A chuck assembly comprising a mandrel portion including an extending member sized and shaped to hold a workpiece; and a piston including a bore receiving the extending member, the piston mounted for supported movement on and relative to the extending member, the piston moving between a first position and a second position, the first position providing for insertion and removal of the workpiece to and from the extending member, the second position causing gripping force to be applied to the workpiece in at least two locations that are spaced longitudinally along the workpiece to inhibit relative movement between the mandrel and the workpiece.

A machine tool clamping device for releasably holding a tool holder having a tapered shank and a knob protruding from the tapered shank, the clamping device having: a spindle, rotatable about an axis, and having a tapered socket at a lower end thereof and an axial passage, the tapered socket being complementary in shape to the shank of a tool holder. Clamping members are pinned to the spindle and extend into the axial passage, the clamping members being pivotal between a clamped position in which the clamping members clamp the tool holder knob, and an unclamped position in which the clamping members release the tool holder knob. A drawbar is slidable within the spindle axial passage between the clamping members, the drawbar having a surface that acts to pivot the clamping members between the clamped and unclamped positions depending on the position of the drawbar within the axial passage. A spring is arranged between the drawbar and the spindle to bias the drawbar to the clamped position.

A machine tool clamping device for releasably holding a tool holder having a tapered shank and a knob protruding from the tapered shank, the clamping device having: a spindle, rotatable about an axis, and having a tapered socket at a lower end thereof and an axial passage, the tapered socket being complementary in shape to the shank of a tool holder. Clamping members are pinned to the spindle and extend into the axial passage, the clamping members being pivotal between a clamped position in which the clamping members clamp the tool holder knob, and an unclamped position in which the clamping members release the tool holder knob. A drawbar is slidable within the spindle axial passage between the clamping members, the drawbar having a surface that acts to pivot the clamping members between the clamped and unclamped positions depending on the position of the drawbar within the axial passage. A spring is arranged between the drawbar and the spindle to bias the drawbar to the clamped position.

A tool holder, particularly a hand-held power tool holder, is provided for an oscillating and/or rotational drive of at least one insertion tool. The tool holder includes at least one holder-side fastening element that is provided at least substantially for a coupling with the at least one insertion tool. The tool holder also includes at least one bearing unit provided for movably mounting the at least one holder-side fastening element in a movement at least partially deviating from an axial direction. The movement at least partially deviating from the axial direction of the at least one fastening element is provided at least substantially for creating a fastening force in the axial direction.