Abstract: A method of forming a socket on a tube where a branch tube is to be joined to it, which consists of the steps of forming an aperture in the side of the tube which aperture is smaller than the internal dimension of the socket required, inserting expandible jaws into the aperture, placing a sliding former into contact with the tube around the jaws, and expanding the jaws while causing relative outward axial movement of the former in relation to the jaws.

Abstract: A tool for shaping the end of a branch tube which is to be engaged in a socket in the side of a main tube which tool comprises a die having an aperture to neatly receive the end of a branch tube to be shaped, and an intersecting bore in which a pair of cutters are disposed to each extend into the aperture, the cutters each having slits into which the end of a branch tube may be inserted, the slits being shaped to notch out diametrically opposed segments from the branch tube against the die, means being provided to displace the cutters outwardly and to return them after displacement.