MEASUREMENTS 



285 



instance, is arranged in a dynamometric support such as that 

 shown on fig. 183, which is self-explanatory. The vertical pres- 

 sure on the vice is thus registered. The special attachments for 

 the file (fig. 184) allow the registration of the effort of the right 



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Dynamometric attachments for file. 



hand on the handle (the horizontal component) and that of the 

 left hand (see 311). 



The dynamometric support, placed in the vice, gives the 

 vertical pressure of the two hands necessary to cause the file to 

 bite. 



The spring attachments give the pressure of the left hand at 

 A and the horizontal component at B (fig. 185) ; also the hori- 

 zontal component of the right hand at C. (fig. 184) . Ball bearings 

 reduce the friction, and the strength of the springs is adjusted to 

 suit the nature of the work. 



