Spindle Speed - Grizzly G0782 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 below.
*
Recommended
Cutting Speed (FPM) x 12
Dia. of Cut (in inches) x 3.14
*
Double if using carbide cutting tool
Figure 56. 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.
Model G0782 (Mfd. Since 10/15)
Setting Spindle Speed
The spindle speed lever and spindle speed range
lever, shown in Figure 57, are used to select one
of the eight spindle speeds.
Figure 57. Location of spindle speed and spindle
The spindle speed and range levers control the
Spindle
gear configuration in the headstock to produce
Speed
=
the selected spindle speed.
(RPM)
The chart below shows the various combinations
of lever positions for achieving a desired speed.
Spindle Speed
Range Lever
Spindle Speed
Lever
speed range levers.
To avoid damaging gears, ALWAYS make
sure the spindle is completely stopped
BEFORE moving the spindle speed levers.
Spindle
Speed Spindle
Range Speed
Lever Lever
Spindle Speed RPM
1255
190
X
min
Figure 58. Spindle speed chart and applicable
spindle speed and range lever positions.
2000 755 460
300 115 70
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