Abstract: A drill includes support pads for supporting and guiding the drill in the drill hole. The support pads are formed as parallelepiped-shaped cemented carbide bodies which each have two wing-shaped protrusions on their longitudinal sides. In a corresponding way, the drill head of the drill includes recesses with two bulged parts on the long sides. This gives the support pad a determined axial position and strengthens the support pad at the weakening caused by the central hole. Further, the support pad can be turned half a revolution if one of its ends becomes damaged since the end spaces do not have to function as abutment surfaces.

Abstract: A rolling cutter drill bit has multiple rows of gage reaming inserts mounted in the gage face of the cutters. A first interlocking row of gage reaming inserts is positioned on the gage face of a cutter in close proximity to the gage row, such that the reaming inserts are closely adjacent to the mouth of the gage insert sockets. A second non-interlocking row of gage reaming inserts is positioned on the gage face of the cutter such that the reaming insert sockets are a predetermined minimum distance from the gage insert sockets and first reaming row sockets, thereby enabling a maximum number of large diameter reaming inserts to be placed in the second reaming row. Both the first and second reaming row inserts are sized and placed to maintain a desired distance between all insert sockets without affecting the size and spacing of gage row inserts.

Abstract: An earth-boring bit is provided with hard gage inserts that protrude from the gage surface of the cutter to engage the side of the borehole for holding gage. The cutting end of the gage insert has a cutting end defining at least one sharp cutting edge and at least one cutting surface that define a negative rake angle with respect to the sidewall of the borehole that is being sheared by the gage insert. The cutting end, cutting edge, and cutting surface of the gage insert are formed of a super-hard and abrasion-resistant material such as polycrystalline diamond or cubic boron nitride. The body of the insert is formed of a hard, fracture-tough material such as cemented tungsten carbide. The improved gage inserts provide an actively cutting gage surface that engages the sidewall of the borehole to promote shearing removal of the sidewall material. Such an improved gage insert provides an earth-boring bit with improved gage-holding ability, and improved steerability in directional drilling operations.

Abstract: A rotary drill bit for drilling holes in subsurface formations comprises a bit body having a shank for connection to a drill string, a number of circumferentially spaced blades on the bit body each extending outwardly away from the central axis of rotation of the bit, a number of cutters mounted side-by-side along each blade, and a passage in the bit body for supplying drilling fluid to the surface of the bit for cleaning and cooling the cutters. The blades comprise alternating primary and secondary blades. The cutters on the primary blades are primary cutters which are located at different radial distances from the bit axis so as to define a cutting profile which, in use, covers substantially the whole of the bottom of the bore hole being drilled. At least the majority of the cutters on the secondary blades are secondary cutters each of which is located at substantially the same radial distance from the bit axis as an associated primary cutter on the preceding primary blade.

Abstract: A pair of stabilizers are placed in a string of drill pipe having a drill bit or a coring bit at its lower end, the placement of the stabilizers being such that the distance (d1) between the midpoint (mean transverse section) of the gauge surface of the bit and the midpoint (mean transverse section) of such first stabilizer bears a relationship to the distance (d2) between the midpoints of the two stabilizers. The ratio of d1 to d2 (d1/d2) should be between 1/1.5 to 1/5, and preferably between 1/2 and 1/3, with d1 being maintained less than five feet, preferably less than three feet. In one embodiment, the drill bit and the two stabilizers are formed in a monoblock.

Abstract: A rotary cone rock bit has bearing inserts pressed into the side of the shirttail portion of the rock bit body for stabilizing the rock bit during drilling. Such a rock bit has a steel bit body with a threaded upper pin for connection to a drill string. Cutter cones are mounted on lower leg portions of the rock bit body. The rock bit body gradually decreases in diameter from the gage diameter adjacent the lower tips of the shirttails adjacent to the cones to a smaller diameter shoulder the pin end of the body. The lowermost bearing insert protrudes laterally from the gradually decreasing diameter part of the bit body approximately half way between the lower tip of the shirttail and the shoulder at the upper end of the shirttail. The outer ends of the bearing inserts are rounded and substantially at the gage diameter of the bit for bearing on the wall of the borehole being drilled without appreciably reaming the borehole.

Abstract: An earth-boring bit of the fixed cutter variety is provided with hard gage inserts that protrude from the gage surface of the cutter to engage the side of the borehole for holding gage. The gage insert has a substantially flat, polygonal face defining at least a pair of sharp cutting edges and at least a pair of cutting surfaces that define a negative rake angle with respect to the sidewall of the borehole that is being sheared by the gage insert. The face, cutting edge, and cutting surface of the gage insert are formed of a super-hard and abrasion-resistant material such as polycrystalline diamond or cubic boron nitride. The body of the insert is formed of a hard, fracture-tough material such as cemented tungsten carbide. The improved gage inserts provide an actively cutting gage surface that engages the sidewall of the borehole to promote shearing removal of the sidewall material.

Abstract: A method to back ream a borehole drilled with a roller cone drill bit is taught. Protruding hard metal cutting inserts are affixed on the upper outside diameter tapered shoulder of each of the bit legs. If the borehole closes to a smaller diameter than the bit gage diameter or loose rock rubble packs around the upper portion of the bit, the protruding cutting inserts fixed on the upper leg tapered shoulder portion back ream the borehole by lifting and rotating the bit.

Abstract: An anti-whirl underreamer comprising a body configured for connection to a drillstring, at least two arms carried by the body which are extendable between a retracted position and a projected position, a movable piston and biased spring assembly for moving the arms, a plurality of cutting elements carried by one of the arms for cutting an axially extending cylindrical sidewall of the borehole within a subterranean formation and for applying a resultant radial force to the body as it rotates, and a low friction bearing region carried by another arm for transmitting the resultant radial force from the body to the sidewall of the borehole during rotation of the underreamer within the borehole. The cutting elements are positioned so that the resultant radial force developed is of sufficient magnitude and direction to substantially maintain the low friction bearing region in contact with the sidewall of the borehole as the underreamer is rotated within the borehole.

Abstract: Rotary drag during drilling is reduced by 1) adding roller bearings to a tubular string and drill bit, and/or 2) adding a bearing assembly to the tubular string, and/or 3) adding a rotary discoupling tool to the tubular string. At the drill bit, this is achieved by miniature rollers built into the gauge section. Along the drill string periodic roller bearings or bearing standoff assemblies are placed along the string length and/or a rotary discoupling tool capable of sealing fluid and transmitting compression and tensile loads is placed in the string. The combination minimizes bit whirl and rotational drag, especially during the drilling of extended reach wellbores.

Abstract: This invention relates to an improved roller cone coring bit that includes spiral stabilizer blades on the bit body. The spiral stabilizer blades reduce the whirling tendency of the bit, thereby enhancing the ability to cut and recover a continuous core.

Abstract: A drill bit sub, which has a drill bit with three equally angularly spaced cutters releasably threaded into its bottom surface, has its lower portion reduced in diameter. A collar is welded to the uppermost portion of the lower portion of the drill bit sub and has its lower surface formed at an angle to its longitudinal axis. A protective sleeve, which is a hollow cylindrical metal tube, is removably mounted on the lower portion of the drill bit sub and has its upper surface at the same angle as the lower surface of the collar. The protective sleeve has three equally angularly spaced wear strips, which are substantially aligned with the three cutters on the drill bit. A first break out ring is mounted between the bottom of the protective sleeve and a support surface on the drill bit so that the drill bit bears against the bottom of the first break out ring.

Abstract: A rotary drill bit comprises a bit body carrying a plurality of preform cutting elements, and a plurality of circumferentially spaced gauge pads which, in use, engage the surrounding formation. Some of the gauge pads carry cutting elements and others are free of cutting elements. To reduce cost, each gauge pad which is free of cutting elements has an outer bearing surface which is more abrasion resistant than the outer surfaces of the gauge pads which carry cutting elements.

Abstract: A drill bit for use in drilling a well bore comprises a main drill body adapted to be rotated about a substantially vertically disposed axis of rotation and having therein a duct extending longitudinally along such axis, for supplying a drill fluid under pressure to the well bore. At least one generally circular, rotatable cutting discs are mounted on the outside of the main drill body at equally spaced locations, with the cutting discs each having cutting elements disposed in a ring-shaped array. Each of the cutting discs has an axis of rotation disposed at an acute angle to the vertical centerline about which the main drill body rotates. The axis of rotation of each cutting disc is slightly offset laterally in a rearward direction from the centerline of the main drill body, thus to cause the entire bit to be placed in a non-equilibrium position with the rotation of the main body enabling the cutting disc to be positioned to be particularly effective and aggressive in cutting the well bore.

Abstract: A subterranean drill bit operable with a rotational drive source is provided for drilling in subterranean earthen materials to create a borehole having a borehole wall. The drill bit comprises a drill bit body having a base portion, a gauge portion and a face portion disposed about a bit axis. A plurality of diamond cutting elements are fixedly disposed on and project from the face portion and are spaced from one another. The cutting elements are disposed for causing a net radial imbalance force during the drilling along a net radial imbalance force vector substantially perpendicular to the bit axis. A substantially continuous cutter devoid region is disposed on the gauge portion about the force point, and a bearing support is disposed in the cutter devoid region about the force point for substantially continuously contacting the borehole wall during the drilling.

Abstract: A rotary drill bit comprises a bit body having a shank for connection to a drill string and a passage for supplying drilling fluid to the face of the bit, which carries a plurality of polycrystalline diamond preform cutting elements. The cutting elements on one side of a diameter of the bit have positive side rake and the cutting elements on the other side of the diameter have negative side rake so that the vectorial sum of the reaction forces between the formation being drilled and the cutting elements provides a resultant lateral imbalance force acting on the bit body as it rotates in use. The gauge of the bit body includes low friction bearing pads so located as to transmit the resultant lateral force to the sides of the borehole. Since the bearing pads are of low friction, they slide around the surface of the formation and any tendency for bit whirl to be initiated is reduced.

Abstract: A rotary drill bit comprises a bit body having a shank for connection to a drill string and a passage for supplying drilling fluid to the face of the bit, which carries a plurality of polycrystalline diamond preform cutting elements. In order to reduce bit whirl, the cutting elements are so disposed as to apply a resultant lateral force to the bit as it rotates during drilling, and the gauge of the bit body is provided with low friction bearing means to transmit said resultant force to the sides of the borehole. Each low friction bearing means includes a roller mounted on the bit body for rotation about an axis parallel to the axis of rotation of the bit, each roller being so disposed that its periphery bears on the formation as the bit rotates.

Abstract: A rotary drill bit comprises a bit body having a shank for connection to a drill string and a passage for supplying drilling fluid to the face of the bit, which carries a plurality of polycrystalline diamond preform cutting elements. In order to reduce bit whirl, the cutting elements are so disposed as to apply a resultant lateral imbalance force to the bit as it rotates during drilling and the gauge of the bit body is provided with low friction bearing pads to transmit said resultant lateral force to the sides of the borehole. Each low friction bearing pad includes an outwardly facing cavity which is connected to the passage by a choked conduit so that, in use, drilling fluid under pressure is delivered to the cavity, which thereby acts as a low friction hydrostatic bearing surface.

Abstract: A milling tool (3-5; 51-53) in combination with a stabilizer therefor has a milling tool with a body (51) with a plurality of radially extending and circumferential blades (3) diposed about the body. The lower portion of the body (51) has a portion (57) upon which is located a stabilizer (70), the stabilizer comprising a sleeve (71) about which are disposed a plurality of helically disposed fins (75). The sleeve (71) has an internal screw thread (73) for mating with an external screw thread (55) on the body (51).By providing a single milling tool on site and a plurality of separate pilot stabilizers so stabilizer sleeves can be quickly and easily secured to the milling tool thereby eliminating the necessity of cutting the fins to the required radial height when on site.

Abstract: An improved rotary rock bit is described having a plurality of wear resistant inserts protruding along the leading edge of the bearing segment shanks. These inserts break up large chunks of formation which protrude inward from the borehole wall while drilling fractured or broken hard formations. Thereby protecting the bit from damage and excessive erosion often incurred while drilling hard fractured and broken formations.

Abstract: A hollow drilling tool is made up of an axially extending tubular carrier part, a cutting body at one end of the carrier part, and guide elements located in the axial direction of the carrier part between the cutting body and the carrier part. The radially outer surface of each guide element is in alignment in the axial direction of the carrier part with the radially outer surface of the cutting body. The guide elements guide the hollow drilling tool in a borehole formed by the cutting body.

Abstract: A drill bit for use in drilling a well bore in accordance with this invention comprises a main drill body adapted to be rotated about a substantially vertically disposed axis of rotation and having therein a duct extending longitudinally along such axis, for supplying a drill fluid under pressure to the well bore. Three generally circular, rotatable cutting discs are mounted on the outside of the main drill body at equally spaced locations, with the cutting discs each having cutting elements disposed in a ring-shaped array. Each of the cutting discs has an axis of rotation disposed at an acute angle to the vertical centerline about which the main drill body rotates. Importantly, the axis of rotation of each cutting disc is slightly offset from the centerline of the main drill body, thus to cause the cutting discs to be positioned to be particularly effective and aggressive in cutting the well bore.

Abstract: A drill bit sub, which has a drill bit with three equally angularly spaced cutters releasably threaded into its bottom surface, has its lower portion reduced in diameter. A protective sleeve, which is a hollow cylindrical metal tube, is releasably attached to the lower portion of the drill bit sub so that three equally angularly spaced lugs are at specific circumferential positions relative to the cutters. The lugs engage three equally angularly spaced wear strips on a wear strip support, which is mounted on the lower portion of the drill bit sub below the protective sleeve, so that the wear strip support rotates with the drill bit sub. The drill bit bears against the lower end of the wear strip support when the drill bit is mounted on the drill bit sub. The specific positions of the lugs on the protective sleeve align each of the three wear strips with the maximum outer protrusion of one of the three cutters on the drill bit.

Abstract: A method and apparatus for drilling highly deviated wells is disclosed. A drilling assembly is attached to a drill string. The drilling assembly includes a bent sub, a pony collar attached to the bent sub, a motor with a bent housing, and a bit. Improved survey collars and bits are also disclosed.

Abstract: An imbalance compensated drill bit is disclosed that takes advantage of undesired and destructive imbalance forces to prevent bit whirl. Methods of designing and making such imbalance compensated drill bits are disclosed whereby a drill bit body has at least one cutting zone with a plurality of cutting elements extending therefrom and at least one bearing zone. The bearing zone has a relatively smooth surface and is located at a position where the net imbalance force (from the cutting elements) is directed towards. When the drill bit is rotated, the imbalance force presses the bearing zone against the borehole wall, and the bearing zone slips along the wall, thereby preventing the center of rotation to shift and create the destructive whirling motion.

Abstract: A drill bit offering improved steerability. Drill bits include gage sections which are adapted to facilitate deflection of the bits within a borehole to facilitate navigational or directional drilling. The gage portions of the bit may be arranged in an arcuate path around a portion of the periphery of the bit. Also, the bit portions may be spaced and adapted to serve, at least in part, as fulcrums, to facilitate deflection of the bit and the bringing of gage cutting portions of the bit in contact with the sidewalls of the borehole.

Abstract: A drill bit for producing an undercut. The drill bit includes a shaft and a cutting edge that is disposed asymmetrically radially beyond the shaft in a front end portion of the drill bit. A planar guide surface is provided on a conical end face of the drill bit. This guide surface is disposed radially opposite the cutting edge. The guide surface terminates at a concentric tip of the drill bit.

Abstract: Apparatus for stabiliing a rotary drill string and drill bit used to drill a borehole in a material, such as a subterranean formation, includes an imbalanced drill collar and a drill bit connected to the drill collar. The imbalanced drill collar creates a drill string imbalance force directed radially outwardly from the center of rotation of the drill collar through a predetermined area on the circumference of the drill collar and urges the predetermined area into contact with the borehole wall as the drill string rotates. The drill bit includes a drilling surface for contacting the material and drilling the borehole in the material, the drilling surface including a cutting zone for cutting the borehole in the material and the bearing zone having a low coefficient of friction relative to the cutting zone.

Abstract: An earth anchor apparatus adapted to be driven by a source of rotational driving force into unbroken soil includes a longitudinally extending hub having first and second axial ends. A recess is provided in one axial end of the hub by which the anchor may be driven, and a radially extending, load-bearing element is affixed to the hub between the axial ends. An earth engaging lead tip extends axially from the second end of the hub and includes a first cutting edge extending in a direction generally transverse to the longitudinal axis of the hub and arranged to cut into and break soil encountered thereby, a front surface extending between the hub and the first cutting edge, and a second cutting edge extending between the first cutting edge and the leading edge of the load bearing element. The second cutting edge is adapted to both cut soil and guide it from the first cutting edge toward the load-bearing element along the front surface so that as soil is cut it is moved away from the unbroken soil.

Abstract: A drilling device for producing drill holes with undercuts comprises a drill having a drill shaft with extending drill blades, a shoulder projecting from the drill shaft, and a guiding sleeve surrounding the drill shaft between the shoulder and the drill blades, the guiding sleeve having two ends provided with openings of different sizes, the guiding sleeve having a sleeve edge which forms a support for the shoulder and a wall abutment for the collar.

Abstract: A rock drill bit having an elongated tubular body with a drilling head portion at one end and a trailing opposite end portion, the head end portion having attached hardened portions for engaging and drilling a work surface, at least one opening through the head end portion for drilling fluid to pass therethrough to the region of the drill face, at least one side of the bit having an axially extending cutout therealong forming an elongated passage with the surface of a bore being drilled through which the drilling fluid and drilling residue carried thereby can pass as it moves rearwardly along the drill bit away from the drill face, and transversely extending grooves formed in the portions of the body between the cutouts dividing the portions into a plurality of spaced outwardly extending body portions.

Abstract: A rotary drill bit (10) having a plurality of roller cutters (20) with rows (32A, 32B, 32C, 32D) of cutting inserts (34,36,38,40) mounted within sockets (35,46) on the frusto-conical cutter body (30). The cutting inserts 34,36,38,40) have cutting surfaces formed with a wear-resistant material with certain cutting inserts (36,38) being formed of a wear-resistant material having a hardness higher than the hardness of the wear-resistant material on the remaining inserts (34,40) in each row. The hard cutting inserts (36,38) are positioned in each row in a predetermined pattern intermingled in a generally uniformly spaced pattern with the softer cutting inserts (34,40) and comprising generally between 20% and 50% of the total number of cutting inserts in a particular row.

Abstract: A whirl resistant drill bit is disclosed for use in rotary drilling. The drill bit includes a generally cylindrical bit body with a plurality of cutting elements extending out from a lower end surface. The cutter elements are grouped in sets such that a first set of cutters are disposed at substantially an equal radius from a center of the bit body to create a groove in the material being drilled. A second set of cutters is connected to the lower end surface with each cutter therein in overlapping radial relationship with each other and extending a maximum distance from the lower end surface less than that of the first set of cutters. At least one cutter of the second set is in overlapping radial relationship with at least one of the cutters within the first set of cutters. This cutter arrangement causes the drill bit to cut grooves within the formation material that tends to prevent destructive bit whirl. Further, adjustments can be made to vary the back rake angle and side rake angle to prevent bit whirl.

Abstract: A stabilizer for driving and radially stabilizing a drill bit. The stabilizer has a fluid passage therethrough for passage of drilling fluid to the drill bit. The stabilizer includes radially extendable wedge-like members for stabilizing abutment thereof with a borehole wall; means affected by drilling fluid pressure or spring tension for controlling extension and retraction of the wedge-like members; and, inclined slide surfaces for frictional interaction with the wedge-like members to prevent radial movement of said stabilizer relative to a borehole.

Abstract: An apparatus and method for drilling and then installing a production conduit (46) within an enlarged bore hole (D) along an underground path (P) between two surface locations (C, D). Upon completion of a pilot bore hole (B), a reamer (48) enlarges the bore hold (B). The drill string (10) is returned to the exit opening (E) for connection to the production conduit (46) for pulling the conduit (46) within the enlarged opening (D). One embodiment (FIGS. 19-21) utilizes canted rollers (168) for supporting the production conduit (46) at the exit opening (E) and effecting rotation thereof as the production conduit (46) is fed into the enlarged diameter opening (D).

Abstract: A stabilized drill bit has a cylindrical main body, a formation cutting face at the lower end of the body, and means by which the upper end of the bit can be connected into a drill string. A drilling fluid flow passageway extends axially through the main body and provides flow of drilling fluid to the drilling face. A plurality of hydraulic actuated stabilizing members are arranged circumferentially about the throat and within the main body. Stabilizing members have a borehole wall engaging face thereon which can be retracted flush with the outer surface of the main body, and extended away from the main body face and into contact with the borehole wall, thereby stabilizing the drill bit as the bit is rotated while making hole.

Abstract: A hole opener for placement in a drill string having a body generally comprising a collar, a triangular mid-section, a triangular shaped pilot and a bull nose. The collar provides means for attaching the tool body to the drill string. The triangular mid-section has three longitudinal, radially spaced apart blade members that are parallel to the central axis of the tool body so that the blades can cut into the walls of the bore hole to enlarge the size of the bore hole. Three annular flow zones span the distance between the blade members so that fluids and cuttings can circulate through the bore hole. The pilot section also has three longitudinal, radially spaced apart blade members that are parallel to the central axis of the tool body bore and three annular flow zones which span the distance between the blade members of the pilot. The pilot section is downhole from the mid-section.

Abstract: A tool, provided in the form of an up-drill sub, is comprised of a cylindrical body having a plurality of lobes integrally formed therewith and radially extending therefrom. Each lobe in turn is provided with a plurality of diamond cutting elements on an upwardly inclined surface of the lobe. The lobes are separated by channels or junk slots. The diamond cutting elements are arranged and configured on the sloping surface of the lobe to provide a cutting or reaming action as the tool is rotated and drawn upwardly in the bore. Tungsten carbide inserts are also provided on the circumferential gage surfaces of the lobes to provide gage protection. The ends of the sub are provided with selected pin or box connections in combination as appropriate so that the up-drill sub can be used anywhere within the drill string. Therefore, the up-drill sub may be used near the bit as a near bit or elsewhere in the drill string, such as a crossover sub between the drill collar and drill pipe or above a stabilizer.

Abstract: There is described a new and improved method and apparatus for boring subterranian holes between horizontally spaced locations, comprising a broaching head having a first trailing and a second leading end for cutting a bore hole through the ground, a rod string releasably connectible to the first end thereof for pushing the broaching head through the ground; a guiding head cooperating with the broaching head for guiding the movement of the broaching head between the horizontally spaced locations, and extruders to extrude the incised core of the bore. The broaching head is pushed between the locations to cut a core, which passes through the head, by forming first and second coaxial incisions, whereby subsequent removal of the core is facilitated.

Abstract: An earth boring bit is shown of the type used to cut a shaft in the earth. The earth boring bit has a central bit body which is adapted to be driven to cut a shaft and which has an outer conical surface thereon. An outer ring segment carried on the central bit body has a conical surface for matingly engaging the central bit body conical surface whereby torque transmitted to the outer ring is transmitted through the mating conical surfaces to drive the central bit body to cut a shaft. The mating conical surfaces are preloaded to assure drivable contact between the surfaces. The effective cutting diameter of the earth boring bit can be varied by interchanging the outer ring segment.

Abstract: A guiding means in rock drilling for guiding a percussion drill string (10) comprises a guide sleeve (17). For purposes of ensuring free rotation between the drill string (10) and the guide sleeve (17) the latter is bound by shape to the drill string at its one end during drilling as well as during withdrawal of the drill string (10).

Abstract: A drill string stabilizer in which the wall-contacting wear elements are secured in their accommodating slots by an undercut along each side and a tapered wedge-receiving notch along the underneath side for accepting one or more wedge pieces. In one embodiment, the tapered notch is along the side of an axially elongate slot and a plurality of wedges are located in securing position along one side. In another embodiment, there are tapered notches along the center between two separated sections of wear elements. In a third embodiment, the slot for the wear elements is not axially elongated but on a spiral angle. In a fourth embodiment, a pluraity of short wear elements are employed end-to-end, each with its own wedge piece and each also located on a thrust-bearing and locating pin.

Abstract: A tool for drilling a cylindrical hole with an enlarged end undercut portion comprises a shank with cutting edges and a drill collet screwed to the shank by a knuckle thread. The collet is provided with a stop collar having a semispherically-shaped face supported in a matingly configurated recess provided in a stop plate so as to form a swivel bearing. A portion of the collet is closed by a bell connected to the stop plate and formed with a central hole to receive the shank of the tool.

Abstract: A rotary drill bit for drilling a bore hole in the surface of the earth is provided in which the drill bit comprises a body having a duct therethrough for carrying drilling fluid. A conical cutting head having an axis at an acute angle with respect to the axis of the drill bit is mounted in the cutting head. An elongated nozzle is positioned at the end of the duct for injecting the drilling fluid into the bore hole. The nozzle has an opening which opens into the bore hole wherein the longitudinal center line of the opening follows the locus of the mid-point between the side wall of the bore hole and the outermost circumference of the cutting head. Drilling fluid injected through the nozzle removes detritus from between the teeth and the cutting head at the bottom of the bore hole. The body of the drill bit has a first portion having a truncated conical surface with the axis of the truncated cone coinciding with the axis of the cutting head.

Abstract: An improved stabilizer is disclosed. In the preferred and illustrated embodiment, a built-up spline is disclosed. The spline is made by drilling a set of holes in a blank of relatively soft metal and inserting hardened inserts into the metal. Typical inserts are made of tungsten carbide. They may be brazed on the back side to firmly affix the inserts in holes drilled in the metal strip. The metal strip is welded to the stabilizer body. It has the advantage in that it can be refaced or built up after wear.

Abstract: The present boring head is constructed for drilling or boring deep holes or bores of substantial axial length whereby so-called veering off from the longitudinal boring axis is to be prevented. For this purpose three cutting members are distributed about the circumference of a base in such a manner that the cutting members are located at 0.degree., 95.degree., and 190.degree. with a position tolerance of .+-.5.degree. for each cutting member relative to a polar coordinate system. At least one guide rod is arranged at an angle of 55.degree. and another guide rod is located at an angle of 305.degree.. Each guide rod position may have a tolerance of .+-.10.degree. in said polar coordinate system.

Abstract: An upper stabilizer and a lower reamer are mounted on an integral or one-piece body adapter to be connected in a tubular drilling string for drilling well bores.

Abstract: A machine for making underground excavations by compacting soil comprises an eccentric shaft having journals on which there are mounted for a free rotation in a sequence, beginning from the front end, a conical member and tapered rolls forming in combination a conically expanding body. The eccentric shaft is coupled to a drive for rotation. The conical member has a through longitudinal diffuser passage, and the eccentric shaft also has a through longitudinal diffuser passage of a cross-sectional area enlarging in the direction away from the face of the excavation being made. The cross-sectional area of the passage of the conical member is smaller than the smallest cross-sectional area of the passage of the eccentric shaft by an amount such that the inside cross-sectional area of the passage of the conical member is substantially within the limits of the inside cross-sectional area of the passage of the eccentric shaft.

Abstract: Boring apparatus comprising a tubular casing containing a cylindrical body adapted for being driven by a boring rod and a filter body adjacent the cylindrical body. A boring tool is mounted outside the tubular casing at the end of the filter body. The filter body has a cross-section of polygon shape with axially extending edges in contact with the inner surface of the tubular casing to define clearance spaces between the inner surface of the tubular casing and the outer surface of the filter body. The cylindrical body has axial grooves extending to the clearance spaces for passage of boring particles. The cylindrical body can also be provided with annular grooves. Preferably, the cylindrical body and filter body are constituted as a single unit.

Abstract: A boring device adapted for deep boring wherein the boring head has a plurality of cutting inserts adjustably mounted on the boring head. Axially extending guide plates are mounted on the periphery of the boring head and are substantially equidistantly disposed between adjacent cutting inserts.