798 



WIRE-MAKING. 



bedded for jewels can be made very useful for 

 draw-plates. Sometimes polished stones can be 

 obtained for wire-drawing, the flaws not being 

 discovered by the diamond-cutter before polish- 

 ing. If the stone is too thick to drill and use 

 economically, it is split in the direction of its 

 cleavage, a.nd made into two or three draw-plates. 

 Thick, round stones are not preferred, as they 

 are not broad enough in surface to split into 

 slabs. The usefulness of the diamond for wire- 

 drawing is more in the surface area than the 

 thickness. To manufacture into draw-plates the 

 diamonds are drilled, set in a soft metal setting, 

 and encased in a holder made of brass, of the 

 size of a half-dollar, but thicker. 



They are very successfully used for drawing 

 copper wire, and diamond dies will often last 

 without wearing for three months, and sometimes 

 for a year. They are used for drawing size No. 

 20 to 0.002-inch, the 0.002-inch being as fine as 

 the hair of a man's head. They are less fre- 

 quently used for drawing larger sizes, but a 5- 



CONTINUOUS FINE-WIRE-DRAWING MACHINE. 



carat die can be used for No. 16 wire, and when 

 worn can be split to make other dies for finer 

 wire. A 2-carat diamond may be used for draw- 

 ing No. 20, 1-carat for No. 25, J-carat for No. 30, 

 and J-carat for smaller sizes. This usefulness 

 of the diamond die is equally true for platinum, 

 brass, and other wires of soft metals or alloys. 



Not so, however, with steel wire. A diamond 

 can be used for drawing No. 32 (0.013-inch) and 

 finer, but will last only two or three days before 

 wearing off size or breaking. For soft steels a - 

 carat diamond can be used where a J-carat would 

 do for copper, and for hard, high-carbon steel a 

 2-carat diamond is not too large for No. 32. At 

 sizes a little larger than No. 32 the usefulness 

 of the diamond for drawing steel wire ceases, as 

 it is so much cheaper to draw in steel dies that the 

 latter are always used, and the diamond would 

 not be used even for drawing fine steel wires were 

 it not for the great exactness in gage and round- 

 ness that is required for some wires. 



One operator can draw from 10,000 pounds of 

 i-inch- to 1-inch-diameter steel wire. This is 

 frequently drawn in straight lengths of 50 or 75 

 feet, on a long draw-bench, on account of the 

 difficulty of coiling wire 1 inch in diameter or 

 near that. A |-inch rod is always drawn in coil, 

 and an operator can take care of but one draw- 

 ing-block, as there is but 266 feet to 100 pounds 

 at this size, and this length being quickly drawn, 



the time of the wire-drawer is taken up in caring- 

 for successive coils of rods and wire. At Nos. 8 

 to 12 wire three blocks can be cared for by one 

 wire-drawer, as the lengths are longer, there be- 

 ing 3,369 feet of wire in 100 pounds at No. 12, 

 but the production per operator is reduced to 

 5,000 pounds a day, owing to the increased length 

 of wire per pound. The rods are in 24- or 36-inch 

 coils, and the large-size wires in 22-inch coil.. 

 At No. 14 the diameter of the coil is reduced to 

 16 inches, and at No. 20 to 8 inches. With these 

 8-inch coils, at Nos. 20 to 32, one man can easily 

 take care of 30 drawing-blocks, and in some 

 mills more, but there is a great length of wire 

 per pound, and the coil of wire on each block has 

 to be changed only once or twice daily. The 

 weight of the coil of wire by the time it has been 

 drawn to No. 32 is reduced to 5 to 15 pounds, 

 which is all that can be conveniently handled by 

 present processes, as there is at No. 32 about 2,288 

 feet in 1 pound of wire. 



For the small sizes there is another method of 

 drawing known as continuous wire-drawing, by 

 which the wire is drawn through 5 to 10 dies, 

 with a roll or winding-block between each 2 dies,, 

 before being finally wound on the coiling-drum. 

 Steel wires are successfully drawn on these ma- 

 chines at Nos. 30 and finer, and can be drawn as 

 coarse as No. 20, or larger, but progress is being 

 made very slowly in this direction. For softer 

 metals, like copper, the continuous wire-drawing 

 machine is a greater success, and not only fine 

 sizes are draw r n, but also sizes as large as ^ inch 

 to No. 12. Although the production of wire by 

 one operator daily is larger than by the ordinary 

 method, the difference is not so great as might at 

 first appear. Where a wire-drawer takes care of 

 30 ordinary blocks for drawing fine steel wire, 

 he will by the continuous method have the charge 

 of 2 machines, with 5 to 10 blocks on each ma- 

 chine. For drawing special wires, like music-wire, 

 where there is more care and expense in manu- 

 facturing, and the wire-dra'wer not allowed more 

 than three or four blocks, if the continuous plan 

 can be used, the difference in production is more 

 in favor of the continuous wire-drawing, yet for 

 such very hard steel as music-wire only the finest 

 sizes, that are used for guitars and mandolins, are 

 made in this w r ay. 



Progress in manufacturing is being made in all 

 processes. The greatest necessity is felt for doing 

 away with the sulfuric- and muriatic-acid clean- 

 ing processes for steel wire, and experiments are 

 being made to attain this. The speed at which 

 wire can be drawn appears for the present to have 

 reached its limit for steel at 40 to 60 revolutions 

 a minute for No. 12 to 20 wire, the large size in 

 22-inch diameter coil, and the small size in 8-inch 

 coil, as at faster speed the wire is likely to have a 

 scratched surface and to break; but for copper 

 wire there is little doubt that much higher speeds 

 can be obtained. 



The demand for all descriptions of wire con- 

 tinues to increase. For trolley and telephone pur- 

 poses, copper wire is always used where possible; 

 but where greater tensile strength is required steel 

 is used for telegraph and telephone lines. There is 

 a demand for a stronger wire than copper that 

 will have nearly the same electrical conductivity, 

 but experiments to produce such a wire with al- 

 loyed copper have not been sufficiently successful 

 to warrant its use in large quantities. Silicon 

 bronze for the same use is much more popular in 

 Europe than in the United States. In steel, 

 barbed-wire fencing is not sold in the Western 

 States so much to the exclusion of other fencing 

 as was the case a few years ago, but there is a 



