NEEDLE. An instrument adapted for passing a thread through fabrics in sewing, consisting of a thin rod of steel, having a pointed end and pierced with a hole or "eye" to carry the thread.
The modern high quality needle is made from Sheffield crucible cast steel. The type of steel varies according to the purpose of the needle, thus hosiery needles are milder, i.e., softer than sewing needles. In addition to grading the initial hardness of the steel to the particular type of needle there has also been a forward move ment in the use of alloy steels for specific purposes. Thus with gramophone needles tungsten alloy steels have proved successful, and the high chromium or rustless steels have a very evident value in the case of surgical and hypodermic needles. The steel is hot rolled down into rod and the rod subsequently cold drawn into wire of the required diameter. The finished drawn wire is fed through straightening machines. which also automatically cut the wire into pre-determined lengths. In hand sewing needles the length cut is always that required to form two needles. The cut lengths are packed in packets of a standard weight, according to diameter of wire, for delivery to the needle maker, The first stage in the making of the needle is to secure absolute straightness and uniformity of physical condition. This is achieved by a method technically termed "rubbing." A number of blanks are heated to a uniform dull red heat, placed within two steel rings, and rubbed to and fro over a flat steel plate. The rotation of the wires within the containing rings results in perfect straight ness and the gradual cooling from a dull red heat gives uniformity of physical condition.
The lengths are then automatically pointed by feeding from a container and being rotated over a revolving grindstone by a wheel running at right angles to the stone. The curvature of the face of the grindstone and the inclination of the traversing wheel are adjusted to the requisite contour of point. The lengths are reversed and the process repeated—thus giving a blank with two pointed ends. This automatic grinding applies to all hand sewing needles; it should be noted that machine needle points are swaged, i.e., the points are formed by cold hammering between dies. The double length hand needle is fed into an automatic press which stamps the grooves at the head of each needle and in a second operation pierces the eyes of each needle and nearly separates the two. Complete separation and dressing of the head and eye are
now effected mechanically.
The needle thus formed is in its soft state and as with steel cutting tools it requires hardening to bring it into service condi tion. Hardening is effected by quenching in oil from a red heat and in practice the operation has become nearly automatic. The hardened needles are then tempered by heating to a blue heat in order to give resilience or springiness. As with hardening, tem pering in bulk is now an automatic process. The tempered needles are to some extent discoloured by the heating and the final stages are found in scouring to remove this discolouration, and polishing to obtain the silver bright finish. Scouring is effected by packing the needles in flexible containers with various mixtures all having a fine emery base and mechanically rolling the container up and down an iron roller path. Polishing is done in a similar manner with polishing reagents replacing the scouring mixtures. The polished needles are rolled down an inclined plane to bring the heads all in one direction; examined; graded, and made up into packets for sale. (P. Lo.) a military breech-loading rifle (Zflndnadel gewehr), famous as the arm of the Prussians in i866 and of the Germans in 187o-71. It was the invention of the gunsmith Johann Nicholas von Dreyse (1787-1867), who, beginning in 1824, had made many experiments, and in 1836 produced the complete needle-gun. From 1841 onwards the new arm was gradually intro duced into the Prussian service, and later into the military forces of many other German states. Dreyse was ennobled in 1864. In practice the needle-gun proved to have numerous defects; its effective range was very short compared to that of the muzzle loading rifles of the day, and conspicuously so as against the chassepot ; the escape of gas at the breech was, moreover, very great. A paper cartridge was used. An improved model, giving greater muzzle velocity and increased speed in loading, was intro duced later, but this was soon replaced by the Mauser rifle.