Grizzly G0492 - Manual (Page 37)

G0492 12" X 36" Combo Lathe/Mill
-35-
To determine and set the mill to the needed
cutting RPM:
1. Select the cutting speed required for the
material of your workpiece using the table in
Figure 46.
NOTICE
Failure to follow RPM and Feed Rate
Guidelines will shorten cutter life and give
poor workpiece results and may threaten
operator safety from ejected parts or broken
tools.
Setting the Spindle
RPM
Never shift gears while lathe or mill is
running; otherwise, the gear teeth will be
chipped or broken.
NOTICE
Note: You will only be able to get an approxi-
mate RPM value with the variable speed
knob.
4. Move the mill gearbox levers to the nearest
milling speed RPM.
Cutting Speeds for High Speed Steel
(HSS) cutting tools:
Workpiece Material Cutting Speed (sfm)
Aluminum & alloys 300
Brass & Bronze 150
Copper 100
Cast Iron, soft 80
Cast Iron, hard 50
Mild Steel 90
Cast Steel 80
Alloy Steel, hard 40
Tool Steel 50
Stainless Steel 60
Titanium 50
Plastics 300-800
Wood 300-500
Figure 46. High speed steel cutting chart.
Note: Double the cutting speed for car-
bide cutting tools. These values are a
guideline only. Refer to the MACHINERY'S
HANDBOOK for more detailed information.
2. Measure the diameter of your cutting tool in
inches.
3. Use the following formula to determine the
needed RPM for your operation:
(Cutting Speed x 4) / Tool Diameter = RPM
The quill feed is controlled by the handle on the
right of the headstock, and a lock bolt on the left
side of the headstock (
Figure 47).
To use the quill:
1. Hold a feed handle, and loosen the quill feed
lock bolt to release the quill.
2. For drilling, pull the handle toward you and the
quill will feed down toward the workpiece.
Note: The quill feed handle is spring loaded.
DO NOT let go of the handle at the end of
a drilling operation or the quill will quickly
retract and slam into the headstock.
3. For milling, hold the quill at a particular depth
and tighten the quill lock bolt.
Figure 47. Quill lock.
Quill
Lock
Bolt
Using the Mill