166 NOTES ON CHAIN CABLES. 



never worked at an oil fire. They further had at their coke fire facilities that 

 they were accustomed to and used every day, whereas at the oil fire they were in 

 a strange shop with facilities to which they were not accustomed, particularly in the 

 matter of handling the links from the fire to the anvil, which was done by means 

 of the traveling crane. A good weld depends largely upon the time between leav- 

 ing the fire and striking the first blow, as oxidation is going on all the time and 

 heat being lost. 



The effect of this is shown to a more marked degree in the following table, 

 showing a comparison of coke- and oil- welded, machine- formed and scarfed links: 



Location of Break. 

 Cw — Pulled out welded crown. 

 W<^ — With and across weld. 

 Wc — With and across weld. 

 Wc — With and across weld. 

 Cw — Pulled out welded crown. 



Average. 



Location of Break. 

 Qo — Quarter opposite weld. 

 Co — Pulled crown opposite weld. 

 Ws. — Across weld. 

 Qo — Quarter opposite weld. 

 IVc — ^With and across weld. 



Average. 



The first break in the oil fire is 568,160 pounds, and this doublet was made 

 with the regular operator in charge of the crane, who was able to move the crane 

 out and down at the same time and so get the link on the anvil promptly. The 

 other breaks are low and were made with an inexperienced operator in charge of 

 the crane, who was able to jnove the crane in but one direction at a time, and so was 

 slow in getting the link on the anvil. This difference in rapidity of handling ap- 

 pears entirely responsible for the difference in results. 



Forming. — In the description of hand-made chain above, the method now em- 

 ployed for forming the links was outlined. In the case of the "machine-made" 

 chain, the links are formed by winding cold on the mandrel, very much as springs 

 are wound (see Fig. 19, Plate 97). The links are then cut from the spiral coil thus 

 formed by shearing each turn of the coil diagonally along the line of the scarf 

 (see Fig. 19 A, Plate 97), the shearing blade operating also to open the link suf- 

 ficient to permit of its being rove into the chain. This process bruises the material 



