Abstract: A locking pipe sub is disclosed including a threaded pin connection for engaging, for example, a pipe stuck in a well bore. The threads on the pin are formed in two sections which are adapted to align upon initial make-up of the sub to the stuck pipe, but to misalign, both axially and radially, when reverse torque is applied to the sub. The result is to create axial and radial forces between the threads of the sub and the threads of the stuck pipe which positively lock the sub against disconnection from the pipe except with the use of a releasing tool.

Abstract: A threaded bolt has two elongated shank parts, the adjoining part ends having mating, stepped shapes. The shank parts when held and rotated in unison can be threaded in a piece such as a nut, but when not so held will frictionally bind in the threads of the piece. A keyway is provided through the shank parts to receive a key for rotating the parts in unison, preventing relative rotational movement therebetween, so that the nut and shank parts may be freely threadingly rotated in the aforesaid piece.