Tool for fastening or loosening threaded couplings for cables

A hand tool for tightening or loosening a threaded cylindrical member relative to a corresponding threaded socket, including a generally rectangular wrench body which contains a generally circular opening for coaxially receiving the cylindrical member, a generally disk-shaped locking cam that is moveably connected with the wrench body for displacement between extended and retracted positions extending within and withdrawn from the circular opening, respectively, thereby clamping the threaded cylindrical member when the locking cam is extended into the circular opening, and a handle member operable when the cam is in the extended position to rotate the wrench body with the cylindrical member clamped thereto relative to the threaded socket.