What a joint is doing

A wood joint is the point where two or more pieces meet and connect. What makes joints interesting is that they are not all doing the same job. Some joints are built to resist being pulled apart, others to register two parts at a fixed angle, and still others to align panels edge to edge.

The shape of the joint, the way it contacts the wood grain, and the adhesive or fastener used all combine to decide how a connection behaves.

Why shape matters more than the name

A dovetail interlocks mechanically, so it holds even if glue weakens. A butt joint has no interlock at all — it relies almost entirely on adhesive, fasteners, or surrounding structure. Between those extremes sit joints that add glue surface area, mechanical alignment, or both.

That spectrum is the practical way to compare joints: how much mechanical interlock and how much glue surface does the geometry create?

Strength is always conditional

No joint is universally the strongest. Real performance depends on wood species, grain direction, joint fit, adhesive, workmanship, and the direction the load is applied. A well-fitted dowel joint can outperform a sloppy mortise and tenon.

The pages in this section explain how each joint works and what it is best at, while staying honest about what changes the result.

Index

All joinery

01 What Is a Biscuit Joint? How the Oval Spline Works A biscuit joint aligns two parts with a thin, oval compressed beech biscuit glued into matching slots. 02 What Is a Butt Joint? The Simplest Joint Explained A butt joint simply places the end of one piece against the face or edge of another, with no interlock. 03 What Is a Dado Joint? The Slot-and-Panel Joint Explained A dado joint seats a panel into a slot cut across the grain of another panel. 04 What Is a Dovetail Joint? How It Works and Why It's Strong A dovetail joint interlocks wedge-shaped pins and tails cut into two boards, holding them together mechanically. 05 What Is a Dowel Joint? How Dowels Align and Join A dowel joint aligns and joins two parts with round wooden dowels fitted into matching drilled holes. 06 What Is a Finger Joint? Interlocking Rectangular Fingers A finger joint interlocks rectangular fingers cut into the ends of two boards. 07 What Is a Lap Joint? How Overlapping Pieces Work A lap joint overlaps two pieces that have each had material removed so their surfaces sit flush. 08 What Is a Mortise and Tenon Joint? How It Works A mortise and tenon joint fits a projecting tenon on one piece into a matching mortise cut into another. 09 What Is a Pocket Hole Joint? Angled Screws Explained A pocket hole joint joins two pieces with screws driven through angled holes drilled in one piece. 10 What Is a Rabbet Joint? The L-Shaped Recess Explained A rabbet joint seats one piece into an L-shaped recess cut along the edge of another piece.