Glossary of Technical Terms 619
raker set: A three-tooth saw set in which
one tooth is angled toward the left, another
one straight, and the next one angled
toward the right, alternating continuously
along the length of the blade. Raker set is
recommended for cutting large solids or thick
plate and bar stock. (Ch. 21)
reamer: A cutting tool used to enlarge, smooth,
and size a drilled hole by removing a small
amount of metal. (Ch. 7)
reaming: To fi nish a drilled hole with a reamer.
(Ch. 12)
red hardness: The ability of a metal to remain
hard even when red hot. (Ch. 28)
reference line: A layout line from which all
measurements are made. Also known as a
“baseline.” (Ch. 6)
repetitive cycle: Predefi ned operations
specifi ed by G-codes. Found on most turning
centers; similar to the canned cycles used on
CNC machining centers. (Ch. 25)
résumé: A summary of an applicant’s
educational and employment backgrounds.
(Ch. 2)
robot: A reprogrammable, multifunctional
manipulator designed to move material,
parts, tools, or specialized devices through
variable programmed motions for the
performance of a variety of tasks. (Ch. 26)
Rockwell hardness test: The most widely
used hardness testing method. A penetrator
is pressed into the metal being tested under
a known load. The hardness reading is based
on the depth of penetration. (Ch. 29)
roller burnishing: A cold-working operation
that used rollers to fl atten the peaks of a metal’s
surface into the valleys. With the process, no
honing or grinding is necessary (Ch. 30)
roughing cut: Deep cut made to remove
considerable material from a workpiece. (Ch. 14)
runout geometric tolerance: A combination
of geometric tolerances used to control the
relationship of one or more features of a part
to a datum axis. (Ch. 4)
S
safe edge: A fi le edge without teeth. (Ch.7)
safety equipment: Tools or equipment
that help prevent or mitigate accidents in
the potentially dangerous environment
of a machine shop. Machine guards, fi re
extinguishers, eye wash stations, vacuum
dust collectors, power switches (for locking
off equipment), and brushes (for removing
machine chips) are a few examples. (Ch. 3)
sawing machine: A machine that cuts away
material from the work by means of a
multitoothed saw blade. (Ch. 1)
scale drawing: A drawing made other than actual
size (1:1). A drawing made one-half size would
have a scale of 1:2. A scale of 2:1 would mean
that the drawing is twice the size of the actual
part. (Ch. 4)
scleroscope: A testing device that drops a
hammer onto the test piece. The resulting
rebound of the hammer determines the
hardness of the material being tested. (Ch. 29)
scriber: A layout tool with a point of hardened
steel used to scribe (scratch) fi ne, accurately
straight lines into metal. (Ch. 6)
semichemical cutting fluid: Cooling and
lubricating liquid that may have a small
amount of mineral oil added to improve the
fl uid’s lubricating qualities. Semichemical
cutting fl uids incorporate the best qualities of
both chemical and emulsifi able (water-based)
cutting fl uids. (Ch. 10)
semiskilled worker: A worker who performs
basic, routine operations that do not require a
high degree of skill or training. (Ch. 2)
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