Anchor with slips having angled interacting tongue and grooves effecting radial expansion

An expandable downhole anchoring tool (800) is positionable within a wellbore for use in cooperation with drilling equipment. The tool (800) has a body including a plurality of angled channels (816,818) formed into a wall thereof, and a plurality of movable slips (820) disposed in the same radial plane around the body. The slips (820) are hydraulically translatable along the plurality of angled channels (816,818) between a collapsed position and an expanded position. Unidirectional teeth (722, 723) provide a rachet mechanism to lock the slips in their expanded position. A method of setting an expandable anchor (800) within a wellbore comprises running the anchor (800) into the wellbore in a collapsed position, and expanding the anchor (800) into gripping engagement with the wellbore. The anchor (800) is adapted to expand up to at least 1.5 times the collapsed diameter of the anchor (800).