Here's a quick tip for you to remember the next time you need to punch a hole in a piece of shim stock. If you've got a drill of the proper size, and a piece of scrap, you've got everything you need to make a custom punch and die.
on large punchesuse the drill to make the punch AFTER you turn the punch from scrap. You will have way better results if you grind the shank end of the drill at a 1-2 degree angle rather than flat. When you chuck the die, hang it on the punch to get better centering and to ensure that the die is square to the punch. This will limit "puckering". To store these dies, put a bunch of finish nails in a board. stamp the decimal size on the outside then stone flush. End mill tubes work for punches.
There are a couple ways to prevent pucker. I'll explain one similar to Stan G. First, make another one exactly like the one you have in the left chuck. Second, make another one exactly like the one in the left chuck with hard rubber material. You now have drill bit, 2 steel dies, one rubber die. I'm running out of space to type. Put rubber/steel die (glued together) on drill bit, so it flush the bit. The rest you can figure. :)
You could try pushing the punch through the shim on a block of Urethane. There will be no need to make a die. Like this method - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-dOAVcJ1CCmY.html Probably best if you want the slug but could be handy to know.
