3a thread class right-hand 0.788" thread length hexagon head style 0.046" hole diameter 28 thread quantity per inch aluminum screw surface treated unjf thread series
2a thread class right-hand 0.337" thread length flat countersunk head style 20 thread quantity per inch cadmium or zinc screw surface treated unc thread series
3a thread class right-hand 0.206" thread length flat countersunk head style 32 thread quantity per inch cadmium screw surface treated unjf thread series