How to Drill a Square Hole in Wood (3-Easy Methods)

Before we show you the various methods of drilling a square hole. Read the table below.

What you need to know about how to drill a hole in wood?

Drilling a square hole, especially in soft material such as wood, can be done quite easily. Traditionally there are many ways to do this but ideally these three ways can be grouped into 3 main methods. Namely:

• Physically Filing (Cheapest but most labor intensive)
• Using a jigsaw blade (Middle of the road in terms of price, time and labor)
• Using a Mortise chisel with drill press(Most expensive, but most accurate and quickest)

Basic principles of drilling square hole in wood

What I want you to note, is that no matter which method you use above, all square holes practically start off as round holes.

The mortise drill bit basically consists of an auger which is connected to a 4 sided square chisel. The auger drills a round hole. The chisel creates the square.

This combination is very common for woodworking professionals and hobbyists and is the most efficient method of drilling a square hole in wood especially for furniture makers.

Circular holes can be created using stock standard high speed steel drill bits or their equivalent.

What I have noticed is when planning your square hole – your circular drill bit is there to determine the diameter that you want.

So choose the circular drill bit for the diameter of your specific application before commencing with creating the square holes.

Let’s look at the various methods of drilling. We have summarized them in the follow up sections. 

I have documented all of the methods above for your convenience. But choose the one that works best for your time and budget.

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Equipment You’ll need to learn how to drill a square hole in wood

For Physically filing the square hole, you will need:

• Straight edge and scribe (Basically ruler and marker)
• Circular drill bit
• Vice and drill press - My Top Pick: ⭐Irwin Drill Press Vice⭐
• 3 square file

Using a Jigsaw Blade

• A jigsaw - My Top Pick: ⭐Black & Decker Jigsaw⭐
• A Straight edge and scribe
• Sanding stone and sanding paper
• Hammer
• Chisel
• Drill Bit

Using a mortise chisel with a drill press

• Mortise chisel - My Top Pick: ⭐Hurricane 4 piece Mortise Chisel⭐
• Auger drill bit
• Bench press
• Vice

It is important to further note that for all such woodworking projects, safety is a massive factor. So please make sure you have all the necessary protective equipment such as glasses, gloves etc.

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How to Drill a square hole in wood (4-Step Guides)

Physically Filing Square Hole

Step 1: Prepare workstation

Make sure that the area you are going to work is clear and clean. This is because as we are drilling there is going to be a lot of wood chips that will be created as debris.

An unorganized workspace also increases the chance of injuries.

Step 2: Drill round hole in wood stock

Place your piece of wood in a vice on your mechanical workstation.

Make sure you fasten the vice as tightly as possible. What I have seen is that If the wood gets loose, the hole will not be aligned as intended.

Step 3: Mark out the square

Remove the wooden piece from the vice, now take your straight edge and marker and create a square as shown in the image below.

The key here is to ensure that your lines intersect the perimeter of the circle and that the angle of contact between the lines is 90°.

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Step 4: Physically file the square

In my experience, using a straight edged file makes this process extremely difficult. What you will want is to use a 3 edged file.

This makes the entire process easier because it will give you more leverage on the corners.

Most people also make the mistake of using a 4 edged filler because they associate 4 edges with a square.

Using a jigsaw blade

Step 1: Mark out the dimensions

First off use your pen, pencil or marker to mark of the dimensions on your wooden sheet or board.

Step 2: Drill holes at the corners

Once you have marked off the dimensions correctly, you should use a small drill  and create circular holes at each of the 4 corners of the square.

This is key, as it will make using the jigsaw much easier.

Step 3: Cut using the jigsaw

Take the jigsaw and move it to one of the corners.

Create an incision with the blade whilst slowly increasing the speed.

Once your jigsaw is through the blade’s edges continue to follow the marked lines that you created in step 1. Until you have created a square hole in the wood.

Step 4: Sand the edges

Use your sand stone and sanding paper to remove any splitters or wood flake debris from the edges of the board. Making sure that the surface remains smoothed out.

One thing I have found is that this method works well if the square hole you are creating is bigger than 4 x 4 inches.

When you go for a smaller square, what tends to happen is that the edges become very roughed out because of the large saw blades on the jigsaw.

You can very easily rectify this by sanding out the edges using a 3 sided wood filler.

So it is not a big issue, it is something just to think about if you want to go with this method.

My advice is avoid the 4 edged filler for this application, simply because it is very cumbersome and does not provide as clean a finish as the 3 edged.

Using a mortise chisel, auger and  drill press

Step1: Assemble the mortise, auger and chisel

The mortise chisel and the auger are usually separate components. So ensure that they are assembled together as below.

Step2: Position wooden piece in the vice

Place the piece of wood, within the vice and fasten the vice tightly as image above.

Ensure the vice is tightened as much as possible as because the moment you turn on the drill press the vibrations from the drilling will move the wooden piece if not tightly fastened.

Step3: Mark out the dimensions of the square hole

Use your marker and a straight edge/ruler to create the dimensions of the square hole.

A key note here is that this method is actively used when creating square or rectangular holes of various shapes and sizes.

Especially for wooden furniture.

Therefore - It is a lot more flexible both in terms of the thickness of wood you can use and the shapes and you can create, than the previous two methods.

Step4: Use the drill press to create Square hole

What I generally do, is create a small punch hole before pulling down the crank at full speed.

The purpose of this small hole with the drill press is to help with the friction and traction. I have seen it creates more accurate square holes with a lot less splinter and wooden debris.

The key here is to pull down the crank, in a controlled manner – making sure the hole comes out with a great square shape.

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Pros and Cons of the various methods

The table below provides a summary of the key pros and cons of all the methods on how to drill as square hole in wood.

Final Thoughts on how to drill a square hole in wood

Drilling a square hole in wood is not that complicated. The principles are the same as drilling circular holes.

The only difference is that wood is more pliable and flexible than hard steel or alimunium.

So you must make sure that you choose drill bits correctly, protect your eyes from splinters and plan your equipment and workstation spaces correctly before commencing the work.