Patent attributes
In a tool holder, when oil supplied via an oil supply passage and an oil introducing passage reaches an atomizing space, the oil is atomized by an air flow of carrier gas consisting of compressed air, and then water supplied from a water supply passage and a water introducing passage is formed into a water drop in the atomizing space by an air flow of oil containing compressed air to generate the water drop with oil film in which the oil film is formed on a surface of the water drop. Since the water drop with oil film is supplied to a work piece through a top nozzle and an in-tool passage, the water drop with oil film is generated at an extremely close location to a tool, and therefore, responsiveness when supplying the water drop with oil film to the work piece can be enhanced.