Patent ID: 7156589

Claim:
A tool holder of a machine tool, comprising: a holder body; a tool receiving surface part for receiving a rear end face of a shaft-like tool so as to form an internal space bounded on one side by the rear end face, said shaft-like tool being fixed on a front end of the holder body and having one or more passages for leading mist cutting fluid from the internal space to a front end face of the shaft-like tool; and mist cutting fluid passages for leading mist cutting fluid fed from a front end part of a spindle to the internal space; wherein an exhaust passage is formed for opening the internal space to the atmosphere, said exhaust passage being in addition to said one or more passages of the shaft-like tool in communication with the space, the internal space being closed on the side bounded by the rear end face of the shaft-like tool except for said one or more passages of the shaft-like tool.