How to Drill a Square Hole Without Any Special Tools

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Drills are ultra-versatile. They’re primarily used for creating round holes and driving fasteners. But you can also do a bunch of unexpected things with an average drill. This includes twisting wires, mixing paint, and sanding curved surfaces.

Although drills have many uses, it can be a challenge to use them to create square holes. To do so, you typically need to purchase specialty parts or equipment that you may not want to invest in.

Thankfully, there’s an easier way to do this. Keep reading to get a look at how you can drill a square hole without any special tools.

What do you need a square hole for?

Square holes can be useful for a variety of reasons. Here are some of the most common reasons why you might want to create one.

PLUG SOCKETS

If you’re adding new plug sockets to your home, then you’re going to need to create a square hole to do so. Traditionally, electricians have done this by manually cutting them out of the wall with hand saws and pencils.

LIGHT SWITCHES

Light switches also need a square hole in the wall to be installed. The method below will enable you to make the square holes that you need effortlessly.

HOLDING CARRIAGE BOLTS

Carriage bolts are a type of bolt that’s commonly used to fasten metal to metal or metal to wood. They’re often used in the construction of wooden decks.

BECAUSE YOU CAN!

Sometimes a round hole just won’t do. Regardless of why you feel the need to drill a square hole, the method below will make it easy for you to create one without having to buy any special tools.

Challenges of drilling square holes

Drilling square holes is difficult because of how most drill bits are made. Virtually all of them, save for specialty products, are round. This means that they have to drill round holes.

It would be a breeze to create square holes with a drill if drill bits were also square. Since they’re not, you need to either purchase a specialty bit or come up with a creative solution to create the square holes that you want.

What special tools would you usually need?

There are several different ways to go about creating square holes with special tools. But the most common and cost-effective way is to purchase drill bits that have been designed to create this type of hole. There are two major options to consider if you decide to go this route.

MORTISE BITS

The first is called a mortise bit. Mortises are square holes and mortise bits are what’s needed to create them. These drill bits are created from two distinct parts. 

They have a standard auger-style bit, which usually would cut a round hole. But this bit is placed inside of a square housing with sharpened edges. The auger-bit cuts a round hole and the square housing squares off the edges of the round hole to turn it into a square one.

REULEAUX TRIANGLE BIT

Reuleaux triangle bits can also be used to create square holes. But they leave small rounded corners, which you would have to go back over with a chisel to square off. Additionally, standard drills won’t work with a rouleaux triangle bit. You would need to buy a special type of tool to use.

What you’ll need

Creating a square hole without any special tools requires a few things. Here’s what you’ll need:

The most important thing here is the broach. That’s what’s going to turn your round hole into a square one. You can either purchase a broach online or create one yourself. More instructions on how to make your own are included below.

How to make a square broach

Square broaches can be very handy to have on hand if you plan on creating square holes often. They’re pretty easy to make yourself if you have a solid set of tools at your disposal. Going the DIY route will save you money and give you more control over the final dimensions of your broach.

STEP 1: GET YOUR STEEL

To create a square broach, you need to begin with a piece of steel that corresponds to the rough diameter that you’d like the square hole to be. Of course, this will depend on your goals and what you think you’ll have the most need for in the future.

STEP 2: CHOOSE YOUR TOOLS

When creating a square broach, your goal is to notch a set of square “teeth” along the length of the steel that you’ve selected. Only the final “tooth” needs to be precise. It’s fine to eyeball the others.

There are two different ways to create these notches. You can do so with a lathe or with a grinder. We recommend that you choose whichever one of these you have on hand and have the most experience with.

STEP 3: CREATE THE BROACH’S TEETH

Now, you’re ready to notch teeth into the broach. If you’ve decided to use a grinder, then start shaving little notches into the piece of steel that you have. Make sure that you measure carefully when you get to the final notch, as this is what will determine the dimensions of your square hole.

If you’ve decided to use a lathe, then your instructions will be a bit more complicated. Check out this handy video to see a full overview of the process.

How to drill a square hole without any special tools

Once you’ve gathered all of your tools, you’re ready to start using your broach to cut square holes into metallic and wooden surfaces. Here’s how to do it.

STEP 1: DRILL A ROUND HOLE

Begin by drilling a round hole in the place that you’d like for your square hole to end up. You can use whatever circular drill bit you want for this. Just make sure that it’s about the same size as you’d like your square hole to be. But don’t worry about making it exact. That’s what your broach is for.

STEP 2: FILE AROUND THE EDGES

Next, you’ll need to grab your square file. Run it through the square hole that you’ve just created. You don’t need to file excessively. The goal here is to just give your broach a little extra room to get itself nicely positioned into the hole during the next step.

STEP 3: PLACE THE BROACH IN THE HOLE

This is what the lubrication is for. You’ll probably need to lubricate the broach and possibly the hole as well to get the broach situated.

STEP 4: PLACE THE BROACH INTO A VICE

A vice will create the pressure that the broach needs to cut through the round hole and create a square one in its place. All that you need to do is place the broach into the vice and tighten it.

Once you do, you’ll need to give it 4-5 minutes to work. But the exact amount of time that’s needed in the vice can vary based on the toughness of the material that you’re working with.

STEP 5: USE A HAMMER TO KNOCK THE BROACH OUT

When you release the vice, you should find the broach stuck in the hole. You can use a hammer to get it out. Just hit it a few times and the broach should pop out without much difficulty. This is another benefit of using lubrication during this process.

STEP 6 (OPTIONAL): FINE-TUNE THE HOLE SIZE

At this stage of the process, you should be left with a square hole that resembles the size and shape that you were looking for. But you may still feel like it could be better. If so, you can use this method to fine-tune the hole until it meets your exact specifications.

Use a blowtorch to heat the broach. Make sure that you’re wearing fire-resistant gloves and clothing while doing this to keep yourself safe.

Once the broach is heated, simply insert it back into the hole. You should be able to this with just your hands at this point. Allow the broach to remain in the hole for a few minutes and twist it around a bit if you can. This should create exactly the square hole that you’ve been looking for.

What’s Next?

If you’ve made it this far, then you must be pretty handy. So why not put those skills to use? Surehand makes it incredibly easy to connect with industrial employers who are looking for candidates with your exact set of skills.

Getting started is a cinch. Begin by downloading the Surehand app here. Then, create a free profile and tell us a bit about yourself. We’ll automatically use that information to connect you with industrial employment opportunities that match your experience and skills.

You can even apply for thousands of other jobs hiring now. Download our app today to get started.

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