US Patent 7300233 Shaft tool and associated coolant/lubricant feeding point

A shaft tool with a machining section and a cylindrical shaft which comprises at least one internal coolant/lubricant duct which on its end facing away from the machining section comprises at least one orifice, wherein the shaft forms a conical fitting surface that encloses the orifice. A device comprising a shaft tool and a connection piece, the connection piece comprising a centric coolant/lubricant supply duct which exits in an apex region of an inner cone which accommodates in a positive-locking manner the conical fitting surface of the shaft tool, the conical fitting surface facing the inner cone.