NAILS, pointed pieces of metal, usually with fl..ttened or rounded heads, used for driving into wood-work, for the purpose of Ito:Jing the pieces together. A variety, in which the head is very large, and the spike portion small, used by shoemakers for pro tecting the soles of boots and shoes from wear, is called the Itab-7,ail; another, which is made by cutting thin plate-iron into thin pointed pieces of various lengths, is called brads; these sometimes are without heads, but are usually made with a slight projection by way of a head. When made small, with flat heads, for cloth or hangings in upholstery-work, they are called tacks; and when very large for heavy caipentry, spikes.
Xail-rnaking.—Formerly, all nails were hand-made, by forging on an anvil; and in Britain and the north of Europe vast quantities are still made in this manner, being pre ferable, for many kinds of carpenters' work, to those made by machinery. In France, the greater part of the nails used for light carpentery-work are made of soft iron wire, pointed with the and in order to head them they are pinched in a toothed vice, which leaves the portion for the head projecting, and makes below it three or four grooves in the nail, which increase its hold on the wood when driven home. The head is beaten into a counter-sinking on the vice, which regulates the size.
The iron used for hand nail-making in Britain is sold in bundles, and is called nail rods; it is either prepared by rolling the malleable iron into rods or small bars of the required thiekness--which process is only employed for very fine qualities—or by cut ting plate-iron into strips by means of rolling-shears; these shears consist of two power ful revolving shafts. upon which are fixed discs of hard steel with squared edges. The discs of one shaft alternate with those of the other; they are of the thickness of the plate to be cut, and the shafts are so placed that a small portion of one set of the discs are inserted between those of the other set. When the shafts are revolving a plate of iron is pressed between the discs% and it is forcibly drawn through. the steel discs cutting the plates into strips with great rapidity. The quantity produced in this way is enormous, seine mills turning out at the rate of ten miles per hour of nail-rods.
Several inventions, in which America took the lead, have been introduced, and are successfully worked, for making nails direct from plate-iron, either by cutting them out cold or hot; and a very large proportion of the nails in use are made in this way. Nail making by machinery was originated in Massachusetts in 1810.