MIL-S-21433A, MILITARY SPECIFICATION: SOCKETS, TURNBUCKLES, AND TURNBUCKLE ASSEMBLIES - WIRE ROPE, WEDGE, AND THREADED LOCK SLEEVE (21 JUL 1959)., This specification covers sockets, turnbuckles, and turnbuckle assemblies for making up end connections in wire rope installations as alternates for other wire rope connections.