Designing the Wedged Mortise and Tenon
Attention to detail yields exceptionally strong joints
Synopsis: When a table wobbles or a chair squeaks, it’s usually just bad joinery design, says Carl Swensson. Good design buys time against use and abuse that all furniture bears. The wedged mortise and tenon is simply made and very effective. He talks about how there are no simple guidelines to cutting a successful wedged mortise and tenon, and he outlines the stresses that break joints. He says quartersawn lumber should be used in all joints, and he addresses grain orientation. Wedge the tenon against the tension the piece is expected to have, and use templates to test thicknesses and angles. He describes proportions for mortise wall relief and tenon kerf, and how to ensure a successful final assembly.
A door can be slammed only so many times before the tenons pull out of their mortises. Even the sturdiest chair will not survive an overweight, hyperactive teen who tilts…