Abstract: A method for producing a connection between at least one metal part having at least one longitudinally extending groove formed at one surface thereof and a thermoplastic part of plate, strip or bar configuration at least a portion of which, to be disposed in said groove, is adapted to soften or melt on the application thereto of a predetermined level of heat, wherein knurling is provided on at least a portion of the groove wall surface and heat is applied to soften or melt a portion of said thermoplastic part disposed in said groove to have at least a part of the softened or melted portion thereof serve to cap and dispose in spaces about raised and projected portions of said knurling and set thereabout to produce a fixed interconnection of said parts. Preferably there is a use of one or more contact pressure elements comprising a portion of electrolyte copper through which current is applied to produce said melting or softening of the thermoplastic part.