3a thread class right-hand 0.775" thread length flat countersunk head style 20 thread quantity per inch cadmium or cadmium or chromate surface treated unc thread series
3a thread class right-hand 0.313" thread length oval countersunk head style 0.678" grip length 32 thread quantity per inch internal drive ribbed unjf thread series
3a thread class right-hand 0.372" thread length fillister countersunk head style 0.240" grip length 28 thread quantity per inch passivate surface treated unjf thread series
3a thread class right-hand 0.589" thread length spline extended washer head style 0.050" hole diameter 1.490" grip length 24 thread quantity per inch navy special project passivate surface treated unjf thread series
2a thread class right-hand 0.169" thread length pan no. 2 head style 40 thread quantity per inch passivate screw surface treated with insulator; mylar polyester film (266 degrees f) unc thread series