Glossary of Technical Terms 605
annealing: A heat treatment process in
which the metal is heated above its critical
temperature and cooled slowly to reduce its
hardness and make it easier to machine or
work. (Ch. 29)
anodizing: An electrolytic process that forms
a protective layer of aluminum oxide on
aluminum parts. (Ch. 30)
apprentice: A student who receives on-the-job
training working with a skilled machinist
while also studying work-related subjects.
(Ch. 2)
approved respirator: A type of mask worn
over the mouth and nose that provides clean
air to breathe, and prevents the inhalation of
dangerous toxins. (Ch. 3)
arbor: A shaft or spindle for holding cutting
tools. (Ch. 18)
arbor press: A manually operated press used
on smaller work that can have a leverage of
several tons. (Ch. 17)
assigned code: A code that has the same
application or function on all machine
controllers, regardless of application.
(Ch. 23)
associate’ s degree: A two-year educational
degree focused on preparing students for
technical positions. (Ch. 2)
automatic screw machine: A variation of
the lathe that was developed for high-
speed production of large numbers of
small parts. The machine performs a
maximum number of operations, either
simultaneously, or in a very rapid
sequence. (Ch. 15)
automatic tool changer (ATC): A device
used by some CNC machine tools that
automatically changes and stores the tools.
(Ch. 22)
B
bachelor’s degree: A four-year educational
degree focused on advanced theoretical
education and skill training in specifi c
disciplines like engineering. (Ch. 2)
backlash: Clearance designed into the
mating of threaded rods and nuts to allow
movement. (Ch. 22)
bacteriostat: A substance that regulates and
controls the growth of bacteria. (Ch. 10)
band machining: A widely used technique
that makes use of a continuous saw blade.
Chip removal is rapid, and accuracy can
be held to close tolerances, eliminating or
minimizing many secondary machining
operations. (Ch. 21)
bar puller: An attachment mounted in the
turret of a turning center used to clamp
and pull bar stock through the spindle for
machining. (Ch. 25)
base metal: A pure, nonferrous, nonprecious
metal. (Ch. 28)
bevel gear: A toothed wheel used to change
the angular direction of power between
shafts. The teeth are either straight or curved.
(Ch. 19)
bill of materials: A listing of the numbers,
names, materials, and quantities of the parts
specifi ed on a set of working drawings.
(Ch. 4)
blind hole: A hole that does not go completely
through the workpiece. (Ch. 7, 12)
block: In a word address format programming
language, groups of words that are written
on a single line and are meant to be executed
together. (Ch. 23)
boring: An internal machining operation in
which a single-point cutting tool is used to
enlarge a hole. (Ch. 15)