3a thread class right-hand 0.389" thread length undercut hexagon head style 0.188" grip length 28 thread quantity per inch cadmium surface treated unjf thread series
3b thread class right-hand 32 thread quantity per inch insert, screw thread 2 slots 180 degrees apart 0.093 wide in top; t thread class mil s 8879 cadmium nut surface treated flange unjc thread series