Patent ID: 7165923

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 radially extending 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 a the cylindrical member; wherein the operation member is rotatable so as to adjust the force that the ball element applies to the cylindrical member to thereby elastically deform a base end portion of the tool attaching portion in such a manner that tip run-out of the tool approaches zero.