Spider; Spindle Speed - Grizzly G0776 Owner's Manual

Spider

Your lathe is equipped with a set of outboard
spindle supports otherwise known as a "spider"
(see Figure 61).
Spider Screw
Jam Nut
Figure 61. Spider assembly located on the out-
board spindle.
Remove spider screws when not in use.
Always DISCONNECT LATHE FROM POWER
when installing, removing, or adjusting spi-
der screws. Ignoring this warning can lead
to personal injury or machine damage.
The spider is especially designed for supporting
gun barrels during chambering operations; how-
ever, it is a great support option for almost any
long workpiece that extends through the outboard
side of the spindle.
The tips of the spider screws have brass wear
pads that hold the workpiece without causing
indents in the finish.
When spider screws are installed, always use the
jam nuts to lock each spider screw in position.
Merely tightening the spider screws against the
workpiece and leaving the jam nuts loose is not
safe. Spiders screws that loosen during operation
can crash into the lathe end cover.
-48-
Spider

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 62. 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 G0776 (Mfd. Since 7/14)
Spindle
Speed
=
(RPM)