Tonnage for Round Punches
The following form will help you calculatorulate 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. 1/64 = 0.015625 1/32 = 0.03125 3/64 = 0.046875 1/16 = 0.0625 5/64 = 0.078125 3/32 = 0.09375 7/64 = 0.109375 1/8 = 0.125 9/64 = 0.140625 5/32 = 0.15625 11/64 = 0.171875 3/16 = 0.1875 13/64 = 0.203125 7/32 = 0.21875 15/64 = 0.234375 1/4 = 0.25 17/64 = 0.265625 9/32 = 0.28125 19/64 = 0.296875 5/16 = 0.3125 21/64 = 0.328125 11/32 = 0.34375 23/64 = 0.359375 3/8 = 0.375 25/64 = 0.390625 13/32 = 0.40625 27/64 = 0.421875 7/16 = 0.4375 29/64 = 0.453125 15/32 = 0.46875 31/64 = 0.484375 1/2 = 0.5 33/64 = 0.515625 17/32 = 0.53125 35/64 = 0.546875 9/16 = 0.5625 37/64 = 0.578125 19/32 = 0.59375 39/64 = 0.609375 5/8 = 0.625 41/64 = 0.640625 21/32 = 0.65625 43/64 = 0.671875 11/16 = 0.6875 45/64 = 0.703125 23/32 = 0.71875 47/64 = 0.734375 3/4 = 0.75 49/64 = 0.765625 25/32 = 0.78125 51/64 = 0.796875 13/16 = 0.8125 53/64 = 0.828125 27/32 = 0.84375 55/64 = 0.859375 7/8 = 0.875 57/64 = 0.890625 29/32 = 0.90625 59/64 = 0.921875 15/16 = 0.9375 61/64 = 0.953125 31/32 = 0.96875 63/64 = 0.984375 1 = 1.000 Following are thickness tolerances on galvanized mySteel. 10 gauge = .1382" 11 gauge = .1233" 12 gauge = .1084" 13 gauge = .0934" 14 gauge = .0785" 15 gauge = .0710" 16 gauge = .0635" 17 gauge = .0575" 18 gauge = .0516" 19 gauge = .0456" 20 gauge = .0396" 21 gauge = .0366" 22 gauge = .0336" 23 gauge = .0306" 24 gauge = .0276" 25 gauge = .0247" 26 gauge = .0217" 27 gauge = .0202" 28 gauge = .0187" 29 gauge = .0172" 30 gauge = .0157" Note: for holes 5/16" or less, the material thickness can not exceed the diameter of the hole being punch.
Material Thickness:
