Tapco Inc. offers the Ref 70 style bolt for use in heavy-duty applications. The bolt accompanies the existing styles: No. 1 Norway Flat Countersunk, No. 3 Eclipse (slotted), Fanged, Pointed End Fanged and Western 3-Prong. It is employed on pulleys more than 20 inches in diameter and is strongest when coupled with an oval washer.
