Types of Building Joints

Biscuit Joints

• Biscuit joints are made using a small ovular piece of composite wood material, called a biscuit. A small impression is cut into each side of the joint using a specialized tool, the biscuit is covered in glue and placed halfway into each hole and then the two sides are pressed together.

Dovetail Joints

• Dovetails are most often seen in drawers. This joint is very strong, but a little difficult to make. Each side is cut into trapezoidal shapes that will fit into each other. Dovetail joints can be cut by hand, but also with a router or a specialized machine called a dovetail jig.

Box Joints

• Box joints are made with square fingers that join with one another at right angles. They can be cut on a table saw with a dado blade or a router with a straight bit. It is very important that the fingers get properly spaced, however.

Dado Joints

• Dado joints are most often used to build bookshelves. They are useful because they don't required any additional fasteners or glue to keep the shelves in place. Dado joints are made by cutting a rut into one piece of wood into which another piece fits tightly. Sometimes, the rut will not be cut wide enough to fit the entire other piece of wood, and an outcropping will be cut onto the other piece of wood to fit into the smaller-sized rut.

Domino Joints

• Domino joints are similar in concept to biscuit joints, except the piece connecting the two sides is rectangular, like a domino.

Tongue and Groove Joints

• Tongue and groove joints consist of one side of the joint that has a piece of wood jutting out, a "tongue," and another piece with a long groove cut into it into which the tongue will fit.