3a thread class right-hand 0.910" thread length 0.105" hole diameter 20 thread quantity per inch shoulder is 0.8106 inch dia. relief groove between head unf thread series
1a thread class right-hand 0.461" thread length hexagon head style 0.183" hole diameter 20 thread quantity per inch cadmium surface treated unf thread series
2a thread class right-hand 1.346" thread length hexagon head style 0.154" grip length 13 thread quantity per inch silver surface treated unc thread series
3a thread class right-hand 0.750" thread length hexagon head style 0.500" grip length 28 thread quantity per inch passivate surface treated unf thread series
3a thread class right-hand 0.590" thread length hexagon head style 12 thread quantity per inch cadmium threads surface treated concentric hole unthreaded unf thread series