3a thread class right-hand 0.370" thread length flat countersunk head style 0.240" grip length 28 thread quantity per inch passivate surface treated unjf thread series
Used on b-1b acft. flush (flat) countersunk (included angle - less than 135 deg w or w/o chamfer) head style 0.655" grip length aluminum sleeve surface treated
Used on B52H. 3a thread class right-hand 0.733" thread length double hexagon extended washer head style 3.150" grip length 20 thread quantity per inch cadmium surface treated unjf thread series
Used on b1b acft. flush (flat) countersunk (included angle - less than 135 deg w or w/o chamfer) head style 0.405" grip length aluminum sleeve surface treated