Abstract: Disclosed is a rolling cone cutter and drill bit employing multiple inserts retained as a cluster in an aperture in the cone cutter. Apertures in which the insert clusters are retained are multilobed apertures formed by intersecting bores formed in the cone steel. The apertures may also be created by forming spaced apart bores and milling regions of the cone steel that extends between the bores. The inserts in a cluster may be retained within the aperture to differing depths, may extend above the cone steel to differing extension lengths, and may have cutting portions having a variety of shapes. The inserts in a cluster may be made of different materials in order to optimize cutting duty.

Abstract: A method is disclosed for forming a drill bit structure to which a cutting element is to be affixed. The method includes applying a layer of hardfacing material to a basic bit structure, removing the layer of hardfacing material in a location to which the cutting element is to be affixed, and forming an attachment structure at the location. In one embodiment, the removing is performed by electrode discharge machining. In one embodiment, the basic bit structure is a roller cone, and the cutting element is an insert adapted to be interference fit within a socket in the roller cone.