How to Drill a Square Hole in Wood?

We mostly talk about round holes in drilling, but they are not the only type of holes you will need to drill if you take up woodworking.

When most of the drill bits we come across drill round holes, every amateur wonders how they can drill a square hole in wood.

There are several reasons you might want to drill a square hole in wood. From aesthetic holes to essentials like mortise and tenon joints, you will need to drill square holes in wood in every other wood-working project.

In this article, you will get all the information you need for drilling perfectly square holes in wood.

How to drill a square hole in wood? To make a square hole in wood, drill a normal round hole and then use a square punch to convert it into square one. You can automate this process with a mortising machine for square holes, mostly used by professionals. You can also use a simple wooden chisel to make a square hole. Wood craftsmen and artisans prefer this method.

Each technique used to drill a square hole in wood differs greatly and depends on the nature of your project. I have given in detail each of these techniques, ranging from the easy fixes one can use to the most professional techniques used by woodworking professionals.

Techniques to Drill a Square Hole in Wood:

drill a square hole in wood

There are a variety of tools you can use to drill a square hole in wood.

For smaller projects with a limited budget, you can use simpler tools to achieve a square hole. But as the scope of the project increases, you need to invest in more specialized tools, which, although are expensive, can significantly ease your job.

Regardless of the tools you choose, you will need to learn some techniques to drill a square hole in wood. You can go through the step-by-step guide for drilling square holes with each tool below.

But before we jump on how to cut a square hole in wood, you need to make sure that you are taking all the necessary safety precautions.

Safety Precautions:

To be able to drill a square hole in wood without hurting yourself, follow these safety precautions:

  1. Wear a pair of safety goggles if you are going to use power tools.
  2. Make sure your workroom is well ventilated or take your work outdoors.
  3. Follow the safety instructions given with the power tools.
  4. Wear protective gloves, a dust mask, and closed shoes.
  5. Make sure the cutting tools have sharp blades.

My favorite list of safety gear. You may not need all of them.

1. Dewalt Safety Glasses
2. Latex Double Coated work gloves
3. 3M professional Dust Respirator
4. Dewalt Industrial Grade Ear Protection
5. 3M Hard Hat
6. Caterpillar Steel Toe Industrial Boot
7. First Aid Kit
8. Fall Protection Kit

Tools & Methods to Drill a Square Hole in Wood:

1. Square Hole Punch:

A relatively new product for woodworking, square hole punch is designed to help you drill a square hole in wood without a hassle. Square hole punches use the principle of a mortise machine but can be used easily with a cordless drill.

Although they are inexpensive and easy to use, square hole punches can only drill square holes of up to 1/2″ depth and hence are better suited for drilling decorative square holes in wood.

Tools:

Square hole punch drill bit set, Cordless Drill, Drill Bits, Frame Guard

Steps to make a square hole with a square punch

  • Start by drawing the square with a frame guard.
  • Now select a square punch that matches the size of your desired hole.
  • Take a drill bit slightly smaller than the punch.
  • Drill the center of the square with the drill.
  • Now place the punch over the square.
  • Start hammering the punch.
  • Remove excess wood from the hole.

2. Chisel:

A chisel is the most basic and inexpensive tool in your toolbox that you can use to drill a square hole in wood. However, it requires a lot of time and energy to get a precise square. Therefore, it is more suited for smaller projects where you are using thin wooden sheets.

Tools:

Chisel, Framing square, Sledgehammer, Sandpaper

Steps to make a square hole in the wood with a chisel

  1. Use a framing square to draw the square you want to drill.
  2. Place the tip of the chisel on one of the corners of the square.
  3. Tap on the chisel with a sledgehammer.
  4. Keep tapping until you reach the bottom of the sheet.
  5. Repeat the steps for each corner of the square.
  6. Take out the square.
  7. Smoothen the edges with sandpaper.

3. Drill and Chisel:

While you can use a chisel to drill a square hole in wood, it is not suited for larger projects where you need to drill thick wood.

Using a cordless drill with a chisel, you can easily drill a square hole in wood without having to break the bank by getting expensive equipment. If you don’t own a cordless drill, you can easily select one from this list of cordless drills under $50 that I have compiled.

Tools:

Cordless Drill, Drill Bit, Chisel, Frame square

Steps to make a square hole in wood with a chisel after drilling it

  • Start by drawing the square you want to drill using the frame square.
  • Now take the largest available drill bit that is smaller than the square.
  • Drill a hole in the center of the square.
  • If there is little wood left on the corners you can stop drilling.
  • If there is still a lot of wood on the corners drill more holes on the sides.
  • Now use the chisel to remove the left wood from the corners.
  • Finish by using sandpaper to smooth out the hole.

4. Drill and Saw:

When the square hole you want to drill is significantly large, you can use a cordless drill, and a cordless circular saw to do the job. You can use this technique for both thick and thin wood sheets.

While using a cordless drill is quite simple, you need some experience to use a cordless saw properly. You can try practising cutting along a straight line on scrap wood until you have a steady hand.

Tools:

Cordless Drill, Cordless Circular Saw, Frame guard, Sandpaper

Steps to make a square hole in wood with a drill and saw

  • Use the frame guard to draw the square you want to drill.
  • Now install a appropriate drill bit in your cordless drill.
  • Put the drill bit on one of the corners of the square and drill through it.
  • Repeat for all the corners of the square.
  • Now use this hole as a starting point for the saw.
  • Cut through the wood along the line of the square.
  • Repeat for each side of the square.
  • Finish by using the sandpaper for smoothing the hole.

5. Use a Square Drill Bit with a Mortiser Machine

drill a square hole in wood

The most professional way to drill a square hole in wood is to use a mortise machine woodworking professionals use to get perfectly square holes in wood without having to put in a lot of time and energy.

To be able to understand the working of a mortise machine, we first need to understand some technical jargon. A square hole is referred to as a mortise and hence the name mortise machine. Mortise machines are available as a stand-alone tool as well as drill press attachments.

Although they are quite expensive as compared to other tools we have mentioned in this article, they are actually worth the investment if you are seriously taking up woodworking as a hobby or a profession.

Working on a mortise machine is quite simple. It uses an auger drill bit enclosed in a square chisel which works together to give you perfectly square holes.

You can follow the instructions given below to drill a square hole in wood using a mortise machine.

Tools:

Mortise Machine, Mortising Chisel Set

Method:

  • Start by marking your square on the wood.
  • Now insert the chisel and drill bit into the machine such that the tip of the auger bit leads the chisel.
  • Set the hold down to prevent the wood from lifting when you remove the chisel.
  • Start drilling using the machine. IF the square you want to drill is the same size as the chisel you can stop after drilling once. If the square is bigger drill multiple holes.
  • Use such a sequence that there is wood on four or two sides of the chisel and never three sides.

Best Square Hole Drill Bits for Mortiser Machine

Here are a few best square drill bits you can get for your mortiser machine. Please note that you can not buy a square hole drill bit for a hand drill and these mortiser machine bits won’t work with a hand drill.

NOTE: They will also not work with a regular drill press. You will have to buy this adapter which is a little expensive to be able to use with a standard drill press. Also, check alternatives. The drill bits selected below are just the bits.

  1. WSOOX Square Hole Drill Bits for Wood, Woodworking Hole Saw Mortising Chisel Drill Bits (Size: 1/4 inch, 5/16 inch, 3/8 inch, 1/2 inch)
  2. BAYICLAN Square Hole Drill Bit, Woodworking Hole Saw Mortising Chisel Drill Bit Tool Set 1/4″ 5/16″ 3/8″ 2/5″ 1/2″ 5Pcs
  3. Necygoo Woodwork Drill Bits 4PCS Wood Square Hole Mortising Chisel Drill Bits 1/4″ 5/16″ 3/8″ 1/2″ or 6.4mm 8mm 9.5mm 12.7mm Only for 3/4″ 19mm
  4. Uxcell Square Hole Drill Bit, 1/2″ High-Carbon Steel Hollow Chisel Mortise

How to Drill a Square Hole in Metal?

drill a square hole in metal

Now that you know how you can drill a square hole in wood, you might be thinking if you can use the same tools and techniques to drill a square hole in metal.

While wood is a relatively soft material on which you can even use manual tools to get a hole of your desired shape, drilling into metal is no joke.

I have listed down some of the ways you can drill a square hole in metal:

  • The simplest way to drill a square hole in metal is to drill consecutive holes on the circumference of the square, remove the metal piece and finish by filling the edges.
  • For thinner metal sheets there are specialized hole punches for different shapes.
  • You can also try drilling the corners of the square and use a small saw blade to cut each edge.
  • Use a dremel with a circular cutting disc and file the edges to shape.
  • If money is no object for you you can get a hand-operated milling machine that will allow you to drill a square hole in metal.

Frequently Asked Questions:

What is a square drill bit called?

Square holes are mortises, and drill bits used to drill square holes are called mortise bits. These bits are used in mortising machines or drill presses. A mortise bit consists of an auger bit and a chisel bit.

Can you drill a square hole in wood without a mortiser?

It is actually possible to drill square holes in wood without using a mortiser. There are specialized square punches available that allow you to drill a square hole. In addition, you can pair up a normal drill bit with a chisel to achieve a square hole.