Used on hgu-56/p aircrew integrated helmet, all sizes. 2a thread class right-hand 0.281" thread length knurled no. 4 head style 40 thread quantity per inch passivate surface treated unc thread series
3a thread class right-hand 0.380" thread length knurled no. 5 head style 32 thread quantity per inch 0.200 in. nom dia by 0.449 in. nom lg boss adjacent to thds passivate surface treated unf thread series
3b thread class right-hand knurled no. 1 head style 0.200" hole diameter 48 thread quantity per inch threaded hole in head 0.190-24 unc-2b unjf thread series
2a thread class right-hand 1.600" thread length knurled no. 1 head style 20 thread quantity per inch enamel semigloss surface treated unc thread series
2a thread class right-hand 1.620" thread length knurled no. 1 head style 18 thread quantity per inch undercut two places .090 in wide .245 in dia. beneath surface of the head un thread series
2a thread class right-hand 0.912" thread length wing no. 2 head style 16 thread quantity per inch undercut beneath the head .303 x .088 in. zinc surface treated unc thread series
3a thread class right-hand 1.250" thread length knurled no. 4 head style 0.069" hole diameter 32 thread quantity per inch 0.045 in. min passivate surface treated unjf thread series
2a thread class right-hand 4.320" thread length flat fillister head style 14 thread quantity per inch hexagon point on end of thread chromium surface treated unf thread series
2a thread class right-hand 0.750" thread length thumb no. 3 head style 24 thread quantity per inch shank hole 0.0620 in. min, 0.065 in.max; 0.085 in. from end unc thread series
2a thread class right-hand 0.645" thread length knurled no. 1 head style 20 thread quantity per inch ball point undercut zinc surface treated unc thread series
2a thread class right-hand 0.440" thread length knurled no. 1 head style 16 thread quantity per inch head chamfered 0.100 in. x 45.0 deg. grip undercut 0.620 in. from fastener end, 0.050 in. wide, porm 0.002 in., undercut dia. 0.3605 in., porm 0.0015 in. passivate surface treated unc thread series
