Used on aircraft, phantom f-4; low altitute navigation & targeting infrared system (lantrin); aircraft, hercules c-130; milstar system; f414 engine (f/a-18 f& g aircraft); aircraft, ac-130h, mc-130h, ec-130e, hc-130; helicopter, mh-53e; helicopter, advance attack, ah-1w; aircraft, stratolifter c-135; aircraft, stratofortress b-52. universal head style 0.313" grip length ns" letters after the material code "b" indicate no preference to lock type (may be visible or internal) . rivets with no letter code (indicating visible lock type) chromate sleeve surface treated
2a thread class right-hand 0.235" thread length flat countersunk head style 32 thread quantity per inch anodize stand-off surface treated unc thread series
2a thread class right-hand 0.160" thread length flat countersunk head style 40 thread quantity per inch cadmium fastener surface treated unc thread series
hexagon extended washer head style extended diameter on threaded end 0.114 min., 0.119 in. max dia by 0.260 in. min., 0.290 in. max lg cadmium surface treated
2a thread class right-hand 0.123" thread length flat countersunk head style 56 thread quantity per inch passivate screw surface treated unc thread series
3a thread class right-hand 1.242" thread length hexagon head style 0.688" grip length 18 thread quantity per inch passivate surface treated unjf thread series