NAIL MANUFACTURE. Until a comparatively recent period almost every kind of nail was produced by hand-labour ; each nail was separately forged from a thin rod of iron, a process which is still followed in the production of what are Aechuically known as wrought nails. As nails so formed possess certain advantages, for particular kinds of work, over those formed either by casting, or by cutting or stamping out of rolled sheet metal, there is no reason to anticipate the total abandonment of this process, notwithstanding the continual im provement of nail-making machinery.
The making of wrought nails, which retains, in most places, the character of a domestic manufacture, forms the employment of a peculiar class of blacksmiths called milers, who are very frequently assisted by the female members of their families. The nailer receives his iron in the form of narrow square rods, of various sizes, according to the kind of nail to be forged from them. Putting the ends of three or four such rods into the forge-fire at once, the nailer commences his work by withdrawing one when it is properly heated, and forging its end upon a small but very firmly bedded steel anvil to a tapering point. The pointed end is then cut off to the proper length, which is adjusted by a gauge, by laying it across a fixed chisel or and giving it a smart blow with the hammer. In some cases, as in making the kind of nail used for fixing horseshoes, this operation completes the nail ; but in most instances a subsequent process is necessary to form the head. For this purpose the red-hot spike just cut off from the nail-rod is taken up and dropped, point downwards, into one of the holes of an instrument called a bore, which is a piece of iron ten or twelve inches long, with a perforated knob of steel at each end. The holes of this instrument are uusde to fit the upper or thicker part of the nail, and are so countersunk at their upper ends as to form it kind of mould for the head of the nail. When dropped into one of these holes, a few well directed strokes of the hammer upon the thick projecting end of the spike or nail converts it into a head of any required shape. In making
small nails it is sometimes practicable to forgo and cut off two lengths from tho nail-rod with one heating; but where this is not the case the nailer is enabled to proceed with his work without interruption by the convenient plan of having several rods in the fire at once, so that as soon as one is cool another is ready to his hand. In many cases, for the sake of economy, two or three sailors work at one hearth, using the same fire and the same bellows in turn; and some heartha have been constructed large enough for five or six men. The hammer used by milers is larger or smaller, according to the size of the nails to be formed ; and its face is inclined considerably upwards towards the handle. Some of the nailer* acquire remarkable dexterity. One of them, a few years ago, made 34,000 flooring nails in a fortnight ; in performing this task, as each nail required about twenty-five strokes of the hammer, he made, including the cutting up of the nail-rods into convenient lengths, and re-uniting them when they became too short, uo less than 1,033,656 strokes, and moved to and from the fire at which the rods were heated 42,836 amts.
For sense purposes nails; formed by the much cheaper process of casting have been long used instead of those wrought ui the manner above described. Common cast .ails are, however, so clumsy and so brittle that they can only be used for a few coarse purposes, as in plasterer's work, and in the nailing up of fruit-trees By the intro duction of great improvements in the manufacture, however, a very useful kind of cast nail, of an exceedingly pure material called malle able cast iron, has been successfully introduced for certain descriptions of woodwork. Nails of thia kind are very neat and regular in their appearance, being cast with great accuracy; and they are annealed to such perfection that the metal will bear far more bending than ordi narywrought-iron without Injury. This extraordinary degree of tenacity is, however, obtained at the expense of rigidity, such nails being often nearly as soft as copper, and therefore quite unsuitable for use in Ian' woods.