Fig. 60.—Chain Making.
80. Chain Making.—[Fig. 60]. Bending, scarfing, and welding links. Material required: 8 pieces of 3⁄8-inch round iron, 6 inches long.
Heat and bend the center of each piece to a semicircle 3⁄4 inch inside diameter; make the ends of equal length and parallel from the semicircle, as at a. Take one of these bent pieces and form a scarf on one end by holding it on the edge of the anvil at an angle of 45 degrees, as shown at b, and delivering overhanging blows, as indicated by the dotted circle, which represents the hammer. Turn the link over, placing the other end in the same position as the first, and scarf. Bend both scarfs toward each other equally until they overlap sufficiently to prevent any opening being formed, as at c; this is called closing the scarf.
Heat and weld the link by delivering the first few blows on its sides while it is resting on the face of the anvil, then by delivering lighter ones, while it is hung on the horn. While striking the light blows, do not hold the link in a fixed position, but move it to receive the blows around the circumference. The finished dimensions are 2 × 3⁄4 inches inside; a slight variation in length does not make any difference, but their ends and widths should be uniform.
Proceed with another piece in like manner, but after scarfing it insert the finished link and continue adding new ones, until there are five links all together. The three extra pieces are for use in the next three exercises.
81. Welded Ring.—[Fig. 61]. Bending, scarfing, and welding a ring of round iron. Material required: one piece of 7⁄16-inch round iron, 8 inches long.
Fig. 61.—Steps in Making a Ring.
Heat, and bend over the horn of the anvil about 11⁄2 inches of each end to an inside radius of no less than 1 inch, as at A. Then heat the straight portion to a uniform temperature and bend it by holding the piece in a vertical position on the anvil, and delivering upright blows, as shown at B; this should produce a form similar to that shown at C. Continue the bending by holding the work as at D. By carefully observing the effect of these blows, you will be able to determine how the work ought to be held to produce the complete ring. These blows are used here to give the same effect as leverage blows. If the position of the metal is changed when and where it should be, almost a perfect ring may be produced without holding it on the horn of the anvil. It is not the best method to hold the work on the horn, because blows delivered in this way have a tendency to produce oval sections where they hit. In forming this ring the ends should be left open about 1 inch.
The directions for scarfing and welding are somewhat similar to those given for links, except that the angle of the scarf should be nearly a right angle. After the welding is completed, the ring should be made perfectly round by placing it over a mandrel or the horn of the anvil. When the ring is welded and complete, connect it to the chain with one of the extra links.