Patent ID: 8196682
Filing Date: 2012-06-12
Classification: E21B

Abstract:
1. A drill bit for drilling a subterranean formation, comprising: at least one leg; a cantilevered bearing shaft comprising a base formed on the at least one leg and having a substantially cylindrical surface extending from the base defining a longitudinal axis; a roller cone disposed about the bearing shaft and configured to rotate about the longitudinal axis, said roller cone comprising an exterior surface for contacting the subterranean formation and an interior surface disposed about the bearing shaft; and a sealing element; an indentation adapted to receive a bearing shaft element, said indentation being formed circumferentially within the bearing shaft; a bearing shaft element secured in the circumferential indentation in the bearing shaft, thereby forming a portion of the exterior surface of the bearing shaft; wherein at least a portion of an exterior surface of the bearing shaft includes a tungsten/tungsten carbide coating, said tungsten/tungsten carbide coating comprising tungsten carbide nano-particles dispersed in a tungsten matrix.