If there was ever a classic wood-to-wood joint, the mortise and tenon is it. With its two halves formed directly from the two members being joined (no separate components — dowels, biscuits, etc.), these joints form strong, reliable bonds for all manner of wood furniture and cabinet assemblies. Like the Chinese yin and yang, the two halves of a mortise and tenon (M&T) are male and female: The male tenon shaped on the end of one member (with shoulders stopping the cut) fits snugly into the female mortise chopped into the side or face of the other member. The joint can be cut with a saw and chisel by hand, or machined using any number of different stationary and/or portable power tools.
Mortise and tenons are most commonly used for frame joinery; M&Ts are a strong and traditional way to join stiles and rails end to edge to make frames for frame-and-panel doors or cabinet face frames. They’re also great for joining aprons or stretchers to the legs of a table, bench or chair, for both square and angled connections. Though less commonly used, M&Ts are also solid options for building strong casework, such as chests and the carcasses for desks and dressers.
Like the other joints we’ve so far examined in this Skill Builder series, there are lots of possible variations with mortise and tenon joints. Standard M&Ts are cut stopped or “blind,” meaning that the entire joint is hidden; through M&Ts are cut so that the end of the tenon shows or sticks out of the bottom of the mortised member.
You can also add wedges, keys or pins to these joints, to add decoration and/or strength. Another option is to cut loose-tenon joints, where two mortised parts are joined by a separate long tenon piece.