pegged through mortise and tenon

The wedged tusk tenon is a concealed wedging joint where a tenon is permanently fixed in a mortise through driven wedges. The connection belongs to the tenon joint family and relates to the Japanese jigoku-kusabi ("hell wedge") and European split wedge connections.
The tenon is inserted into the mortise and spread by wedges driven into prepared slots at the tenon end. The mortise walls run parallel to the wedges and are tapered, creating a dovetail-like expansion. This geometry prevents withdrawal of the tenon.
The joint provides high strength without metal parts and leaves a flush surface as the wedges remain concealed. The irreversible nature suits permanent constructions. Manufacturing requires precise fitting and adequately dried wood. Subsequent adjustments are not possible.
The mechanical locking principle transfers tensile and compressive forces effectively and shows resistance to dynamic loads. The spreading action of the wedges creates a positive connection.
Traditional applications include furniture making for table legs, chair constructions, and frame furniture. In carpentry, the joint serves T-connections and beam-to-post attachments. Modern use appears in design furniture and restoration work.
Manufacturing begins with seasoned wood to minimize shrinkage. The tenon is made 5mm shorter than the mortise depth. Wedges with two-thirds of the tenon length are inserted into slots at the tenon end before assembly. The tapered mortise walls enable controlled spreading when wedges are driven.