Abstract: A mill for use in a wellbore includes a tubular housing having a bore therethrough, a plurality of pockets formed in a wall thereof, and a blade disposed in each pocket. Each blade includes a body having a first side opposite a second side, wherein the first side faces in a direction of rotation of the mill. The blade also includes a blade portion disposed on the first side of the body, wherein the blade portion has a first cutting face stepped relative to a second cutting face. Each blade is movable between a retracted position and an extended position, wherein a portion of the first side and the second side protrude from the housing in the extended position.

Abstract: An earth-boring tool includes a tool body configured to rotate in a wellbore and carrying at least one extendable element. The at least one extendable element is configured to move between a retracted position and an extended position projecting radially beyond the tool body. The at least one extendable element has a mating surface. The earth-boring tool includes a support structure located in the tool body and having a support surface that is located and configured to face the mating surface of the at least one extendable element when the at least one extendable element is in the extended position. The support surface of the support structure is configured to bear at least a portion of the tangential forces acting on the extendable element during rotation of the earth-boring tool in the wellbore when the at least one extendable element is in the extended position.

Abstract: A mill for use in a wellbore includes a tubular housing having a bore therethrough, a plurality of pockets formed in a wall thereof, and a blade disposed in each pocket. Each blade includes a body having a first side opposite a second side, wherein the first side faces in a direction of rotation of the mill. The blade also includes a blade portion disposed on the first side of the body, wherein the blade portion has a first cutting face stepped relative to a second cutting face. Each blade is movable between a retracted position and an extended position, wherein a portion of the first side and the second side protrude from the housing in the extended position.

Abstract: Disclosed drilling systems offer multiple methods providing access to the open borehole without first tripping the drill string. In some embodiments, a drill bit has a tool port that is blocked by a plug during normal drilling operations. When a tool is deployed through the interior of the drill string, the tool port opens, enabling the tool to enter the borehole beneath the drill string and perform logging or sampling operations. The plug may be attached to the drill bit by a hinge or pivot, or alternatively, the plug may be discarded and a replacement seated in place after the tool is retracted into the drill string. In other embodiments, the drill bit itself is detachable, allowing the bit to be parked in the hole or in a side bore. If desired, the bit can be re-attached by lowering the drill string to the bottom of the hole.

Abstract: An under-reaming pile bore excavator by which a straight pile bore is first excavated vertically to a given depth by rotating the main drill bits and the under-reamed bore is next excavated downward and outward into a given shape by rotating the slidable wing bits, allowing a relatively larger diameter ratio of the under-reamed pile bore to the straight pile bore. The under reamed pile bore excavator of the present invention comprises a plurality of guide rails disposed so as to cross the axis of the drill pipe, and a plurality of slidable wing bits mounted on the guide rails which excavate the under-reamed bore, in addition to the conventional main drill bits which can excavate the straight pile bore.

Abstract: A tool which makes an undercut in the surface surrounding a drill hole in a layer of coal has a head plate which abuts against the surface at the inner end of the hole when the tool is inserted and which is installed at the front end of a rotary tubular guide for two bit holders constituting one-armed levers and having front portions provided with bits and being movable radially outwardly through windows in the guide. The rear portions of the holders are coupled to the front part of a reciprocable rotary shank which can be moved forwardly to expel the bits from the guide while moving the holders forwardly. When the shank is retracted, the bits are withdrawn into the guide. Such movements of the bits are caused by a transverse pin mounted in the guide and extending through elongated cam grooves in the median portions of the holders.