A method for making a valve assembly is disclosed. The method includes providing a first work piece having a longitudinal axis and a first end and providing a second work piece having a surface. The method also includes disposing the first work piece and the second work piece axially between a pair of aligned elements that are relatively movable toward and away from each other along the longitudinal axis of the first work piece. Additionally, the method includes relatively moving the pair of aligned elements toward each other to axially clamp the first work piece and the second work piece and actuating the pair of aligned elements and delivering to the first work piece and the second work piece a controlled clamping force that acts to coin a zone of surface contact between the first end and the surface. Further, the method includes repeating the actuating of the pair of elements a plurality of times. An apparatus used to perform the method is also disclosed.