Abstract: An end mill tool holder body and a tool suitable for use in a boring mill or any other metal-cutting machine. The tool has a round body with shank to suit the machine tool and a flat, laterally-disposed surface at one end of the body terminating in a shoulder. An axial bore extends through the body and a draw bar in the bore has a pin which extends through an opening in a cutting insert and a nut on the other end of the draw bar clamps the cutting insert against the shoulder, holding it rigidly in position for milling or boring.The inserts are of the throw-away type and are made of precision dimension so that the body and cutting insert can be used in a computerized operation.