How to Cut a Square Hole in Wood (9 Simple Ways Detailed!)

Remember trying to fit square blocks into round holes as kids? In woodworking, sometimes we actually need square holes. But why? Our drills make round holes just fine, and things like screws and nails are round too.

One big reason for square holes is to make strong joints called mortise and tenon. But there are other reasons too, both for looks and use. Whether you’re using power tools or just your hands, there are several ways to make these square holes.

Comparison of Square Hole Cutting Methods

Method	Pros	Cons
Square Drill Bits	Precise square holes Ideal for mortise and tenon joints	Requires a specific drill press Not common in home workshops
Drilling Without a Drill Press	Uses common tools Suitable for smaller projects	Less precise than dedicated machines Requires multiple tools
Multi-Point & Large Square Punch	Good for larger holes Efficient material removal	Requires multiple drill bits Might not be as precise as other methods
Jigsaw	Versatile tool Can navigate corners easily	Cuts might not be perfectly smooth Requires pilot hole
Router	Efficient for initial cuts Can be combined with other tools	Not as precise for finishing touches Requires other tools for refinement
Mortising Machines	High precision Designed specifically for square holes	Expensive Might be overkill for hobbyists
Oscillating Multi-Tool	Precise cuts Good for tight spaces	Might require additional refinement Not as efficient for larger projects
Hand Saw Technique	Offers control and precision No need for power	More time-consuming Requires skill and patience
Chisel	High degree of control Can achieve sharp edges and corners	Requires patience and precision Might not be suitable for larger or deeper square holes

Making Square Holes Using Power Tools

Use power tools to quickly and easily make square holes in wood.

1) Square Drill Bits

Yes, you read that right! Square drill bits do exist, but they’re not common in everyday woodworking kits.

Often called “mortise bits”, these are used in big drill presses to make square holes in wood. These machines, whether they sit on a bench or stand on the floor, use levers to push the bit into the wood.

Most home workshops might not have these, but it’s good to know they’re out there. Now, let’s look at tools you might actually have at home.

2) 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.

1. Gather Your Tools: Ensure you have a power drill, square punch, framing square, chisel, and hammer ready.
2. Measure and Mark:
   • Measure the desired location for the square hole from all sides of the wood piece.
   • Use a framing square to accurately mark the square shape you intend to drill.
3. Choose the Right Drill Bit:
   • Select a drill bit slightly smaller than the dimensions of the desired square hole.
   • Securely attach the drill bit to your power drill.
4. Drilling:
   • Drill a hole through the wood at the center of the marked square.
5. Position the Square Punch:
   • Align the square punch over the hole, ensuring its sharp corners match the corners of the marked square.
6. Hammering:
   • Apply force using a hammer on the handle of the square punch, pushing it through the wood. The pre-drilled hole will guide the punch, making the process smoother.
7. Refine the Hole:
   • Use a chisel to remove any excess wood and perfect the square shape of the hole.

Square hole punches come in various sizes. Ensure you choose one that fits your project’s requirements. If any rough edges or excess material remains, a light chisel touch-up will give you a clean square hole.

3) Multi-Point and Large Square Punch Technique

1. Determine Hole Size:
   • Assess if the desired square hole is larger than standard sizes. If so, this technique is suitable.
2. Gather Necessary Tools:
   • Ensure you have a power drill, a large square hole punch, a chisel, a hammer, and both large and small drill bits.
3. Initial Drilling:
   • Attach the larger drill bit to your power drill.
   • Drill a hole at the center of where you want the square.
4. Additional Drilling for Material Removal:
   • Replace the larger drill bit with a smaller one.
   • Drill additional holes around the initial hole to remove more wood, making the subsequent punching process smoother.
5. Position the Square Punch:
   • Align the larger square hole punch with the corners of the marked square on the wood.
6. Hammering:
   • Firmly hammer down on the square punch handle, ensuring it penetrates the wood and creates the square shape.
7. Refinement:
   • Use a chisel to clean up any rough edges or excess wood, ensuring a smooth and perfect square hole.

Square hole punches, especially the ½-inch size, are available at many DIY stores or online, typically priced around $35.

4) Making Square Holes with a Jigsaw

1. Preparation:
   • Ensure you have a jigsaw, drill, chisel, and hammer on hand.
2. Mark the Square:
   • Measure and mark the desired square shape on the wood where you want the hole.
3. Drill a Pilot Hole:
   • Within the marked square, drill a starter hole (also known as a pilot hole) through the wood. This hole will serve as the entry point for the jigsaw blade.
4. Begin Cutting with the Jigsaw:
   • Insert the jigsaw blade into the pilot hole.
   • Start cutting along the marked lines of the square, following the shape.
5. Change Directions as Needed:
   • As you cut, you may need to adjust the jigsaw’s direction to navigate the square’s corners.
6. Refine the Square Hole:
   • After cutting, inspect the hole for any uneven cuts or rough edges.
   • Use a chisel to smooth out any imperfections and achieve sharp square corners.
   • For minor adjustments, light taps with a hammer or gentle pressure with the palm of your hand can help set the chisel and refine the hole.

While the jigsaw is a versatile tool, the cuts might not always be perfectly smooth. A chisel is handy for final touch-ups, ensuring a clean and precise square hole.

5) Using a Router To Cut a Square Hole

1. Gather Your Tools:
   • Ensure you have a router (or a Dremel with the right attachment), a jigsaw, and a chisel ready.
2. Mark the Square:
   • As with previous methods, start by measuring and marking the desired square shape on the wood.
3. Create the Pilot Hole with the Router:
   • Use the router to drill a pilot hole within the marked square. This hole will serve as a starting point for further cutting.
4. Expand the Hole:
   • Depending on your preference, you can:
     • Use a jigsaw to cut along the marked lines, following the square’s shape.
     • Use a Dremel with the appropriate attachment to remove material within the marked square.
5. Refine the Square Hole:
   • After cutting, inspect the hole for any uneven cuts or rough edges.
   • Use a chisel to smooth out any imperfections and achieve sharp square corners.

6) Mortising Machines to Create Square Holes

Mortising machines are specifically designed to create mortises, which are essential for mortise and tenon joints.

1. Variety of Machines:
   • There’s a wide range of mortising machines available, catering to both industrial needs and simpler tasks. Notable manufacturers include Powermatic, Jet, Makita, and Wen.
2. Highlight: The Festool Domino:
   • While not strictly a square hole-making tool, the Festool Domino stands out for its ease of use. It creates mortises in a single pass, albeit with rounded corners.
   • The tool uses “Dominos” (advanced versions of biscuits) that fit into the mortises, ensuring a secure joint.
   • Although on the pricier side, the Festool Domino is regarded as a top-tier power tool.
3. Cost Considerations:
   • Heavy-duty floor model mortisers can be quite expensive, ranging from $1,000 to $ 2,000. These might be overkill for hobbyists or occasional woodworkers.
   • More budget-friendly options include the Powermatic, priced just under $1000, and the Jet, available for around $550.
   • The Festool Domino, while exceptional in its performance, comes with a price tag between $1000 to $1100.

While mortising machines can be a significant investment, they offer unparalleled precision and efficiency, especially for those frequently working on mortise and tenon joints.

7) Oscillating Multi-Tool Approach

An oscillating multi-tool, often referred to simply as a multi-tool, is a versatile power tool that can be equipped with various attachments. One of the attachments is a wood-cutting blade, which can be used to cut square holes in wood.

Steps:

1. Mark the Square: Start by marking the square on the wood where you want the hole.
2. Pilot Hole: Drill a pilot hole inside the marked square to allow the multi-tool blade to start its cut.
3. Cutting: Insert the wood-cutting blade of the multi-tool into the pilot hole and start the tool. Move the tool along the marked lines, ensuring you maintain a steady hand to get a clean cut.
4. Refine the Edges: After cutting out the square, you might need to refine the edges. You can use a file or sandpaper to smooth out any rough edges and perfect the square shape.

This method is particularly useful for precision cuts and when working in tight spaces where larger tools might not fit. The oscillating motion of the blade allows for controlled cuts, making it easier to follow the marked lines accurately.

Making Square Holes By Hand

Try these manual methods to cut square holes without using machines.

8) Hand Saw Square Hole Technique

1. Gather Your Tools:
   • Ensure you have a hand saw with a thin blade, a drill or router, and a chisel if needed.
2. Mark the Square:
   • Begin by measuring and marking the desired square shape on the wood.
3. Create the Pilot Hole:
   • Use either a drill or a router to make a pilot hole within the marked square. This hole will serve as a starting point for the hand saw.
4. Begin Sawing:
   • Insert the thin blade of the hand saw into the pilot hole.
   • Carefully saw along the marked lines, ensuring you create straight sides for the square. Adjust the saw as needed to navigate the square’s corners.
5. Refine the Square Hole:
   • After sawing, inspect the hole for any uneven cuts or rough edges.
   • If necessary, use a chisel to smooth out any imperfections and achieve sharp square corners.

9) Using a Chisel to Cut a Square Hole

1. Gather Your Tools:
   • Ensure you have a sharp chisel and a hammer at hand.
2. Mark the Square:
   • Start by measuring and marking the desired square shape on the wood.
3. Position the Chisel:
   • Place the chisel’s sharp edge on one of the marked lines, aligning it with the outer edge of the square.
4. Begin Chiseling:
   • Using the hammer, gently tap the chisel inward, directing it toward the center of the marked square. Ensure you maintain control and precision with each tap.
5. Rotate and Repeat:
   • Move to the next line of the square and repeat the chiseling process. Continue this method for all sides of the square, gradually removing material.
6. Refine and Perfect:
   • As you progress, the chisel will naturally create sharp edges and precise corners. Continue chiseling until all material within the marked square is removed and you achieve a clean square hole.
7. Final Touches:
   • Inspect the hole for any uneven cuts or rough edges. Use the chisel to make any necessary refinements, ensuring sharp corners and straight edges.

This method requires patience and precision. Rely on the chisel’s sharpness and use light, controlled taps with the hammer. This technique offers a hands-on approach, allowing for a high degree of control and accuracy.