Abstract: A substantially rigid structural joint can be assembled from an assembly made up of a pair of separate joinery parts. Each joinery part is preferably in the form of a rigid rectangular-shaped, sheet metal strip. One joinery part has a bracing member connected to and extending outwardly from one of its longitudinal sides in an orthogonal relationship. The bracing member also extends toward and along one of the longitudinal sides of the other joinery part when the latter is placed in an erected condition with the one joinery part. In such condition, they extend in orthogonal relationship to one another and have end portions which form a corner therebetween. Interengagable male and female elements on end portions of the joinery parts adjacent the corner are mated together when the parts are placed in their erected condition.