I wish i had thought of this idea but I can't take credit. I bought this thru a kijiji ad and it works great;
Originally it came with one belt but I wanted two different grits, one for metal and one for wood. With one belt it was easy to adjust the tracking to center the belt with a little help under the bed with bent metal "fence". With two belts not so easy anymore. I'm using the same idea of fences but it's causing the belt to stretch at the outside edges;
I believe the solution would be two separate rollers at the bed end, which I'll do as soon as they come in.
The original owner was using this for wood only, which worked great until I started grinding metal. The metal dust collected on the "motherboard" and shorted. I was lucky in that I was able to clean the board and it fired back up. I decided that a barrier between the belts and motor/board was a very good idea;
I hot glued some foam to the black plastic cover creating a [hopefully] dust free motor enclosure. The only place for ingress is the belt opening. I also flipped the board over so all the exposed metal tracing is at the bottom, I hope that any metal filings that make it in don't defy gravity too much. Also is a computer fan blowing filtered air into the motor enclosure making it a positive pressure enclosure.
I built a quick fence;
I'm grinding an edge to this plate to use in a homemade press brake.
The torque of the DC motor is great and there is variable motor speed control, tho I leave that on high so far.
This uses stock off the shelf belts 6"x[IIRC]89"
With a fence at the back tubing could be ground on the roller for cage fit-up purposes.
I'd like to re-design the bed to make belt changes easier and so the belt rides at the edge of the bed. Right now it needs to be taken totally apart to change a belt.
I thought this was a great re-purposing of an expensive coat hanger.
I have a total of $75.00 into it including new belts.