304 



STRENGTH OF MATERIALS 



252. Strength of leather and rubber belting. Leather belts are 

 made from tanned oxhide. That portion of the hide that originally 

 covered the back gives the best leather for this purpose. The " flesh 

 side," or side originally next to the animal, wears better when placed 

 in contact with the pulley, while the outside gives the greater 

 adhesion when placed in contact with the pulley. 



Single belts are made from one thickness of leather, the desired 

 length being obtained by cementing or splicing the short lengths cut 

 from the hide. Double belts are made by cementing two thicknesses 

 of the leather together. The strength of good leather varies from 

 600 to 700 Ib. per inch of width, and from one half to two thirds 

 as much when spliced. The following table gives the strength of 

 cemented belt laps as determined by the Watertown Arsenal.* A 

 complete series of tests on helt lacings is also reported i' 1 the same 

 volume, and the student is referred to this report for the results. The 

 allowable stress on a single l.elt i> !n>iu 250 to :;uu lit. per inch 

 of width. 



| E8T8 OF I.KATIM.K m.i.i i\. 



* Watertown Arsenal Report. 1KW. 



t The letter to in the table stands for waterproofed. 



