A note on the width of a good industrial belt...

A belt should be wide enough to bear safely and for a reasonable length of time the greatest tension that will be put on it; this will be the tension T1 of the driving side of the belt. As belts are usually laced, or fastened with metallic fasteners, both of which require holes to be punched in the ends, it is customary to use the breaking strength through the lace holes, divided by a suitable factor of safety, as the greatest allowable tension. The average breaking strength for single leather belts, through the lace holes, is 200 pounds per inch of width. This divided by 3, which is a suitable factor of safety for belting, gives 66 2/3 pounds. Thus, in the last example, the tension of the driving side of the belt was assumed to be 400 pounds. Hence using 66 2/3 pounds as the safe working stress per inch of width, a belt 400 /66 2/3 = 6 inches wide would be required.

And there you have it.

This belt is in use at the Pewabic Pottery in Detroit, Michigan.