Knockout Punches

An essential for electricians at both trade and domestic level, the knockout punch is a tried and trusted mechanism for achieving precision hole cuts in your metalwork and other materials. At RS, we stock a range of traditional manual knockout punch sets alongside a selection of heavier duty hydraulic knockout punch sets to deliver results on any project you need.

Shop from hundreds of knockout punch tools, covering a wide range of cutting sizes and material capabilities. Read on to find out more about knockout punches and how to use them, or start shopping our range of knockout kits now, using the filters provided to narrow down your search.

What is a knockout punch?

A knockout punch, sometimes known as a chassis punch or panel punch, is a tool or set of tools most commonly used to cut holes in sheet metal and electrical boxes or panels. Traditional knockout punch tools are very simple devices consisting of three parts - a punch, a die and a screw, and cut via a simple threading mechanism enacted by the user (typically via the use of a socket wrench).

Knockout tools are typically sold as part of knockout punch kits, which offer the user a number of different punches and therefore a number of different cutting sizes for their project. They represent a more precise alternative to using a hole saw and drill, using less effort and noise to make a cleaner cut.

What are knockout punches used for?

Knockout tools are primarily used for work on electrical boxes and panels to create precision holes for wiring, which is why knockout kits are sometimes referred to as electrical knockout sets.

Knockout punches aren't exclusively used for metalwork, however, as they can also be used for cutting through other materials such as plastic and fibre glass. The different gauges and power delivery formats make them suitable across a variety of domestic, trade and industrial applications - including in plumbing, for example.

What are the different types of knockout punch?

There are two basic specifications of knockout punch to choose from:

• Manual knockout punch sets offer a cheaper option that use a wrench or ratcheting mechanism to draw the punch into the die to cut the panel. They're not as powerful as hydraulic knockout tools but are typically more than capable of delivering results at domestic and trade level - for residential wiring, for example.
• Hydraulic knockout punch sets utilise hydraulic power to offer a powerful, easier to use solution. Hydraulic knockout punch machines are more commonly found at industrial level, where cutting of thicker gauges of sheet metal is required.

The type of knockout tool you require will depend on your project - more specifically the thickness of the material you're working with. Traditional knockout tools will typically cut up to 4-inch holes in thinner metals (a 1.5-inch knockout punch is a commonly used gauge), while hydraulic punches are best used with the likes of 10-gauge sheet metal to ensure precision cuts with the thicker material.

You can also choose from a number of punch finish types, including round knockout punch kits and square knockout tools. Across the RS range, you'll find a variety of brands, but we primarily supply Greenlee knockout punch sets as the most trusted manufacturer in the industry.

How do you use a knockout punch?

Both types of knockout punch require a pre-existing or pre-drilled hole to be inserted into for use. For manual knockout punch sets, you should take the following steps:

• Drill a pilot hole, the size of which will be determined by the screw or draw stud on your knockout punch.
• Slide any spacers and the die onto the screw.
• Insert the screw into the hole until the die lies flat against one side of the sheet.
• Screw the punch onto the screw on the other side of the panel.
• Tighten the screw until the punch is drawn through the metal and into the die to complete the cut.

For hydraulic knockout punch sets:

• Attach the correct punch mandrel to the hydraulic cylinder on the female side of the punch die.
• Drill a pilot hole big enough to clear the selected punch mandrel.
• Insert the mandrel through the hole and attach the male punch component on the other side of the panel so both sides are pressed firmly against the material.
• Pump the hydraulic tool's handle until the punch is drawn through the panel.

Get knockout results with RS

As one of North America's premier suppliers of electronics and tools, we're confident you'll find everything you need here at RS. If you're wanting to find out a little more about our knockout punch sets or discuss what the right tool is for your project, please don't hesitate to give our customer service team a call.

Alternatively, take a look at our expert content hub, where you'll find handy tips and advice on many of the items in the RS catalogue and how to get the best from them.