1. Iron is reduced to the form of wire by drawing rods of it through
conical holes in a steel plate. To prepare the metal for the operation
of drawing, it is subjected to the action of the hammer, or to that of
rollers, until it has been reduced to a rod sufficiently small to be
forced through the largest hole. The best wire is produced from rods
formed by the method first mentioned.
2. Various machines are employed to overcome the resistance of the
plate to the passage of the wire. In general, the wire is held by
pinchers, near the end, and as fast as it is drawn through the plate,
it is wound upon a roller, by the action of a wheel and axle, or other
power. Sometimes, a rack and pinion are employed for this purpose, and
sometimes a lever, which acts at intervals, and which takes fresh hold
of the wire every time the force is applied.
3. The finer kinds of wire are made from the larger by repeated
drawings, each of which is performed through a smaller hole than the
preceding. As the metal becomes stiff and hard, by the repetition of
this process, it is occasionally annealed, to restore its ductility.
Wire is formed of other metals by the same general method.