Grizzly G9249 owner manual Spindle Speed, Calculating the Correct Spindle RPM

Spindle Speed

To set the correct spindle speed for your opera- tion, you will need to: 1) Determine the spindle speed needed for your workpiece, and 2) config- ure the belts and gears for the calculated spindle speed.

Calculating the Correct Spindle RPM

1.Use the table in Figure 48 to determine the recommended cutting speed for the workpiece material.

Recommended Cutting Speeds

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Note: These values are based on HSS cutting tools. For carbide cutting tools, double the aver- age speed. These values are a guideline only. Refer to the MACHINERY’S HANDBOOK for more detailed information.

Figure 48. Cutting speed table.

2. Determine the final diameter, in inches, for the cut you are about to take.

Note: For this step, you will need to aver- age out the diameters or work with the finish diameter for your calculations.

3. Use the following formula to determine the correct spindle speed (RPM) for your opera- tion:

Spindle Speed = Cutting Speed (SFM) x 4 Diameter of Cut

Configuring the V-Belts and Back Gear

There are twelve spindle speeds are available by properly positioning the motor V-belt, spindle V-belt, and back gears.

To configure the V-belts:

1.DISCONNECT LATHE FROM POWER!

2.Refer to the chart in Figure 49 and find the value closest to your calculated spindle speed.

Note: This chart is also on the front of the headstock. The "Direct" speeds are with the back gear disengaged. Instructions for engaging the back gear are on Page 35.

	6 7			& ' (
	B					/min.
A	B	&		'		(
DIRECT		550	1200 410		900	300	655
BACK GEAR		100	220	75	165	50	120

Figure 49. Spindle speed configuration chart.

-34- G9249  12" x 37" Belt Drive Gap Bed Lathe