Yet another homemade belt grinder

I've been meaning to build a belt grinder for some time. I was finally pushed into it by the need to clean up some aluminum castings that I made. Using a file for that was impossible and a grinder is perfect.

For my grinder, it was essential that it not take any floor space (none available) and ideally it would sit on a shelf. I wanted good access/clearance around the contact wheel and I wanted belt changes to be fast and easy. Because of my limited machining experience, it needed to be simple (minimum parts and precision).

The result:

By using a treadmill motor, I could mount it on top, keep the contact wheel clear while minimizing the footprint, and avoid another "stage" of belt and pulley. The motor is only 3" diam. and 8" long yet it is rated for 8 amps @ 120 volts (1 hp +-). It also is variable speed (pulley-ed for 0 - 6000 sfpm). I haven't yet solved the problem of keeping metal dust out of the insides (so far I just use shop air to blow it out occasionally).

It uses 2 x 42 belts. To change belts, tension is released by reaching behind with my right hand to pull/squeeze the idler arm while I slide the belt off or on with my left hand. Only takes a few seconds. It takes much longer to find the new belt that I want to use.

The wheels were all home cast and turned. My first lathe project - what a hoot! The drive wheel was a challenge - the motor shaft is not keyed but has a left hand thread that on the treadmill screwed into a flywheel/drive-pulley. I cut down that flywheel and cast my drive pulley around it. The contact wheel is 6" diam. and does not have a "tread". I'm thinking that maybe it should. I'll probably try a piece of inner tube.

The platen can be removed by loosening the two bolts holding it. Tracking is adjusted via the thumb screw under the right side of the motor mount. This is accomplished by having the motor pivot on the single bolt on the left.

The aluminum box holds the motor speed controller.

Bottom line is that this was a fun project. I got to use my lathe for real (there were 4 spindles/arbors/axles as well as the wheels) and I have a tool that works really well.

Oh, yeah - in keeping with my chea.. er, frugal .. nature, the only store-bought parts were the bearings for the wheels ($6 on eBay). And the belts, of course - $19 (shipped) for a variety pack of 14. The motor and it's controller came from the dump.

Bob

BTW - should I have used smaller pix (to fit a browser window)? I made them big to show detail, but then they have to be scrolled. I dunno.