Abstract: An electronic control system is programmed to control movement of a cutting tool relative to a rotating workpiece. After engagement of the stock, the tool is controlled to follow a curved path until the cutting surface of the tool reaches a predetermined depth of cut in the stock. The tool is then controlled to follow a straight/linear path, with the cutting surface of the tool engaged with the stock at said predetermined depth of cut. The control system varies the feed rate as the tool rolls into cut along a known path of curvature, to control the thickness of the material which is removed as the tool rolls into cut, e.g. to induce fracture as the material begins to coil. The feed rate as the tool rolls into cut is programmed to vary in relation to an arc of engagement between a cutting surface of the cutting tool and the stock into which the cutting tool is being moved.

Abstract: An electronic control system is programmed to control movement of a cutting tool relative to a rotating workpiece. After engagement of the stock, the tool is controlled to follow a curved path until the cutting surface of the tool reaches a predetermined depth of cut in the stock. The tool is then controlled to follow a straight/linear path, with the cutting surface of the tool engaged with the stock at said predetermined depth of cut. The control system varies the feed rate as the tool rolls into cut along a known path of curvature, to control the thickness of the material which is removed as the tool rolls into cut, e.g. to induce fracture as the material begins to coil. The feed rate as the tool rolls into cut is programmed to vary in relation to an arc of engagement between a cutting surface of the cutting tool and the stock into which the cutting tool is being moved.

Abstract: For cutting a facing such a countersink or a spot facing a rotary cutter is provided with a body having a central aperture arranged to receive a drill or other guide and at least one cutting insert carried by the body rotates with the drill or guide to cut the facing. The insert has a forward cutting edge which projects radially inwardly to form a step projecting inwards relative to the main body of the insert behind the cutting edge region. The drill has a radially recessed portion, such as the radial relief or the flute of the drill, to accommodate said step of the cutting edge region. Such a cutter can be designed to operate at high metal removal rates and can be used with standard forms of drill and reamer.

Abstract: The solid metal to be melted is placed on a support, within an induction coil which is adapted to provide a greater electromagnetic force towards the lower portion of the quantity of metal. When energy is provided to the coil, the metal melts from the top downward, but the concentration of electromagnetic force towards the bottom of the metal causes the liquid metal to retain a cylindrical shape. When most of the metal is melted, the liquid metal passes through an opening in the support. In a preferred embodiment, the coil is movable relative to the quantity of metal, and at the beginning of the melting process only the top portion of the quantity of metal is disposed within the coil. As the quantity of metal melts, the coil is moved downward. The method may also be used for removing impurities from the quantity of metal.