It depends upon what the parent material is and how rounded over you want the edges.
You could put them in a rock tumbler. I've seen someone freeze rubber parts in dry ice and then put them in a tumbler.
Media changes depending upon how smooth you want the finish. Usually its some kind of ceramic cone or ball bearings.
A less severe method is to use a vibratory bowl.
If you just want corner chamfering, you might be able to set up a fixture and use a flat bed sander. |