 .0935 .0890 .0860 .0820 .0810 .0785 .0760 .0730 .0700 .0670 .0635 .0595 .0550 .0520 .0465 .0430 .0420 .0410 .0400 3.264 3.048 2.946 2.870 2.819 2.794 2.705 2.642 2.578 2.527 2.489 2.438 2.375 2.261 2.184 2.083 2.057 1.994 1.930 1.854 1.778 1.702 1.613 1.511 1.397 1.321 1.181 1.092 1.067 1.041 1.016 3..., 4 5... 33.. . 34 35.. . 36 37 38 39 40.. .. 41 42 43 44 45 46 47 6 7 8 9 10.... 11 12... 13 14 15.... 16 17 18 19 20 .164 .161 .157 .155 .153 .151 .148 .146 .143 .139 .134 4.166 4.089 3.988 3.937 3.886 3.835 3.759 3.708 3.632 3.531 3.404 .1660 .1610 .1590 .1570 .1540 .1520 .1495 .1470 .1440 .1405 .1360 4.216 4.089 4.039 3.988 3.912 3.861 3.797 3.734 3.658 3.569 3.454 48 49 50.. ., 51 52 53 54 55 . 21... 22 23 24 25... 26 27 56 57 58 59 60 28 29 For sizes i to 60 the dimensions for both drill gages Standard Tool and "various manufacturers" are identical, but differ from the Stubs' steel wire gage. Jewelers' Weights and Measures 35 TABLE 46. Numbered Sizes, 60 to 80, for Drills and Stubs' Steel Wire Gage Gage No. Stubs' steel wire gage Standard Tool Co. drill gage Various manu- facturers Inch mm Inch mm Inch mm 60 60^ 61 62 63 64 0.039 "'.'038 .037 .036 .035 .033 .032 .031 .030 '".'629' 0.991 '".'%5' .940 .914 .889 .838 .813 .787 .762 "'.'737' 0. 0400 .0390 .0380 .0370 .0360 .0350 .0330 .0320 .0310 .0300 . 02925 .0290 .0280 .0270 .0260 .0250 .0240 .0230 .0225 .0220 .0210 .0200 .0180 .0160 .0150 .0145 .0140 .0135 .0130 1.016 .991 .965 .940 .914 .889 .838 .813 .787 .762 .743 .737 .711 .686 660 iess .610 .584 .572 .559 .533 .508 .457 .406 .381 .368 .356 .343 .330 0.0400 '".'6396" .0380 .0370 .0360 .0350 .0330 .0320 .0310 '".'62925' .0280 .0260 '".6256" .0240 '".'6225" .0210 .0200 .0180 .0160 1.016 ".'99i .965 .940 .914 .889 .838 .813 .787 ".'743 .711 .660 ".'635 .610 ".'572 .533 .508 .457 .406 65 66 67 68 T 2 :::::: 69H 70 71 71J-6 .027 .026 .686 .660 72 73 73^ .024 .023 .610 .584 74 74H 75 76 - 77 78 78V .022 .020 .018 .016 .015 .559 .508 .457 .406 .381 79 79^ 80 .014 '".'ois' .356 '".'336' .0145 "".Q\3S" .368 ".'343 TABLE 47. Index to Numbered Sizes, 60 to 80, for Drills and Stubs' Steel Wire Gage Diameter of drill Gage numbers Diameter of drill Gage numbers Inch mm Stubs' steel wire gage Standard Tool Co. drill gage Various manu- facturers Inch mm Stubs- steel wire gage Standard Tool Co. drill gage Various manu- facturers 0.0400 1.016 59 60 60 0.0250 0.635 71H 72 .0390 .991 60 60J4 61 .0240 .610 7 2 72 73 .0380 .965 61 61 62 .0230 .584 73 73 . . . _ . . . .0370 .940 62 62 63 .0225 .572 73>i .0360 .914 63 63 64 .0220 .559 ""74"" 74 .0350 .889 64 64 65 .0210 .533 .......... 743^ 75 .838 65 65 66 .0200 .508 75 76 !0320 .813 66 66 67 .0180 .457 76 76 77 .0310 .787 67 67 68 .0160 .406 77 77 78 .0300 .762 68 68 0150 .381 78 78 . 02925 .743 68^ ""69"" .0145 .368 ...... 78H ' ' 79 ' ' ' .0290 .737 69 69 .0140 .356 79 0280 711 69J4 . . . _. . . . .0135 .343 79H . .^. . . . !0270 .686 .......... 70 .0130 .330 80 80 .0260 .660 71 71 - 7 y V. WATCH GLASSES 1. GAGE SIZES FOR WATCH GLASSES The systems upon which the gaging of watch glasses is based are in need of revision. Most manufacturers and dealers are labeling their glasses with several sets of numbers, each set indi- 36 Circular of the Bureau of Standards eating the diameter according to some system of gaging, most of which are based upon some subdivision of the ligne. 11 The most common of these units based upon the ligne is frequently referred to as "sixteenths," because in this system the fraction over an integral number of lignes is expressed in sixteenths. Some of these labels include systems of gaging which are practically, if not entirely, obsolete. On the other hand, several manufacturers use the metric system, the unit for diameters being the tenth- millimeter. 2. REASONS FOR ADOPTION OF METRIC GAGE SIZES The metric system of gaging is recommended for use in prefer- ence to the ligne and its division into sixteenths, for the following reasons : (a) The step, or change in diameter, between consecutive sizes in the tenth-millimeter system is less than the corresponding steps for glasses gaged by lignes and "sixteenths," thereby making it possible to secure a better fit in placing a glass into a watchcase. (6) Many watch glasses are manufactured in metric sizes and are sold in ligne sizes to satisfy the habits of the retail trade in the United States. On the continent of Europe metric sizes are used. (c) The ligne as a unit of length is obsolete except in a few industries, and among them it is falling into disuse; the millimeter is universal in most commercial countries. 3. SPECIMEN LABELS In Fig. 2 there are shown two sample labels of watch glasses giving the diameters in tenth-millimeters and in lignes (frequently spoken of as sixteenths) ; the last number given on each of these labels indicates by gage number the free height under the center of the glass to the plane formed by the circumference or rim. FIG. 2. sped- (See Table 49, p. 37). The basis by which the men watch height of a watch glass is gaged is that a flat glass glass labels j s g a g e N O IOj an( j that for each unit distance of 0.4 millimeter in height, the gage number decreases by unity. This system of labeling is recommended by the Bureau of Stand- ards as the most satisfactory for the present, at least so long as the ligne sizes are used in appreciable quantities. The manufac- turers would prefer that metric sizes be used exclusively, but it depends largely upon the retail establishments to simplify existing conditions. 11 The origin of the ligne is from the old, now practically obsolete, French toise (fathom) as follows: 12 lignes=l pouce, 12 pouce=l pied, 6 pied=l toise. The relation between the toise and meter is 1 toise= 1.949090 meters. (Guillaume, '' Unites et fitalons," page 64.) Jewelers' Weights and Measures 37 4. INFLUENCE OF WATCHCASE DESIGN The number of sizes of watch glasses which it is necessary for retail establishments to carry in stock is almost appalling. In the table of diameters given below (Table 48), there are 272 sizes shown, which apply to each of the various models. The Bureau desires to suggest that the number of necessary sizes can be eventually reduced about 50 per cent if watchcase manufacturers would confine themselves to the manufacture of cases requiring only glasses whose sizes are an integral number of millimeters ; to provide for odd sizes resulting from inaccurate workmanship, there would be supplied about two tenth-millimeter sizes below and above each integral or whole millimeter size. 5. CONVERSION TABLES Table 48 is a conversion table for the reduction of diameters expressed in lignes into tenth-millimeter sizes. Table 49 gives the height of glasses in both millimeters and inches. TABLE 48. Diameter of Watch Glasses Conversion of Lignes (16ths) into Tenth-millimeters [lligne= 2.2559 mm] Size 16 16 2 16 3 16 4 16 5 F6 6 16 A 8 16 9 16 10 16 11 16 16 13 16 14 16 15 16 6 135 137 138 140 141 142 144 145 147 148 149 151 152 154 155 157 7 158 159 161 162 164 165 166 168 169 171 172 173 175 176 178 179 8 180 182 183 185 186 188 189 190 192 193 195 196 197 199 200 202 9 203 204 206 207 209 210 211 213 214 216 217 219 220 221 223 224 10 226 227 228 230 231 233 234 235 237 238 240 241 243 244 245 247 11 248 250 251 252 254 255 257 258 259 261 262 264 265 266 268 269 12 271 272 274 275 276 278 279 281 282 283 285 286 288 289 290 292 13...: 293 295 296 297 299 300 302 303 305 306 307 309 310 312 313 314 14 316 317 319 320 321 323 324 326 327 329 330 331 333 334 336 337 15 338 340 341 343 344 345 347 348 350 351 352 354 355 357 358 360 16 361 362 364 365 367 368 369 371 372 374 375 376 378 379 381 382 17 384 385 386 388 389 391 392 393 395 396 398 399 400 402 403 405 18 406 407 409 410 412 413 415 416 417 419 420 422 423 424 426 427 19 429 430 431 433 434 436 437 438 440 441 443 444 446 447 448 450 20 451 453 454 455 457 458 460 461 462 464 465 467 468 470 471 472 21 474 475 477 478 479 481 482 484 485 486 488 489 491 492 493 495 22 496 498 499 501 502 503 505 506 508 509 510 512 513 515 516 517 TABLE 49. Height of Watch Glasses Gage No. Height Gage No. Height TTITH Inch mm Inch 10 0.0 .4 .8 1.2 1.6 2.0 0.000 .016 .031 .047 .063 .079 I 4 2.4 2.8 3.2 3.6 4.0 0.094 .110 .126 .142 .157 9 8 7 6 5 1 3 2 1 o Circular of the Bureau of Standards VI. SIZES OF WATCHES Watch sizes are based upon the diameter of the pillar plate. Watch movements made on the continent of Europe have their diameters expressed either in millimeters or in lignes, the former method being somewhat uncommon. A watch movement made in the United States has its diameter expressed in terms of a certain "Size No." The diameter of the o-size watch is i 5/3oths of an inch; the size number increases for each 3oth of an inch. The diameter of a i2-size watch movement is therefore 47/3oths of an inch (1.567 inches, or 39.79 millimeters). From the third column of Table 50 it is seen that an iS-ligne watch equals almost exactly a i3-size and that a i5-ligne equals very closely a 5 -size. In connection with the most common sizes it is well to note that the diameter of a i6-size watch is nearest to 19 lignes, 12 -size to 18 lignes, and o-size to 13 lignes. TABLE 50. Watch Sizes [Based upon the diameter of pillar plate. 1 ligne= 2.2559 millimeters; 1 inch= 25.40005 millimeters, Size No.= Number of thirtieths (30th's) of an inch in excess of 35 thirtieths (35/30) of an inch] Watch size No. .Pillar plate diameter Watch size No. Pillar plate diameter Lignes mm Inches SOth's of an inch Lignes irm Inches SOth's of an inch 32 56.73 56.40 55.88 55.03 54.19 54.14 53.34 52.49 51.89 51.65 50.80 49.95 49.63 49.11 48.26 47.41 47.37 46.57 45.72 45.12 44.87 44.03 43.18 42.86 42.33 41.49 40.64 40.61 39.79 38.95 38.35 38.10 37.25 2.233 2.220 2.200 2.167 2.133 2.132 2. 100 2.067 2.043 2.033 2.000 1.967 1.954 1.933 1.900 1.867 1.865 1.833 1.800 1.776 1.767 1.733 1.700 1.687 1.667 1.633 1.600 1.599 1.567 1.533 1.510 1.500 1.467 67 "66 ' 65 64 '"es"' 62 '"ei"' 60 59 '"ss"' 57 56 8 'is 36.41 36.09 35.56 34.71 33.87 33.84 33.02 32.17 31.58 31.33 30.48 29.63 29.33 28.79 27.94 27.09 27.07 26.25 25.40 24.81 24.55 23.71 23.69 22.86 22.56 22.01 21.43 20.30 19. 18 18.05 16.92 15.79 13.54 .433 .421 400 367 333 332 300 267 243 233 200 167 155 133 100 067 066 1.033 1.000 .977 .967 .933 .933 .900 .888 .867 .844 .799 .755 .711 .666 .622 .533 43 42 41 40 '"39"' 38 "'37 36 35 '"34"' 33 32 31 30 '"29 " 28 '"27"' "'26 25 31 30 29 7 6 5 "is".' 24 28 27 4 3 26 25 24 '"23 " 22 21 2 1 22 13.. 2/0 3/0 4/0 ' i2 21 20 19 55 54 53 52 51 '"56"' 49 48 46 5/0 6/0 . ii .'. 20 . 18 17 16 7/6 8/0 ' ' 9/6' ' ' 19 .. 15 14 13 is 10 10/0 9 12 11 8 " . 17 .... 714 10 9 45 44 7 ;; :: 6 Jewelers' Weights and Measures 39 VII. RING SIZES 1. ORIGINAL STANDARD The gages for finger rings that are in use in the United States are almost universally of the cone type, and are designated by two trade names. One is "F. E. Allen's"; the other is "U. S. Standard. ' ' Apparently the principle of a metal cone with gradua- tions from i to 13 or o to 13 is the same on the two gages, the only apparent difference between the two being in the shape of the wooden handles. All attempts to find any printed statement as to what the dimensions of the various sizes are supposed to be, have been unsuccessful. The earliest known patent on the conical ring gage was obtained by F. H. Allen on February 3, 1874, U. S. Patent No. 146974. In this patent there is described quite accu- rately the conical gage with sizes i to 13, and quarter sizes, as is used to-day; there is also described the auxiliary scale on the side for showing the circumference for each of the various sizes. The dimensions of the sizes are not stated. 2. INTRODUCTION OF ERRORS From the accurate description of the present gage in Allen's patent, it may be presumed, perhaps erroneously although prob- ably correctly, that the scale of sizes now in use was well known and in use at that time. There probably also is little doubt but that the present gage sizes have descended from those in use at that time, but by what steps and intermediary process it is impossible to state. Differences in the sizes have likely been introduced by the adoption of a common commercial copy as a pattern or standard. In fact, a standard was once obtained in this manner. A manu- facturing company in 1917 wrote to the Bureau of Standards stating that they had been making these gages for nearly 25 years and that "our standard was probably obtained from a commercial Allen ring gage and there appears to be considerable variations in the ring gages on the market.'" 3. MANY SIMILAR STANDARDS While there apparently is only one standard in use in the United States, in reality, because of the lack of specific dimensions and because of the errors introduced by the adoption of a common commercial article as a pattern, there are many, although similar, standards. One establishment recently purchased a considerable number of platinum blank rings from a certain well-known and highly advertised manufacturer. The ring blanks as delivered 4O Circular of the Bureau of Standards tested out about one-quarter size smaller than the size ordered, and as can be readily understood, there is no means of recourse even though there had been a desire on the part of the purchaser to obtain it. From the gages examined in a few retail establish- ments in the, same city, there were discovered differences corre- sponding to about a third of a size. Continued search in other cities may be expected to disclose much larger differences. Letters from one important manufacturer of ring gages state that the diameters they use corresponding to sizes i and 13 are 0.485 and 0.877 inch, respectively; from another, they are 0.491 and 0.877 inch, respectively. On the other hand, measurements obtained during one afternoon for gages in use in retail houses in one locality gave a range of values for size i from 0.480 to 0.491 inch, and for size 13 from 0.870 to 0.878 inch. 4. CONFUSION ALSO IN USE OF GAGE Not only is there confusion in the ring sizes and standards but confusion also exists in the method of use of the gages. Some companies bring the top of the ring to the mark on the gage, others use the middle of the ring, while still others use the lower edge of the ring. These differences in the method of use are equivalent for broad rings to an appreciable part of a size, and serve to increase the differences between the various standards. The differences between the various gages for any one size are somewhat small in comparison with the latitude permissible in the retail trade, but for the jobbers and manufacturers it seems desirable, however, that the diameter used for each of the various sizes and the method of use of the gage should be identical. 5. OUTLINE OF THE PROBLEM The figures given in the preceding paragraphs show approxi- mately the dimensions of the gages in use as compared with those of the standards of two ring gage manufacturers. The Bureau of Standards intends to take up this problem by obtaining more com- plete information as to the dimensions of gages in different parts of the country, and with the cooperation of those fundamentally interested in this problem, it hopes to be able to select some values which best represent the average dimensions of existing standards. Jewelers' Weights and Measures VIII. MISCELLANEOUS TABLES TABLE 51. Decimal Equivalents of Gold Karats a [The number oi karats indicates the number of 24ths of pure gold in an alloy] Number of karats Pure gold Number of karats Pure gold IK 2K 3K Fineness 0.0417 0833 1250 13 K ... 14K 15 K Fineness 0. 5417 .5833 6250 4K.. . 1667 16 K .6667 5K 6K 7K 2083 2500 2917 17K.... 18 K 19 K .7083 .7500 7917 8K.. . 20 K .8333 9K 3750 21 K .8750 10 K UK 12 K 4167 4583 5000 22 K ... 23K 24K .9167 .9583 1.0000 The spelling "karat" is in general use among jewelers to designate the gold karat (fineness of gold) and is consistent with the accepted abbreviation for this term, " K"; also, it affords a distinctive term as compared with "carat," which, abbreviated by " c " designates a unit of weight used in measuring precious stones. TABLE 52. Densities a of Various Metals Metal Density Metal Density Aluminum Antimony g/cm' 2.70 6.618 Manganese Nickel g/cm 3 7.42 8.75 Bismuth Cadmium Chromium Cobalt Copper 9.781 8.648 6.92 8.71 8.89 Osmium Palladium Platinum Rhodium Silver 22.5 12.16 21.37 12.44 10.48 Gold ... Iridium Iron Lead 19.33 22.42 7.86 11.342 Tantalum Tin Tungsten Zinc 16.6 7.29 18.8 7.10 ' The values in this table are taken from "Smithsonian Physical Tables," 7th revised edition, p. no. TABLE 53. Melting Points o O f Various Metals & Metal Melting point Melting point Metal Melting point Melting point Mercury Tin C - 38.87 +231.9 F - 37.97 +449. 4 Manganese Nickel C 1230 1452 OF 2246 2646 Bismuth 271 320 9 * 520 609 6 Cobalt 1480 1530 2696 2786 Lead Zinc 327.4 419.4 621.3 786.9 Palladium Chromium 1550 1615 2822 2939 Antimony 630.0 658 7 1166.0 1217 7 Platinum Rhodium 1755 1950 3191 3542 Radium 700 1292 Iridium 2350(?) 4260 Silver Gold Copper 960.5 1063.0 1083. 1760.9 1945. 5 1981. 4 Osmium Tantalum Tungsten 2700(?) 2900 3400 4890 5250 6152 o At high temperatures some of the values are somewhat uncertain. Temperatures centigrade are rounded off, and the exact Fahrenheit equivalents are usually given. 6 This table is taken from B. S. Circular No. 35, 4th edition (revision of melting points for all of the elements. Dec. 1, 1919), which gives the 42 Circular of the Bureau of Standards TABLE 54. Conversion of Centigrade Temperatures (C) into Fahrenheit Temperatures (F) [Temperature Fahrenheit= 9 5 temperature centigrade +32] c OF C F C F 40 40 60 140 200 392 -35 - 31 65 149 300 572 -30 - 22 70 158 400 752 -25 - 13 75 167 500 932 20 - 4 80 176 600 1112 -15 + 5 85 185 700 1292 -10 14 90 194 800 1472 - 5 23 95 203 900 1652 Zero 32 100 212 1000 1832 + 5 41 105 221 1100 2012 10 50 110 230 1200 2192 15 59 115 239 1300 2372 20 68 120 248 1400 2552 25 77 125 257 1500 273L 30 86 130 266 1600 2912 35 95 135 275 1700 3092 40 104 140 284 1800 3272 45 113 145 293 1900 3452 50 122 150 302 2000 3632 55 131 155 311 2500 4532 TABLE 55. Conversion of Fahrenheit Temperatures (F) into Centigrade Temperatures (C) [Temperature centigrade- 5/9 (temperature Fahrenheit -32)] F C F C F C F C 40 40.0 60 15.6 165 73.9 500 260.0 -35 -37.2 65 18.3 170 76.7 600 315.6 -30 -34.4 70 21.1 175 79.4 700 371.1 25 -31.7 75 23.9 180 82.2 800 426.7 -20 -28.9 80 26.7 185 85.0 900 482.2 -15 -26.1 85 29.4 190 87.8 1000 537.8 -10 -23.3 90 32.2 195 90.6 1100 593.3 - 5 -20.6 95 35.0 200 93.3 1200 648.9 Zero -17.8 100 37.8 205 96.1 1300 704.4 + 5 -15.0 105 40.6 210 98.9 1400 760.0 10 -12.2 110 43.3 212 100.0 1500 815.6 15 - 9.4 115 46.1 215 101.7 1600 871.1 20 - 6.7 120 48.9 220 104.4 1700 926.7 25 - 3.9 125 51.7 225 107.2 1800 982.2 30 - 1.1 130 54.4 230 110.0 1900 1037. 8 32 Zero 135 57.2 235 112.8 2000 1093.3 35 + 1-7 140 60.0 240 115.6 2500 1371. 1 40 4.4 145 62.8 245 f!8.3 3000 1648. 9 45 7.2 150 65.6 250 121.1 3500 1926. 7 50 10.0 155 68.3 300 148.9 4000 2204.4 55 12.8 160 71. 1 400 204.4 4500 2482. 2 Jewelers' Weights and Measures 43 Degrees Fahrenheit 300 200 Degrees Centigrade KOO I30O 12- OO White I9OO 1800 1. APPROXIMATE TEMPER- ATURES BY COLOR The estimation of tem- perature by the color of a hot body is influenced by so many factors that it is attended with great uncertainties. The chart I7O shown in Fig. 3, taken from Bullens' "Steel and I60 Its Heat Treatment," page 369, is appended as isoo a rough guide for such temperature estimation. 1300 (ZOO 1100 IOOO 9OO BOO Light Yellow I0 Lemon Orange 9OO Salmon Bright Red 8OO 700 600 5OO Cherry or Pull Red Medium Cherry Dark Cherry Blood Red Faint Red FlG. 3. Temperature and color of hot body INDEX [For analytical outline see "Contents," p. 3.] Abbreviations u, 12, principles Acre American Steel and Wire Co.'s wire gage American wire gage 8 : Apothecaries' units (see also under the name of each unit) Are Area, units tables Avoirdupois units of mass (see also under the name of each unit) Barrel (for dry commodities) Birmingham wire gage Board foot (British) Standard wire gage Brown & Sharpe wire gage Bushel... Capacity, tables units Carat, metric metric, new, adoption old, in use in United States previous to July i, 1913 27 Centare Centi- (prefix) Centigrade temperatures Centigram Centiliter Centimeter 7, Centimeter and inch, chart showing relative values of Centimeter, cubic 9, square Chain square Color, approximate temperatures by use Contents, table Cord Cubic measure, units (see also under the name of each unit) Deci- (prefix) Decigram Deciliter Decimeter cubic square Deka- (prefix) Dekagram Dekaliter Dekameter cubic Densities of metals Douzieme . . , Page. Page. , 13) 14 Douzieme caliper 32 10 Dram, apothecaries' 14 12 avoirdupois 14 30,33 fluid 13,21 5,30,33 Drill gages 31. 34,35 Dry units of capacity (see also under the name 14 of each unit) 13 12 II Fahrenheit temperatures 42,43 20 Fathom 1 Finger rings sizes 14,22 Firkin ' Fluid units (see also under the name of each 13 13 unit) 31,33 Foot ii I - beard 12 31,33 cubic 12, 2O ,30,33 square 12,20 13 Fractions, common (binary), of inch, conver- sion into millimeters IS 21 Fundamental relationships of metric system. 9 13 , 28, 29 Furlong II 6 Gages (see also Wire gages; Drill gages; and Plate gage) 29 , 28, 2 9 Gallon British imperial 21 12 United States 9, I 8 Gill '- a 42,43 Gold karat (fineness of gold) 41 14 Grain 9.10.14 22,23 13 ,11,15 Gram 9, 10, 14, 22, 23, 24, 25 * Hand II Hectare 12 , 12,20 Hecto- (prefix) 8 12,20 Hectogram 14 11 Hectoliter 13 12 Hectometer ii 43 cubic 12 3 Hot body, approximate temperature, by use 12 of color 43 14 12,20 Imperial wire gage , 31 8 Inch 9, 10, n, 15, 16,18 14 cubic 9, 12,20 13 12, 2O ii Introduction 6 12 12 Karats, gold, decimal equivalents 41 8 Kilo- (prefix) 8 14 Kilogram 7, 9, 14, 22,26 13 Kilometer 7," II cubic 12 12 square 12 41 32 Length conversion tables 15, 16, 17, 18,19 45 4 6 INDEX Page. Length, units of n Ligne 32,36,37,38 Link ii square 12 Liquid units (see also under the name of each unit) i3> 21 Liter 7,8,9,13,20,21 Liter, distinction between, and 1000 cubic centimeters 8,9 "Manufacturers' standard" drill gage 31, 34, 35 Mass (weight) 9, 14, 22, 33, 24, 25, 26 tables 22, 23, 24, 25, 26 units 14 Melting points of metals 41 Metal, density 41 melting points 41 Meter 7,9, xi, 15 cubic 12, 20 square 11,20 Metric carat. See Carat, metric. Metric system 7 fundamental relationships 9 general outline 7 legal status 7 units of xi Use in medical work of War Department. . . 6 Metric ton. See Ton, metric. Metric units, subdivisions 8 spelling and abbreviations 10 Micron. 8,11,19 Mil ii Mile, geographical ii nautical (sea) ii square 12 statute ii Milli- (prefix) 8 Milligram 7, 9, 14, 27, 28, 29 Milliliter 7,8, 13, 21 Millimeter 7, 8, 10, n, 15, 18 cubic 12 square 12 Minim 13.21 Old English or London wire gage. . . Ounce, apothecaries' avoirdupois fluid troy , 31 14 . .. 14,22 ... 13,21 14, 22, 25 Peck 13 Pennyweight 10, 14, 22, 24 Pint, dry 13 liquid 13, 21 Plate gage, United States standard 29 Point Pound, apothecaries' avoirdupois troy Page. 11,16,32 Quart, dry. liquid . . . . 13 9,13,21 Rings, ringer, sizes 39 Rod n square ia Roebling wire gage 30,33 Scruple, apothecaries' 14 Sizes of watches 38 Span ix Spelling of metric units 10 Square (see also under the name of each unit) 1 1 , 12, 20 Standard Tool Co.'s drill gage 31,34,35 Standard wire gage 31,33 Steel wire gage 30,33 Store ia Stubs' steel wire gage 30,31, 33, 34,35 Stubs' wire gage 33 Subdivisions of metric units 8 Tables, use Temperatures by color of hot body . Toise Ton, long metric short Troy, ounce 9, 10, 27 43 14 7)14,22 . .. 14,22 14, 22, 25 Use of tables 9, ">, 27 United States standard plate gage 29 "Various manufacturers'" drill gage 31,34,35 Volume, tables 20 units 12 Washburn & Moen wire gage 30, 33 Watch glasses, gage sizes 35,37 height 36,37 labels 36 Watchcase design, influence upon sizes of watch glasses 36 Watches, size 38 Weight, tables (see also Mass) 22, 23, 24, 25, 26 units 14 Wire gages 29,30 tabular comparison 33 Yard ii, 15 cubic 12, 20 square ix, 20 THE LIBRARY UNIVERSITY OF CALIFORNIA IX)S ANGELES University of California REGI NA an? 2V Tf !5^ N REGION ALliBRARY FACILITY 405 Hilgard Avenue, Los Angeles, CA 90024-1388 Return thjs material to the library from which it was borrowed 24HEEKS URL-LO i REC'D LD-UI 1