Section II. DEFINITION OF UNUSUAL TERMS
ABRASION - A roughened surface.
ABRASIVE CLOTH - A cloth coated with grit, used for hand cleaning, polishing, removing corrosion and
paint, etc. Sometimes referred to as emery cloth.
ACCESSORY - A self-contained unit, mounted on a higher assembly, designed to do a specific job. Fuel
pumps, fuel controls and like parts are typical accessories.
ADAPTER - Any device that makes it possible to use parts or pieces of equipment that were not designed
to be used together.
ASSEMBLY - A unit normally removed and reassembled as a single item, consisting of accessories and
components that operate together for a specific purpose. Typical assemblies are: engine, torque sensor
shaft and sleeve assembly, power takeoff assembly.
AVERAGE DIAMETER - A number found by adding several measurements, usually 3 or more, of the
same diameter and dividing the sum by the number of measurements taken.
BACKLASH - A term used to describe the distance that a working part has to move before it moves its
mating part. The motion lost between two connected parts when the direction of motion is changed is
also considered backlash. This loss of motion or looseness, is caused by design tolerances or by the wearing
of working parts (such as clevis pin in rod-end bearing).
BEND - Distortion in a part.
BLENDING - An operation in which surfaces are worked by hand to produce a smooth surface without
abruptly changing its contour.
BREAK - Separation of part.
BUCKLING - A large-scale deformation of the original contour of a part, usually due to pressure or
impact from a foreign object, structural stresses, excessive localized heating, high-pressure differentials,
or to any combination of these.
BULGE - An area on a sheet metal part that has swelled outward.
BURR - A rough or sharp edge on a hole or comer, usually caused by machining, sometimes by wearing.
CALIBRATE - The work done in testing and/or adjusting an instrument or accessory to known standards.
CHIPPING - Breaking away of metallic particles.