164 NOTES ON CHAIN CABLES. 



about three minutes, and the scarfs made by hammering down the end of the boh 

 with the peen of the hammer, requiring two minutes. The form of the scarf 

 and the shape of the link, upon completion of this operation, are shown in Fig. i6, 

 Plate 94. The link is then re-heated for final closing in preparatory to making the 

 weld, the heating requiring three minutes, and the work one minute. The welding 

 heat is then taken, requiring two minutes, and the weld is then made, requiring two 

 minutes. The bolt is then re-heated for setting the stud. This heat is not actually 

 required, and the stud should be set with the heat remaining after the weld is 

 made, but the chainmakers are in the habit of taking the additional heat in order 

 to make the work of setting the stud easier. The stud is set by turning the link 

 on its side, and striking so as to close it in, as shown in Fig. 17, Plate 95. This 

 operation requires the heaviest blows struck in making the chain link. 



The making of chain should be considered under the following heads: 



I. — Heating. 6. — Handling the chain. 



2. — Forming. 7. — Heat treatment. 



3. — Scarfing. 8. — Tests. 



4. — Welding. 9. — Arrangement of plant. 

 5. — Setting the stud. 



Heating. — Machine-made chain is heated in oil or gas forges with a number of 

 openings in the top, through which the links are suspended from hooks. As one link 

 is taken out another is put in to take its place, so that there is always a link ready 

 for welding and no time is wasted between links. In some cases the chain- 

 maker manages his own fire, while in others he has a boy to keep his fire "busy." 

 In any case there is not much time lost and little waste motion. The work of 

 these men is a delight to watch. 



Practically all hand-made chain is heated in coke fires. The pre-heating for 

 forming is done in the same fire as the heating for welding. This means that 

 upon completing each link the chainmaker and his gang must wait for the next 

 to heat. In the case of 3-inch chain this means about twelve to fourteen minutes 

 wasted on each link. This time can be saved by installing a central oil-fired pre-heat- 

 ing furnace capable of heating a number of bolts to about 1,700° F. The num- 

 ber of bolts to be heated depends upon the number and output of the chain gangs. 

 The design of such a furnace presents no special difiiculties, and any of the usual 

 types of oil furnaces of proper size will serve. 



With such provision the chainmaker's fire becomes a welding fire solely. 

 There has been some question as to whether welding heats on wrought iron can 

 be obtained in an oil fire as reliably as in a coke fire. Old chainmakers and fore- 

 men favor the coke fire, and are skeptical as regards the oil fire. 



Considerable experimenting along this line has been done at the Boston Navy 

 Yard, and as a result of this I am convinced that satisfactory welds can be made 

 with the oil fire, and believe that in the end it will prove more satisfactory than the 

 coke because of the absence of dirt likely to foul the weld, closer control, more 



