Spindle Speed - Grizzly G0750GV 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, keeping in mind the length
of the workpiece on both sides of the headstock,
and 2) configure the lathe controls to produce the
required spindle speed for the best cut with the
safest means possible.
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 60.
*
Recommended
Cutting Speed (FPM) x 12
Dia. of Cut (in inches) x 3.14
*
Double if using carbide cutting tool
Figure 60. 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
Determine spindle speed, then use the spindle
speed lever, shown in Figure 61, to select the
spindle speed range that best suits your cutting
task.
Spindle
Speed
=
(RPM)
To adjust spindle speed:
1.
2.
3.
Spindle Speed
Digital Readout
Spindle
Speed
Lever
Variable
Spindle
Speed Dial
Figure 61. Spindle speed controls and display.
To avoid damaging gears, ALWAYS make
sure the spindle is completely stopped
BEFORE moving the spindle speed levers.
Make sure spindle is turned OFF and has
come to a complete stop.
Set spindle speed lever to low (L, 60–400
RPM) or high (H, 380–2200 RPM).
Headstock label indicates allowable spindle
speed for cutting operations within that
range. If knob is set to H (high speed), do
not attempt cutting operations at less than
380 RPM, and do not exceed 400 RPM in L
(low speed).
Turn spindle ON, then turn variable spindle
speed dial to adjust speed shown on spin-
dle speed digital readout to your calculated
speed (see Figure 61).
Model G0750GV (Mfd. Since 03/18)