3b thread class right-hand 28 thread quantity per inch round castellation, 0.090 in. h, 0.308 in. dia w/6 equally spaced slots 0.065 in. min 0.075 in. max w 0.90 in. depth cadmium surface treated
3b thread class right-hand 36 thread quantity per inch upper threaded portiondeformed elliptically to produce self-locking action silver surface treated