your lathe is equipped with a set of outboard
spindle supports known as a "spider," shown in
figure 46. spider assembly located on the out-
use the spider when a long workpiece has the
potential to wobble or vibrate when it 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 or marring.
When the spider screws are installed, and regard-
less if they are used to hold a workpiece or not,
always lock each spider screw in place by tight-
ening the jam nuts. if a workpiece is installed,
merely tightening the spider screws against the
workpiece and leaving the jam nuts loose is not
safe. spider screws that loosen during operation
can crash into the lathe end cover.
To avoid creating an entanglement hazard,
remove the spider screws when not in use,
and always disconnect the lathe from power
when installing, removing, or adjusting the
spider screws. Ignoring this warning can
lead to personal injury or machine damage.
Model G0709 (Mfg. Since 5/11)
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 lathe
controls to produce the required spindle speed.
Determining Spindle Speed
Many variables affect the optimum spindle speed
to use for any given operations, 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
Cutting Speed (FPM) x 12
Dia. of Cut (in inches) x 3.14
Double if using carbide cutting tool
figure 47. 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. All of these sources will help you
take into account all the applicable variables in
order to determine the best spindle speed for the