Countersunk Square Holes for Cutting Edges and End Bits(STABILIZED Oct 2011)
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 defined in SAE J737, J739 and J1304.
End bits are further defined in SAE J63.
When section thickness exceeds A in drawing 1 (Figure 2) (countersunk one side) or B in drawing 4 (countersunk both sides), use counterbore with diameter D, as shown in cross section drawings 2, 5 and 6, or extended countersink C, as shown in cross section drawings 3 and 7.
The inscribed circle of the square holes shall be concentric with countersink or counterbore within 0.03 in (0.8 mm).