stub tenon joint

The stub tenon joint is an I-connection executed as a reinforced butt joint. A short tenon (stub tenon) is worked into one component and engages into a corresponding mortise in the other component. The connection combines the large contact area of the butt joint with the additional stability of a tenon connection.
This joint belongs to the group of tenon joints and shows similarities with the Japanese Mechigai-tsugi and other reinforced butt connections. Comparable principles can be found in longitudinal connections in timber construction where both load transmission and positional security are required.
The short tenon is worked centrally into the end grain of one component, while the other component receives a corresponding mortise. The main load transmission occurs through the large end grain-to-long grain connection, with the tenon serving primarily for positioning and additional security against lateral sliding and twisting.
The stub tenon joint combines the advantages of both connection types: the large contact area of the butt joint for optimal load transmission and the positive fit through the tenon. The connection is self-positioning and prevents lateral sliding during assembly. However, it is susceptible to shrinkage cracks in the end grain area and can be weaker than a simple butt joint if improperly executed.
Traditionally, this joint is used in structural timber construction for sills, purlins, and other longitudinal connections where precise positioning is important. In furniture making, it finds application in high-quality frame connections and door or window frames. It is particularly suitable for interior construction applications where both stability and visual quality are required.
Manufacturing involves precise marking and machining of the tenon as well as exact drilling or chiseling of the mortise. Tenon length typically amounts to 1.5 to 2 times the component thickness. Accurate alignment of both components is important to avoid stresses.