What’s a KO punch?

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A hole punch is a tool used to create holes in electrical boxes or panels, made up of a cutting head and a threaded pin. They can be operated manually or with a hydraulic pump attachment. Punch sets come in various sizes and are made from high carbon steel.

A hole punch is a tool or set of tools used to punch a hole in electrical boxes or panels. These tools also cut through heavy sheet metal, plastic, and fiberglass. The two-part punch includes a cutting head or die and a threaded pin. The tool is sold separately or in sets which include various standard sizes for electrical, plumbing and other types of industry.

Most types of electrical panels today are made with pre-molded pre-molded plugs, which eliminate the need for a pulling tool. The pre-molded plugs are easily removed by using a pair of electric pliers or similar tool by piercing the plug and twisting it to loosen it. Conduit connects to these holes to accommodate additional electrical circuits. In certain situations it is necessary to create additional holes or enlarge existing ones to accommodate the ducts.

The operation of a puncher is done manually or with a hydraulic pump attachment for easier handling. Both types of hole punches require drilling or using an existing hole in the electrical box or panel. The threaded pin fits through the hole. Then, the cutting head or die threads onto the pull pin until it is snug against the switch box.

Hand punches have a large bolt head located on the pull pin. An adjustable wrench, standard wrench, or socket tightens the bolt head. This tightening then pulls the cutting head through the material, creating an appropriately sized hole.
Hydraulic versions of the puncher use a hydraulic hand pump for easier operation. The portable water pump looks like a common grease gun. It attaches to the drawing pin and is manually pumped to pull the cutting head or die through the material to create the hole.

Common knockout punch sets include a case, dies — or cutting tools — and pull rods. These are designed to create standard sized punches of conduit ranging from 0.5 inch (about 1 cm) to 2 inch (about 5 cm) and 2.5 inch (about 6.3 cm) to 4 inch (about 10 cm). The hydraulic versions of the knockout punch sets also include a hydraulic hand pump. The pieces in the set are typically made from high carbon steel, allowing the pierce punches to cut lighter steel up to 10 gauge (about 25cm) thick.




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