Metal dating sites

Not all metals and metallic alloys possess the physical properties necessary to make useful wire.

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The object of utilising precious stones is to enable the dies to be used for a considerable period without losing their size, and so producing wire of incorrect diameter.

Diamond dies must be rebored when they have lost their original diameter of hole, but metal dies are brought down to size again by hammering up the hole and then drifting it out to correct diameter with a punch. It forms the raw material of many important manufacturers, such as the wire netting industry, engineered springs, wire-cloth making and wire rope spinning, in which it occupies a place analogous to a textile fiber.

Special purpose wire is however made from other metals (e.g.

tungsten wire for light bulb and vacuum tube filaments, because of its high melting temperature).

Such twisted strips can be converted into solid round wires by rolling them between flat surfaces or the strip wire drawing method.

The strip twist wire manufacturing method was superseded by drawing in the ancient Old World sometime between about the 8th and 10th centuries AD.This strip drawing technique was in use in Egypt by the 2nd Dynasty.From the middle of the 2nd millennium BCE most of the gold wires in jewellery are characterised by seam lines that follow a spiral path along the wire.Square and hexagonal wires were possibly made using a swaging technique.In this method a metal rod was struck between grooved metal blocks, or between a grooved punch and a grooved metal anvil.Although usually circular in cross-section, wire can be made in square, hexagonal, flattened rectangular, or other cross-sections, either for decorative purposes, or for technical purposes such as high-efficiency voice coils in loudspeakers.

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