What is Drawboring?

 

Drawboring is a means of fastening mortise and tenon joints using wooden pegs. In drawboring, the holes for the peg are slightly offset, with the hole in the tenon slightly closer to the shoulder. When the peg is driven in, it pulls the tenon into the mortise. In surviving examples, the peg was sometimes left "proud" (protruding), perhaps so that the joint could be tightened as changes in humidity loosened the joint.

In modern woodworking, a mortise and tenon joint is usually clamped and glued together. If a peg is to be used at all, a hole is bored through the already-glued joint and a peg inserted, but given the strength of modern glues, it serves more as a decoration than a fastener.

Drawboring has a number of advantages. It provides a strong joint, and it uses nothing that the joiner cannot make (such as screws, glue, etc.). It also avoids the problems of using iron in contact with acidic woods such as oak, which can discolor it over time.