Steel, aisi 1137-1141, rockwell hardness 30-37, 3.172 in. Lg o/a, 9/16-18 unf 2a thd end, 0.391 in. Thd lg, 0.652 in. @hex wrenching flats at thd end, second set of thds at other end of wrenching flats, 0.500 in. Thd lg, 0.490 in. Stem od, 0.086 in. Kia of fitting hole