604
Glossary of
Technical Terms
A
abrasive: A material that penetrates and cuts
a material that is softer than itself. It may
be natural (emery, corundum, diamond) or
artifi cial (silicon carbide, aluminum oxide).
(Ch. 7)
abrasive cutoff saw: A sawing machine that
uses a rotary abrasive wheel either with
or without a liquid coolant. Wet abrasive
cutting uses a liquid coolant, can cut to close
tolerances, and produces a fi ne surface fi nish.
Dry abrasive cutting uses no coolant and is
used for rapid, less critical cutting. (Ch. 11)
absolute positioning: A programming mode,
indicated by the G90 code, in which the
coordinate values for any point are interpreted
in relation to the X0,Y0 position. (Ch. 23)
actual size: The measured size of a part after it
is manufactured. (Ch. 4)
addendum: That portion of a gear tooth that
projects above or outside the pitch circle.
(Ch. 19)
adhesive: A material that provides one of the
newer ways to join metals and keep threaded
fasteners from vibrating loose. In some
applications, the resulting joints are stronger
than the metal itself. Adhesive-bonded joints
do not require costly and time-consuming
operations such as drilling, countersinking,
and riveting. (Ch. 8)
all-hard blade: One of two types of power
hacksaw blade (the other is a fl exible-
back blade). It is best for straight, accurate
cutting under a variety of conditions.
(Ch. 11)
alloy: A mixture of two or more metals.
(Ch. 28)
Aluminum Association Designation System:
A method of identifying aluminum with a
four digit code plus a temper designation.
The identifi cation code and temper
designation are separated by a hyphen.
(Ch. 28)
American National Standards Institute
(ANSI): An association that serves as a
clearinghouse for nationally coordinated
voluntary standards for fi elds ranging
from information technology to building
construction. Standards are established
for such areas as defi nitions, terminology,
symbols, materials, performance
characteristics, procedures, and testing
methods. (Ch. 4)
American National Thread System: The
common thread form used in the United
States, characterized by the 60° angle formed
by the sides of the thread. (Ch. 7)
angularity: The condition of a surface, center
plane, or axis at any specifi ed angle from a
datum plane or axis other than 90°. (Ch. 4)