Interlocked metal seam structure with in-plane stabilization

A metal cylindrical ring having an axis, an inside surface, and an outside surface, said ring having been formed from a strip having a tongue on one end of said strip and a recess on the other end of said strip, said tongue and recess being interlocked to form said ring with an in-plane seam, which seam comprises abutting edges of said tongue and recess, at least part of which are thrust into an interference with one another by movement of metal, at least one of said edges against the metal of the other said edge, said ring having in its surfaces the shapes resulting from the of an out-of-plane dimple which when initially formed had a closed perimeter in said surfaces, and within said perimeter a raised portion on one said surface, and a complementary indented portion in the other said surface, followed by the flattening of said dimple so that no portion of said dimple projects above either of said surface, said shapes lying close enough to said seam that said movement of metal to form said interference was formed at least in part by the flattening of said dimple.