Used on c-130j-30 aircraft flight controls. 3b thread class right-hand 18 thread quantity per inch nut, hexagon, castellated captive washer, nylon inser, 250 deg f 8opposite slots must coincide within 0.005 cadmium nut surface treated
20 thread quantity per inch zinc plated, low strength steel nut for light duty applications; stamped from 0.03" to 0.06" thick steel; class 2b thread fit zinc surface treated