Here is a little glimpse of my homemade magnetic polisher that I made from a free craigslist treadmill.
As you can see, it is very, very rough. If I had my druthers, I would rebuild it for compactness and aesthetics but as it stands, other things have taken precedence.
The frame is primarily re-cannibalized parts from the treadmill itself. The motor reuses the mounts as well as the tensioning belt and I installed a drive shaft to an MDF platten to house the magnets. If you want me to find out the exact dimensions of the magnets I can, but they are held in pockets, routed into the MDF, and then covered with a piece of plexiglass.
The controller is just the treadmill control hung on the wall. Don’t underestimate the decor value!
The bowl that holds the stainless steel pins, the soapy water, and the jewelry to be polished is a salad spinner. I tried using a large yogurt container, but the thin plastic started to wear through. Whatever vessel is chosen, it needs to have a raised center section or a lot of the material will congregate in the middle and not be spun around.
There are some YouTube videos on this type of project that are much better examples of what is possible both in aesthetics and construction but here’s what I got to work on my first try.
It sits right near my polishing machine, so it benefits from the general distribution of polishing dust and other detritus. Once again, decor value!