Editor's note: Joe Brott has kindly submitted this chart for calculating the speed of pulleys and wheels for those of use that are concerned about how fast our grinding and buffing wheels are turning. Perhaps now we will be able to keep our tools from being damaged by the excessive heat caused by touching tools to wheels that are turning too fast :-)
For a motor running @ 1725rpm with pulley sizes (as indicated below) produces rpm shown under each diameter.
Diameters of Driven pulleys Dia. of Motor Pulley 4" 6 1/2" 8" 10" 12" 1 1/4" 540rpm 430 265 215 175 2" 850rpm 530 430 345 230
Note: For a 3450 rpm motor, just double the speeds listed.