Selecting a Punch or Press
The following information, while not totally applicable to all fabricating machinery included in this product area, is provided as a convenient general reference for metal punching operations up to and including large power presses. Specific questions not answered by this data may be directed to Roper Whitney without obligation.
Hole Size vs. Material Thickness
Punching holes in metal is the fast, economical way to get precise hold size, smoothness and minimum burr. Compressive strength of the punch steel determines that the thickness of the metal being punched must not exceed the diameter of the punch. This relationship varies with the type of material. For example, the minimum hole diameter will be 1/4″ in 1/4″ mild steel, 1/4″ in 3/16 stainless steel and 1/4″ in 5/16″ aluminum.
Maximum Rated Capacity
All punching tools have their maximum capacities for safe, dependable operation over a long life span. Tools listed on this site have a “rated capacity” based on their design strength. Before selecting a tool, use the charts to determine the specific tonnage required to punch the size and shape holes through the type and gauge metal considered. These figures are for flat punch points. Shear on the punches will reduce the tonnage required.