Abstract: A stabilizer for deep well drilling tools is disclosed which includes a tubular outer casing having a plurality of slit openings distributed around its periphery with a tubular adjusting mandrel supported in the casing for relative axial movement therewith in response to well fluid pressure applied to the well. A separate elongated ribbed body is movably mounted in each slit opening. Each of the ribbed bodies has a rear wedge face facing opposite to the relative motion of the mandrel which cooperates with a separate mating wedge face on the mandrel such that the ribbed body moves radially outwardly in its respective slit opening upon contact between said mating wedges upon axial movement of the mandrel relative to the casing in response to well fluid pressure applied to the well. Also, each end of each ribbed body has an axially projecting guide projection which terminates in a reduced dimension at its end.

Abstract: A drill bit for drilling bore holes in underground formations comprising a bit body with a connecting spigot for connecting to a drill string or the like, and a cutting head which comprises a circumferential face extending parallel to its longitudinal axis and an end face having a drilling axis which is aligned with the axis of the connecting spigot. The drilling axis is parallel to and is offset relative to the axis of the cutting head. It is preferred that the end face is, at least in part, conical in shape.