Method of manufacturing a coaxial electrical transmission line

Claim 1

IN THE MANUFACTURE OF A COAXIAL ELECTRICAL TRANSMISSION LINE, THE STEPS OF CLAMPING AN ELONGATED TUBULAR CONDUCTOR COMPONENT AT TWO AXIALLY SPACED POINTS, POSITIONING A MANDREL HAVING A SUPPORT SURFACE OF CONFIGURATION SUBSTANTIALLY THE SAME AS THE CONFIGURATION OF SAID ELONGATED TUBULAR CONDUCTOR COMPONENT OF THE TRANSMISSION LINE IN SUPPORTING RELATION TO SAID CONDUCTOR COMPONENT, SAID SUPPORT SURFACE HAVING AN ANNULAR RECESS THEREIN, APPLYING PRESSURE IN A RADIAL DIRECTION TO SAID TUBULAR CONDUCTOR COMPONENT AT THE POINT AT WHICH SAID MANDREL IS POSITIONED TO FORCE THE METAL IN SAID CONDUCTOR COMPONENT INTO THE RECESS IN SAID MANDREL TO FORM AN ANNULAR GROOVE IN SAID CONDUCTOR COMPONENT WHILE MAINTAINING THE SMOOTH CONTINUITY OF THE SURFACE OF SAID CONDUCTOR COMPONENT, AND MOVING ONE OF SAID CLAMPING POINTS TOWARD THE OTHER CLAMPING POINT TO APPLY FORCE TO SAID CONDUCTOR COMPONENT IN THE DIRECTION OF ITS LENGTH DURING THE APPLICATION OF SAID PRESSURE TO SAID CONDUCTOR COMPONENT TO REDUCE THE LENGTH OF SAID CONDUCTOR COMPONENT SO THAT SAID ANNULAR GROOVE IS FORMED WITHOUT ANY SUBSTANTIAL REDUCTION IN THE THICKESS OF THE WALL OF SAID CONDUCTOR COMPONENT AT THAT POINT.