LATHE OPERATIONS - OD1645 - LESSON 1/TASK 1
(2) Cutting Speed.
(a) The cutting speed of a cutter bit is defined as the number of feet
of workpiece surface, measured at the circumference, that pass the cutter
bit in 1 minute.
The cutting speed, expressed in feet per minute (fpm),
must not be confused with the spindle speed of the lathe which is expressed
in revolutions per minute (rpm). To obtain uniform cutting speed, the lathe
spindle must be revolved faster for workpieces of small diameter and slower
(b) The proper cutting speed for a given job depends upon the hardness
of the material being worked on, the material of the cutter bit, and the
feed and depth of cut to be used. Table 2 lists specific ranges of cutting
effect on the cutter bit
TABLE 2. LATHE CUTTING SPEEDS FOR
STRAIGHT TURNING AND THREADING.