Spindle Speed - Grizzly G0824 Owner's Manual

Spindle Speed

Using the correct spindle speed is important for
getting safe and satisfactory results, as well as
maximizing tool life.
To set the spindle speed for your operation, you
will need to: 1) Determine the best spindle speed
for the cutting task, and 2) configure the lathe
controls to produce the required spindle speed.
Determining Spindle Speed
Many variables affect the optimum spindle speed
to use for any given operation, but the two most
important are the recommended cutting speed
for the workpiece material and the diameter of
the workpiece, as noted in the formula shown in
Figure 64.
*
Recommended
Cutting Speed (FPM) x 12
Dia. of Cut (in inches) x 3.14
*
Double if using carbide cutting tool
Figure 64. Spindle speed formula for lathes.
Cutting speed, typically defined in feet per minute
(FPM), is the speed at which the edge of a tool
moves across the material surface.
A recommended cutting speed is an ideal speed
for cutting a type of material in order to produce
the desired finish and optimize tool life.
The books Machinery's Handbook or Machine
Shop Practice, and some internet sites, pro-
vide excellent recommendations for which cutting
speeds to use when calculating the spindle speed.
These sources also provide a wealth of additional
information about the variables that affect cutting
speed and they are a good educational resource.
Also, there are a large number of easy-to-use
spindle speed calculators that can be found on
the internet. These sources will help you take into
account the applicable variables in order to deter-
mine the best spindle speed for the operation.
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Setting Spindle Speed
The spindle speed and speed range levers,
shown in Figure 65, are used to select one of the
eight spindle speeds.
The spindle speed lever and speed range lever
control the gear configuration in the headstock to
produce the selected spindle speed.
Spindle
Speed
=
(RPM)
The chart below shows the various combinations
of lever positions for achieving a desired speed.
Spindle
Speed
Lever
Figure 65. Spindle speed and speed range
levers.
To avoid damaging gears, ALWAYS make
sure the spindle is completely stopped
BEFORE moving the spindle speed levers.
Spindle Speed RPM
1 2
rev/min
H 1255 2000
190 300 125
L
Figure 66. Spindle speed chart.
Model G0824 (Mfd. Since 12/16)
Speed
Range
Lever
3 4
755 460
70