Heat exchanger plates (30) for stacked flat plate heat exchangers include tapered collars for alignment of one plate relative to another in the stack. The tapered collar (80) extends from the major surface portion of the plate and is tapered so as to have a constricted free end. The collar of one plate receive a collar of a neighboring plates as the plates of the stack are internested one in another. The collars are wedgingly engaged one in another to provide accurate alignment of the heat exchanger plates. <IMAGE>
