Abstract: A fabricating jig for building components is disclosed, including a horizontal frame, a pair of longitudinally extending stop plates connected with the frame for relative transverse parallel displacement toward and away from each other, and a device for displacing the stop plates together, whereby structural components arranged therebetween are pressed together and are held firmly in place during the fastening of the components to form a building unit. Stud supports are connected with the frame between the plates for supporting structural components that extend transversely between longitudinal components which are in contiguous engagement with the stop plates, respectively. Preferably the stud supports are longitudinally adjustable relative to the frame. An elevating device may be provided for raising the assembled building unit from the frame.