Abstract: A system includes a unit of a first part, and a proximal portion through an intermediate portion extended by a distal portion including a first extremity surface. A second part with a second portion includes a second surface to be friction welded with the extremity surface. A second portion is bordered laterally by a lateral surface and has a proximal portion, which extends through an intermediate portion extended by a distal portion. The distal portion of the second portion is carried in a malleable state during a friction welding. The intermediate portion of the second portion flares from the distal portion by the second towards and till the proximal portion of the second portion such that the bead of material from the deformation of the distal portion of the second portion during welding rubs against the lateral surface of the intermediate portion of the second portion during welding.