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106 and in reasonable time; fortunately, however, the cost is lower for hammer- forged chain. The same requirements as to quality are imposed for hammer- welded chain as for hand-welded chain; and actually are surpassed. The chain is uniform; all links are of the same size, a very. important matter, as_bat- tleship cables are hove over wild cats which grip only a few links. The breaking stress is in excess of require- ments. On some 3-inch chain, open link—that is, without studs—the test triplets from the hand welders’ work broke, on the average, at about 485,000 pounds; the test of hammer-welded chain averaged about 525,000 pounds. In every way, quantity, quality and cost, the hammer welding process has THE MARINE REVIEW This bending operation was first done by hand, as by the old hand meth- ods, but is now done in a hydraulic bull- dozer. The mandrel around which the scarfed bolt is to be warped, is stationary. A collar around its base, carries a stud on which is mounted a flanged wheel. The outside of the collar is toothed, gearing with a toothed sector which is linked to the ram of the bulldozer. Thus when the ram comes forward, the collar is rotated around the mandrel, and there- fore the little flanged wheel, carried on this collar, is moved around like- wise, wrapping the bolt around the mandrel. Then the scarfs are pried apart by a crow bar, that the link may be threaded into the last one made. the result of many months of exper}. mental work. At first, the dies wer built to suit wooden models of the links, and every decision was made by rule of thumb. But after making the process a success, and before going too far with the construction of the dies, the work was put on an engin. eering basis, and could now be put jp a hand book. Recently the designs for the dies for 33-inch chain were completed in the drafting room and sent into the shops; the dies were made and set up in their respective machines; and from the start the new chain was successful. Briefly, the process of welding js as follows. A preheated link jg threaded through the last link made, proved superior to the hand method. In this process, the bar iron is sheared up into bolts, each bolt long enough to make one link. Each bolt is then scarfed at both ends, each scarf requiring three operations. The first operation, done in an upsetting ma- chine, puts in a right-angled bend and at the same time slightly upsets the metal. The second operation, done in a steam drop hammer in the same heat, shapés . the “metal’ “into: ia’ scart; he third operation trims off the flash. When the two ends are thus treated, it is only necessary to bend the bolt into an approximate U-shape, where- upon the right angle bend of the scarf brings the two scarfs close together. BENDING BOLTS FOR MAKING LINKS The scarfing and bending operations are: very “short, soa stock of each size in process is maintained for the welders. To avoid the necessity for the welder to start each weld with a cold link, a pre-heating furnace is provided, from which the welder gets his bent links for welding. The welding process is performed in two heats. Each welding plant -is composed of an 1,800-pound «steam drop hammer, with a 250-pound single frame forging hammer on each side, thus employing two gangs. The two gangs divide the drop hammers _ be- tween them, but each has its own 250-pound hammer, fire and crane. The details of the cranes, hoists and dies, and their relative locations, are and the scarfs pushed together by the dies in the 1,800-pound hammer. The dies of both hammers, and the center of the oil forge, being on the arc of the crane, the new link is swung over to the forge and lowered into the heating chamber. When at welding heat, it is taken out and over to the 250-pound hammer, where it is hammered between the horns of the dies. This operation does the major part of the welding. The link is swung back to the fire for a second welding heat, when it is taken to the forming dies, in the 1,800-pound hammer. There the tips of the scarfs are thoroughly welded, and the link exactly formed, all in 4 few blows. After trimming off the ata = ; {