170 



sm:\i:L\<; TACKLE. 



of pounds. It will be noticed that the ratios obtained are 

 somewhat lower than the one which is often quoted, 

 namely 0'80, being most frequently in the. neighbourhood 

 of 075. At the same time this ratio is variable over a 

 limited range. It will be noticed that for each metal, 

 bar> of smaller diameter give the larger ratios. This result 

 is curious and cannot be accounted for by the bending 



TABLE. COMPARISON OK SHEARING AND TKNSILK STRENGTHS OF 

 RIVET MATERIAL. 



effect produced, because this would have the opposite 

 tendency, and give a lower shearing strength for the smaller 

 bars. Ihe author of the paper in which the experiments 

 are described suggests that the lower shearing strength of 

 the larger bars is probably due to the fact that the bearing 

 stress must be greater in this case, greater indentation is 

 produced, and probably this leads to the shearing taking 

 place at lower loads. 



101. Choice of Shearing Tackle. Some difficulty may 

 be experienced in choosing a suitable form of apparatus for 

 the purpose of carrying out shearing tests. In any shear- 



