How to Cut a Blind Mortice with a Chisel | Step 7 of 55 - Beginners Woodworking

How to Cut a Blind Mortice with a Chisel | Step 7 of 55

Part of the 55 Cuts & Joints for Beginners series.

In this lesson, we’re introducing the blind mortice — a key step towards one of the most important joints in carpentry: the mortise and tenon.

This is a practical skill you’ll use in real-world work, from fitting locks to building strong timber joints.

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🎯 Aim of the Lesson

To learn how to mark out and cut a blind mortice accurately using a chisel.

📚 What You’ll Learn

• What a blind mortice is and where it’s used
• How to mark out using a combination marking gauge
• How to control depth safely and accurately
• The difference between a bevel edge chisel and a mortise chisel
• How to avoid splitting and damaging the timber

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🧰 Tools & Resources

🔧 Tools, PPE, and materials used in this lesson:

• Combination marking gauge
• Bevel edge chisel
• Mortise chisel (optional)
• Mallet
• Vice or clamps
• Measuring tools (rule / square)
• Timber (practice piece)

👉 View Full Tool & Resource List

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📏 Step-by-Step Process

1. Mark out the mortice
   Measure and mark the length (e.g. 60mm) and position on the timber.
2. Set your marking gauge
   Adjust to the width of your chisel (e.g. 10mm or 12mm).
3. Mark the mortice lines
   Run the marking gauge along the timber to create parallel lines.
4. Mark the depth
   Use tape on your chisel to indicate the required depth (e.g. 25mm).
5. Secure the timber
   Clamp firmly to prevent movement while cutting.
6. Start cutting away from the edge
   Begin around 8–10mm from the end to avoid splitting.
7. Work in small steps
   Cut every 2–5mm along the mortice to break up the fibres.
8. Remove waste carefully
   Lever gently — avoid twisting side to side.
9. Keep the chisel square
   Maintain 90° for clean, straight sides.
10. Clean and refine
    Work back to your lines and tidy the bottom.

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🧠 Key Learning Points

• A blind mortice does not go all the way through the timber
• You can complete this task with a bevel edge chisel if needed
• Mortise chisels give cleaner, straighter results
• Cutting in small steps prevents splitting
• Good marking out leads to better results

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❓ Quick Quiz

• What is a blind mortice?
• Which chisel gives cleaner results — bevel edge or mortise chisel?
• Why should you cut in small steps?

👉 (Add your YouTube or Google Form quiz here)

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📺 Watch the Full Video

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Next Lesson: Continue with Step 8 in the 55 Cuts & Joints series.

View the 55 Cuts & Joints for Beginner Woodworkers series