3a thread class right-hand headless (setscrew) head style 28 thread quantity per inch hole through drive end 0.070 min., 0.090 max. from top of drive, 0.046 min., 0.051 max. diameter unf thread series
3a thread class right-hand hexagon head style 32 thread quantity per inch 2 keyways in fastener 0.049 in. w by 0.044 in. dp by 0.545 in. lg, spaced 180 deg apart cadmium surface treated unf thread series