Patent ID: 7320568

Claim:
A tool holder comprising: a holder body having an elastically deformable tool attaching portion adapted to receive a tool; a ring member rotatable about a center axis of the holder body but not movable along the center axis; a cylindrical member adapted to be located adjacent to the ring member; and a force generation mechanism provided in the ring member and adapted to generate a force in a direction substantially parallel to the center axis to actuate the cylindrical member so that the tool attachment portion is elastically deformed in a radial direction perpendicular to the center axis such that tip run-out of the tool approaches zero; wherein the force generation mechanism comprises: an operation member disposed within the ring member, the operation member extending radially through the ring member and being rotatable about a radially extending axis; and a ball element disposed within the ring member and located between the operation member and the holder body or the cylindrical member; wherein the operation member is rotated so as to adjust the force that the ball element applies to the holder body or the cylindrical member, to thereby elastically deform the tool attaching portion in such a manner that tip run-out of the tool approaches zero.