Patent ID: 8186458

Claim:
A method of milling a window through a casing in a primary well bore and drilling an enlarged sidetracked well bore comprising: running into the primary well bore a cutting apparatus comprising a bit adapted to drill an enlarged diameter borehole, the bit including one or more movable cutter blocks and one or more stationary cutting structures; milling a window through the casing with the one or more movable cutter blocks moved axially downward and secured in a collapsed position and allowing the one or more movable cutter blocks to mill the window while preventing the one or more stationary cutting structures from engaging the casing; continuing to drill the sidetracked well bore with the one or more movable cutter blocks until the cutting apparatus exits the casing; retracting a movable piston disposed in the cutting apparatus and, via links, retracting and radially expanding the one or more movable cutter blocks, thereby exposing the one or more stationary cutting structures; and drilling an enlarged diameter sidetracked well bore with the bit, wherein the diameter of the sidetracked wellbore is enlarged by about 20%; wherein the milling, drilling, actuating and drilling the enlarged sidetracked well bore are preformed in one trip into the primary well bore.