Abstract: A directional drilling sub comprises a housing, a coupling mechanism arranged within the housing, and a tilt drive shaft extending within the housing and has a first end coupled to the coupling mechanism and a second end coupled to a drill bit. The sub further comprises an upper eccentric assembly arranged within the housing to support the tilt drive shaft at the first end which includes an upper inner eccentric ring nested within an upper outer eccentric ring and a lower eccentric assembly arranged within the housing to support the tilt drive shaft at the second end which includes a lower inner eccentric ring nested within a lower outer eccentric ring, wherein rotational movement of at least one of the upper and lower inner or outer eccentric rings tilts the tilt drive shaft within the housing and thereby alters an azimuthal tool face orientation of the drill bit.

Abstract: A disclosed directional drilling sub includes a housing, a coupling mechanism arranged within the housing, a tilt drive shaft extending within the housing and having a first end coupled to the coupling mechanism and a second end coupled to a drill bit, an upper eccentric assembly arranged within the housing to support the tilt drive shaft at the first end and including an upper inner eccentric ring nested within an upper outer eccentric ring, and a lower eccentric assembly arranged within the housing to support the tilt drive shaft at the second end and including a lower inner eccentric ring nested within a lower outer eccentric ring, wherein rotational movement of at least one of the upper and lower inner or outer eccentric rings tilts the tilt drive shaft within the housing and thereby alters an azimuthal tool face orientation of the drill bit.