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Woodworking Hand Tool
Updated September 20, 2025
Mortise chisel
A mortise chisel is a strong, thick-bladed woodworking tool. It is used to chop out the square holes, called mortises, for joinery.
Category
Woodworking Hand Tool
Use Case
Cutting and shaping mortise joints in wood
Key Features
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A Strong And Sturdy Woodworking Tool A Rectangular Cross-Section Blade A Beveled Cutting Edge For Precision A Robust Handle For Mallet Strikes Its Primary Use For Mortise Holes
In Simple Terms
What It Is
A mortise chisel is a strong, sturdy hand tool used in woodworking. It looks a lot like a regular chisel, but it’s built tougher. It has a thick, heavy blade and a strong handle designed to take a lot of force. The blade is also usually straight and flat on the sides, which helps it work in tight spaces without getting stuck. Think of it as the heavy-duty version of a standard woodworking chisel.
Why People Use It
People use a mortise chisel for one main job: cutting square or rectangular holes, called mortises, in a piece of wood. These holes are meant to fit a matching piece, called a tenon, from another board. When you fit them together, you create a mortise and tenon joint, which is one of the strongest ways to join wood. The mortise chisel is perfect for this because its strength lets you chop out the wood and clean up the sides of the hole with precision, making a neat, strong joint.
Everyday Examples
You can find mortise and tenon joints in many well-made wooden items around you. A classic example is a wooden chair. The legs are often attached to the seat or the rails using these strong joints. Another common place is in wooden tables, where the legs join the apron. Even in older-style doors and windows, the frames might be held together with mortise and tenon joints. So, whenever you see a piece of furniture that has stood the test of time without wobbling, there’s a good chance a mortise chisel helped build it.
Technical Details
Definition
A mortise chisel is a specialized woodworking hand tool designed for cutting mortises—rectangular holes or recesses—that receive a tenon to form a mortise and tenon joint. It is characterized by its thick, heavy, rigid blade and robust construction, enabling it to withstand significant mallet blows and levering forces without bending or breaking. Unlike paring or firmer chisels, its primary function is not fine shaving but the removal of waste wood through chopping and levering.
How It Works
The tool is used by first making a series of chopping cuts with a mallet along the marked perimeter of the mortise. The thick blade acts as a wedge, severing wood fibers. The user then leverages the chisel's strength to pry out the waste material. The process is repeated, working incrementally along the length and depth of the mortise. The chisel's mass and rigidity allow it to transfer the energy from mallet strikes efficiently into the cut, while its blunt bevel angles provide the necessary strength for prying without damaging the tool's cutting edge or the surrounding workpiece.
Key Components
Blade: Typically made of high-carbon or tool steel, it is notably thicker and heavier than other chisel types to resist bending.
Tang: A long, tapered section of the blade that extends into the handle, providing a strong mechanical connection.
Handle: Often crafted from impact-resistant wood like ash or hickory, or modern polymers, and frequently reinforced with a metal ferrule at the top to prevent splitting from mallet strikes.
Bevel: Features a steep primary bevel (often 30-40 degrees) to create a durable, strong edge suitable for chopping, sometimes accompanied by a secondary micro-bevel for sharpness.
Tang: A long, tapered section of the blade that extends into the handle, providing a strong mechanical connection.
Handle: Often crafted from impact-resistant wood like ash or hickory, or modern polymers, and frequently reinforced with a metal ferrule at the top to prevent splitting from mallet strikes.
Bevel: Features a steep primary bevel (often 30-40 degrees) to create a durable, strong edge suitable for chopping, sometimes accompanied by a secondary micro-bevel for sharpness.
Common Use Cases
Cutting mortises for traditional mortise and tenon joints in furniture making, cabinetry, and timber framing.
Chopping the waste from through, stopped (blind), and haunched mortise variations.
Cleaning up and squaring the corners of mortises initially roughed out by other methods, such as drilling.
Heavy-duty chopping and prying tasks in joinery where a standard chisel would be insufficient.
Chopping the waste from through, stopped (blind), and haunched mortise variations.
Cleaning up and squaring the corners of mortises initially roughed out by other methods, such as drilling.
Heavy-duty chopping and prying tasks in joinery where a standard chisel would be insufficient.
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