What is a Knock-Out Punch Tool?

A knock-out punch tool is a hand-held, power-operated, mechanical device that has one or more punches with the type of tips to suit the application. 

These tools are primarily used for punching holes in metal sheets and plates. Knock-out punches come in various sizes from 1/8 inch up to 3 inches in diameter. 

The hole size depends on what you need it for; often, they’re used for cutting out shapes like circles. They can be bought at most hardware stores as well as online retailers such as Amazon and eBay. 

A knock-out punch tool is an essential electrician’selectrician’s tool for connecting wires. The best way to use a knock-out punch is by using the back of the blade and pressing down on the wire being connected. 

This will cause the wire to be pushed through and a hole to form on both sides, making it much easier for you to connect your wires.

This blog post will give you all the information you’ll need about this handy tool!

Knock-out Punch

The best way to make a hole in an electrical box is with the help of a knock-out punch. This tool will give you many different options, and it’s perfect for creating clean holes that are needed when installing wiring or devices on your property. 

You may use this option if drilling isn’tisn’t possible due to time restraints, lack of space around wall fixtures, etc., but using one over another is more personal preference than anything else.

A professional electrician’selectrician’s favorite choice would be a heavy-duty hydraulic pump-type hand-held knock-out punch; however, manually operated punches work just as well for most residential needs too!


First, a pilot hole is drilled slightly larger than the screw of the knock-out punch. Then the die is placed on top of it and in line with its threads before guiding them into place by threading downwards using pressure to push through any resistance. 

Once fully threaded into place, you tighten down until there’sthere’s no wiggle or play left at all – this ensures that your job will be done right every time!

The manual system uses a standard hex head or square head with an Allen key for extra leverage when tightening things up after inserting from either side (and nobody wants to use their fingers). 

A ratchet wrench can also come in handy if you need something more powerful; these offer quick speed while ensuring accuracy without too much effort.

This system is a 220:1 mechanical advantage and can punch holes from 3-6 inches in diameter. It’sIt’s the easiest to use, yet it weighs the most of any other option, but that means you don’t have to spend time swapping out dies like with hydraulic systems, which are bulkier and heavier.

Size families and shapes

There are several different sizing systems for these punches. The two most common sizes are those designed for standard electrical knock-outs and intended to make true, dimensional holes. 

A 3/4 inch conduit size punch will create a hole that is approximately 1.1 inches in diameter – perfect if you’re looking to place something like an electric cable through it (like your TV power cord). 

Suppose you need a larger or smaller-sized hole than this one provides. In that case, there are also available sets of punches meant specifically with metric measurements to be used internationally!

A particular type of punch called “chassis” is made out of many shapes, including round, which seems preferable because more people have access to them worldwide, giving everyone equal opportunity.

Other shapes include square, hexagonal, and unique shapes for holes with key tabs and D-sub connectors. Uniquely shaped pieces often use bolts that are already squared off or have a particular type of head to ensure the punch hole aligns correctly without any wiggle room.

Using a Knock-out Punch Set

The knock-out punch should always be made with a specific set of materials, including the draw stud and die. To make this sturdy hole in metal:

  1. Drill a hole through the material using a drill and metal-cutting bit. The hole must be sized for the draw stud. Small draw studs are usually 3/8″ in diameter, while large ones can go up to 3/4″.
  2. The appropriate size of the die should be fitted onto the draw stud, then inserted into a pilot hole.
  3. Thread the desired size of punch onto the draw stud and hand-tighten it to your material’smaterial’s backside.
  4. With a ratchet wrench, turn the draw bolt. This pulls the punch toward the die and cuts through any material in its way.
  5. Separate the draw stud and punch to remove a little ring of waste material lodged inside. This is called a slug, which usually splits in half when it’sit’s hit by this kind of punch, so they call them “slug-busters.”

Reminders When Using a Knock-out Punch Set

The best tool for drilling the pilot hole is a step drill bit. This cone-shaped bit drills holes of various sizes and made for sheet metal and other thin materials. 

The self-tapping or self-drilling step bits don’tdon’t need to have a pilot hole to get started, but if you’ve ever drilled into metal before, then know it can be impossible without using one or making progressively larger ones as needed with your desired size until you reach success!

You never have to fumble around for a standard ratchet wrench and socket with knock-out punch sets. 

The input is always right at your fingertips, no need to search through drawers or in the garage when you’re trying to quickly remove an old pipe from just one hole on a spool of wire. Knock-out punches come in handy, too, because they can create holes anywhere between 1/2″ up until 2″.

A knock-out tool’stool’s essential components include a punch and die, a draw stud, and a device to pull the stud. 

Tools are rated for mild steel or stainless steel with many possible uses from punching holes in aluminum fiberglass plastic. Standard size hole punches range from ½ inch – 6 inches making them perfect tools no matter what you’re working on!

As of May 2017, Milwaukee Tool introduced Exact Rapid Reset Draw Studs for use with its established lithium-ion-­powered M18 Force Logic knock-out system. 

This newly developed product by the company is designed to provide improvements through evolution in a fast process. It has helped many contractors across North America save time on their projects and improve efficiency without sacrificing quality or performance.

About Blake Sutton

Blake has worked as an electrician for over 10 years, receiving his Journeyman Electrician license in 1998. Looking to take his professional electrical career further, in 2008 he received his Bachelor of Science in Electrical Engineering (BSEE) from the University of Texas in Austin. Blake now works full time as an electrical engineer, specializing in power systems.