A tube fitting assembly is disclosed comprising a fitting having a first orifice through a portion of the fitting and a second orifice larger than the first orifice and coaxial with and through a portion of the first orifice. The second orifice extends from an outside surface of the fitting. One of the first and second orifices contains a shoulder defining areas of different cross-sectional areas within that orifice. The shoulder includes a shoulder surface facing axially inwardly relative to the outside surface of the fitting. A tubing having a diameter substantially equal to the first orifice occupies the first and second orifices with a first deformed portion formed from a radially expanded tubing wall engaging the other of the first and second orifices. The tubing has a second deformed portion formed from continued radial expansion of the tubing wall engaging the shoulder surface to seal the tubing to the fitting and preventing axial separation of the tubing from the fitting. The foregoing is merely a resume of one general application, is not a complete discussion of all principles of operation of applications, and is not to be construed as a limitation on the scope of the claimed subject matter.