Belt Speed Calculator for 2x72 Belt Grinders
With that said, there are many factors that come into play when determining the best belt speed such as:
Buying your first grinder is always fun, the best target speed is between 40 and 60 MPH.
It depends on your electric motor's speed. Use the calculator to determine the size of your "Drive Wheel" once you know your target speed, here are a few examples
Belt Speed with 4" Drive Wheel
1200 RPM - With 4" Drive Wheel = 14 MPH (Best for Small Wheels and knife sharpening)
1800 RPM - With 4" Drive Wheel = 21 MPH (Okay for Small Wheels and knife sharpening)
3450 RPM - With 4" Drive Wheel = 41 MPH
3600 RPM - With 4" Drive Wheel = 43 MPH
Belt Speed with 5" Drive Wheel
1200 RPM - With 5" Drive Wheel = 18 MPH
1800 RPM - With 5" Drive Wheel = 26 MPH
3450 RPM - With 5" Drive Wheel = 51 MPH (Best Option for general Grinding)
3600 RPM - With 5" Drive Wheel = 53 MPH
Belt Speed with 6" Drive Wheel
1200 RPM - With 6" Drive Wheel = 21 MPH
1800 RPM - With 6" Drive Wheel = 32 MPH
3450 RPM - With 6" Drive Wheel = 61 MPH
3600 RPM - With 6" Drive Wheel = 65 MPH
Belt Speed with 7" Drive Wheel
1200 RPM - With 5" Drive Wheel = 25 MPH
1800 RPM - With 5" Drive Wheel = 37 MPH
3450 RPM - With 5" Drive Wheel = 72 MPH
3600 RPM - With 5" Drive Wheel = 75 MPH
The formula to calculate SFM (Surface feet per minute) which is the same as Belt Speed is as follows:
The higher the RPM or the larger the drive wheel the faster the belt speed.
This is what Wikipedia has to say about
Surface Speed Per Minute – SFM the industry standard is defined as the number of linear feet that a location on a rotating component travels in one minute. Its most common use is in the measurement of cutting speed (surface speed) in machining. It is a unit of velocity that describes how fast the cutting edge of the cutting tool travels. It correlates directly to the machinability of the workpiece material and the hardness of the cutting tool material. It relates to spindle speed via variables such as cutter diameter (for rotating cutters) or workpiece diameter (for lathe work).