COMB. The name of en instrument made of a thin plate, either plane or curved of wood, horn, tortoise-shell, ivory, bone, or metal, cut out upon` one or both of its sides or edges, into a series of somewhat long teeth, not far apart ; which is employed for disentangling, laying parallel and smooth the hairs of man, horses, or other animals.
A thin steel saw bow, mounted in an iron or wooden handle, is the implement used by the comb-maker to cut the bone, ivory, and wood, into slices of from a twelfth to a quarter of an inch tiller, and of a size suitable to that of the comb. The pieces of tortoise-shell as found in commerce are never flat, or, indeed, of any regular curvature, such as the comb must have. They are therefore steeped in boiling water sufficiently long to soften them, and set to cool in a press between iron and brass moulds, which impart to them the desired form which they pre serve after cooling. After receiving their outline shape and curvature, by proper flat files or fine rasps, the place of the teeth is marked with a triangular file, and then the teeth themselves are cut out with a double saw, composed of two thin slips of tempered steel, such as the main-spring of a watch, notched with very fine sharp teeth. These slips are mounted in a wooden or iron stock or handle, in which they may be placed at different distances, to suit the width of the eomb-teeth. A comb-nicker, how ever, well provided in tools, has an as sortment of double saws set at every or dinary width. The two slips of this saw have their teeth in different planes, so that when it begins to cut, the most prominent slip alone acts ; and when the teeth of this one have fairly entered into the comb, the other parallel blade begins to saw. The workman, meanwhile, has fixed the plate of tortoise-shell or ivory between the flat jaws of two pieces of wood, like a vice made fast to a bench, so that the comb intended to be cut is placed at an angle of 45° with the hori zon. He now saws perpendicularly, forming two teeth at a time, proceeding truly in the direction of the first tracing. Dr. Ure mentions a much better mode
of making combs, which is to fix upon a shaft or arbor in a lathe a series of circu lar saws, with intervening brass washers or discs to keep them at suitable dis tances ; to set in a frame like a vice, in front of these saws, the piece of ivory or bore to be cut ; and to press it forward upon the saws at an angle of 45 degrees, by means of a regulated screw motion. When the teeth are thus cut, they are smoothed and polished with files, and by rubbing with pumice-stone and tri poli.
Mr. Bundy, of Camden Town, Eng land, obtained a patent so long ago as 1796, for an apparatus of that kind, which hind an additional arbor fitted with a se ries of circular saws, or rather files, for sharpening the points of the comb-teeth. More recently, Mr. Lyne has invented a machine in which, by means of pres sure, two combs are cut out at once with chisels from any tough material, sneli as horn or tortoise-shell, somewhat softened at the moment by the application of a heated iron to it. The piece of horn is made fist to a earriage, which is moved forward by means of a screw until it comes under the action of a ratchet wheel, toothed upon a part of its circum ference. The teeth of this wheel bring a lever into action, furnished with a chisel or knife, which cuts out a double comb from the flat piece, the teeth of which combs are opposite to each other. By this means, no part of the substance is lost, as in sawing out combs. The same carriage may be used, also, to bear a piece of ivory in the hard state toward a circular saw, on the principles above explained, with such precision, that from 80 to 100 teeth can be formed in the space of one inch by a proper disposition of the tool.
Bullocks' horns, after the tips are sawed off, are roasted in the flame of a wood fire, till they are sufficiently soft- ened ; when they are slit up, pressed in a machine between two iron plates, and then plunged into a trough of cold water, whereby they are hardened. A paste of quicklime, litharge, and water, is used to stain the horn to resemble tortoise-shell.