Abstract: A method of manufacturing a rotary drill bit includes the steps of forming the bit body with a plurality of sockets, inserting in each socket a projecting carbon former, applying a fusible hard facing material to the surface of the bit body, and around the formers, by the localised application of heat to the solid material so as to melt it and weld it to the surface of the bit body, and then replacing the formers with cutters. During the application of the hard facing material, each former is also heated by the application of heat directly to it, so as to raise the temperature of the former to a level greater than the temperature to which it would otherwise be raised solely by conduction of heat from the hard facing material.