F. 9 represents the horse-shoe nails ingeneral use ; :formerly the heads were made square, which are now nearly disused the preference to the counter-sunk being chiefly given on account of their lying flush in the groove made for them, and more securely attaching the shoe to the hoof.
J. 10 repreeents on of a large class of very useful nails, called brads ; they are made of various thicknesses, according to the strength of the work, and saryiss in length frank 1. to 3 inches.
Deck-vikes do not have rose-heads, as they would leave greater holes in the surface; but either a neat, square, flat head, that beds in flush with the surface, or a clasp or diamond bead, u shown in Fig. 3. Scupper-nails have extremely broad heads for fastening down the:lead lining.. Sheathing-nails, of the ordinary kind, are stout, flat, pointed nails, with clasp heads. There are also peculiarly formed nails for the rudders, the ribs, and various other parts of ships. The nails used in barge-building are chiefly very broad and flat in the shanks, with chisel points. Pound-nails are extensively used in Essex, Suffolk, and Norfolk ; their form will be understood by reference to the rose-sharp, which they resemble n form, but are made stiffer, and with better and more solid heads ; they are excellent for come, strong work, such as field-fencing, in oak.
Tats are also a very numerous and useful class of nails ; they are techni cally divided into rose-tacks, Flemish-tacks, and clout-tacks ; the Flemish-tacks, however, chiefly obtain ; and the heads of these are " Flemished," that is, not raised so much as a rose-head, nor so flat as a. clont-head. The sizes of these are from an. eighth to three-quarters of an inch in length ; or, as they art denominated, from 1 oz. to 16 oz. per thousand. The chief place of manufac ture for these, and other very small kinds, is Bromsgrove, m Wercestenhire, where it is a common feat of the work-people to forge a thousand (1200) tacks so small as to easily fill the barrel of an ordinary goose-quill, the weight of the tacks.bekg about 20 grains.
We could extend our description to numerous other denominations of forged To:ought-iron nail a; but as these, for the most part, differ in merely unessential points from those we hare explained, we shall next proceed to the eoasideration ef- Cast-iron nails. These, from their greet brittleness, are applicable to comparatively few purposes, such as garden-walls, the lathing of plasterers, coarse shoes and boots, &c. ; and they are desirable for those rposes merely on account of their great cheapness. It should, however, be obe ed, that cast-iron nails are made of three distinct qualities, two of which are produced by annealing processes subsequent to that of casting. In the state the nails come from the moulds, they are so extremely brittle as to be only applicable to shoes, and those only of the very small short kinds, called sparrow-bills. The cast nails for the use of plasterers, as well as those for garden-walls, and those of similar sizes, undergo a process of annealing to prevent their flying into pieces on being driven by a hammer. The best sort of cut-iron nails are called "malleable cast-iron," from their actually being rendered partially so by • long continued process of annealing ; but the metal used for this purpose is very pure, having been deprived of the greater part of its carbon. It is, however,
only a few sorts of small nails of this kind, such as tacks, that have stood the test of experience ; the annealing process having the effect of not merely destroying the brittle quality, but of rendering the metal nearly as soft as copper, and, consequently, not sufficiently stiff for the purposes designed. All attempts to combine in cast iron nails the properties of adequate stiffness free from brittleness, having failed, the manufacture of cod or pressed iron nails by machinery, from sheets of wrought iron, has been resorted to, and it has been attended with considerable success.
Cid or pressed iron nails.—Sheets of rolled iron, of the thickness of the intended nails, are cut into strips or ribands, that are in width equal to the length of the intended nails; bemg then held horizontally, with a flat side upwards, the ends are pushed in a slide against a regulated stop, under a cutter, fixed to a powerful lever, or, as is generally the case, to the lower extremity of a fly-press, which cuts off a portion constituting a brad, or nail. In making brads or sprigs, which have no heads, and are merely wedge-formed pins, the strip of iron is turned upside down, alternately, at every cut, which keeps the inclination of the angle of the cut uniform throughout the length of the strip of iron without any waste. In making brads with half-heads, or bills, the strip of iron is kept with the same side upwards, and the position of the cutter is alternately reversed by making a half turn backwards and forwards ; thus are formed two billed-brads out of one parallelogram. To make this matter under stood, we add the annexed illus tration :—a represents a strip of sheet-iron, which is passed between two guides b b against the stop c; the line d d marks the direction of the edge of the cutter, which may be supposed to have descended and cut off a portion e, forming a brad : it will now be seen that if the strip a be turned upside down, and pushed against the stop c, the next por tion/ will take the place and position of e, and, consequently, be cut off by the next descent of the cutter d d ; and thus, by repeatedly turning the strip over and back again, and pushing it forward every time with one band, while the other is occupied in working the lever of a fly-press, the brads are formed with !great rapidity. It will be seen, likewise, on reference to those lines marked g in the figure, that they represent two brads, with half-heads, or bills, which, being placed in that manner, head to point, it is obvious that, by turning the cutter half-way round alternately, they will be cut both alike, out of one paral lelogram, as represented. Except for making the larger kind of cut nails, the strength of boys and women is fully competent, who are, consequently, employed in most manufactories, each of them working a distinct press ; and headless nails are thus made by each worker with nearly the rapidity and regu larity of the ticking of a watch. Ingenuity has, however, devised much more expeditious modes of working, of which the machine we shall next describe is a respectable specimen. It is a recent invention of Messrs. Ledsam and Jones, of Birmingham, to whose enrolled specification of their patent we stand indebted for the following information.