O/a w across flats 0.554 to 0.564 in.; o/a h 0.530 to 0.550 in.; 2 holes 0.045 to 0.055 in. Diameter bore through 0.450 in. C to c; holes 0.140 to 0.160 in. From outer edge; spherical head 0.203 to0.234 in.; internal bore diameter 0.269 to 0.275 to lg 0.250 in.Threaded 0.312-24 nf 3b; 90 degrees countersink to 0.320 to 0.360 in; matl steel ams 4120