A mortise is essentially a hole in a piece of wood. Usually, they are square or rectangular, but there are some other options as well, including tools like the Festool Domino (which is like a crazy cross between a mortiser and biscuit joiner.) But like a lot of woodworkers, I can’t afford too many Festools and I wanted to make traditional joints. The domino felt a little like cheating to me.
In the context of this post, I want to talk about making mortises for use in mortise and tenon joinery. A mortise and tenon joint is one of the strongest joints you can make to join two pieces of wood together.
The tenon from one piece of wood slots perfectly into the mortise of the other piece and when glued, you can usually avoid having to use nails altogether it’s so strong!
I’ve tried several different ways to make a good clean mortise over the years. At first I used a router and chisel to make my mortises, then I tried a drill press for a time until I finally found the technique I use today.
How to Make Mortises
The are a couple challenges when making mortises because they have to be so exact. You need to make sure your mortises are:
- The proper length
- The proper width
- The proper depth
- Have clean, perfectly squared corners
- Positioned on the board in the exact same place your tenon will intersect