Steel mil-s-6758 comp 4130, one end 0.750-16 unf 3a thd, other end 0.375-24 unf 3a thd, internal relief through smaller end 1.359 in. Deep by 0.144 in. Dia, 0.141 in. Diameter drilled hole through larger shank, 0.120 in. Diameter drilled hole through smaller shank, 4.547 in. O/a lg