Punches are fabricating tools used to perforate material and create cuts or holes in the shape of the punch edge. They include a variety of tools, dies and machine stamping devices that are used to produce components with specific shapes. Hand-held punches come in sets of different-sized dies with handles. They are struck with a hammer or mallet to cut the material on impact.

Types of Punches

The Engineering360 SpecSearch database provides information about these and other punch types.

• Center punches are used to mark an indentation for guiding drill bits and identifying a location on a surface.
• Drift punches or drift pins are used to align bolt or rivet holes so that a fastener can be inserted.
• Ejector punches are designed to knock-out material or eject parts after a pressing or stamping operation.
• Marking punches are used to emboss or create a specific texture on the surface of a material or workpiece.
• Pilot punches have an inner pin that is used for aligning the punch to an existing hole, and allowing the outer point to cut out a larger hole.
• Pin punches are used to drive a pin into a mating bore.
• Prick punches are similar to center punches, but have a narrower point and are used for marking a design or layout.
• Solid or regular punches have a solid flat point with no voids or internal bores
• Straight punches are used to cut through sheet metal or other sheet materials such as leather or plastic.
• Transfer punches have a set shank diameter and are designed to transfer the geometry of several tapped holes by fitting the bore with close tolerances and marking the hole's center on another surface.

Each of these punches has a point with a specific shape and features. For example, some tools have D-shaped or hexagonal point that is flat or hollow.

Image credits:

AMPCO METAL | Carr Lane Manufacturing Co.