Traditional woodworking uses different types of joints in the construction of a chair. The most common joint used is the mortise and tenon joint where a hole, the mortise, is cut into one piece of wood that matches a wedge (the tenon) on the other piece of wood. The joint uses wood glue and pressure to create stability. The joint typically weakens with age. Reinforcing the joints to keep the chair sturdy requires a brad nailer and a few minutes of your time.
Disengage any loose connections. Pull loose joints apart so that you expose the joint or groove for regluing.
Squeeze a small amount of wood glue into the groove and reinsert the tenon into the joint.
Tap the joint with a rubber mallet until the joint is tight.
Use a brad nailer to put a nail through the side of the joint into the tenon. For example, place a nail through the side of the leg into the support beam that inserts into the leg. Angle the nail so that it intersects the tenon.
Repeat the process for two sides of the joint so that you the brads cross in the center of the tenon.
Brads are virtually invisible when flush with the surface of the wood. Use a standard nail and a hammer to tap the brad to flush or just beneath the surface of the wood if the brad nailer leaves the brad partially exposed. Place the point of the nail on the tip of the brad and lightly tap the nail until the brad is flush.
This process applies to any form of joint with wood furniture.
Select the size of brads you will use carefully. Brads come in sizes up to 2 inches. Choose one that is no longer than three-quarters the width of the piece of wood you will be nailing otherwise you will end up with a sharp point coming out the other side.