2GO 



TESTING OF WIRE. 



provided with a quick return motion in order to save time. 

 The ultimate elongation of a definite length of the wire 

 may be most accurately found by making two marks on 

 the wire at the required distance before the test, and 

 measuring the elongation on the two broken halves when 

 placed together after fracture. Sometimes this is measured 



FIG. 127. 



during the progress of the test by a measuring apparatus 

 supplied with the machine. This particular machine has 

 a maximum capacity of 1 ,000 Ib. A somewhat similar 

 machine by the same maker's is shown on Fig. 127. This 

 machine is made with capacities of 6,000 Ib. and 8,000 Ib., 

 The straining is effected by means of a worm-wheel and 

 screw gear arranged in two speeds, one being 15 times as 



