Need Help!- Building a paper punch, need help designing the punches.

[basalt]

Hi guys,
I am going to build a paper punch because I want to punch 44 ea. 1/8" dia. holes for 10 only calendars (about 13 pages each). My question is -- will mild steel be sufficient for the punches or should I use O1 heat treated steel? Also, should the business end of the punches be concave, flat or? Any other suggestions would be welcome.
Thank you for taking the time to read this.
Colin

[Peter H]

If you are talking about punching 44x10, 440 holes in 10 calenders and never use the punch again, probably don't need to be too worried about the material. I'd go in my bin of broken drill bits (have broken on or two but it really was because the manufacturer mess up the heat treatment), find a 1/8" bit and use the stub. Grinding on an angle means less force to cut. If the grind is flat, then you have to cut through the whole perimeter at one time. Grinding it at an angle means you only are cutting at 1 or two contact points at a time.