NAILS. A nail is a headed pin or spike of metal, commonly of iron. The primary and principal use of nails is in wood work (joinery and carpentery), but they are also employed in upholstery, shoemaking, saddlery, slating, sheet-metal working, horse-shoeing, and numerous other trades. The consumption in all civilized communities is enormous, but it is exceptionally great where timber houses and wooden erections generally prevail, as in the United States of America, and in many British colonies.
Size, form of head, nature of point, and special uses all give names to different classes of nails. Thus we have the names tacks, sprigs, and brads for very small nails; rose, clasp, and clout, according to the form of head; and flat points or sharp points according to the taper of the spike.
Arranged according to the manner in which they are manufactured, nails may fall into four principal classes:-- (1) ordinary or hand-wrought nails; (2) machine-wrought and cut nails; (3) wire or French nails; and (4) cast nails.
The nailer handicraft was at one time a great industry in the country around Birmingham, and to this day in conjunction with chain-making it constitutes an important though declining trade. It is essentially a family industry, carried on in the meanest of workshops, with a very few simple blacksmiths tools and appliances.
The nails are forged from nail-rods heated in a small smith's hearth, hammered on a low anvil, the nail length cut off on a chisel attached to the anvil, and the head formed by dropping the spike into a hole in a " bolster " of steel, from which enough of the spike is left projecting to form the head, which is variously flattened out. The head, in the case of clasp nails, is formed with two strokes of the hammer, while rose nails require four blows. The heads of the larger-sized nails are made with the aid of an " oliver " or mechanical hammer, and for ornamental or stamped heads "swages" or dies are employed.
The conditions of life and labour among the hand nailers in England are exceedingly unsatisfactory: married women and young children of both sexes are set to work long hours in small filthy sheds attached to their dwellings, and their employment is controlled by middle-men or nail-masters, who supply them with the nail-rods and pay for work done, sometimes in money and sometimes in kind on the truck system. The handicraft is, however, an expiring industry, as machine-wrought and cut nails are rapidly supplanting most corresponding kinds of hand-made nails.
Horse nails alone continue to be made in large measure by hand labour (at St Ninians near Stirling, as well as in the Birmingham district). These are made from the finest Swedish charcoal iron, hammered out to a fine sharp point. They must be tough and homogeneous throughout, so that there may be no danger of their breaking over and leaving portions sunk in the hoof.
The credit of perfecting machinery for the making of nails belongs to American inventors, and by numerous stages the nail-making machines have arrived at a high degree of efficiency. Of late years mild steel, such as the plates employed for shipbuilding, has been largely used for machine-made nails.
Without much detail it would be impossible to convey an idea of how the machine, fed with heated (to black heat only) strips of metal having a breadth and thickness sufficient for the nail to be made, shears off by means of its slicer the "nail blank," which, falling down, is firmly clutched at the neck till a heading die moving with sufficient force strikes against its upper end and forms the head, and the nail now completed is liberated, passing out through an inclined shoot.
In the case of large nails the taper of the shank and point is secured by the sectional form to which the strips are rolled; brads, sprigs, and small nails, on the other hand, are cut from uniform strips in an angular direction from head to point, the strip being turned over after each blank is cut so that the points and heads are taken from opposite sides alter-nately, and a uniform taper on two opposite sides of the nail, from head to point, is secured.
The machines turn out nails with wonderful rapidity, varying with the size of the nails produced from about 100 to 1000 per minute.
Wire or French nails are made from round wire, which is unwound, straightened, cut into lengths, and headed by a machine the same in principle as the pin-making apparatus (see PINS), but the pointing is accomplished by the pressure of dies in the same manner as the head is formed.
Cast nails, which are cast in sand moulds by the ordinary process, are used principally for horticultural purposes, and the hob-nails or tackets of shoemakers are also cast.