Abstract: A rotatable cylindrical extension member, and cutting tool incorporating such extension member, provided with a coolant inlet, for alignment with a ring bore, extending inwardly from the peripheral surface of the extension member for directing coolant towards the axis of the extension member when it is coupled to the cutting tool and rotated while coolant is being supplied to the inlet from the ring bore.

Abstract: A tool holder assembly which comprises a tool holder adapted to be connected with a machine spindle for rotation together therewith, a stationary support member for rotatably supporting the tool holder and adapted to be connected to a fixed portion of the machine, a fluid supply circuit defined in the tool holder for the supply of a cutting fluid from an external source thereof towards a fluid discharge passage defined in a machine tool replaceably carried by the tool holder, and a vane-type displacement pump for forcibly pumping the cutting fluid from the fluid supply circuit to the fluid discharge passage in the machine tool for pouring the cutting fluid onto the workpiece being machined by the cutting tool. The displacement pump has its rotor constituted by a portion of the tool holder, and a pump casing constituted by a portion of the stationary support member.