At the dump today Jill found me a grindstone just sitting neglected in the dumpster. Now it has a new home. I paired it with a small piece of rubber and a drill bit:
Then I attached it to my drill and went to town on some hard-to-sharpen blades, like my two machetes and Jill’s whittling knife.
They’re not quite “easily cut through paper” sharp but they’re plenty sharp for what I need them for 🙂