flush (flat) countersunk (included angle - less than 135 deg w or w/o chamfer) head style 0.438" grip length powder blast top of head passivate sleeve surface treated
3a thread class right-hand 0.338" thread length flat countersunk head style 0.365" grip length 32 thread quantity per inch cadmium surface treated unjf thread series
2a thread class right-hand 0.190" thread length flat countersunk head style 32 thread quantity per inch passivate screw surface treated unc thread series
Used on aircraft, stratofortress b-52. aal thread class right-hand 0.910" thread length spline extended washer head style 1.302" grip length 20 thread quantity per inch cadmium surface treated unjf thread series