Section Three

Lancashire Gage for round steel Wire, and also for Pinion Wire.

sizes distingusihed by Numbers. The larger by letters, and called the Letter Gage.

1. The first column of the table refers to the gage used for most kinds of wire, and is thence called for the sake of brevity, the "Wire gage," although it is also known as the " Birmingham wire gage," the " Birmingham iron wire gage," and the " Sheet iron gage." This gage, which is specified in the column of the table headed section one, is the most common of the three principal kinds, and is employed not only for iron wire, as its name implies, but also for brass and other wires, for black steel wire, also for sheet iron, sheet steel, and various other materials, and likewise for some manufactured works, including screws for joiners' use.

On reference to the table it appears the largest notch of the Birmingham iron wire gage is marked 0000, and measures 454 thousandths of an inch, or 4.1/2 tenths of an inch nearly; and further, that the smallest notch, marked 36, measures 4 thousandths, or the 1 -250th part of an inch. Although this gage seems only to possess 40 terms, in reality not less than 60 sizes of wire are made, as intermediate sizes are in many cases added; and occasionally, although the sizes are retained, their numbers are variously altered; thus.

The sizes of wires drawn for manufacturing needles correspond with some of the ordinary wire sizes, but the numbers are different; thus No. 1, of the needle wire, agrees with 18i of the Birmingham wire gages as here shown: -

Are respectively alike.

Sometimes half-sizes of both series are interpolated, and the manufactured needles when bought and sold are designated by another series of numbers unrelated to either of these wire sizes.

In the wire used for the strings of piano-fortes, the sizes now commonly used, are known as Nos. 6 to 20, and these agree very nearly with the sizes and half-sizes of some of the notches of the Birmingham wire gages, as follows: -

Are respectively alike.

The number 6, or the thinnest music wire now commonly used, measures about the fifty-fifth part of an inch in diameter, and the No. 20, or the thickest, measures about the 25th of an inch.

Piano-fortes were formerly always strung with brass wire, but steel is now alone employed, and they are "strung much heavier," or thicker wires are employed, from which cause the numbers 1 to 5 have probably fallen into disuse. The covered

-triage are of steel, upon which a fine copper wire is spirally wound; and in very short strings, as those of Mr. Pape's Console Piano-fortes and some others, two covering wires are used, that the bulk of the doubly-corored strings may compensate for their want of length.

The manufacturers of the patent screws made from iron wire fur joiners' use, also give the intervals of the wire gage a new system of numbers. Thus in the annexed table, the left hand columns shew the number of the screws, the right hand the numbers of the wires from which they are respectively made.

Examples of other and similar conversions of the numbers might be shown, but which would only servo further to illustrate the irregularity, and arbitrary nature of gages, used in the mechanical and other arts.

The second column of the table, page 1013, refers to the gage employed for most of the sheet metals, (excepting iron and steel,) namely, copper, brass, gilding-metal, gold, silver, platinum, etc. This gage is called the "Birmingham metal gage," and for brevity, simply the "Metal gage," or the "Plate gage," in contradistinction to the " Wire gage " specified in the first column of the table.

The intervals in the metal or plate gage, are closer or smaller than those of the wire gage. Thus the No. 1, which in this series is the smallest sized notch, is 4 thousandths or the 250th part of an inch wide, whilst the largest notch or 36 measures 167 thousandths, or is evidently meant for the sixth part of on iuch.

When thicker metals are wanted, their measures are sought in the Birmingham wire gage, thus the 36 on the plate gage, nearly agrees with the 8 on the wire gage, and therefore the numbers 7, 6, 5, to 0000 of the latter, are then employed for thicker metals than can be measured by the plate gage. Frequently the plate gage ends at 24, which number agrees with 14 of the wire gage, and then the numbers 13. 12. 11. to 000 of the hitter are similarly resorted to for thicker metals. These combinations of different series of numbers, running in reverse orders, are evidently liable to lead to confusion.

The method in which sheet metals are commercially described, also present much variation, for instance sine has a gage thus constituted -

These thin sheets of zinc, which measure only from one to about four hundredths of an inch thick, are principally used for gutters, roofs, and small works manufactured with the hammer.

Thicker zinc plates, or those from about 5 to 18 hundredths thick, and which are used for zincography, door plates, and engraved works, are commonly made to the notches, 18 to 7 of the Birmingham Wire Gage, without alteration of the numbers, but which run the reverse way of those of the other series used for sine

Several of the metals are estimated by the weight of every superficial foot, and that the more especially when the value of the material in the sheet, exceeds the value of the labour afterwards expended upon it in converting the metal to its intended purpose; thus

Cast and milled lead are both described as of from 4 to 12 pounds to the superficial foot, the variation being one pound to the foot.

Coppersmiths and braziers do not acknowledge the plate gage at all, but reckon their metal as from about 3 to 66 pounds to the sheet; the sheet measures 2 feet by 4 feet, and therefore contains 8 superficial feet

The precious metals are sometimes estimated as of so many ounces or penny weights troy to the superficial foot; and it will be hereafter shown, how by aid of the proposed scheme, derived from the decimal subdivision of the inch, the correspondence between the relative weights and thicknesses of metals, may be critically arrived at with great simplicity.

The third, fourth, and fifth column of the table, page 1013, constitute one scric3 of gages, employed exclusively for the bright steel wire prepared in Lancashire, and the steel pinion wire for watch and clockmakers.

The smallest notch of this series is called No. 80, and measures 13 thousandths of an inch, or about the 120th of an inch; and the first part of this series continues unto No. 1, which measures 227 thousandths, or nearly one quarter of an inch.

The steel wire gage apparently ended at this size in the first instance, but has since been extended by a second series to the diameter of 494 thousandths, a measure doubtless intended for half an inch. In order to avoid the confusion attendant upon two series of numerals, meeting at zero in the midst, the larger sizes are distinguished by the letters A to Z, and these terms are then continued under the denominations A 1, B 1, C 1, D l to H 1, which latter size is the largest and measures 494 thousandths of an inch, as shown by the table. This second part of the Lancashire wire gage, is called by way of distinction, the "Letter gage."

Many other gages of arbitrary characters came to the author's knowledge in this inquiry, several of which are applicable alone, to particular trades; amongst these may be mentioned, the rod iron gage, the nail rod gage, the button-maker's gage, others used in watchwork, and the gage used by gun-makers for the bores of guns and rifles; three of which gages alone will be described.

The rod iron gage, employed by Messrs. Bradleys, and some other iron masters, and also by Messrs. Stubs, for steel, has measures derived from the division of the inch into 8ths and 64ths as follows -