Patent ID: 6971825

Claim:
A tool holder apparatus comprising: an elongated spindle adapted to be rotated about a turning axis, and having an internally tapered opening at one end thereof connected to an internally threaded bore formed along said turning axis; an elongated tool holder having a first end for supporting a cutting tool in a cutting position, and an externally tapered shank complementary to and receivable in the tapered opening of the spindle; the tool holder having a threaded bore with a threaded section opening to the end opposite the cutting position of a tool; the tool holder having a radially expandable collar adjacent said shank and joined to said shank; the threaded bore of the tool holder and the internally threaded bore of the spindle having opposite hand threads; a screw having a first externally threaded section threadably receivable in the internally threaded bore of the spindle, and a second externally threaded section threadably receivable in the threaded bore of the tool holder, such that as the screw is turned in a first direction about said turning axis, the tool holder is moved toward the spindle and as the screw is turned in the opposite direction, the tool holder is moved away from the spindle camming structure on the screw engageable with the radially expandable collar of the tool holder to expand the radially expandable collar thereof to engage and wedge the tool holder radially expandable collar in the spindle opening for a cutting motion.