Equations for Determining Correct Required Tonnage


There are many factors that contribute to a successful operation. Determining the correct tonnage required for punching mild steel is just one of those variables. Cleveland Steel Tool recommends the following formula for computing the approximate tonnage required to punch a single round hole in mild steel.



Cleveland Steel Tool recommends the following formula for computing the approximate tonnage required to punch a single shaped hole in mild steel.


For punching materials with different tensile strength, first determine the tonnage required using the given formulas, then use the following multiplier:

Material
Multiplier
Aluminum
.38
Brass
.70
Copper
.56
Steel (mild)
1.00
Steel (50% carbon)
1.50
Steel (cold drawn)
1.20
Stainless Steel (303)
1.50