Used on t-38 acft. flush (flat) countersunk (included angle - less than 135 deg w or w/o chamfer) head style 0.720" grip length original name: fastener cadmium bolt surface treated
3a thread class right-hand 0.566" thread length flat chamfer head style 13 thread quantity per inch threads undercut for relief, 0.154 in. max. width x 0.414 in. max. dia. cadmium surface treated unc thread series
2a thread class right-hand 0.120" thread length flat chamfer head style 40 thread quantity per inch non-magnetic; threads undercut for relief, 0.036 in. wide x 0.086 in. dia.; shoulder undercut for relief, 0.031 in. wide x 0.114 in. dia. unc thread series
3a thread class right-hand 0.323" thread length flat countersunk head style 0.240" grip length 32 thread quantity per inch cadmium surface treated unjf thread series