I know the frustration with damaging a small wheel in the middle of finishing a knife. The delay and cost aren’t fun to deal with. So, I set out to design a small wheel where the drum could be easily replaced. It is held to the shaft with a mechanical connection instead of glue. If one gets damaged, grab one from your tool box, tap out the shaft and tap on the new drum. I chose polyurethane over rubber for a couple reasons. It’s tougher and has 4-5 times the wear resistance to natural rubber. And, it can be 3d Printed for testing. Testing is ongoing and they should be available soon for purchase.