Determining Spindle Speed

Spindle Speed

Using the correct spindle speed is important for safe and satisfactory results, as well as maximiz- ing 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 con- trols to match the closest 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 26:

*Recommended

Cutting Speed (FPM) x 12

= RPM

Tool Diameter (in inches) x 3.14

*Double if using carbide cutting tool

Figure 26. 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, pro- vide 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 easy-to-use spindle speed calculators that can be found on the internet. These sources will help you take into account all applicable variables to determine the best spindle speed for the operation.

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The procedures for setting the spindle speed for the Models G0747 and Model G0748 differ. Use the appropriate section on the following pages for your mill when selecting the speed range.

To avoid damaging the spindle, gears, or cutting tools when setting the spindle speed range:

•Spindle rotation must be turned OFF and the spindle must be at a complete stop BEFORE you change the spindle speed range.

•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.

•When the spindle speed range is changed, the spindle rotation direction reverses. You will need to either change the cutting tool to match the direction of spindle rota- tion or use the spindle direction switch to compensate for the reversal.

Model G0747/G0748 (Mfg. Since 8/12)

G0747 and G0748 specifications

The Grizzly G0747 and G0748 are advanced metal lathes designed for precision machining and versatility, catering to both amateur machinists and professional workshops. These machines stand out in the realm of metalworking equipment, thanks to their robust construction and innovative features.

One of the key attributes of the G0747 and G0748 is their solid cast iron construction, which provides excellent vibration dampening during operation. This enhances stability and precision, crucial for producing high-quality machined parts. Equipped with powerful motors, both models are capable of handling a wide range of materials, from aluminum to harder metals like steel.

The G0747 features a variable speed drive system, allowing users to adjust the spindle speed based on the project at hand. This flexibility is beneficial for tasks that require different cutting speeds, enabling machinists to optimize cutting performance and tool longevity. Its variable speed output ranges, alongside smooth torque delivery, make it ideal for intricate turning operations.

On the other hand, the G0748 includes an advanced digital readout (DRO) system. This feature provides real-time feedback on the machine's position and speed, significantly improving accuracy in measurements during machining tasks. The DRO system allows operators to set precise limits and keep track of their progress, essential for complex projects where exact dimensions are critical.

Both lathes are equipped with a user-friendly interface, making them accessible for beginners while still offering advanced functionalities that seasoned professionals appreciate. They include multiple tooling options, allowing for an expansive range of machining techniques including turning, threading, and drilling.

Moreover, the G0747 and G0748 come with a comprehensive assortment of accessories, such as different types of chucks and tool holders, which further extends their capabilities. The ease of changing tooling and quick setup times are significant advantages for shops aiming for efficiency and versatility in their operations.

In conclusion, the Grizzly G0747 and G0748 metal lathes are exemplary units that balance power, precision, and user-friendliness. Their advanced features, such as variable speed capabilities and digital readouts, equip machinists with the tools necessary to produce exceptional work. Whether for hobbyists or industrial applications, these lathes are built to meet a variety of machining needs with impressive performance and reliability.