Grizzly G0517g Milling Speed, To determine the needed speed for milling, Example

Milling Speed

Closely follow the proper cutting speed—with a reasonable feed speed—to reduce undue strain on all moving parts and increase operator safety.

Prior to machining, you need to determine the best speed to cut your workpiece, and then set that speed on the machine.

To determine the needed speed for milling:

1.Use the table in Figure 32 to determine the cutting speed required for the material of your workpiece.

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

Note: For carbide cutting tools, double the cut- ting speed. These values are a guideline only. Refer to the MACHINERY'S HANDBOOK for more detailed information.

Figure 32. Cutting speed table for HSS cutting

tools.

2.Measure the diameter of your cutting tool in inches.

Model G0517 Mill/Drill

3.Use the formula in Figure 33 to determine the needed speed for your operation:

Figure 33. Speed formula for milling.

Note: Always round to the closest RPM given on the spindle speed chart.

Example 1

You have a piece of aluminum stock, and you are using a 1⁄2" diameter HSS cutting tool.

Step 1:

300 (SFM from chart) x 4 = 1200

Step 2:

1200 / .5" (Diameter of cutting tool) =

2400 RPM

Result:

The best speed for this workpiece is 2400 RPM.

Example 2

You have a piece of stainless steel, and you are using a 1" diameter 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 cutting tool) = 480

RPM

Result:

The best speed for this workpiece is 480 RPM.

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