Spindle Speed; Determining Spindle Speed; Setting Vertical Spindle Speed - Grizzly G0757 Owner's Manual

Spindle Speed

Using the correct spindle speed is important for
safe and satisfactory results, as well as maximiz-
ing 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 mill con-
trols to match the closest 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
cutting tool, as noted in Figure 25:
*
Recommended
Cutting Speed (FPM) x 12
Tool Diameter (in inches) x 3.14
*
Double if using carbide cutting tool
Figure 25. Spindle speed formula for milling.
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 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 all applicable variables to determine the
best spindle speed for the operation.
Model G0757 (Mfg. Since 6/13)

Setting Vertical Spindle Speed

Tools Needed
Wrench 22mm ................................................... 1
Wrench 24mm ................................................... 1
To set vertical spindle speed:
1. DISCONNECT MACHINE FROM POWER!
2. Remove vertical spindle V-belt covers to gain
access to vertical V-belts and pulleys (see
Figure 26).
Center Pulley
Hex Nut
=
RPM
Figure 26. V-belt covers removed to gain access
3.
Loosen center pulley hex nut.
4.
Loosen the two motor mount hex bolts (one
on each side of motor).
5.
Use motor handle to pull motor towards the
front of machine and release V-belt tension.
Motor Mount
Hex Bolt
(1 of 2)
to vertical spindle V-belts and pulleys.
Qty
Motor
Handle
-31-