Abstract: The use of a bifurcated joint to attach a conveniently sized metal flange to a flexible bellows material has been widely used, for example, in the manufacture of a building construction expansion joint cover. The known bifurcated joint is formed by clamping and engaging a marginal edge of the bellows material between opposed folded portions of the metal flashing. It has been found that the attaching force provided by this joint can be enhanced by providing teeth or protrusions in a portion of the metal bifurcated joint. Preferably a punch is used to upset teeth from one surface of the joint, preferably a corrugated portion of the joint, and then bend the thus toothed and corrugated portion into clamping engagement with the marginal edge of the bellows. The toothed hole clampingly engages the bellows material without piercing it and prevents pull out, both prior to curing of the adhesive bond as well as thereafter.