Dresser Industries, Inc.

Smith International, Inc.

George A Espiritu

Robert W Arfele

Ed R Martin, Jr

Charles H Dewey

Alexander Craig Mackay

An expandable drilling apparatus includes a main body comprising a central bore and at least one axial recess configured to receive an arm assembly operable between a retracted position and an extended position, a biasing member to urge the arm assembly into the retracted position, a drive position configured to thrust the arm assembly into the extended position when in communication with drilling fluids in the central bore, a selector piston translatable between an open position and a closed position, wherein the selector piston is thrust into the open position when a pressure of the drilling fluids exceeds an activation value, wherein the drilling fluids are in communication with the drive piston when the selector piston is in the open position, and a selector spring configured to thrust the selector piston into the closed position when the pressure of the drilling fluids falls below a reset value.

Drilling and hole enlargement device

Steel bit bodies are manufactured with polystyrene patterns in a lost foam casting process. The patterns are machined in complex shapes that cannot be extractable from reusable, two-piece pattern molds. The patterns are machined in a basic, programmed, five-axis machining process to form multiple copies of a complex pattern body. The process is modified to produce multiple copies of a modified design. Multiple bit patterns of variable forms are produced without an intermediate, reusable pattern mold that would require multiple mold pieces, thus eliminating the time and expense in variation of the bit design. The pattern is machined in a single chucking operation in a machine tool adapted for machining plastics in a three-dimensional global process. The plastic composition and density permit it to be machined into a pattern having relatively small, unsupported structural projections and smooth surface features. Bit patterns formed in the process have forward canted blades that are machined from mating planar surfaces to simplify the machining process. The edges of the forward canted blades form a spiral surface for mounting cutter elements. The forward canting makes the blades stronger and permits the blades to be thinner than non-canted blades to increase the clearance between blades, which improves the movement of cuttings. Recesses are machined into the pattern gauge face to produce a recess in the casting for receiving hardfacing. The hardfacing forms a layer that cooperates with the surrounding blade material to form a smooth transition area as the bit wears during usage.

Steel-bodied bit

Steel bit bodies are manufactured with polystyrene patterns in a lost foam casting process. The patterns are machined in complex shapes that cannot be extracted from reusable, two-piece pattern molds. The patterns are machined in a basic, programmed, five-axis machining process to form multiple copies of a complex pattern body. The process is modified to produce multiple copies of a modified design. Multiple bit patterns of variable forms are produced without an intermediate, reusable pattern mold that requires multiple mold pieces, thus eliminating the time and expense in variation of the bit design. The pattern is machined in a single chucking operation in a machine tool adapted for machining plastics in a three-dimensional global process. The plastic composition and density permit it to be machined into a pattern having relatively small, unsupported structural projections and smooth surface features. Bit patterns formed in the process have forward canted blades that are machined from mating planar surfaces to simplify the machining process. The edges of the forward canted blades form a spiral surface for mounting cutter elements. The forward canting makes the blades stronger and permits the blades to be thinner than non-canted blades to increase the clearance between blades, which improves the movement of cuttings. Recesses are machined into the pattern gauge face to produce a recess in the casting for receiving hardfacing. The hardfacing forms a layer that cooperates with the surrounding blade material to form a smooth transition area as the bit wears.

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Houston, TX, United States of America

George A Espiritu