Abstract: The present invention comprises an improved method and apparatus, associated with a self-piercing valve assembly for mounting the self-piercing valve on a pipe and for constraining movement of the valve on the pipe. In accordance with a preferred embodiment of the present invention, a self-piercing valve assembly comprises a clamping assembly and a crimping member associated with the clamping assembly, which crimping member "automatically" crimps a pipe and forms a recess therein when the self-piercing valve clamping assembly is tightened about the pipe, and simultaneously effects a crimping member/recess interface (much like a key-and-keyway interface) which inhibits relative angular rotation between the pipe and valve. The crimping member is, preferably, a rigid, projection or tab.