54 THE POWER-FORGING OF CHAIN CABLES. 
power-welded links. Yet they were submitted as test triplets by a private manu- 
facturer. The hand-welded triplet No. 2 failed at 364,000 pounds; No. 1, at 390,000 
pounds; but the power-welded triplet, No. 3, went to 532,000 pounds before failure. 
One power-welded triplet went to 586,000 pounds without breaking and was then 
removed from the machine for exhibition (Figs. 1 to 7, Plates 35 to 38, inclusive). 
DEFICIENCIES OF HAND-WELDED CHAIN. 
The causes of the inferiority of hand-made welds become apparent after ex- 
perience in the testing pit. The helpers cannot hit hard enough with their sledges 
to drive the two scarfs together. The welding surfaces are not smooth, because 
they are formed by peening; pockets are thus formed, which retain slag; and the 
hammering does not work out this slag. Thus the weld is incomplete. Sometimes 
a pocket as big as a half-dollar is found, occasionally open to the sea by a small crev- 
ice. Fractures have been produced in proofing old chain which showed that not over 
10 per cent of the surfaces was welded; only the strength due to form, assisted by the 
tacking together of the scarfs, had held those links intact in service. 
In the large chain it was impossible to finish the inside of the link at the welded 
end, thus leaving a hollow and reducing the sectional area. 
Another serious defect in the hand-welded chain is the wasting of the material, 
in the fire, just back of the weld. There is no way to make this up, except to in- 
crease (uniformly) the diameter of the metal in order to have the full diameter in 
this quarter. In the power-forged link, however, the metal is upset slightly before 
scarfing, completely avoiding this deficiency. 
To sum up, the hand-made welds are not complete, not uniform, and not 
reliable. 
As stated above, the need of a power-forging process had been foreseen at the 
Boston Navy Yard.. Naval Constructor E. F. Eggert, United States Navy, had 
some years ago prevailed upon the master shipsmith, Mr. William Paul, to attempt 
the development, with the results given in Assistant Naval Constructor Otterson’s 
paper. 
The first attempt was made with a Bradley helve hammer, because that hammer 
hits a rapid, elastic blow, which appeared to simulate the blows of the hand sledge. 
That method was found impracticable, and resort was then had to ordinary steam 
hammers. All the experiments had been made on the 3-inch size, and at the time 
referred to there were available the dies that had been made for the purpose. Briefly, 
the process consisted of shearing the bolt to length as usual for the hand-welders, in 
a large power shears; bending up the end of the bolt in a 6-inch Ajax upsetting 
machine; putting on the scarf in a 2,500-pound steam drop hammer; bending the link 
by hand around a mandrel; welding the link under a 350-pound single-frame steam- 
forging hammer; and then, in another heat, finishing the link under dies fitted to 
a 3,000-pound double-frame forging hammer ; trimming off the “flash” by hand. 
While this process made chain that looked good, it would not meet the breaking 
stress requirements. 
