170 NOTES ON CHAIN CABLES. 



In order to avoid these objections it was decided to attempt welding under a 

 steam hammer. As the steam hammer has been used in England for the welding 

 of large sizes of chain, there appeared to be sufficient reason for attempting this. 



The experiments have shown, that its use greatly simplifies the welding of 

 chain and reduces the hand labor to a minimum. There is still some doubt, how- 

 ever, as to whether it will produce satisfactory welds, and upon the experiments 

 to date the conclusion must be that it will not. There are so many interlocking 

 conditions, however, that the difficulty cannot definitely be charged to the hammer. 

 The experiments are being made at the present time to determine this point defi- 

 nitely. The form of dies used in this connection is shown in Figs. 29 and 30, 

 Plate 103. "A" is the impression in the die for welding, and "B" is a backstop for 

 preventing the link from backing out of the welding dies and for supporting the 

 link being welded and the weight of the previous link, thus relieving the chain- 

 maker. The manner in which the link being welded rests in the dies is shown in 

 Fig. 30. 



Setting the Stud. — This operation requires the heaviest blows struck in the 

 process of making a link. In some private plants the chainmakers use a heavier 

 sledge for this purpose. This was tried in the Boston Navy Yard, but the men 

 preferred to use the same sledge as in welding, and this is the practice to-day. 



The most satisfactory way to set the stud is under a hydraulic press with 

 dies so formed as to properly shape the link, removing any deformations that may 

 exist. This will require special equipment in connection with each chain fire or pair 

 of fires. It is desirable, if practicable, to set the stud under the same hammer as 

 is used for welding. This was accomplished in connection with the dies shown in 

 Figs. 29 and 30, by means of the groove "C," shown on the side of the die, which 

 proved exceedingly simple and an easy method for setting the stud. The fact that 

 dies under a large hammer can be adapted to this purpose is an additional reason 

 for the use of such a hammer. 



Handling the Chain. — The present method of handling chain is exceedingly un- 

 satisfactory, the chain hanging from a ring or bail overhead as shown in the illus- 

 tration accompanying description of hand-making process. The importance of 

 suitable handling facilities is frequently overlooked in considering improvements in 

 the chain-making process. 



Experiments have been made at the Boston Navy Yard to develop a crane of 

 suitable design, and two types are being tried out. These are indicated in Figs. 31 

 and 32, Plates 104 and 105, respectively. Both types have certain advantages and 

 are considerably in advance of the crude methods in use at present in connection 

 with the hand-making process. 



Heat Treatment. — It is the practice commercially to anneal chain after it has 

 been in service from six months to a year, but no heat treatment is given immedi- 

 ately after manufacturing. Such heat treatment would appear to be necessary, in 

 that it will refine the grain of the iron, remove stresses due to non-uniform heat- 

 ing and forging, render the product more uniform and improve its physical prop- 



