Check out the Moe's Belt Grinder DVD on the DVD's page and the video on the Grinders page at
www.WayneCoeArtistBlacksmith.com. It does call for a VFD but you can make it with a single speed motor and step pulleys. It has no tubing in the build for a build with the tolerances much closer and no grindings causing the tool arm to get stuck. Keep in mind that you will lose power due to friction losses with the step pulleys, you will spend about $100.00 for the pulleys, belt, shaft and pillow blocks. That money and the $50.00 for the under powered motor could go toward the cost of a 1.5 or 2 hp motor and VFD. You would be amazed at the additional power, smoothness and less vibration with the VFD.
Let me know if I can help you.
Wayne