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Model M1099 (Mfg Since 8/07)
Determining Correct
Spindle RPM
To determine the correct spindle RPM, do these steps:
1.
Use the table in Figure 28 to determine the cutting
speed required for the material of your workpiece.
2. Measure the diameter of your workpiece in inches
and subtract the depth of the cut that will be taken
on the initial pass.
3. Use the formula in Figure 29 to determine the
needed RPM for your operation.
Note: Always round to the closest RPM given on the
spindle speed chart, and adjust your speed as the
workpiece diameter decreases.
Example 1
You have a piece of
and you are using workpiece with a HSS cutting tool.
Step 1:
300 (SFM from chart) x 4 = 1200
Step 2:
1200 / 0.5" (Diameter of workpiece) = 2400 RPM
Result:
The needed speed for this workpiece is 2400 RPM.
Example 2
You have a piece of 1" diameter stainless steel stock,
and you are using a workpiece with a carbide cutting
tool.
Step 1:
60 (SFM from chart) x 2 (for carbide tool) = 120
Step 2:
120 (determined SFM) x 4 = 480
Step 3:
480 / 1" (Diameter of workpiece) = 480 RPM
Result:
The needed speed for this workpiece is 480 RPM.
⁄
" diameter aluminum stock,
1
2
Failure to follow RPM and feed rate
guidelines may threaten operator safe-
ty from ejected parts or broken tools.
Cutting Speeds for High Speed Steel
(HSS) Cutting Tools
Workpiece Material
Aluminum & alloys
Brass & Bronze
Copper
Cast Iron, soft
Cast Iron, hard
Mild Steel
Cast Steel
Alloy Steel, hard
Tool Steel
Stainless Steel
Titanium
Plastics
Wood
Note: For carbide cutting tools, double
the cutting speed. These values are a
guideline only. Refer to the MACHIN-
ERY'S HANDBOOK for more detailed
information.
Figure 28. Cutting speed table for HSS
(SFM) x 4
Workpiece
Diameter
Figure 29. Formula to determine required
spindle speed for lathes.
-27-
Cutting Speed
(sfm)
300
150
100
80
50
90
80
40
50
60
50
300-800
300-500
cutting tools.
= RPM
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