Shrink fit tool holder

A shrink fit tool holder comprising a shank portion which can be detachably mounted to a machine tool, and a chuck portion configured to hold a cutting tool by shrink fitting and formed with a cylindrical retaining bore, wherein the cutting tool comprises a columnar insert portion which can be inserted into the retaining bore and has an outer peripheral surface formed with a flat surface lying on a plane extending in an axial direction of the cutting tool, and extending from a distal end of the insert portion of the cutting tool, and with a groove continuous with the flat surface and extending in a circumferential direction of the cutting tool,

• wherein an anti-pull-out protrusion and an anti-rotation protrusion are provided on an inner wall of the retaining bore with the anti-pull-out protrusion spaced from the anti-rotation protrusion in the axial direction of the cutting tool,
• wherein the tool holder A is configured such that when the cutting tool is inserted into the retaining bore, the anti-pull-out protrusion can pass through a space defined between the flat surface and the inner wall of the retaining bore and can be received in the groove, and when, thereafter, the cutting tool is turned about an axis of the cutting tool relative to the chuck portion, the anti-pull-out protrusion moves in a length direction of the groove until the anti-pull-out protrusion engages side edges of the groove, thereby preventing the cutting tool from being pulled out of the chuck portion, and
• wherein the tool holder is further configured such that when the anti-pull-out protrusion is received in the groove, the anti-rotation protrusion is located in the space, and when, thereafter, the cutting tool is turned about the axis of the cutting tool relative to the chuck portion, the anti-rotation protrusion is received between the flat surface and the inner wall of the retaining bore at one end of the space, thereby preventing rotation of the cutting tool relative to the chuck portion.