[TheForge] Punching holes with Hydrolic press

[Andrew Vida]

On 10/4/2011 2:22 PM, Bob Ehrenberger wrote:
> The
> only problem is that the material sticks to the punch and has to be knocked
> off after raising it up.  It's a whole lot easier than drilling big holes in
> thin material.

Your clearance is too large.  I'd keep it to 0.010".  Also, a 1* or 2* 
negative draft angle for clearance with perhaps a 0.30" margin, like so:

          |          |
          |___    ___|
             /    \
            /      \<--- 2* - 4* included relief
            |______|<--- Margin

The margin serves two purposes: it strengthens the edge and provides 
some allowance to redress the punch for wear.