Patent ID: 8708623

Claim:
An angle tool holder attached in an exchangeable manner to an attachment unit for five-face machining having a ring-shaped cylinder member fit to an outer circumference of a spindle housing supporting a spindle and protruded from a lower end of a spindle head of a vertical machining center and thereby secured to the spindle head, a clamp unit directly connected to a ring-shaped piston disposed within the ring-shaped cylinder member and moved vertically, and four collet chucks disposed at even angular intervals on a circumference on a lower side of the clamp unit, wherein the angle tool holder comprises a shank inserted to the spindle of the vertical machining center, a housing supporting the shank and an angle tool in a rotatable manner and having in the interior thereof a transmission mechanism for converting a drive force of the shank to an orthogonal direction and transmitting the same to the angle tool, an arm connected to the housing, and three pull stud bolts disposed on the arm and held via three collet chucks out of the four collet chucks disposed on the attachment unit for five-face machining.