The great usefulness of steel for all kinds of implements used for cutting or exposed to wearing friction, depends upon its property of acquiring a high degree of hardness when heated and suddenly cooled, and of then being capable of softening again in various degrees by reheating moderately. See TEAIPERING METALS.
Table-forks are forged rudely into the shape of the tang and shank, first as though but a single thick prong were required; the part for the prongs is then beaten out, and a stamping-die is brought down upon it, which forms the prongs, with a thin film of steel between them; this is cut out by a cutting-die. Then they arc softened and filed up, again hardened, and tempered, and ground, to smooth and finish. The dry-grinding of forks, needles, etc., is a very deleterious trade, on account of the particles of steel which enter the nostrils of the workmen, and produce most painful irritation, followed by a peculiar disease called "grinders' asthma," which is said to shorten life so seriously that few dry-grinders, exposed to the steel dust, reach forty years of age. Many remedies have been proposed for this. A magnetic mouthpiece was invented; but the workmen would not wear it, on account of its novelty, its grotesque appearance, the trouble of cleaning it, and the belief that if their trade were made more healthy, greater numbers would enter it, and wages would be reduced. A revolving fan, which sets in motion a
current of air, that is carried a pipe to the outside of the building, has been used with greater success, and is now in general use when it can be applied, though its intro duction was much opposed by the workmen. In the needle-trade especially, it has been most beneficial, entirely removing all danger from the operator. The use of wet stones would, of course, entirely obviate the evil, but they arc not applicable to ninny kinds of work, especially that which is ground before hardening, as the stone wears away very rapidly under these circumstances.
Penknives and other pocket-knives are the work of many hands. Besides the blades, there are the separate pieces of the spring, the handle, rivets, etc., the making of each of which is a distinct trade. All these pieces are finally fitted and put together by the finisher; a good two-bladed knife passes through his hands from 70 to 100 times. The i difference in the amount of labor bestowed on the best and the commonest C. is very remarkable, and the difference of price is, of course, proportionate.