6 Ways to Drill a Square Hole into Wood

22 September 2023

Most people are used to drilling round holes, but square ones? That’s a bit trickier. And yet, you often need them, especially for things like mortise and tenon joints or furniture fittings. If you've ever wondered how to cut a clean square into wood without buying a workshop’s worth of gear, you're not alone. Whether you're doing some home DIY or working in a trade, this guide runs through practical, cost-conscious ways to do it, from classic chiselling to machines built for the job.

Quick Comparison Table

Method	Skill Level	Precision	Speed	Tools Needed	Best For
Chisel	Moderate	High (with time)	Slow	Chisel, mallet	Low-cost, detailed joinery
Drill & Chisel	Easy–Moderate	Good	Moderate	Drill, chisel, mallet	Deep square holes in thick timber
Drill & Jigsaw	Moderate	Fair	Fast	Drill, jigsaw	Larger square cut-outs
Mortise Machine & Bit	Advanced	Excellent	Very Fast	Mortise machine, square chisel bit	Precision joinery, trade-level jobs
Hacksaw (Rough Cuts)	Low	Poor	Slow	Drill, hacksaw, chisel	Temporary or rough DIY fixes
Corner Chisel	Easy	Very High	Very Fast	Corner chisel, mallet	Finishing off routed or jigsawed holes

1. Chisel: The No-Power Option

If you’re not in a rush and like working by hand, a chisel can do the job — it just takes a bit of patience. Clamping your wood securely in a bench vice makes the whole process more stable and accurate.

Here’s how:

Sketch it out – Lightly draw the square on the wood.
Score the outline – Use a utility knife to slice along the lines.
Chisel carefully – Tap with a mallet, starting from the corners.
Chip it out – Remove small chunks steadily.
Refine – Square the corners, smooth the inside.

Pros: No need for electricity, extremely precise.
Cons: Slow-going, takes effort.

2. Drill & Chisel: A Bit of Both

This method works well if the wood’s thick or tough because the drill does the bulk of the job, and the chisel tidies things up. It’s quicker than using just a chisel, and easier on your hands.

Try this:

Mark your square – Lines and corners nice and clear.
Drill out the centre – The drill bit should be slightly smaller than the square.
Chisel the edges – Remove leftover wood.
Smooth it off – Use a file or sandpaper to finish.

Pros: Quicker than hand tools alone.
Cons: Needs both a drill and a steady hand.

3. Drill & Jigsaw: For Bigger Cuts

When you’ve got a larger square to cut, such as sockets or panel openings, then a jigsaw can be a real time-saver. It isn’t as precise as chiselling, but it’s fast and gets the job done.

How to go about it:

Draw your square – Keep it neat.
Drill a starter hole – In the centre or near the corners.
Get the jigsaw in – Slip the blade into one of the holes.
Cut it out – Stay on the lines as best you can.
Clean it up – Sand any rough bits with sandpaper.

Pros: Fast for big holes.
Cons: Less accurate around tight corners.

4. Mortise Machine & Bit: Quick and Spot-On

If you are a joiner or fine cabinet maker then a mortise machine might already be on your radar. This machine drills square holes cleanly in one go using a special hollow chisel bit.

To use one:

Measure and mark – Get your square spot on.
Set up the machine – Fit the drill bit and align everything.
Clamp your wood – Lock it firmly in place.
Drill the hole – Slow, steady pressure.
Touch up – Chisel or sand if needed.

Pros: Fast, clean and accurate.
Cons: Bulky kit and pricey for casual use.

5. Hacksaw: Only If You Have To

Honestly? This one’s not ideal, but if you're short on tools and need a square hole urgently, a hacksaw can work. Think of it as a rough-and-ready option, not one for fine joinery.

Here’s the gist:

Mark your square – Corners clearly shown.
Drill each corner – Just wide enough for the hacksaw blade.
Saw the sides – One at a time.
Tidy it up – Chisel and sandpaper to neaten.

Pros: Uses common tools.
Cons: Messy and slow.

6. Corner Chisel: For Finishing Off Roughed-In Squares

If you’ve used a router or jigsaw and ended up with rounded corners, a corner chisel is the tool you’ll want. It’s spring-loaded and made exactly for this job, squaring up the corners cleanly without needing a full chisel setup.

How it works:

Line it up – Right in the rounded corner.
Tap once – One firm hit with a mallet or hammer presses the blade into both edges at once.
Pull the waste out – And you’re done.

Pros: Fast and accurate finishing tool.
Cons: Doesn’t cut the whole square, just the corners.

Safety and Finishing Tips

Before you get started, here’s a quick reminder:

Always wear eye protection – flying chips aren’t fun.
Clamp your workpiece – secure wood = better cuts.
Keep tools sharp – sharper = safer.
Sand the edges – smooth edges make a clean fit.

A neat hole’s only worth it if you’ve made it safely.

So, which method suits you best? That depends on what you're working with and what you’ve got in your toolbox.

If precision matters and time isn’t pressing, the chisel is a solid, budget-friendly bet. However, for something sturdier, a drill and chisel offers more muscle. Although if you’re after professional results, and you’ve got the gear, go straight for the mortise machine.