Used on aircraft. 3a thread class right-hand 0.781" err default 1.000" overall length cadmium or zinc surface treated round slotted, external thread, boss
3a thread class right-hand 0.500" err default 1.188" overall length head slot 0.188 in. deep followed by a 0.188 in. deep 30 deg seat int round slotted, external thread, boss
3b thread class right-hand 1.375" err default 0.313" hole diameter 2.625" overall length tapped for setscrew 1/4 in. 20 thd located on periphery 5/16 in. on threaded end round, internal thread, shouldered
3a thread class right-hand 0.437" err default 1.050" overall length radius on shoulders 0.093 in. min to 0.109 in. max round slotted, external thread, boss