Modern Machine-Shop Practice Part 105

By an Order in Council dated August 23rd, 1883, and which took effect on March 1st, 1884, the standard department of the British Board of Trade subst.i.tuted for the old Birmingham wire-gauge the following:--

+-------------+--------------++---------------------------+ | Descriptive | Equivalents || Descriptive | Equivalents | | number | in parts || number | in parts | | B. W. G. | of an inch. || B. W. G. | of an inch. | +-------------+--------------++-------------+-------------+ | No. | Inch. || No. | Inch. | | 7/0 | 0.500 || 23 | 0.024 | | 6/0 | .464 || 24 | .022 | | 5/0 | .432 || 25 | .020 | | 4/0 | .400 || 26 | .018 | | 3/0 | .372 || 27 | .0164 | | 2/0 | .348 || 28 | .0148 | | 0 | .324 || 29 | .0136 | | 1 | .300 || 30 | .0124 | | 2 | .276 || 31 | .0116 | | 3 | .252 || 32 | .0108 | | 4 | .232 || 33 | .0100 | | 5 | .212 || 34 | .0092 | | 6 | .192 || 35 | .0084 | | 7 | .176 || 36 | .0076 | | 8 | .160 || 37 | .0068 | | 9 | .144 || 38 | .0060 | | 10 | .128 || 39 | .0052 | | 11 | .116 || 40 | .0048 | | 12 | .104 || 41 | .0044 | | 13 | .092 || 42 | .0040 | | 14 | .080 || 43 | .0036 | | 15 | .072 || 44 | .0032 | | 16 | .064 || 45 | .0028 | | 17 | .056 || 46 | .0024 | | 18 | .048 || 47 | .0020 | | 19 | .040 || 48 | .0016 | | 20 | .036 || 49 | .0012 | | 21 | .032 || 50 | .0010 | | 22 | .028 || | | +-------------+--------------++-------------+-------------+

[Ill.u.s.tration: Fig. 1494.]

[Ill.u.s.tration: Fig. 1495.]

The gauge known as the American Standard Wire-Gauge was designed by Messrs. Brown and Sharpe to correct the discrepancies of the old Birmingham wire-gauge by establis.h.i.+ng a regular proportion of the thirty-nine successive steps between the 0000 and 36 gauge-number of that gauge. In the American Standard (which is also called the Brown and Sharpe gauge) the value of 0.46 or 46/100 has been taken as that for 0000 or the largest dimension of the gauge. Then by successive and uniform decrements, each number following being obtained from multiplying its predecessor by 0.890522 (which is the same thing as deducting 10.9478 per cent.), the final value for number 36 is reached at 0.005, which corresponds with number 35 of the Birmingham wire-gauge.

The principle of the gauge is shown in Fig. 1495, which represents a gauge for jewelers, having an angular aperture with the gauge-numbers marked on the edge, the lines and numbers being equidistant.

The advantage of this system is that the instrument is easy to produce, the difference between any two gauge-numbers being easily found by calculation; and the gauge is easy to originate, since the opening, being of the proper width at the open end, the sides terminating at the proper distance and being made straight, the intermediate gauge-sizes may be accurately marked by the necessary number of equidistant lines.

Wire, to be measured by such a gauge, is simply inserted into and pa.s.sed up the aperture until it meets the sides of the same, which gives the advantage that the size of the wire may be obtained, even though its diameter vary from a gauge-number. This could not be done with a gauge in which each gauge-number and size is given in a separate aperture or notch. A comparison between the Brown and Sharpe and the Birmingham wire-gauge is shown in Fig. 1494, in which a piece of wire is inserted, showing that No. 15 by the Birmingham gauge is No. 13 by the Brown and Sharpe gauge.

The gauge-numbers and sizes of the same in decimal parts of an inch, of the American standard or Brown and Sharpe gauge, are given in the table following:--

------+--------------------------++------+-------------------------- |American or New Standard. || | American or New Standard.

+--------------------------++ +------------+------------- No. of|Size of each| Difference ||No. of|Size of each| Difference Wire- | number in | between ||Wire- | number in | between Gauge.| decimal | consecutive ||Gauge.| decimal | consecutive | parts of | numbers in || | parts of | numbers in | an inch. |decimal parts|| | an inch. |decimal parts | | of an inch. || | | of an inch.

------+------------+-------------++------+------------+------------- 0000 | .460 | ---- || 19 | .03589 | .00441 000 | .40964 | .05036 || 20 | .03196 | .00393 00 | .36480 | .04484 || 21 | .02846 | .00350 0 | .32495 | .03994 || 22 | .02535 | .00311 1 | .28930 | .03556 || 23 | .02257 | .00278 2 | .25763 | .03167 || 24 | .0201 | .00247 3 | .22942 | .02821 || 25 | .0179 | .00220 4 | .20431 | .02511 || 26 | .01594 | .00196 5 | .18194 | .02237 || 27 | .01419 | .00174 6 | .16202 | .01992 || 28 | .01264 | .00155 7 | .14428 | .01774 || 29 | .01126 | .00138 8 | .12849 | .01579 || 30 | .01002 | .00123 9 | .11443 | .01406 || 31 | .00893 | .00110 10 | .10189 | .01254 || 32 | .00795 | .00098 11 | .09074 | .01105 || 33 | .00708 | .00087 12 | .08081 | .00993 || 34 | .0063 | .00078 13 | .07196 | .00885 || 35 | .00561 | .00069 14 | .06408 | .00788 || 36 | .005 | .00061 15 | .05707 | .00702 || 37 | .00445 | .00055 16 | .05082 | .00625 || 38 | .00396 | .00049 17 | .04525 | .00556 || 39 | .00353 | .00043 18 | .0403 | .00495 || 40 | .00314 | .00039 ------+------------+-------------++------+------------+-------------

This gauge is now the standard by which rolled sheet bra.s.s and seamless bra.s.s tubing is made in the United States. It is also sometimes used as a gauge for the copper wire used for electrical purposes, being termed the American Standard; but unless the words "American Standard" are employed, the above wire is supplied by the Birmingham wire-gauge numbers. The bra.s.s wire manufacturers have not yet adopted the Brown and Sharpe gauge; hence, for bra.s.s wire the Birmingham gauge is the standard.

Gauges having simple notches are not suitable for measuring accurately the thickness of metal, because the edges of the sheets or plates frequently vary from the thickness of the body of the plate. This may occur from the wear of the rolls employed to roll out the sheet, or because the sheets have been sheared to cut them to the required width, or to remove cracks at the edges, which shearing is apt to form a burr or projection on one side of the edge, and a slight depression on the other.

Again, a gauge formed by a notch requires to slide over the metal of the plate, and friction and a wear causing an enlargement of the notch ensues, which destroys the accuracy of the gauge. To avoid this source of error the form of gauge that was shown in Fig. 1370 may be used, it having the further advantage that it will measure thicknesses intermediate between the sizes of two contiguous notches, thus measuring the actual thickness of the sheet when it is not to any accurate sheet metal gauge thickness.

It is to be observed that in the process of rolling, the sheet is reduced from a greater to a lesser thickness, hence the gauge will not pa.s.s upon the plate until the latter is reduced to its proper thickness.

In applying the gauge, therefore, there is great inducement for the workman to force the gauge on to the sheet, in order to ascertain how nearly the sheet is to the required size, and this forcing process causes rapid wear to the gauge.

It follows, therefore, that a gauge should in no case be forced on, but should be applied lightly and easily to the sheet to prevent wear. Here may be mentioned another advantage of the Brown and Sharpe gauge, in that its gauge-number measurements being uniform, it may be more readily known to what extent a given plate varies from its required gauge thickness.

Suppose, for example, a sheet requiring to be of Number 1 Birmingham gauge is above the required thickness, but will pa.s.s easily through the 0 notch of the gauge, the excessive variation of those two gauge numbers (over the variations between other consecutive numbers of the gauge) leaves a wider margin in estimating how much the thickness is excessive than would be the case in using the Brown and Sharpe gauge. Indeed, if the edge of the plate be of uniform thickness with the body of the plate, the variation from the required thickness may be readily ascertained by a Brown and Sharpe gauge, by the distance the plate will pa.s.s up the aperture beyond the line denoting the 0 gauge number, or by the distance it stands from the 1 on the gauge when pa.s.sed up the aperture until it meets both sides of the same.

In addition to these standard gauges, some firms in the United States employ a standard of their own; the princ.i.p.al of these are given in comparison with others in the table following.

DIMENSIONS OF SIZES, IN DECIMAL PARTS OF AN INCH.

------+---------+--------+----------+---------+---------+------------ Number| American|Birming-| Washburn | Trenton | G. W. |Old English, of | or Brown| ham, | & Moen |Iron Co.,|Prentiss,| from Bra.s.s Wire | & | or | Mfg. Co.,| Trenton,| Holyoke,| Manu- Gauge.| Sharpe. |Stubs's.|Worcester,| N. J. | Ma.s.s. | facturers'

| | | Ms. | | | List.

------+---------+--------+----------+---------+---------+------------ 000000| ---- | ---- | .46 | ---- | ---- | ---- 00000| ---- | ---- | .43 | .45 | ---- | ---- 0000| .46 | .454 | .393 | .4 | ---- | ---- 000| .40964 | .425 | .362 | .36 | .3586 | ---- 00| .3648 | .38 | .331 | .33 | .3282 | ---- 0| .32495 | .34 | .307 | .305 | .2994 | ---- 1| .2893 | .3 | .283 | .285 | .2777 | ---- 2| .25763 | .284 | .263 | .265 | .2591 | ---- 3| .22942 | .259 | .244 | .245 | .2401 | ---- 4| .20431 | .238 | .225 | .225 | .223 | ---- 5| .18194 | .22 | .207 | .205 | .2047 | ---- 6| .16202 | .203 | .192 | .19 | .1885 | ---- 7| .14428 | .18 | .177 | .175 | .1758 | ---- 8| .12849 | .165 | .162 | .16 | .1605 | ---- 9| .11443 | .148 | .148 | .145 | .1471 | ---- 10| .10189 | .134 | .135 | .13 | .1351 | ---- 11| .090742 | .12 | .12 | .1175 | .1205 | ---- 12| .080808 | .109 | .105 | .105 | .1065 | ---- 13| .071961 | .095 | .092 | .0925 | .0928 | ---- 14| .064084 | .083 | .08 | .08 | .0816 | .083 15| .057068 | .072 | .072 | .07 | .0726 | .072 16| .05082 | .065 | .063 | .061 | .0627 | .065 17| .045257 | .058 | .054 | .0525 | .0546 | .058 18| .040303 | .049 | .047 | .045 | .0478 | .049 19| .03539 | .042 | .041 | .039 | .0411 | .04 20| .031961 | .035 | .035 | .034 | .0351 | .035 21| .028462 | .032 | .032 | .03 | .0321 | .0315 22| .025347 | .028 | .028 | .027 | .029 | .0295 23| .022571 | .025 | .025 | .024 | .0261 | .027 24| .0201 | .022 | .023 | .0215 | .0231 | .025 2S| .0179 | .02 | .02 | .019 | .0212 | .023 26| .01594 | .018 | .018 | .018 | .0194 | .0205 27| .014195 | .016 | .017 | .017 | .0182 | .01875 28| .012641 | .014 | .016 | .016 | .017 | .0165 29| .011257 | .013 | .015 | .015 | .0163 | .0155 30| .010025 | .012 | .014 | .014 | .0156 | .01375 31| .008928 | .01 | .0135 | .013 | .0146 | .01225 32| .00795 | .009 | .013 | .012 | .0136 | .01125 33| .00708 | .008 | .011 | .011 | .013 | .01025 34| .006304 | .007 | .01 | .01 | .0118 | .0095 35| .005614 | .005 | .0095 | .009 | .0109 | .009 36| .005 | .004 | .009 | .008 | .01 | .0075 37| .004453 | ---- | .0085 | .00725 | .0095 | .0065 38| .003965 | ---- | .008 | .0065 | .009 | .00575 ------+---------+--------+----------+---------+---------+------------

In the Whitworth wire-gauge, the mark or number on the gauge simply denotes the number of 1/1000ths of an inch the wire is in diameter; thus Number 1 on the gauge is 1/1000 inch, Number 2 is 2/1000ths inch in diameter, and so on.

Below is given the Washburn and Moen Manufacturing Company's music wire-gauge.

SIZES OF THE NUMBERS OF STEEL MUSIC WIRE-GAUGE.

+--------+------------------++--------+------------------+ | No. of | Size of each No. || No. of | Size of each No. | | Gauge. | in decimal parts || Gauge. | in decimal parts | | | of an inch. || | of an inch. | +--------+------------------++--------+------------------+ | 12 | .0295 || 21 | .0461 | | 13 | .0311 || 22 | .0481 | | 14 | .0325 || 23 | .0506 | | 15 | .0343 || 24 | .0547 | | 16 | .0359 || 25 | .0585 | | 17 | .0378 || 26 | .0626 | | 18 | .0395 || 27 | .0663 | | 19 | .0414 || 28 | .0719 | | 20 | .043 || ---- | ---- | +--------+------------------++--------+------------------+

These sizes are those used by the Washburn and Moen Manufacturing Company, of Worcester, Ma.s.s., manufacturers of steel music wire.

In the following table is the French Limoges wire-gauge.

-------+-----------+-------++--------+-----------+------ Number | Diameter, | Inch. || Number | Diameter, | Inch.

on | milli- | || on | milli- | gauge. | metre. | || gauge. | metre. | -------+-----------+-------++--------+-----------+------ 0 | .39 | .0154 || 13 | 1.91 | .0725 1 | .45 | .0177 || 14 | 2.02 | .0795 2 | .56 | .0221 || 15 | 2.14 | .0843 3 | .67 | .0264 || 16 | 2.25 | .0886 4 | .79 | .0311 || 17 | 2.84 | .112 5 | .90 | .0354 || 18 | 3.40 | .134 6 | 1.01 | .0398 || 19 | 3.95 | .156 7 | 1.12 | .0441 || 20 | 4.50 | .177 8 | 1.24 | .0488 || 21 | 5.10 | .201 9 | 1.35 | .0532 || 22 | 5.65 | .222 10 | 1.46 | .0575 || 23 | 6.20 | .244 11 | 1.68 | .0661 || 24 | 6.80 | .268 12 | 1.80 | .0706 || | | -------+-----------+-------++--------+-----------+------

The following table gives the Birmingham wire-gauge for rolled sheet silver and gold.

+---------+------------++---------+------------+ | Gauge | Thickness. || Gauge | Thickness. | | number. | || number. | | +---------+------------++---------+------------+ | | Inch. || | Inch. | | 1 | .004 || 19 | .064 | | 2 | .005 || 20 | .067 | | 3 | .008 || 21 | .072 | | 4 | .010 || 22 | .074 | | 5 | .013 || 23 | .077 | | 6 | .013 || 24 | .082 | | 7 | .015 || 25 | .095 | | 8 | .016 || 26 | .103 | | 9 | .019 || 27 | .113 | | 10 | .024 || 28 | .120 | | 11 | .029 || 29 | .124 | | 12 | .034 || 30 | .126 | | 13 | .036 || 31 | .133 | | 14 | .041 || 32 | .143 | | 15 | .047 || 33 | .145 | | 16 | .051 || 34 | .148 | | 17 | .057 || 35 | .158 | | 18 | .061 || 36 | .167 | +---------+------------++---------+------------+

The following table gives the gauge thickness of Russia sheet iron,[25]

the corresponding numbers by Birmingham wire gauge, and the thicknesses in decimal parts of an inch.

[25] This iron comes in sheets 28 56 inches = 10.88 square feet of area.

+----------+------------+-------------------+ | Russia | Birmingham | Thickness in | | gauge | wire-gauge | decimal | | number. | number. | parts of an inch. | +----------+------------+-------------------+ | 7 | 29 | .013 | | 8 | 28 | .014 | | 9 | 27 | .016 | | 10 | 26 | .018 | | 11 | 25 | .020 | | 12 | 24-1/2 | .021 | | 13 | 24 | .022 | | 14 | 23-1/4 | ---- | | 15 | 22-3/8 | ---- | | 16 | 21-1/2 | ---- | +----------+------------+-------------------+

The following table gives the gauge numbers to which galvanized iron is made.[26]

[26] Galvanized iron is made to the Birmingham wire-gauge, the thickness includes the galvanizing, the sheets being rolled thinner to allow for it.

+---------+------------++---------+------------+ | Gauge | Thickness. || Gauge | Thickness. | | number. | || number. | | +---------+------------++---------+------------+ | | Inch. || | Inch. | | 14 | .083 || 23 | .025 | | 16 | .065 || 24 | .022 | | 17 | .058 || 25 | .02 | | 18 | .049 || 26 | .018 | | 19 | .042 || 27 | .016 | | 20 | .035 || 28 | .014 | | 21 | .032 || 29 | .013 | | 22 | .028 || | | +---------+------------++---------+------------+

In the following table is given the American gauge sizes and their respective thicknesses for sheet zinc.

--------------------------------++-------------------------------- Gauge and Thickness. || Gauge and Thickness.

-------+-----------+------------++-------+-----------+------------ Number.|Approximate|Thickness in||Number.|Approximate|Thickness in |Birmingham |fractions of|| |Birmingham |fractions of |wire-gauge.| an inch. || |wire-gauge.| an inch.

-------+-----------+------------++-------+-----------+------------ 1 | ---- | 0.0039 || 16 | ---- | 0.0447 5 | ---- | 0.0113 || 17 | ---- | 0.0521 6 | ---- | 0.0132 || 18 | ---- | 0.0596 7 | ---- | 0.0150 || 19 | ---- | 0.0670 8 | 28 | 0.0169 || 20 | ---- | 0.0744 9 | 27 | 0.0187 || 21 | ---- | 0.0818 10 | 26 | 0.0224 || 22 | ---- | 0.0892 11 | 25 | 0.0261 || 23 | ---- | 0.0966 12 | 24 | 0.0298 || 24 | ---- | 0.1040 13 | ---- | 0.0336 || 25 | ---- | 0.1114 14 | ---- | 0.0373 || 26 | ---- | 0.1189 15 | ---- | 0.0410 || | | -------+-----------+------------++-------+-----------+------------

The Belgian sheet zinc gauge is as follows:

+---------+-------------++---------+-------------+ | Gauge | Thickness in|| Gauge | Thickness in| | number. |decimal parts|| number. |decimal parts| | | of an inch. || | of an inch. | +---------+-------------++---------+-------------+ | 1 | .004 || 14 | .037 | | 2 | .006 || 15 | .041 | | 3 | .008 || 16 | .045 | | 4 | .009 || 17 | .052 | | 5 | .011 || 18 | .059 | | 6 | .013 || 19 | .067 | | 7 | .015 || 20 | .074 | | 8 | .017 || 21 | .082 | | 9 | .019 || 22 | .089 | | 10 | .022 || 23 | .097 | | 11 | .026 || 24 | .104 | | 12 | .030 || 25 | .111 | | 13 | .034 || 26 | .120 | +---------+-------------++---------+-------------+

The gauge sizes of the bores of rifles are given in the following table,[27] in which the first column gives the proper gauge diameter of bore, and the second the actual diameter containing the errors found to exist from errors of workmans.h.i.+p. The standard diameters are supposed to be based upon the number of spherical bullets to the pound weight, if of the same diameter as the respective gauge sizes.

[27] From _The English Mechanic_.

No. of Diameter of Bore.

Gauge.

4 varies from 1.052 to 1.000 6 " .919 " .900 8 " .835 " .820 10 " .775 " .760 12 " .729 " .750 14 " .693 " .680 16 " .662 " .650 20 " .615 " .610 24 " .579 " .577 28 " .550 " .548

The following table gives the result of some recent experiments made by Mr. David Kirkaldy, of London, to ascertain the tensile strength and resistance to torsion of wire made of various materials:

+-----------------------+--------------------------+ | |Pulling stress per sq. in.| | Kind of wire tested. +-------------+------------+ | | Unannealed. | Annealed. | +-----------------------+-------------+------------+ | | Pounds. | Pounds. | |Copper | 63,122 | 37,002 | |Bra.s.s | 81,156 | 51,550 | |Charcoal iron | 65,834 | 46,160 | |c.o.ke iron | 64,321 | 61,294 | |Steel | 120,976 | 74,637 | |Phosphor bronze, No. 1 | 159,515 | 58,853 | | " No. 2 | 151,119 | 64,569 | | " No. 3 | 139,141 | 54,111 | | " No. 4 | 120,900 | 53,381 | +-----------------------+-------------+------------+

+-----------------------+------------+----------------------+ | | Ultimate | No. of twists in | | Kind of wire tested. |extension in| 5 inches. | | | per cent. +-----------+----------+ | | Annealed. |Unannealed.| Annealed.| +-----------------------+------------+-----------+----------+ |Copper | 34.1 | 86.8 | 96 | |Bra.s.s | 36.5 | 14.7 | 57 | |Charcoal iron | 28 | 48 | 87 | |c.o.ke iron | 17 | 26 | 44 | |Steel | 10.9 | [28] | 79 | |Phosphor bronze, No. 1 | 46.6 | 13.3 | 66 | | " No. 2 | 42.8 | 15.8 | 60 | | " No. 3 | 44.9 | 17.3 | 53 | | " No. 4 | 42.4 | 13 | 124 | +-----------------------+------------+-----------+----------+

[28] Of the eight pieces of steel tested, three stood from forty to forty-five twists, and five stood one and a half to four twists.