After the untimely demise of the much lauded mechanical pencil punch some time ago, I asked about alternatives and Micron pens were suggested. I'd used them extensively as an art student and had a few that were just about ready to go in the trash.
The 005 is the smallest pen Micron offers, with a tip of just 0.20 mm. That's a full tenth of a millimeter smaller than the mechanical pencil I bought! (cue sarcasm ;) )
It was painfully easy to disassemble, and I was so excited to give it a go!
Sadly, the highest expectations fall the hardest. The very first punch, and it snapped like a twig. Perhaps wider nibs work better; I'll probably never know, since anything larger than 0.3 mm is too large for what I do. If you have an old set of Microns that are about done, give it a go but if you ask me, don't go out and buy one of these expensive pens just to try it as a hole punch.