2a thread class right-hand 0.210" thread length flat countersunk head style 56 thread quantity per inch cadmium screw surface treated unc thread series
2a thread class right-hand 0.074" thread length flat countersunk undercut head style 56 thread quantity per inch zinc screw surface treated unc thread series
2a thread class right-hand 0.580" thread length flat chamfer head style 14 thread quantity per inch end has 0.094 in. spherical radius point, 60.0 deg angle 0.275 in. lg unc thread series
2a thread class right-hand 0.428" thread length flat chamfer head style 20 thread quantity per inch std point style no. 16 with 0.170 in. dia extends 0.125 in. beyond the thd end of fastener passivate surface treated unc thread series
3a thread class right-hand 0.823" thread length round w/wrench flats head style 18 thread quantity per inch circumferential groove 0.140 in. wide, 1.946 from bearing surface of head carburized to rockwell c scale 50 to 60 hardness phosphate manganese or phosphate zinc surface treated unf thread series