Calculating Belt Speed on Your 2x72 Grinder

To calculate belt speed, also known as Surface Feet per Minute (SFM), use the following formula:

Where:

• π/2 is approximately 1.57

• D = Diameter of your drive wheel (in inches)

• RPM = Revolutions per minute of your motor

Example:
For a 5" drive wheel running at 3450 RPM:
Belt Speed = 1.57 × 5 × 3450 = 27,082.5 inches/min
Divide by 12 to convert to feet:
SFM ≈ 2,256.9 ft/min

The takeaway:

• A larger drive wheel = faster belt speed

• A higher RPM motor = faster belt speed

Use this formula or our Belt Speed Calculator to find the right combination for your grinding setup. Knowing your SFM helps you dial in optimal cutting performance and avoid overheating or excessive wear.