Well known little instruments, usually made of steel, pointed at one end, and perforated at the other, to receive a thread, for sewing with, etc. The processes of manufacturing needles have been much varied, but the following account combines the most recent improvements.
Steel wire of the size required, after having been annealed, is cut from the coils into lengths of four or five inches; these are gathered up into cylindrical bundles of three or four inches in diameter, over the ends of which are passed two stout iron rings, and more wires in their curved state are forced amongst those in the bundle, until the rings are tightly packed. This bundle is laid upon an iron slab, and over it a bar of iron about two feet long is placed, transversely between the two iron rings; the workman then takes hold of each end of the iron bar, and, pressing it against the bundle of wires, he rolls the latter backwards and forwards over the iron slab until every steel wire in the bundle becomes perfectly straightened. These wires are next pointed upon a grindstone running dry. In this operation, the workman, sitting astride before the stone on a block shaped like a saddle, takes up 20 or 30 wires, laid side by side across a small wooden ruler, covered with soft leather, another similar ruler being laid over the needles to confine them. The workman holds the rulers in his hands, and thus presenting the wires to the grindstone, points them with great dexterity, each wire revolving whilst in contact with the stone.
After pointing, the wires are cut off the length of the required needles. The next operation is flattening a little the ends that have to receive the eyes. This is effected by a workman taking three or four pieces of wire between his finger and thumb, placing them upon an anvil, and, striking one blow upon each, expands the ends sufficiently to receive the point of the punch, which pierces the eye. This the same person does, before he lays them down, with a small instrument, fixed on the same block as that to which the handle is fixed. The end of the needle is placed in a small notch in the bed of the instrument, and is put exactly beneath the punch, and a slight stroke of the hammer punches the eye, and at the same time forms the semicircular groove near the eye of the needle, to bury the thread. The notch which receives the needle is made in a piece of steel, which fits into a dove-tailed notch in the bed of the instrument, so that it can be changed for a larger or smaller, correspondent to the size of the needles to be pierced.
The workman holds the needles in the same manner as he did for flatting; and placing them one by one successively in the notch in the bed-piece, pierces them through by a single blow of his hammer in the end of a slider, which recoils to its former position by the reaction of a spring. He now places the next needle under the punch; and when they are all pierced in this manner, he rolls them over by moving his thumb, so as to turn them all half-round, and bring them upwards on the opposite side to that which was pierced; this being done, he repeats the punching on the other side with a view to finish and clear the eye, and to complete the groove which there is in all needles. They are now rounded at the eye end to take off the roughness, which is effected in an instant by applying them to a grindstone.
In making the larger kinds of needles, the grooves are formed, and the eyes pierced, by a stamp and fly-press. A piece of wire of the length of two needles, and pointed at both ends, is placed exactly in the middle, upon a steel die, having the form of the eye groove, etc. projecting from its surface; and over this die is suspended another exactly similar, so that, by means of a blow from the stamp hammer, the two needles between the dies are exactly impressed on both sides with the grooves already mentioned. The piece of pointed wire is then in a similar manner placed under a fly-press, where, by means of two very delicate steel punches falling over corresponding holes in a die, the two eyes are instantly pierced with great precision. These needles are then divided, and the heads corrected with a smooth file. During these operations the needles have become more or less crooked; these are, therefore, placed in files on a smooth metal plate, and with an iron rolled until they are straight.
The next processes are hardening and tempering. To effect these, the needles are placed several thousands together, covered with ashes, in a cast-iron box, and heated in a close furnace to a cherry red, when the box is withdrawn, and its contents dropped into a tub of cold water; they are next taken out of the water, and placed upon an iron plate, kept nearly red hot by means of a fire underneath; here they are carefully distributed about, so as to heat them equally, and until they acquire the blue tinge, when they are immediately removed. Some manufacturers make use of oil or tallow, and other ingredients, instead of water, which substances are supposed by them to improve the process. The needles, thus hardened, are returned to the furnace with the oil upon them, and remain there till the oil inflames, when they are withdrawn and again cooled in cold water. This second process tempers them; at first they were quite hard, and so brittle as to break with the slightest touch; the tempering renders them tough, yet sufficiently hard to take a good point.
When they are hardened in water, according to the former method, it is considered that the proper heat for tempering them can only be determined by long experience and observation; but that the flaming of the oil determines the precise temperature. If the needles be now examined, many of them will be found to have become crooked in the hardening; these are discovered by rolling them over as they lay in rows on a board, and such are selected and made straight by a blow in a notch in a small anvil for the purpose. In some manufactories the needles are next pointed and finished; in others, where the pointing has been already effected, the next process is that called -