270 



THE TESTING OF CHAINS. 



stud-link chain is used. Besides these there are a number 

 of smaller chains, such as the "single jack," "double 

 jack," and the American "Triumph" chain (shown 

 respectively at A, B, and C, Fig. 134), all of which have 

 their special uses. 



B 



FIG. 134. A, Single Jack Chain ; B, Double Jack Chain ; 

 C, "Triumph" Chain. 



The chains which most frequently have to be tested are 

 the ordinary short link Avelded and the long link chains. 

 The tests to which a chain is subjected are as follow : 



(a) Tests require to be made of the material of which 

 the chain is composed, in the form of bars. 

 These tests are simply tension tests carried out 

 in the ordinary way. The results required are 

 the maximum stress, the percentage elongation 

 on a given length, and the reduction in area. 



(6) Breaking tests of a given specified length of the 

 finished chain, often on 36 inches. The 

 measurements taken are the breaking load, and 

 the extension on the given length before fracture 

 occurs. 



