THE TESTING OF CHAINS. 



The writer has found the alloy of equal parts of lead 

 and tin, by weight, melting at 370 deg., to be a convenient 

 mixture. When an alloy is used, a mercury thermometer 

 may be used for the temperatures, the thermometer being 

 kept in the fluid metal, and the temperature noted 

 frequently, and at various points. Care must be taken 

 that the metal is not allowed to solidify when the 

 thermometer is in it. 



THE TESTING OF CHAINS. 



142. In no branch of engineering constructive work is 

 careful and thorough testing of more importance than in 

 the case of chains. This is due partly to the fact that in 

 many cases the failure of a chain may be attended with 

 injury to, or loss of, human life, and also because chains, 



FIG. 132 Short Link Chain. 



are made up of a number of separate parts, each of which 

 contains a joint, and the fracture of any one of these 

 separate pieces will probably cause the failure of the 

 whole chain. The kind of chain which is most frequently 

 used for haulage and lifting purposes is the ordinary 

 " short link " iron welded chain ; a sketch of one of the 

 links of a chain of this kind is shown on Fig. 132. The 





FIG. 133. Long Link Chain. 



proportions of these links are as follow : The total outside 

 length is four and a half times the diameter of the iron 

 forming the link, and the greatest outside width is three 

 and a quarter times the diameter. There is also the long 

 link chain, shown in Fig. 133. For some purposes the 



