3a thread class right-hand 0.234" thread length 0.336" overall length first thd chamfer to 0.375 dia, end chamfer 45.0 deg by 0.016 in. zinc or cadmium surface treated hexagon, external thread, boss
3a thread class right-hand 0.364" thread length 0.564" overall length two holes drilled thru drive end 0.300 in.from center of nut to center of hole, 0.057 in.min, 0.062 in.max dia hole; used on grumman aircraft, model A10 hexagon, external thread, inverted flare
2a thread class right-hand 0.235" thread length 0.625" overall length paint under side of hex head in accordance w/mil spec mil-p-15128 formula 5nb hexagon, external thread, inverted flare