Patent ID: 6321858
Filing Date: 2001-11-27
Classification: E21B

Abstract:
A drill bit for directional drilling, comprising:a housing including means at a rear end thereof for mounting the bit on a trailing component of a drill head, and passages for ejection of drilling fluid into a borehole;a first axle mounted to extend forwardly from a front end of the housing;a first roller rotatably mounted on the first axle having cutting projections thereon, which first roller extends outside of the outer diameter of the housing by a distance which defines the size of the borehole when the drill bit is rotated over 360 degrees;a second axle mounted to extend forwardly from a front end of the housing;a second roller rotatably mounted on the second axle, which second roller extends outside of the outer diameter of the housing by a distance less than the distance the first roller extends outside of the housing and which is configured to provide a reaction surface for the first roller as the first roller bores the borehole with the cutting projections.