2a thread class right-hand 0.634" thread length flat countersunk head style 20 thread quantity per inch navy special project cadmium surface treated unc thread series
3a thread class right-hand 1.062" thread length hexagon head style 4.296" grip length 16 thread quantity per inch passivate surface treated unf thread series
3a thread class right-hand 0.291" thread length flat countersunk head style 28 thread quantity per inch cadmium screw surface treated unjf thread series