As for interpreting the size chart for the shapes: they make
square punches from 1/8"x1/8" through 9/16" x 9/16" for the No. 24
punch on this page:
http://roperwhitney.com/punching/2-13.cfm. Other punches do other
size ranges.



Please read the last line.

It is all right where I told you to look. Here is a quotation
from the page referenced (http://roperwhitney.com/tech/tech2.cfm)
:
For Irregular Shape Holes
For punching irregular shaped holes (square, rectangular, obround,
triangular, etc.) multiply the length of metal to be cut by the
multiplier given for a 1" length in chart #4.


Example: The shear length (or total distance around a 1" x 2"
rectangular hole) is 6". To punch such a hole in 20 gauge mild
steel multiply 6" x 1.01 (from chart #4) = 6.06 tons. For
stainless steel this would be 6 x 1.50 = 9.0 tons.

Please read the last line. They use a simple multiplier to
calculate tonnages for stainless steel.

(top posted for your convenience)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Keep the whole world singing . . . .
DanG (remove the sevens)




"Grant Erwin" wrote in message
...
DanG wrote:

Go to any one of their pages under the "Punching" heading.
Scroll to the bottom of the page. There is a picture and sizes
of the punches that fit each particular punch. The very first
page I sent you told how to calculate the number of tons you
would need to accomplish your task.

I didn't see anything on their site which showed punching force
in tons for stainless steel, only for mild steel.

GWE