The oil path tool handle (external cooling to internal cooling tool handle) enables the machine tool without internal cooling to realize internal cooling and improve the tool life.

The handle of the oil path cutter (from external cooling to internal cooling tool handle) is suitable for boring and milling machines or rocker drills without internal cooling. The cooling ring is fixed through the retaining rod to make the machine tool realize internal cooling and improve the service life of the cutter.

High speed automatic tool changing oil path tool holder (external cooling to internal cooling tool holder), so that the machining center with only external cooling can realize internal cooling and improve the tool life.