All of us want our tools to be as sharp as possible so we can do our best work. One of my pet peeves is dull punches, especially rotary ones. 40 years ago, we could get new tips or a new rotary punch and even the cheapest ones would cut well by today’s standards. These days it seems to be a different story. I would buy a new one but if they were crap 30 years ago so they’re not going to be better now. I decided to sharpen the tips in the ones I have.
To use as a holder to sharpen the tips, the handle from my Tandy 3003-00 Mini Punch Set worked great. The thread size is the same as the rotary punch tips so I got to work.
To hold the tips, I chucked the handle in my hand drill.
While running the drill, I lightly touched the tips against my grey-green extra-fine grit CRATEX wheel at an oblique angle, being careful to not heat them. Also I didn’t want to take too much material off.
Then I did the same with the leather polishing wheel on my knife grinder using red jeweler’s rouge. Note that the grinder is turned around so the polishing wheel rotates upward. The tip is not digging into it.
You can tell when you have the tip sharp enough when it will not slip off your thumbnail when held at a very low angle.
I did this for all 6 tips on both of my good quality punches and when done, they all cut effortlessly, as good as any punches I’ve ever used.
If you don’t have a grinder with a CRATEX wheel and a low RPM knife grinder, get creative but don’t use a normal grinding wheel or you may wind up with tips that are too short or ground lopsided and still won’t cut right. You might be able to do the same thing by dragging the tip across a stone while turning in the drill. Then following that with a piece of leather with your polishing compound on it. I hope this gives some direction to others with the same dull rotary punches.