Abstract: A variable length tool in the form of a socket extension, screwdriver or other type of tool or tool holder which includes an externally threaded adjustable shaft having an unthreaded portion to prevent removal of the adjustable shaft from the tool. The body of the tool or tool holder is broached only at the end having an adjustment nut or screw for ease of manufacture and to enable some flexing and bending to a slight degree to eliminate critical alignment problems. In some instances, an adapter having a shear-type retaining pin is provided for over torque protection. The adjustment nut or screw is attached to the body of the tool or tool holder by rolling a portion thereof into an angled groove in the body to form a permanent connection and eliminating the need for a retaining ring and angled surfaces are provided between the tool holder or tool and the interior of the adjustment nut or screw to provide larger bearing surfaces and ease of alignment.

Abstract: A variable-length tool holder having a shank assembly including a hollow shank into which a shaft is adjustably inserted. Mounted on the shaft is a bit holder for retaining a tool bit on the shank assembly. The hollow shank forms a hole having a non-circular cross section, with the shaft also having a non-circular cross section and mating in the cross section of the hole of the shank for rotating with the shank. External screw threads are cut into the shaft for threadedly engaging with the internal screw threads of a nut rotatably attached to the shank in order to permit axial movement of the shaft relative to the shank by rotation of the nut.