3a thread class right-hand 0.500" thread length 0.500" overall length 8 slots 5/32 in. w by 1/8 in. deep spaced 45 deg apart round slotted, external thread, boss
3b thread class right-hand 0.500" thread length 1.000" overall length smallest od on bottom of nut 47/64 in. 1/4 in. lg hexagon, external thread, inverted flare