Abstract: In combination with a lathe having a headstock and a tailstock, a method of machining a metal workpiece includes: forming in a first end of the metal workpiece a cavity; positioning a spherical member in a predetermined position within the cavity; fixedly locating the spherical member in the predetermined position; mounting a second end of the metal workpiece in driving relation with the machine headstock; providing a means for rotatably supporting the first end of the metal workpiece; forming in a first end of the rotatable support means a cavity suitably dimensioned to conformably receive a predetermined portion of the spherical member; mounting a second end of the rotatable support means in the tailstock; mounting the first end of the metal workpiece in rotatable supporting relation with respect to the first end of the rotatable support means such that the cavity of the first end of the rotatable support means supportingly receives a predetermined portion of the spherical member which extends from the firs