Glossary Terms

Crystal manufactured from boron nitride under high pressure and temperature. Used to cut hard-to-machine ferrous and nickel-base materials up to 70 HRC. Second hardest material after diamond. See superabrasive tools.

Arrangement of multiple nozzles that apply fluid to a broad cutting area, as is found on a horizontal, post-type band machine or a large hacksaw.

Step that prepares a slug, blank or other workpiece for machining or other processing by separating it from the original stock. Performed on lathes, chucking machines, automatic screw machines and other turning machines. Also performed on milling machines, machining centers with slitting saws and sawing machines with cold (circular) saws, hacksaws, bandsaws or abrasive cutoff saws.

Blade mounted on a shank or arbor and held in a milling-machine spindle for simple cutoff tasks.

Rotating cutting wheel that cuts bar stock, pipe, etc., to a desired length.

Feature that allows the operator to compensate for tool diameter, length, deflection and radius during a programmed machining cycle.

Liquid used to improve workpiece machinability, enhance tool life, flush out chips and machining debris, and cool the workpiece and tool. Three basic types are: straight oils; soluble oils, which emulsify in water; and synthetic fluids, which are water-based chemical solutions having no oil. See coolant; semisynthetic cutting fluid; soluble-oil cutting fluid; synthetic cutting fluid.

Engagement of a tool’s cutting edge with a workpiece generates a cutting force. Such a cutting force combines tangential, feed and radial forces, which can be measured by a dynamometer. Of the three cutting force components, tangential force is the greatest. Tangential force generates torque and accounts for more than 95 percent of the machining power.

Tangential velocity on the surface of the tool or workpiece at the cutting interface. The formula for cutting speed (sfm) is tool diameter 5 0.26 5 spindle speed (rpm). The formula for feed per tooth (fpt) is table feed (ipm)/number of flutes/spindle speed (rpm).

Cutting tool materials include cemented carbides, ceramics, cermets, polycrystalline diamond, polycrystalline cubic boron nitride, some grades of tool steels and high-speed steels. See HSS, high-speed steels; PCBN, polycrystalline cubic boron nitride; PCD, polycrystalline diamond.

Casehardening method that introduces carbon and nitrogen to the workpiece simultaneously.

Grinding operation in which the workpiece is rotated around a fixed axis while the grinding wheel is fed into the outside surface in controlled relation to the axis of rotation. The workpiece is usually cylindrical, but it may be tapered or curvilinear in profile. See centerless grinding; grinding.