Abstract: A method of joining tubular elements to provide fluid tight connections is disclosed in which the mating portions of the joined tubes are preformed so as to be able to be located with respect to each other prior to soldering, brazing, or other joining process. The preforming operations involve the punching or shearing of an opening in the sidewall of a body tube to which a branching tube is to be joined, in which shearing operation a pair of cusps or tabs are formed at opposite locations on either side of the sheared hole. The punching or shearing is carried out by a punch tool moved to intercept a segment of the body tube sidewall to form an opening, with portions of the tubing wall on either side of the opening formed remaining, these portions being displaced upwardly by the tool to provide the locating cusps or tabs at the periphery of the opening so-formed.