Expandable underreamer/stabilizer

An expandable downhole tool for use in a drilling assembly positioned within a wellbore having an original diameter borehole and an enlarged diameter borehole, comprising:

• a body;
• and
• at least one non-pivotable, moveable arm;
• wherein said at least one arm is moveable between a first position defining a collapsed diameter that is smaller than said original diameter borehole, and a second position defining an expanded diameter approximately equal to said enlarged diameter borehole.

A method of underreaming a wellbore to form an enlarged borehole and controlling the directional tendencies of a drilling assembly within the enlarged borehole, comprising:

• using a drill bit to drill the wellbore;
• disposing a first expandable tool having at least one arm configured for underreaming directly above the conventional drill bit;
• using the first expandable tool to form the enlarged borehole;
• disposing a second expandable tool having at least one arm configured for stabilizing above the first expandable tool;
• and
• using the second expandable tool to control the directional tendencies of the drilling assembly within the enlarged borehole;
• wherein both the first expandable tool and the second expandable tool operate between a collapsed position and an expanded position.

An expandable downhole tool for use in a drilling assembly, comprising:

• a body including a plurality of angled channels;
• at least one non-pivotable, moveable arm that translates along said angled channels between a collapsed position and an expanded position;
• and
• at least one moveable nozzle that translates to remain adjacent said at least one moveable arm.