Homestead · Woodworking & Building · demo dispatch
Cut a mortise by hand
Sam Okonkwo · About an hour for one joint · intermediate · low · 1 proofs · 0 saves · 0 reactions
Mark both faces, drill out the waste or chop it, and pare to the knife line. The tenon is a later problem. This post stops at a square hole.
mortise · chisel · joinery · wood
Tools and materials
- A chisel narrower than the mortise
- A mallet
- A marking knife and square
- A piece of scrap the size of the real work
Steps
1. Knife the layout
Mark the mortise on both faces. The lines should meet if the stock is square. If they do not, fix the stock before you cut.
2. Chop the waste
Start inside the lines. Vertical chops, bevel toward the waste, then lever the chips out. Work from the middle toward the ends.
3. Pare the walls
Flip the piece and meet in the middle so you do not blow out the far face. Pare to the knife line. A mortise gauge is optional. A square is not.
Safety
Chisels leave the cut when the mallet glance does. Clamp the work. Both hands stay behind the edge. A loose chisel handle is how a palm gets opened.
Common mistakes
- Chopping on the line first and crushing the shoulder
- Trying to pry with the cutting edge
Drill overlapping holes if you would rather remove waste with a bit, then pare. The layout rules stay.
Proofs
Practice mortise in pine. Walls meet the knife line. I clamped it. No prying with the edge.