Abstract: The method of making a roller cone rock bit wherein a main body having a tool joint adjacent one end and a plurality of leg stubs adjacent the other end, has the outer surfaces of those leg stubs on a common conical locus tapering longitudinally inwardly from the radially outer extremity to the radially inner extremity. A like number of cone bases have their trunnions emplaced in respective recesses in a common fixture, in which the recesses are oriented with respect to one another in the same manner as is desired for the relative orientation of the trunnions on the finished rock bit. The end surfaces of the leg extensions which are integral with these trunnions are then simultaneously machined to lie on a common conical locus corresponding to that of the outer surfaces of the leg stubs. The trunnions are removed from the fixture, and each of the adjoining leg extensions has its machined end surface mated with an welded to a respective one of the outer surfaces of the leg stubs.