How to cut a square hole in wood?

FAQs

What is the fastest way can I cut a square hole in the wood?

Use a square hole mortising bits attached to a drill press.

I don't have a drill press, what else could I use?

See if you have these tools in your workshop: a jigsaw, woodworking chisels, a wood router, or an oscillating tool.

What type of sander can get into tiny square holes so I can smoothen them?

A file sander could reach tiny spots in your square holes.

Here’s a quick answer.

Aaron Barnett of BangingToolbox suggests: Knowing how to cut a square hole into wood only takes a few moments and tools depend on the size of the hole you want to cut out. If you want to cut a hole in thick material it’s best to use an electric or cordless jigsaw.

For thinner materials, you can just use a coping saw. Before you start you will need to first pre-drill a hole using an electric drill with a half-inch drill bit to feed in your coping saw or jigsaw blade.

Determine the square hole size and cutting method

• Small repetitive holes are faster to cut out with what’s known as a “square hole drill bit” these types of holes can be used for rebates and joining timber in a similar way to dowel joins, however using a square rod jointing system made with a table saw. Square dowels can stop twisting when only a single dowel is used.
• Small and medium-sized holes can be simply carved out using a sharp wood chisel.
• Medium-sized holes can be cut out using a coping saw, given that the hole isn’t too far from the edges so the copping saw blade can reach.
• Large low-depth holes can be carved out by using an electric wood router, the corners can then be finished with a sharp wood chisel blade.
• Medium to large square holes can be cut using an electric or cordless jigsaw, this is the fastest method but take note that edges will need to be sanded with a file sander or scraped with a chisel depending on how smooth your cuts are.
• If you are cutting from a tricky spot like through wall framing you can cut out a square more easily using a portable osculating saw.

1. Use a “square hole drill bit”

Do you know how to make a square hole in wood fast again and again? A DIY’er can make many repetitive square holes in wood with only a few seconds using a square hole drill bit designed to do just that!

Fit the drill bit known as a square hole bit into a drill press or a mortiser drill and start drilling with your square drill bit.

With pressure or a strong hammering function from a mortiser drill, the sharp blades on the corners of the drill bits will finish with a square hole instead of a circular hole. 

1. Mark the center of your hole.
2. Insert the square hole cutter drill bit into a drill press or mortiser drill.
3. Align the drill bit to the mark on your wooden piece.
4. Lower the drill bit down to drill the square hole.

2. How to cut a square hole in wood by hand?

If you haven’t yet invested in quality power tools for your DIY work yet, or if the hole you intend to cut is relatively small and you want to know how to cut a square notch into wood; then you can use a wooden mallet and a sharp chisel [1] to carve into your wood and finish with a square hole.

Take note to carve the final edge separately on both sides of the hole to stop the wood chipping on the edges. And make sure you have a quality sharp chisel.

1. Use a pencil to mark out the square hole edges.
2. Run a sharp Stanly knife on both sides of the timber on this line (This will help avoid chipping).
3. Make sure your chisel is sharp.
4. Start carving out chunks from the center of the hole leaving the edges to last.
5. Finalize the square edges with a fast up and down motion taking of thin slivers at a time.
6. Finalize with some sandpaper using it on the back edge of your chisel to keep a flat surface.

You will properly also like my guide on how to cut metal without power tools.

3. Use power tools to cut a hole in wood

The real DIY’ers method for a decent-sized square hole in thin wood like plywood is to use a corded or cordless jigsaw like the cordless jigsaws available here.

As you can fast and conveniently cut into the corner edges.

If the hole you intend to cut is larger than a circular saw blade or thicker than an inch it’s better to use a circular saw for a nice straight cut.

Then use a jigsaw tool to cut into the corners at the end, just be careful not to take shortcuts when you are lowering the blade into your cut to avoid kickback.

Jigsaw tools are much easier to use here.

How to cut a square hole through wood with a router?

1. Mark your square hole.
2. Set up a wood router to the depth you want to router out.
3. Take out the middle meat of your cut.
4. Use some wood clamps to attach a straight edge, then follow the straight edge with the router to achieve a straight line.
5. Remember to work from the center of the hole outward, this will always leave support for the wood router to sit on.

Use a jigsaw to cut out a square hole.

1. Mark your hole.
2. If the wood is thick and your cut-out is large, you can lower a circular saw to cut the bulk of the cut staying away from the corners. Then use a jigsaw to cut the corners.
3. If you don’t want to use a circular saw use a cordless drill to pre-drill a hole to then feed through a jigsaw blade.
4. Complete the square cut with a jigsaw tool on the corner edges.

4. Cut a square hole using an oscillating tool

Oscillating tools are great when you need to cut into difficult spots and plunge cuts [2], like into an existing wall, or into the wall framing. The blade vibrates so quickly that you just need to push the tool into what you want to cut using for example; a Makita oscillating tool.

However, the cutting motion is a lot slower than a jigsaw. But its ability to get into tight spaces is competitive with many other tools to keep up with.

1. Mark your hole clearly.
2. If the wood is thick and your cut-out is large, you can lower a circular saw to cut the bulk of the cut staying away from the corners. Then use a jigsaw to cut the corners.
3. If you don’t want to use a circular saw use a cordless drill to pre-drill a hole to then feed in a jigsaw blade.
4. Complete the square cut with a jigsaw tool.

Tidy up your cut for smooth edges

No matter what tool you decide to use to achieve your desired result, any hole you do might need some extra attention to reach that level of smoothness that you consider tidy and noteworthy.

Consider first using sand-paper on the back edge of your chisel for fast flat sand.

Second, if you’re after speed and power for a larger job consider using a file sander, these sanders are made especially for reaching in tight holes and taking away what’s not needed.

Sometimes there is not much a chisel cant do, but with patients and the right branded gear, you can get a relatively smooth cut from the first place.

More info on this Makita finger sander here.

For the wrap up

There you have it, the tools and methods needed, so know how to cut a square hole in wood. Whether you choose to tackle the job by hand using a coping saw, or a square dill bit for efficiency, you still can’t beat a jigsaw tool.

No matter what your chosen method is you want the right-sized carving chisel handy, and some medium and low grit sandpaper.

Remember to keep your squares square.