Understanding Belt Speed: SFM vs MPH

In the world of belt grinders, SFM (Surface Feet per Minute) is the industry standard for measuring belt speed. It refers to how many feet of belt pass over the platen in one minute. While this is great for technical specifications, it’s not very intuitive for most people—especially if you’re just getting started in knifemaking or fabrication.

That’s where MPH (Miles Per Hour) comes in.

MPH gives you a relatable sense of speed—because we all understand what 20 MPH or 40 MPH feels like. By converting belt speed to MPH, you can more easily visualize and adjust your grinding setup for different tasks, whether you’re removing stock, finishing bevels, or doing detail work.

Use our Belt Speed Calculator to find both SFM and MPH based on your motor RPM and drive wheel size. It’s an easy way to fine-tune your grinder to match your workflow.