I used an old file and then a cut off wheel on my Foredom to shape the tip. After that I used course and then finer silicone wheels to polish it down. Finally, I used a polishing wheel to bring it up to a nice shine so it won't mar the bezel when I tap it down.
Do note though that if you do this you need to make sure you "break the edges" of the punch when you make it. That means that none of those surfaces you created should be pointed edge sharp. All of them are rounded. They might look sharp in the photos but I carefully made sure that those edges are "broken" in all directions like the drawing.
Now go forth and make really thick bezels!!!!