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See also:WIRE (A.S. wir, a wire; cf. Swed. See also:vire, to twist, M.H.G. wiere, a See also:gold See also:ornament, See also:Lat. viriae, armlets, ultimately from the See also:root wi, to twist, bind) , a thin See also:long See also:rod of See also:metal, generally See also:round in See also:section . The uses of See also:wire are multifarious and diverse beyond all enumeration . It forms the raw material of important manufactures, such as the wire-See also:net See also:industry, wire-See also:cloth making and wire-rope See also:spinning, in which it occupies a See also:place analogous to a textile fibre . Wire-cloth of all degrees of strength and fineness of mesh is used for sifting and screening machinery, for draining See also:paper pulp, for window screens, and for many other purposes . Vast quantities of See also:copper and See also:iron wire are employed for See also:telegraph and See also:telephone wires and cables, and as conductors in electric See also:lighting . It is in no less demand for See also:fencing, and much is consumed in the construction of suspension See also:bridges, and cages, &c . In the manufacture of stringed musical See also:instruments and philosophical apparatus wire is again largely used . Among its other See also:sources of See also:consumption it is sufficient to mention See also:pin and See also:hair-pin making, the See also:needle and See also:fish-See also:hook See also:industries, See also:nail, peg and See also:rivet making, and See also:carding machinery; indeed there are few industries into which it does not more or less enter . The See also:physical properties requisite to make useful wire are possessed by only a limited number of metals and metallic See also:alloys . The metals must in the first place be ductile; and, further, the wire when See also:drawn out must possess a certain amount of tenacity, the quality on which the utility of wire principally depends . The metals suitable for wire, possessing almost equal ductility, are See also:platinum, See also:silver, iron, copper, See also:aluminium and See also:gold; and it is only from these and certain of their alloys with other metals, principally See also:brass and See also:bronze, that wire is prepared . By careful treatment wire of excessive tenuity can be produced . See also:Diameter . See also:Strain . In. lb . Gold . . . . •0162 5.61- 5.42 Platinum . .0161 6.70- 6.59 Silver . . .0157 7.86- 7.78 Copper . .0177 I0•II-I0.2O Iron . . . . •o169 II.I2-10.89 Copper . . . . .0605 233 Brass . . . . .0640 203 See also:Steel . . •o600 342 Phosphor Bronze .0630 394 Dr W . H . See also:Wollaston first succeeded in See also:drawing a platinum wire ~a-,5-6- See also:inch in diameter by encasing a See also:fine platinum wire within silver to ten times its diameter . The cored wire he then reduced to -auu inch, and by dissolving away the silver coating the platinum wire imv inch thick only remained . By continued treatment in this way wires of platinum for spider-lines of telescopes have been obtained of such extreme tenuity that a mile length of the wire 11 eighs not more than a See also:grain; and it is said that platinum wire has been made which See also:measures not more than 12 010 o mm., equal to less than the fifty-thousandth See also:part of an inch . The accompanying table shows the See also:comparative tenacity of the wire of metals and metallic alloys . Wire was originally made by beating the metal out into plates, which were then cut into continuous strips, and afterwards rounded by beating . The See also:art of wire-drawing does not appear to have been known till the 14th See also:century, and it was not introduced into See also:England before the'second See also:half of the 17th century . Wire is usually drawn of cylindrical See also:form; but it may be made of any desired section by varying the outline of the holes in the draw-See also:plate through which it is passed in the See also:process of manufacture . The draw-plate or See also:die is a piece of hard See also:cast-iron or hard steel, or for fine See also:work it may be a See also:diamond or See also:ruby . The See also:object of utilizing See also:precious stones is to enable the See also:dies to be used for a considerable See also:period without losing their See also:size, and so producing wire of incorrect diameter . Diamond dies must be rebored when they have lost their See also:original diameter of hole, but the metal dies are brought down to size again by hammering-up the hole and then drifting it out to correct diameter with a See also:punch The form of a die in section is shown by fig. i; the See also:bell-mouthed opening receives the wire, and when it is pulled through the hole at the end its diameter becomes reduced accordingly . The See also:action of drawing has the effect of hardening the wire and rendering it brittle, so that See also:annealing must be done at intervals to soften it again for further drawing; the annealing is done in cast-iron pots, holding coils of wire which are raised to a red See also:heat and then allowed to cool . Although the wire is kept See also:air-tight as much as possible, some amount of scaling occurs, and pickling must be done to remove this See also:scale before redrawing . An important point in wire-drawing is that of See also:lubrication to facilitate the operation and to lessen the See also:wear on the dies . Various See also:lubricants, such as oil, See also:tallow, soapy See also:water and stale See also:beer, are employed . Another method is to immerse the wire in a sulphate of copper See also:solution, so that a film of copper is deposited which forms a See also:kind of lubricant, easing the drawing considerably; in some classes of wire the copper is See also:left after the final drawing to serve as a preventive of See also:rust . The wire-drawing See also:machines include means for holding the dies, accurately in position and for drawing the wire steadily through the holes . The usual See also:design consists of a cast-iron See also:bench or table having a See also:bracket See also:standing up to hold the die, and a See also:vertical See also:drum which rotates and by coiling the wire around its See also:surface pulls it through the die, the coil of wire being stored upon another drum or " See also:swift " which lies behind the die and reels off the wire as fast as required . The wire drum or " See also:block " is provided with means for rapidly coupling or uncoupling it to its vertical See also:shaft, so that the See also:motion of the wire may be stopped or started instantly . The block is also tapered, so that the coil of wire may be easily slipped off upwards when finished . Before the wire can be attached to the block, a sufficient length of it must be pulled through the die; this is effected by a pair of gripping pincers on the end of a See also:chain which is See also:wound around a revolving drum, so drawing the pincers along, and with them the wire, until enough is through the die to be coiled two or three times on the block, where the end is secured by a small See also:screw clamp or See also:vice ready for the drawing operation . Wire has to be pointed or made smaller in diameter at the end before it can be passed through the die; the pointing is done by hammering, filing, See also:rolling or swaging in dies, which effect a reduction in diameter . When the wire is on the block the latter is set in motion and the wire is drawn steadily through the die; it is very important that the block shall rotate evenly and that it shall run true and pull the wire in an even manner, otherwise the " snatching " which occurs will break the wire, or at least weaken it in spots . Continuous wire-drawing machines differ from the single-block machines in having a See also:series of dies through which the wire passes in a continuous manner . The difficulty of feeding between each die is solved by introducing a block between each, so that as the wire issues it coils around the block and is so helped on to the next die . The speeds of the blocks are increased successively, so that the See also:elongation due to drawing is taken up and slip compensated for . The See also:opera See also:ion of threading the wire first through all the dies and around the blocks is termed " stringing-up." The arrangements for lubrication include a See also:pump which floods the dies, and in many cases also the bottom portions of the blocks run in lubricant . The speeds at which the wire travels vary greatly, according to the material and the amount of reduction effected; rates from Too ft. up to 900 ft. are possible, the higher speeds being those of continuous machines . Wires and cables for See also:electrical purposes are covered with various insulating materials, such as See also:cotton, See also:silk, jute and paper, wrapped in See also:spiral See also:fashion and further protected with substances such as See also:paraffin, some kind of preservative See also:compound, See also:bitumen or See also:lead sheathing or steel taping . The stranding or covering machines employed in this work are designed to carry supplies of material and See also:wind it on to the wire which is passing through at a rapid See also:rate . Some of the smallest machines for cotton covering have a large drum, which grips the wire and moves it through toothed gears at a definite See also:speed ; the wire passes through the centre of disks mounted above a long See also:bed, and the disks carry each a number of bobbins varying from six to twelve or more in different machines . A See also:supply of covering material is wound on each bobbin, and the end is led on to the wire, which occupies a central position relatively to the bobbins; the latter being revolved at a suitable speed bodily with their disks, the cotton is consequently served on to the wire, winding in spiral fashion so as to overlap .
If a large number of strands are required the disks are duplicated, so that as many as sixty spools may be carried, the second set of strands being laid over the first
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For the heavier cables, used for electric See also:light and See also:power, and submarine cables, the machines are somewhat different in construction
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The wire is still carried through a hollow shaft, but the bobbins or spools of covering material are set with their spindles at right angles to the See also:axis of the wire, and they See also:lie in a circular cage which rotates on rollers below
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The various strands coming from the spools at various parts of the circumference of the cage all lead to a disk at the end of the hollow shaft
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This disk has perforations through which each of the strands pass, thence being immediately wrapped on the See also:cable, which slides through a bearing at this point
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Toothed gears having certain definite ratios are used to cause the winding drum for the cable and the cage for the spools to rotate at suitable relative speeds which do not vary
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The cages are multiplied for stranding with a large number of tapes or strands, so that a See also:machine may have six bobbins on one cage and twelve on the other
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In the See also:case of sub-marine cables, coverings of jute-served See also:gutta-percha are employed, upon which a protective covering of steel wires is laid, subsequently treated with jute yarns or tapes and protected with coatings of compound
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Messrs See also: Tapes of paper, See also:rubber or jute are served from bobbins on disks and also in some designs from See also:independent bobbins, each mounted on its own pin, set at a suitable See also:angle in a See also:frame, to give the spiral lead . In some instances seventy-two layers of paper are applied to high-tension cables . These cables are subsequently put into steam-heated tanks, hermetically sealed and connected to a vacuum pump, by which the moisture is drawn off as quickly as possible . When the cable is thoroughly dry a quantity of compound is admitted to the tank and so permeates the insulation . Lead is put on the outside of the paper in a See also:press, which has dies through which the cable passes, and is covered with a See also:uniform coating or See also:tube of lead, forced into the dies and around the cable by See also:hydraulic pressure . Steel tapes are in some cases used to See also:armour cables and protect them from See also:external injury; the tape is wound in a similar manner to the other materials already described . Rubber covering of wires and cables is done by passing them through grooved rollers simultaneously with rubber strips above and below, so that the rubber is crushed on to the wires, the latter emerging as a wide See also:band . The See also:separate wires are parted forcibly, each retaining its rubber sheathing . Vulcanizing is afterwards done in steam-heated drums . Many See also:auxiliary machines are necessary in connexion with wire-and cable-covering, as plant for preparing the rubber and paper, &c., cutting it into strips, winding it, measuring lengths, &c . Wire Gauges.—In See also:commerce, the sizes of wire are estimated by gauges which consist of plates of circular or oblong form having notches of different widths round their edges to receive wire and See also:sheet metals of different thicknesses . Each notch is stamped with a number, and the wire or sheet, which just fits a given notch, is stated to be of, say, No . 1o, Et, 12, &c., of the wire See also:gauge . But it is always necessary to See also:state what particular gauge is used, since, unfortunately, uniformity is wanting . Holtzapffel investigated the subject, and published a valuable collection of facts See also:relating thereto in 1846 . A more exhaustive See also:report was published by a See also:committee of the Society of Telegraph See also:Engineers in 1879 (Journ . See also:Soc . Tel . Eng. viii. p . 476), a result of which was the sanctioning by the See also:Board of See also:Trade, in 1884, of the New ImperiaLStandard Wire Gauge . That report stated: " The different gaug8 in use might he counted by hundreds . . . . Every wire-drawer has gauges adjusted to suit See also:special See also:objects . When competition is keen, wire is commonly drawn by one gauge and sold by another; half sizes and See also:quarter sizes are in See also:constant use among the dealers, the wire being sold as whole sizes .
Sometimes four or five different gauge plates have been made by one maker—some by which the workmen are paid, and others by which the wire is sold
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. The whole See also:system is in confusion, and lends itself to those who See also:desire to use fraudulent practices." See also: They established a regular progression of See also:thirty-nine steps between the English sizes, No . 0000 (46o mils) and No . 36 (5 mils) . Each diameter was multiplied by 0.890522 to give the next See also:lower size . This is now the See also:American gauge, and is used to a considerable extent in the U.S.A . The Imperial See also:Standard Wire Gauge, which has been sanctioned by the See also:British Board of Trade, is one that was formulated by J . See also:Latimer See also:Clark . Incidentally, one of its recommendations is that it differs from pre-existing gauges scarcely more than they differ among themselves, and it is based on a rational system, the basis being the mil . No . 7/0, the largest size, is 0.50 in . (500 mils) in diameter, and the smallest, No . 50, is 0.001 in .
(1 mil) in diameter
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Between these the diameter, or thickness, diminishes by 10.557%, and the See also:weight diminishes by 20%
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But the fact remains that a large number of gauges are still in common use, and that gauges of the same name differ and are therefore not authoritative
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Sheet iron wire gauge differs from Stubs' steel wire gauge
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Gauges for wire and plate differ
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Accuracy can only be secured by specifying precisely the name of the gauge intended, or, what is generally better, the dimensions in decimals, which can always be tested with a See also:micrometer
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A decimal gauge has been proposed
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Tables of decimal equivalents of the wire gauges have been prepared, and are helpful
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The circular forms of gauge are the most popular, and are generally 3; in. in diameter, with thirty-six notches; many have the decimal equivalents of the sizes stamped on the back
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Oblong plates are similarly notched
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Rolling See also: The graduations are those of standard wire, or in thousandths of an inch . In some cases both edges are graduated differently to serve for comparison between two systems of measurement . A few gauges are made with holes into which the wire has to be thrust . All gauges are hardened and ground to dimensions . |
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