Mortise and Tenon — Lutherie Encyclopedia

Mortise and TenonType: techniqueA classical joinery method used in lutherie for neck joints, brace attachments, and structural connections throughout the instrument.## Overview The mortise and tenon is one of the oldest and most reliable woodworking joints, used extensively in lutherie for structural connections. A projecting tenon on one piece fits into a matching rectangular hole (mortise) in the other. In instrument building, this joint appears in neck-to-body connections, internal brace attachments, bridge plate joints, and many other applications where strength and precision are required. ## Process The tenon is cut on the piece that will be inserted—often the end of a brace, a neck heel, or a structural block. The dimensions are carefully marked and the tenon is cut using a fine-toothed saw, then cleaned up with chisels. The tenon should have clean, square shoulders that seat firmly against the mortised piece. The mortise is cut into the receiving piece using a drill to remove the bulk of the waste, followed by careful chisel work to clean the walls and square the corners. Alternatively, a router with a straight bit can hog out the mortise, with final fitting done by hand. The fit should be snug—a gentle push-fit that requires no excessive force. The luthier tests the fit repeatedly, paring small amounts from either the tenon or mortise until the joint closes fully with firm hand pressure. Glue is then applied to both surfaces and the joint is clamped until cured. In lutherie, variations include through-tenons (visible on the other side), stub tenons (shorter, for lighter duties), and wedged tenons (where a wedge expands the tenon…