Glossary Terms

Number related to the height of rebound of a diamond-tipped hammer dropped on the material to be tested. Hardness measured on the Model C Scleroscope is expressed as a 2-digit number followed by the letters HSc, and hardness measured on the Model D Scleroscope is expressed as a 2-digit number followed by the letters HSd.

Dynamic hardness test using a calibrated instrument that drops a diamond-tipped hammer from a fixed height onto the surface of the material being tested. The height of rebound of the hammer is a measure of the hardness of the material. The result is expressed as the Scleroscope hardness number.

Water-based chemical solution that contains some oil. See synthetic cutting fluid.

Heat-treatment, whether accidental, intentional or incidental (as during welding), that causes precipitation of constituents at grain boundaries, often causing the alloy to become susceptible to intergranular corrosion or intergranular stress-corrosion cracking.

Refers to control of motion. Applied to the industrial robot, it describes automatic feedback, or “closed-loop,” operation in which sensing devices monitor movement and report any deviation between commands as issued and movement as monitored. Deviations trigger corrective action. Robots without servocontrol may be “open-loop” but most often are controlled by preset mechanical or electric stop-switches.

Control mechanism in a machine tool to feed the cutting tool into the part and slow or speed up the drive motors as required.

Main body of a tool; the portion of a drill or similar end-held tool that fits into a collet, chuck or similar mounting device.

Single-point tool that traverses the workpiece in a reciprocating fashion to machine a desired shape.

Using a shaper primarily to produce flat surfaces in horizontal, vertical or angular planes. It can also include the machining of curved surfaces, helixes, serrations and special work involving odd and irregular shapes. Often used for prototype or short-run manufacturing to eliminate the need for expensive special tooling or processes.

Narrow, slanting ridge along the edge of a fracture surface. Term sometimes also denotes a narrow, often crescent-shaped, fibrous region at the edge of a fracture that is otherwise of the cleavage type, even though this fibrous region is in the same plane as the rest of the fracture surface.

Plane along which the chip parts from the workpiece. In orthogonal cutting, most of the energy is used to create the shear plane.

Stress required to produce fracture in the plane of cross section, the conditions of loading being such that the directions of force and of resistance are parallel and opposite although their paths are offset a specified minimum amount. The maximum load divided by the original cross-sectional area of a section separated by shear.