How to Enlarge an Existing Hole in Metal?

How to Enlarge an Existing Hole in Metal

You all know that we need to make a hole in metal for attaching different metal pieces and making metal items. But sometimes, it also needs to enlarge the existing hole; it becomes a harrowing and ridiculous experience to enlarge the existing hole to fit the wider metal pipe in that hole. A professional knows well how to enlarge the existing hole in a metal, but what will you do if you are not a professional?

Today here we will describe to you each and everything about how to enlarge the existing hole. It will help you know how to make a hole in the metal, and also, you will learn how to enlarge the existing hole in the metal.

What will you need to enlarge the existing hole in metal?

What will you need to enlarge the existing hole in metal

Materials and tools are your power, so you should arrange the required tools for completing your task before doing anything.


Holesaw is one of the best tools that you will need to cut the hole in metal surfaces, and it also helps to enlarge the existing holes in metal, wood, plastic, and many other hard surfaces. Holesaw comes with sharp blades which efficiently work to widen the hole in the metal. Professional workers widely use the holsesaw for digging holes in the metal and enlarging the metal’s existing holes.

You may think it is pretty easy; it is a challenging job that needs proper guidelines to complete your project safely and efficiently.


One of the most accessible tools for drilling and enlarging the existing holes in metals is Unibit. But you can only work with that tool on softer surfaces like acrylic, plywood, and such other surfaces. It is also helpful to dig holes in thinner surfaces of any material and even stainless steel.

It allows you to enlarge the holes by using different diameters step by step and drilling with a staunch profile. If you want to enlarge the hole size, you will need to use a more significant bit.

Knockout Punch

Are you working with some electrical works? Then the Knockout punch is the better tool to enlarge the existing hole in the metal surface. Electricians use that tool for enlarging the holes in electrical boxes. It is pretty easy to operate; you can easily enlarge the holes in the metal sheet by using Knockout Punch.

What mechanical engineers recommend?

What mechanical engineers recommend

When we consider the mechanical engineer’s recommendation, they recommend many types of reamers to enlarge the existing holes, such as jobbers’ reamer, hand reamer, taper pin reamer, chucking straight and fluted reamers, etc.

But the principle of working is identical in all of them because they follow the rotatory cutting principle to dig and enlarge holes in the metal surfaces. Reamers are made up of high-grade carbon steel material with great strength and work awesomely with hard surfaces.

Step by Step guide to enlarge the existing hole in the metal

Follow below simple step-by-step guidelines and enlarge the existing holes in metal.

Step one

Start with fixing the metal workpiece securely; it is necessary to keep the workpiece in the same place firmly while working; otherwise, you will feel uncomfortable or hurt.

Step two

You may have many options to use reamers to enlarge holes in metal, but it does not mean all of the reamers are good to use. It would help if you had an appropriate reamer for digging the hole. 

For that purpose, measure the size of the hole and then choose the reamer according to the size of the required hole. It would be best to consider reamers diameter, desired accuracy, and finishing selecting the right one for your project.

It is essential to choose the right one and choose great care because, if you choose the wider size, it is hard for you to shorten the width of the hole in metal surfaces. So consider the size and then select only the required reamer.

Step three

The next step is to attach the reamer with the drive tool. When you connect it with a reamer, make sure you have correctly fit the reamer to the drive tool. Loosely attached or improperly attached reamers affect your performance and make it hard for you to work.

Step Four

Now choose the correct adapter; selecting the correct adapter is necessary for drive tools for proper functioning. After selecting the right one, then fit the adapter to the drive tool and then inject the reamer. Once you have attached the adapter, then fit that reamer into the drill machine and then secure it properly.

Step Five

Now use the reamer to widen the hole. Just insert the reamer in the existing hole. Place the reamer on the spot, switch on the drill machine, and apply pressure, and cut the metal pieces to widen the hole. Do not lose your control over the machine and follow a consistent pattern until you get the right size of the hole.

Helpful tips

  • Do not run the reamer in the reverse direction.
  • Before doing anything, arrange for your safety first
  • Use cutting oil while you are working
  • Always use the reamer at a right angle

Final Thoughts

We need to dig and enlarge the existing holes in the metal surface. Reamers are the best way to reaming the existing holes. Reamers allow you greater flexibility to drill different sizes of holes in metal. You need to choose the proper reamer according to your needs. After selecting the suitable reamer then follow the above simple steps to enlarge the existing hole.

How to Enlarge an Existing Hole in Metal?
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