Countersunk Square Holes for Cutting Edges and End Bits
This standard specifies the principal shapes and dimensions for countersunk square holes. To be used on cutting edges and end bits in conjunction with No. 3 head plow bolts (Ref. ANSI B18.9) typically used on off-road self-propelled work machines as described in SAE J1116. Cutting edges are further in SAE J737, J739 and J1304. End bits are further defined in SAE J63.