For Machines Mfg. Since 8/09 | O P E R A T I O N | SB1024/SB1025/SB1026 |
Setting Spindle Speed
Using the correct spindle speed is important for safe and satisfactory results, as well as maximizing 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 mill controls to produce the required spindle speed.
Determining Spindle Speed
Many variables affect the optimum spindle speed to use for any given operation, but the two most important are the recommended cutting speed for the workpiece material and the diameter of the cutting tool, as noted in Figure 31:
*Recommended
Cutting Speed (FPM) x 12
= SpindleSpeed (RPM)
Tool Dia. (in inches) x 3.14
*Double if using carbide cutting tool
Figure 31. Spindle speed formula for milling.
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, provide 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
Setting Spindle Speed Range
Setting the spindle speed range involves engaging and disengaging a spindle spline that uses gearing to increase or decrease the range of spindle speeds.
The procedures to set the speed range for the Model SB1024 and Model SB1025/SB1026 differ slightly. Use the appropriate section on the following pages for the mill when selecting the speed range.
To avoid damage to the spindle, gears, or cutting tools:
ss3PINDLENROTATION MUSTTBE TURNED /&& AND the spindle must be at a complete stop BEFORE you change the spindle speed range.
ss4HEHMILL ISSDESIGNED TOO/.,9 OPERATE WITHH the spindle speed range selector in either the high or low position. To avoid damaging the moving parts inside the headstock, never start spindle rotation without the range selector detent pin firmly seated in either the high or low position.
ss7HEN CHANGINGGTHEESPINDLELSPEEDDRANGEE and the direction of spindle rotation reverses, you will need to either change the cutting tool to match the direction of spindle rotation or use the spindle direction switch to compensate for the reversal.
Note: Regardless of the model of the mill, you MUST properly perform the Meshing Spindle
&Spindle Clutch procedure as instructed on Page 40 when using the high spindle speed range.