2a thread class right-hand 0.310" thread length flat countersunk head style 40 thread quantity per inch cadmium screw surface treated unc thread series
3a thread class right-hand 0.420" thread length button head style 40 thread quantity per inch navy special project cadmium surface treated unrc thread series
3a thread class right-hand 0.569" thread length dished hexagon head style 1.115" grip length 20 thread quantity per inch cadmium surface treated unjf thread series