This is a vintage self-centering chassis punch (often referred to today as a knockout punch, radio punch, or coin ring punch set). It is designed to cleanly cut precision holes through sheet metal, electrical panels, chassis boxes, or coins.

How the Components Work Together: The Main Cylinder (Die Housing): The tall steel tube acts as the guide sleeve and die receiver. It holds the material flat and ensures everything stays completely vertical and centered.

The Interchangeable Discs (Spacers / Die Inserts): The different flat steel rings are sized to step down the inner diameter of the cylinder. You swap these out depending on the specific diameter of the stock or hole size you are targeting.

The Center Pin & Tapered Mandrel: The pin assembly acts as the driver. It passes directly through the center of the discs to keep the punching force perfectly aligned without tearing or warping the edges.

How It Is Used:A pilot hole is drilled into the center of the metal sheet or workpiece. The piece is sandwiched between the die cylinder and the cutting discs.The center pin guide is inserted through the stack.The top of the pin assembly is either struck with a heavy mallet or loaded into a manual hydraulic press to cleanly shear out a perfect circular slug.