Abstract: An adjustable bent housing for use in downhole drilling which includes a housing, mandrel, ring and locking mechanism. The housing has a housing central axis, a downward facing end face defining a plane whose normal is offset from the housing central axis, and an inner shoulder parallel to the downward facing end face. The mandrel has a mandrel central axis, a first end dimensioned to fit inside the housing and having a downward facing outer shoulder defining a plane whose normal is offset from the mandrel central axis. The ring is axially slidable on the mandrel, with a ring central axis and an upward facing end face defining a plane whose normal is offset from the ring central axis. A locking mechanism, a mandrel head threaded onto the mandrel, engages and disengages the upward facing end face of the ring with the downward facing end face of the housing and simultaneously engages and disengages the inner shoulder of the housing with the outer shoulder of the mandrel.

Abstract: An adjustable bent sub for a down hole drill is disclosed consisting of a hollow housing and a hollow mandrel shaped to fit within the housing. A jam nut is positioned on the end of the mandrel to retain it within the housing by abutting a shoulder provided on the inner surface of the housing. A 1 degree off-normal face is machined on the shoulder and on the abutting face of the jam nut. By positioning the mandrel/jam nut assembly at different angular positions with respect to the housing, a linear deviation of 0 to 2 degrees is possible through the length of the sub.