We had 100 pieces of these custom double thread hardened turnbuckle studs produced for our customer in 4140 steel material, hardened to 45-48 HRC. Local induction heat hardening was performed at the longer hex key, targeting 53-57 HRC. 3/8-24 UNJF 2A thread was rolled with right hand thread on one side and left hand thread on the other. Overall length was to be between 10.33" and 10.38", with the unthreaded portion diameter between .345" and .375".