for Round Punches
following form will help you calculate how much tonnage
is needed to punch round holes through a given thickness
of metal. There are some limitations that you should be
aware of. If you do not need a flat slug you can lower
the tonnage required by adding a shear cut to the punch.
Maxium amount of shear will cut tonnage in half as long
as you have enough stroke movement on the punch. All input
into the form below should be placed in decimal equivalants.
Following are thickness tolerances on galvanized steel.
Note: for holes 5/16" or less, the material thickness
can not exceed the diameter of the hole being punch.