An assembly of at least two components joined together by at least one mechanical connection formed in sheet-like portions of the components and in an area of faying contact between the components. The assembly includes an integral collar projecting from one of the components and an outer integral collar projecting from the other components circumscribing the first collar. The inner collar has a cylindrical inner surface portion and a wall of varying thickness. At least a portion of this wall increases in thickness toward the outboard end of the collar to lock the collars together.
