How To Cut Square Holes In Wood

How To Cut Square Holes In Wood

Square pegs in round holes and all, yes.  We remember those toy games from our youth, or at least from our kids’ youth.  But what about square holes?  

Why would you need square holes, though?  Our drills and their bits, and our routers and their bits, will create nice, neat, and usable round holes, and why can’t they be enough?  After all, screws are round, and so aren’t nails.

We can think of one obvious reason why you would want a square hole – mortise and tenon joints.  However, there are others, whether aesthetic or functional and no matter the purpose, the method of creating a square hole is the same among several ways they are cut.  

We’ll explore the use of power and hand tools in cutting a square hole in a piece of wood.

Square Drill Bits

This is not a misprint.  There really are such things as square drill bits, although they are not usually a part of a home woodworking shop.

They are also referred to as mortise bits, and they commonly fit in drill presses that are used to hammer square holes through wood.  These drill presses are large, whether bench-top or floor models and are operated by levers to drive the bit through the wood.

As we said, you are not likely to have this in your home workshop, but we thought we’d mention it at the outset and then move on to more real-world home workshop tools.

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Drilling Square Holes Without a Drill Press

Your power drill and a square punch can accomplish the same thing on a smaller scale outside the industrial workshop.  The process is fairly straightforward and does not require any special woodworking skills.

Measuring is a bit more involved in this process, but again not difficult.  Measure your spot from all directions on the piece of wood and use a framing square to make the square you need to drill.

Choose a drill bit that is slightly smaller than the dimensions of the square to be drilled and the square punch tool, and drill through the wood.  Then, line up the square punch on the marks over the hole you just drilled, and use a hammer to push the square punch through the hold.  

Use a chisel to clear away any excess wood from the square hole you have just drilled and punched, and the job is done.  

Square hole punches are exactly what the name implies.  They have four protruding corners with sharp points that will align with the four corners of the square hole you have measured and marked.  

They also come in a variety of sizes and dimensions, and it is likely you will be able to acquire one that will be the right size for your project.  What’s neat, too, is that they are perfect squares and will give you a square hole.

The metal “blades” of the four sides of the square hole punch are sharp, and they will create the four square corners of the hole by removing the wood around the hole you have drilled with your power tool.  

A little force with the hammer on the handle of the square hole punch will easily push it through the wood, as the drill bit has already removed most of the wood.  If there is any excess material in the corners, some light chisel action will remove it, resulting in a square hole.

Using Multiple Drilling Points and a Larger Square Hole Punch

If the square hole you need is larger than the one anticipated in the previous section, there are other steps you can take to create the same effect.  In such a case, a larger drill bit and a larger square hole punch will be needed.

Using a larger drill bit with your power drill to create the first hole is a good start.  Switch out the larger drill bit with a smaller one and drill extra holes around it to remove more material.  You get the idea – using the power tool to do as much of the material removal as possible to make the work of the square hole punch easier.

Line up the corners of the square hole, punch on the mark lines you’ve measured, grab your hammer and persuade it down.  The work of the hole punch and the hammer should be easy, and the corners of the square hole will be created.  Again, a chisel can remove any excess materials where the hole punch might not have punched smoothly, resulting in a larger square hole.

If you are curious about square hole punches, a ½ ‘ punch will run you around $35, and they are easily found online and at the large DIY stores.  They have sturdy handles that can stand up to a hammer and work well in the function they were designed for.

Using a Jigsaw To Cut a Square Hole

Jig Saw

This method is pretty common, and you are likely familiar with it.  It’s simple, quick, and uncomplicated, and if you are a serious woodworker, you will likely have one in your woodworking shop.

A starter hole, or as we call them, a pilot hole or hole, is drilled through the wood within the square you have measured and marked.  The jigsaw blade is then inserted into the pilot hole, and the cuts are made to create the square hole.  

It may require you to move the jigsaw and change directions in your cuts, but those moves are easy to figure out.  The point of the cut is to remove material to create the square hole, and that’s all you do.  

The cuts may not be smooth, and you might need to chisel out any remaining material to create the square corners of the hold.  That’s an easy process too, and some light taps with a hammer or the ball of your hand should do the trick.

Using a Router To Cut a Square Hole

The process of cutting a square hole with a router is no different than drilling pilot holes and using a jigsaw or even a square hole punch.  Use the router to create that pilot hole and finish off the corners with either tool, all as described above.

In the same vein as your router, a Dremel is another powerful tool that can be used for the same purpose.  The right attachment on the Dremel can remove material within the marks you’ve made, and either a jigsaw or a chisel can be used to finish the hole.  

We’ve written about Dremel tools recently, showing the many available bits for its use.  If you’re curious and want to learn more, you will find that article here.

These rotary tools rely upon speed rather than torque to do their work.  Since creating a hole in your piece of wood is the task, they are well suited for the job. 

Using a Hand Saw to Cut a Square Hole

RUITOOL Japanese Hand Saw 6 Inch Double Edge Sided Pull Saw Ryoba SK5 Flexible Blade 14/17 TPI Flush Cut Beech Handle Wood Saw for Woodworking Tools

Again, we have the same concept as outlined previously but simply use a different tool to finish the square hole.  This time, it’s not a power tool but rather a hand saw.

The pilot hole can be created with a drill or a router, which doesn’t change.  The saw blade will need to be thin, but the sawing is the same – create the straight sides of the square and the corners, and the result is the square you measured and marked on the wood before you began.  

Using a Chisel to Cut a Square Hole

If you want to ditch the idea of pilot holes and rely upon muscle alone and some well-chosen hand tools, this is the method for you.  A sharp chisel and a hammer can give you a square hole.

Measure and mark carefully, place the chisel at one of the lines, and hammer inward toward the center of the square you’ve marked.  Move to the next line around the square and do the same thing, and then continue until you’ve removed some material all around the square

Continue this process until all of the material has been removed, and you have your square hole.  The chisel will put a fine point on the sides of the hole and make a true square in each corner.  Light taps and relying on the sharpness of the chisel to remove material with patience is the smart way to create your square hole.

Mortising Machines to Create Square Holes

At the outset of this article, we mentioned mortise and tenon joints as an obvious reasons to create a square hole.  In fact, there are machines that will create those mortises for you.

It used to be that the measure of a woodworker’s talent would be taken by how he or she created a mortise by hand.  Today, machines do that for us and do it well.

There are a variety of mortising machines, from industrial to simple, and they include manufacturers such as Powermatic, Jet, Makita, and Wen.  Each has their talent and strength, although not all are for the home woodworker.

One that is, though, is among our favorite:  Festool.  Although technically not a square hole-making tool, the Festool Domino is a brilliant power tool that does what it does with excellence.

The mortise is cut in a single pass (albeit with rounded corners) quickly and efficiently.  Dominos (more sophisticated versions of biscuits) fit into the mortises on the pieces being joined, and the job is done.

They are expensive and probably beyond the budget of the casual weekend woodworker or hobbyist, but the Festool Domino is considered an elite power tool.

Festool 574432 Domino Joiner DF 500 Q Set
  • NOTE: The DF 500 only come with the 5MM cutter which is installed.
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  • Mortise width adjustment with the turn of a dial allows for easier alignment when joining panels.
  • Pivoting Fence allows you to create angled mortises from 0-90° with positive stops at 22.5°, 45°,…

Heavy-duty floor model mortisers can run you between $1000 – $2000, which is pretty steep.  However, the weekender or hobbyist won’t need anything that powerful.  

The Powermatic comes in at just under $1000;  the Jet at around $550.  By comparison, the Festool Domino runs between $1000 – $1100.

If you want to see something really cool, the following video shows a drill/square hole punch combo sort of tool.  Again, it may not be for the hobbyist or weekender, but it truly does the job.  

YouTube video

As with all woodworking tasks, safety matters.  You’ll be removing material from your piece of wood, and some may fly out.  Goggles or a face plate are essential.  Take all precautions to remain safe in every shop task, and cutting square holes is no exception. 

Last update on 2023-03-26 / Affiliate links / Images from Amazon Product Advertising API

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