Glossary Terms

Device having a ring or clamp on one end that slips over the workpiece to be turned; a screw secures the workpiece in place. The dog’s opposite end (tail) fits into a drive plate attached to the machine spindle. See centers; drive plate.

Ferrous alloys in which graphite is present as tiny balls or spherulites. The spheroidal graphite structure is produced by adding one or more elements to the molten metal, among which magnesium and cerium are commercially important.

Fracture characterized by tearing of metal accompanied by appreciable gross plastic deformation and expenditure of considerable energy.

Ability of a material to be bent, formed or stretched without rupturing. Measured by elongation or reduction of area in a tensile test or by other means.

Measure of a machining system’s ability to dampen vibration from a forced input. If the dynamic stiffness of a system is not sufficient to dampen vibration, chatter occurs. See static stiffness; stiffness.

When drilling, a device for measuring the generated torque and axial force (thrust). When milling, a device for measuring the generated torque and feed force. When turning, a device for measuring the tangential, feed and radial forces.

Electromagnetic, nondestructive testing method in which eddy-current flow is induced in the test object. Detects changes in flow caused by variations in the object.

Gage mounted in the spindle of a vertical mill and used, while rotating, to find the center of a part relative to the toolholder.

Conditioning of the cutting edge, such as a honing or chamfering, to make it stronger and less susceptible to chipping. A chamfer is a bevel on the tool’s cutting edge; the angle is measured from the cutting face downward and generally varies from 25° to 45°.

Hand, gripper, toolholder, magnet, spray gun, drill, welding head or other electronic/mechanical device for holding workpieces and/or performing functions.

Maximum stress that a material can sustain without deforming.

Property of a material to deform under stress and recover its original shape and dimensions after release of stress.