HOW PINS ARE MADE.

Star (Christchurch), Issue 10418, 23 March 1912, Page 1

HOW PINS ARE MADE.

An Interesting Process. ' ("Harper's Weekly.") Although the manufacturo of a pin is loss complicated than that of a needle, the pin requires many manipulations to fit it for market. Most of the pins used are of yellow copper or of iron, but commerce also demands pins made of steel. By the common method of manufacturo the metal is cast into cylinders a little less than three feet long and a little more than a foot in breadth. The cylinders are seized by a wire-drawing machine, drawn fine, and hammered, or rolled, until fit for the bench, whore they are reduced to the desired diameter.

That is tho old process. In the latest improved method red copper and zinc are put into the crucible, and tho amalgam obtained by fusing the two metals is run into moulds to form oval plates, experiment having proved that labour and expense are saved by using that form rather than the circular. Tho plates are sheared and then cut into wires. While being cut they are HELD FAST BY MASSIVE CLAMPS. At this point a device similar to a glazier's diamond is driven down upon the plates by a simple, truck-like machine consisting of four grooved wheels and a chain run over a pulley. While the plate is held in position by the nippers or clamps its outer edge rests against tho tangent of two _ circular shears mechanically turning in opposite directions. Tho machine starts, the shears work, and the metal slats or wires receive their points and are cut into square sections, which are seized by workmen and hooked to one of tho shears posts. The wire-drawer draws the plate along and the shears force it to turn. While the shears are paring it into tho required shape tho sixtypound weight drags the truck along, pressing on the shears. The work is simple and practical; the shears cut incessantly until the plate is pared to the diameter of forty-five milimetres. The wire given by the square section goes to tho wire-drawers, where the ends are pointed, by file or by hammer and passed on to the drawing-frame. The drawing-frames for the wires intended for the finest size of pins are formed by "black diamonds" carried by steel chassis. The diamond is an important tool of tho pin manufacturer; every diamond demand 3 fifteen days' labour for its piercing, and costs thirty dollars. The upper part of tho pin wire drawing-bench is like a bowl. In it is soapy water, the bath into which the machine and the material are run. The bath lubricates the wire and fits it for the work which follows. After each visit to the bench the wirn is dipped in a ten per cent solution of sulphuric acid and washed in puro water, then

WASHED IN BRAN WATER AN'D DRIED. Whether the wire is brass or iron, it goes on the rollers to be mechanically turned, drawn and straightened. It .presents its extremity and is instantly met by a littlo mallet which gives it the three short, sharp raps which form its head. The fully formed pin wire, with its heads, is cut into sections. A3 the sections are cut they fall on a grooved slide. Tho groove catches the pins by thoir heads and, with heads caught and bodios hanging, they are manipulated by a long, rapidly revolving moulder running on a horizontal axis.

The pin is then subjected to four actions. # It is pushed away from the machine from behind, pushed to tho side of tho slide, drawn back and then forced forward, revolving as it moves on. As tho pins advance along tho screen or sieve their bodies lie almost wholly on the runner. When they reach the end of tho long screen they fall, one by ono, in a box set to catch them.

Pins are not fit for the market until guaranteed against oxidation. Tho brass and steel pins, previously galvanised, are bleached in a bath of hot salts of tin._ After tho salt bath the butt is emptied and tho pins are washed