Abstract: A garden earth auger operating by repeated twisting its handle is comprised of a drive mechanism at the center of the handle, a gear shaft erected inside the drive mechanism and extending downward to connect to a tooling feeder; a circular yoke inserted onto the gear shaft to control two mobile pawls on one side or both sides of the turning gear shaft to engage or disengage in or from the ratchet for the pawls to drive the ratchet for the tooling feeder to continue circulating for earth excavation in an effort saving fashion while the auger can be easily replaced with a fork or other forms of tooling head to excavate for a pit or scrap soil as desired.

Abstract: A pilot tool assembly for a core drill comprises a pilot tool unit that fits within the core drill and expandable means engagable with the interior surface of the core drill for releasably locking the pilot tool unit to the core drill, the pilot tool assembly being removable from the core drill by application of an axial force to the pilot tool unit. The pilot tool unit comprises a pilot tool that projects from the front end of the core drill and serves as a centering aid for the core drill. The pilot tool may be inserted into a predrilled pilot hole whereby to keep the core drill centered on a desired location. The pilot tool may be a small diameter drill that is used to drill the pilot hole.

Abstract: A drill bit for use in horizontal boring includes a bit body with a central axis of rotation including a forwardmost pilot section, a reaming section rearwardly of the pilot section including a forwardly inclined arcuate steering surface and a plurality of gauge cutting teeth disposed rearwardly of the pilot section in opposed relationship to the inclined steering section, the gauge teeth extending farther from the central axis in a radial direction than the steering section such the arcuate steering section lies entirely within a circular profile corresponding to the path of the gauge teeth when the bit is rotated 360° and a coupling section at a rear end portion of the body configured for attachments to an adjacent component of the drill sting.

Abstract: A bi-center drill bit is disclosed which includes a bit body having pilot blades and reaming blades distributed azimuthally around the body. The blades have cutting elements disposed thereon at selected positions. The body and blades define a longitudinal axis of the bit and a pass-through axis of the bit. In one aspect, selected ones of the pilot blades include thereon, longitudinally between the pilot blades and the reaming blades, a pilot hole conditioning section including gage faces. The gage faces define a diameter intermediate a pilot hole diameter and a pass-through diameter defined, respectively, by the pilot blades and the reaming blades.

Abstract: A drill bit for drilling a borehole having a bit body with an axis of rotation, a leading face, and a plurality of blades upstanding from the leading face. At least one of the blades terminates in a gauge pad having a gauge surface arranged, in use, to face a wall of the borehole. The gauge surface being devoid of cutting elements and terminating at an end remote from the blade at a junction with a gauge pad end wall. The gauge pad carries a cutter having a face and a cutting edge located radially inward of the gauge surface, and the junction of the gauge surface and the gauge pad end wall crosses, radially, between the face of the cutter and the wall of the borehole. The gauge surface may be a substantially continuous surface, and may have at least one additional cutter located angularly between two adjacent blades of the drill bit.

Abstract: A drill bit for drilling a borehole, the drill bit comprising a bit body 10 having an axis of rotation 12, a leading face, a plurality of blades 26 upstanding from the leading face, at least one of the blades terminating in a gauge pad 28 having a gauge surface 29 arranged, in use, to face a wall 30 of the borehole 32, the gauge surface 29 being devoid of cutting elements, the gauge surface 29 terminating at an end thereof remote from the blade at a junction 58 with a gauge pad end wall 56, wherein the gauge pad 28 carries a single cutter 62 having a face 64 and a cutting edge 65 located radially inward of the gauge surface 29, and wherein the junction 58 of the gauge surface 29 and the gauge pad end wall 56 crosses, radially, between the face 64 of the cutter 62 and the wall 30 of the borehole 32.

Abstract: A tubing shoe (30) comprising: a body (32) for mounting on the end of a tubing string; and reaming members (36) extending longitudinally and helically around the body, the reaming members providing substantially complete circumferential coverage of the body whereby, in use, when the tubing shoe is advanced axially into a bore, the reaming members (36) provide reaming around the shoe circumference. A rotatable torque reducing sleeve or centraliser (38) may also be mounted on the body, rearwardly of the reaming members.

Abstract: A drill bit suited for impact-assisted directional boring in rock includes a bit body having a frontwardly facing, circular main cutting surface having a number of main cutting teeth disposed thereon. A gage cutter extends radially outwardly from the main cutting surface, which gage cutter mounts at least one frontwardly facing gage cutting tooth thereon suitable for cutting in a circle during straight boring and over an angle defined by less than a full rotation of the bit in order to steer the bit. A heel on an outer side surface of the bit body at a position opposite to and behind the gage tooth provides a reaction surface for the gage cutter. The bit body and gage cutter have a nearly circular side profile along a front portion thereof such that a maximum radial clearance between the side profile and a side wall of a hole being drilled is not greater than about 10 percent of the radius of a circle cut by the gage tooth.

Abstract: A hole opener for use in the Horizontal Directional Drilling (HDD) Industry is provided having an interchangeable sleeve reamer. The hole opener is in the form of a three-piece tool comprising a top shaft member, an interchangeable sleeve member and a bottom sub member, the interchangeable sleeve member being configured to be securely and removably mounted onto the top shaft member such that is does not rotate freely about the axis of the shaft member. In one embodiment, the bottom sub member also is interchangeable with other bottom sub members.

Abstract: A bi-center downhole drilling bit is disclosed, which bit includes a body defining proximal and distal ends, where said distal end defines a pilot and a reamer where the reamer defines a first cutting face having a selected diameter “d” and the pilot defines a second cutting face having a selected diameter less than “d”, where each the first and second cutting faces includes upsets defining proximal and distal surfaces where the distal surfaces are provided with cutting elements and the proximal surfaces are provided with one or more gauge pads.

Abstract: The present invention is a bi-center drill bit designed to drill out the cement and other material in the casing and then proceed to drill out the full gauge drilling diameter borehole with a diameter greater than the inside of the casing. The bi-center drill bit is configured with non-drilling bearing elements that contact with the casing when the bit is drilling the cement without allowing the gauge cutting elements of the bi-center drill bit to contact the casing. The bi-center drill bit also has a cutting element configuration which prevents reverse scraping of the cutting elements when drilling both the cement and the formation.

Abstract: A reamer for drilling a hole having a diameter larger than a pass through diameter in one aspect includes a body having reaming blades affixed at azimuthally spaced apart locations. These blades have cutters attached at selected positions. An outermost surface of each blade conforms to a radially least extensive one, from a longitudinal axis of the reamer, of a pass through and a drill circle, The drill circle is substantially coaxial with the axis. The pass-through circle is axially offset from the drill circle and defines a section wherein the pass-through circle extends from the axis past the drill circle, so that cutters disposed on the reaming blades in the section drill at full drill diameter, while avoiding wall contact at the pass-through diameter. In another aspect, the reamer includes a pilot hole conditioning section including azimuthally spaced apart blades affixed to the body longitudinally ahead of the reaming blades.

Abstract: A hole opener and method for using same which allows for a greater number of cone utters to be attached to the hole opener. The support structure provided by the present invention uses a barrel which is attached to the drill stem to effectively increase the diameter of the drill stem so that additional cutters may be attached to the hole opener. Using the barrel structure, the structural integrity of the tool is not compromised, and a strong support structure for the cutters is provided. The cone cutters may be removable from the barrel. The removable structure is provided by placing a bolt inside the segments which is used to mate the segment with a pocket attached to the barrel. This results in a very versatile tool in that the same boring head may be used for boring various types of materials. The barrel structure of the present invention also provides a means for trapping cones inside the barrel to prevent the cone cutters from being left inside the hole.

Abstract: By using a reaming machine which arranges a plurality of hydraulic hammer driven drill bits in parallel on a cross section to be reamed, a horizontal or gently inclined pilot hole is reamed. A pressurized water introducing drill pipe and a drill pipe as a discharge pipe are connected to the reaming machine, a seal which forms a sealing between the drill bits and a reamed hole is provided, and a passage for feeding drilling water into the drill pipe is provided, whereby the reaming machine can be propelled while discharging cuttings with a small amount of water through the drill pipe.

Abstract: A garden tool for planting flower bulbs and ornamentals includes an elongated shaft culminating at one end in a boring bit for starting a planting hole. A pair of fins, each radiating at a non-perpendicular angle from each side of the body of the boring bit for widening the hole and breaking up the dislodged soil. The pulverized soil remains in the hole for covering the seed or bulb after planting. The garden tool cultivates to a depth of approximately 6 inches. The tool is driven from the other end of the elongated shaft by a conventional ⅜ inch to ½ inch electric drill. The tool is suitable for use by the landscape professional doing volume planting or the home gardener and can be used in either prepared or unprepared seed beds. The tool presents an easy to use device which greatly reduces the time and labor associated with the planting process.

Abstract: A drillout bi-center bit includes first and second axes of rotation separated by a distance D, a first region of radius D centered on one of the axes of rotation, a second region of radius D centered on the other of the axes of rotation, and a third region defined by the overlap between the first and second regions, wherein the cutters provided within the third region are designed to withstand cutting in opposing cutting directions. This may be achieved by providing each cutter with two cutting faces, or by providing two groups of cutters, one group arranged to cut in one direction, the other group being designed to cut upon rotation in the other direction, one of the groups protruding from the bit body of the bit to a greater depth than the other group.

Abstract: A bi-center bit adapted to be consecutively used in casing and in formation without the need of removing the bit from the borehole, the bit comprising a bit body defining a proximal end adapted for connection to a drill string, a distal end and a pass-through gauge, where the distal end defines a pilot bit and an intermediate reamer section, where each the pilot and reamer section define a cutting face. A plurality of cutting or wear elements are situated on cutting blades disposed about the cutting face of the pilot and reamer sections. Cutting or wear elements are disposed on one or more of the blades which extend to or are proximate to the pass-through gauge define an angle between the line of contact on the cutting or wear element and the material to be drilled of between 5-45 degrees.

Abstract: An earth boring bit for boring a hole having a predetermined depth into the earth. The earth boring bit includes a cylindrical drum for being mounted for rotation on the end of a boom of a mobile machine and connected to and rotated by a power supply mounted on the boom. The drum includes an exterior for defining the diameter of the hole being bored and an interior adapted for receiving upturned earth therein as the hole is being bored. A plate is mounted in the drum adjacent a lower end thereof for movement between a closed position for cooperating with the interior of the drum for retaining the upturned earth therein and an open position for dispensing the upturned earth out of the interior of the drum at a predetermined location away from the hole being bored. At least one cutting member is carried on the plate for cutting the earth in a progressive slice and directing the earth into the drum, thereby boring the hole into the earth.

Abstract: A bi-center downhole drilling bit is disclosed, which bit includes a body defining proximal and distal ends, where said distal end defines a pilot and a reamer where the reamer defines a first cutting face having a selected diameter “d” and the pilot defines a second cutting face having a selected diameter less than “d”, where each the first and second cutting faces includes upsets defining proximal and distal surfaces where the distal surfaces are provided with cutting elements and the proximal surfaces are provided with one or more gauge pads.

Abstract: Although particular detailed embodiments of the apparatus and method have been described herein, it should be understood that the invention is not restricted to the details of the preferred embodiment. Many changes in design, composition, configuration and dimensions are possible without departing from the spirit and scope of the instant invention.

Abstract: A one trip whipstock system includes both a one trip combination mill and associated whipstock. The one trip combination mill comprises an upper cutter and lower cutter below the upper cutter. The upper cutter and lower cutter are joined by a cone that widens towards the upper cutter. In operation, a whipstock is connected to the drilling sub by shear bolts. A guide lug on the whipstock faces the drilling sub between the lower cutter and upper cutter for riding on the cone when the drilling sub is advanced along the whipstock. Preferably the shear bolts connect to the lower cutter. Also, the lower cutter has smaller gauge than the upper cutter, to such an extent that the relative gauge sizes of the lower cutter and upper cutter permit the upper cutter to exit casing during drilling before the lower cutter exits casing. Further, there may be provided a watermelon mill and a string mill above the upper cutter and the watermelon mill, string mill and the upper cutter preferably have the same gauge.

Abstract: A twist drill (1) has a plurality of of protuberances (9) arranged in the grooves (6) of the helix (4) which project radially outward partially into the groove cross section to prevent clumps.

Abstract: A bi-center drill bit includes pilot and reaming blades affixed to a body at azimuthally spaced locations. The blades have PDC cutters attached at selected positions. In one aspect, the pilot blades form a section having length along the bit axis less than about 80 percent of a diameter of the section. In another aspect, selected pilot blades and corresponding reaming blades are formed into single spiral structures. In another aspect, shapes and positions of the blades and inserts are selected so that lateral forces exerted by the reaming and the pilot sections are balanced as a single structure. Lateral forces are preferably balanced to within 10 percent of the total axial force on the bit. In another aspect, the center of mass of the bit is located less than about 2.5 percent of the diameter of the bit from the axis of rotation. In another aspect, jets are disposed in the reaming section oriented so that their axes are within about 30 degrees of normal to the axis of the bit.

Abstract: An adapter usable for interconnection of a pair of drill components according to the invention includes an elongated adapter body having a first end and a second end, wherein the first end includes one of (1) a tubular wall defining a socket that opens outwardly at one end of the adapter and having at least one transverse opening therethrough configured to receive a removable retainer for mechanically interlocking a projection in the socket, and (2) the projection which fits into the socket, which projection has at least one transverse opening therein to receive the removable retainer. The second end includes a connecting portion different from the projection and the tubular wall defining the socket, such as a threaded projection or recess. The adapter preferably has a lengthwise fluid passage through it suitable for passing lubricating drilling fluid through the adapter to a drill head or back reamer.

Abstract: A drilling tool, especially for the rotary percussion drilling of preferably rock, has a drilling body equipped toward the drilling side preferably with cutting bits, and with an axially arranged bore for receiving an exchangeable centering drill. In order to achieve axial movability and a reliable rotational takeup of the centering drill in the drilling tool, the drilling tool has a transverse bore which is arranged centrally relative to its drill longitudinal axis and into which can be inserted a bar-shaped or tubular holding means which centrally penetrates a corresponding recess on the shank of the centering drill so that the centering drill can be moved in the axial direction.

Abstract: A rock drilling tool includes a pilot bit screw threaded into a front end of a drill rod. A reamer is mounted on the outside of the pilot bit. The reamer includes a central opening having a front portion and a rear portion. The front portion is connected to the pilot bit, and the rear portion constitutes a stiffening sleeve which extends around the outside of the drill rod.

Abstract: A drill bit and method of drilling employing a gage definition region on the bit to relatively gradually and incrementally increase the diameter of the borehole being drilled from a diameter that is cut by fixed face cutters or rolling cone cutters on the bit body to a larger diameter. Preferably, the diameter of the gage definition region defined by cutting structures thereon varies along a longitudinal length of the bit, being smallest nearest the leading end of the bit. In a preferred embodiment, the gage definition region includes a plurality of helically arranged cutting elements disposed around the perimeter of the gage definition region. Such a configuration of cutting elements helps to reduce the loading on, and wear of, each individual cutting element. Thus the effective life of the bit is extended by enhancing its ability to drill the borehole to the gage diameter over a longer interval than may be achieved with conventional bit designs.

Abstract: A drilling tool, in particular for rotary percussion drilling preferably of rock, is proposed, with a drill body preferably equipped with cutting tips toward the drilling side and with an axially arranged bore for receiving an exchangeable center drill. In order to carry out easy mounting and demounting of the center drill, the drilling tool is designed in two parts, the center drill being capable of being introduced into the drilling tool on the clamping side.

Abstract: A method and apparatus for reaming or enlarging a borehole with enhanced stability. A pilot stabilization pad (PSP) having an axially and circumferentially tapered entry surface and a circumferential transition surface thereabove is employed to enhance the transition from the smaller diameter borehole to be enlarged while accommodating the side force vector generated by the cutting assembly used to effect the enlargement. In addition, one or more eccentric stabilizers are employed above the reaming apparatus to laterally or radially stabilize the bottomhole assembly, which may comprise either a straight-hole or steerable, motor-driven assembly.

Abstract: A drilling tool for boring in earth and rock formations includes a pilot bit which defines a longitudinal tool axis and includes a cam part having a cam axis arranged eccentrically relative to the tool axis. A reamer includes a hollow reamer body mounted on the cam part for rotation relative thereto about the cam axis. Relative rotation in one direction causes the reamer to be radially extended, and relative rotation in an opposite direction causes the reamer to be radially retracted. The reamer body carries cutting elements for enlarging a hole drilled by the pilot bit when the reamer is in its extended position. The cam part carries a first removable insert on which a first stop surface is formed. The reamer carries a second removable insert on which a second stop surface is formed. The stop surfaces are engageable with one another when the reamer body is radially extended, for transmitting rotational cutting forces to the reamer.

Abstract: A rock drilling tool includes a drill body on which a radially extendible reamer is mounted. The reamer, when extended, enlarges the hole diameter to enable a hole casing to be pulled down by the tool. The body includes a front pilot bit, a rear shank adapted to be connected to a drill string, and a guiding member disposed between the pilot bit and the rear shank for pulling the hole casing along with the tool. The pilot bit, the rear shank and the guiding member are non-removable from one another. The reamer, which is mounted between the guiding member and the pilot bit, is formed of two U-shaped pieces that are hinged together to enable the reamer to be installed and removed.

Abstract: The present invention is an apparatus for use in drilling operations. It uses an under-reamer having a plurality of elongated arms with cutting elements at the ends of the arms for enlarging a previously drilled borehole drilled by a drill bit. One or more stabilizers in close proximity to the under-reamer provide stability to the under-reamer and the drill bit. The stabilizer could be rotating or non-rotating; and could be positioned between the under-reamer and the drill bit, or above the under reamer or above a directional device on the drillstring. The cutting arms are selectively operable to perform the enlargement. The stabilizer may be provided with members that closely fit the size of the borehole.

Abstract: A rotary drill arrangement comprising a combination spade drill body having a rotational axis, a shank portion, and a generally planar spade cutter portion with a pair of oppositely directed cutting edges extending radially of the axis, and a rotatable frusto conical cutter mounted on the spade cutter portion adjacent the maximum radial extent of each cutting edge.

Abstract: An improved bi-center bit with improved directional stability and wear resistance is disclosed, which bit optimally utilizing a plurality of shaped PDC cutting elements selectively situated about the cutting surfaces of the pilot and the reamer to produce a minimal force imbalance, where further the pilot bit and the reamer are force balanced to further reduce imbalance in the operation of the tool.

Abstract: A rotary drill bit for use in drilling holes in subsurface formations comprises a bit body having a leading face and a gauge region, a number of blades formed on the leading face of the bit and extending outwardly away from the axis of the bit so as to define between the blades a number of fluid channels leading towards the gauge region, a number of cutting elements mounted side-by-side along each blade, and a number of nozzles in the bit body for supplying drilling fluid to the fluid channels for cleaning and cooling the cutting elements. In each of the fluid channels, adjacent the gauge region, is an opening into an enclosed passage which passes internally through the bit body to an outlet which, in use, communicates with the annulus between the drill string and the wall of the borehole being drilled. The gauge region of the drill bit comprises a substantially continuous bearing surface which extends around the whole of the gauge region.

Abstract: A method and apparatus for reaming or enlarging a borehole using a bi-center bit with a stability-enhanced design. The cutters on the pilot bit section of the bi-center bit are placed and oriented to generate a lateral force vector longitudinally offset from, but substantially radially aligned with, the much larger lateral force vector generated by the reamer bit section. These two aligned force vectors thus tend to press the bit in the same lateral direction (which moves relative to the borehole sidewall as the bit rotates) along its entire longitudinal extent so that a single circumferential area of the pilot bit section gage rides against the sidewall of the pilot borehole, resulting in a reduced tendency for the bit to cock or tilt with respect to the axis of the borehole.

Abstract: In a method for use in dry, rotary, crushing full-area drilling, use is made of suction air alone for removing cuttings produced during drillings. To carry out the method, two suction nozzles (13) are arranged on the underside of a cutterhead (1). These nozzles together have a substantially diametrical extent and the length of a radius on the cutterhead and are provided with suction intakes (14A) in the vicinity of the periphery of the cutterhead. The suction intakes (14A) are connectible a common suction channel (11) in the drill string (6) of the cutterhead. The suction channel (11) has substantially constant diameter.

Abstract: A drilling unit is formed of a hollow annular drill bit (1) and a centering drill (2) where the centering drill is a single piece including a chucking shank (2a) and a drill head (2b). A detachable connection is provided between the annular drill bit (1) and the centering drill (2), preferably in the form of a thread (3) whereby the drilling unit can be provided with different diameter annular drill bits (1) and can be adapted to different applications as well as to different power tools presently in use.

Abstract: A method and apparatus for reaming or enlarging a borehole with enhanced stability. A pilot stabilization pad (PSP) having an axially and circumferentially tapered entry surface and a circumferential transition surface above is employed to enhance the transition from the smaller diameter borehole to be enlarged while accommodated the side force vector generated by the cutting assembly used to effect the enlargement. In addition, one or more eccentric stabilizers are employed above the reaming apparatus to laterally or radially stabilize the bottomhole assembly, which may comprise either a straight-hole or steerable, motor-driven assembly.

Abstract: A drag rotary bit (10) has a bit body (12) with a center cutter element (34) for projecting from the bottom (22) of the bit body (12) at the axial center of the bit body (12). The center cutting element (34) has a pair of cutters (42) with cutting faces (46) thereon in opposed relation to each other. A pair of opposed relatively long blades (54) are mounted on the bottom (22) of the bit body (12) and extend across the entire bottom (22) of the bit body (12) to the center cutter (34) to divide the bottom (22) into two separate areas. A single nozzle (26) having a large diameter discharge port (28) is provided for each of the separate areas for cleaning the bottom of the hole and washing of the blades.

Abstract: The instant invention is an improved cutter head with a salvageable end cap for hollow stem augers. The end cap includes a mechanism for retrieval upon completion of a drilling operation thereby allowing the end cap to include various bit formations so as to assist in the drilling operation. The side wall of the cutter head is modified to include a keyhole slot for maintaining of the end cap in a rigid position to prevent rotational movement.

Abstract: A drilling system employs spaced apart cutting members arranged in a helical pattern to form a helical thread within a rock bore. The thread is efficiently fragmented by a wedge-shaped trailing cutting member. Advantageously, a substantial portion of the rock is removed by the fracturing of the internal thread in the rock bore by the uppermost cutting member, taking advantage of the weakness of rock in tension. The rotational speed of the helical cutting system may be controlled as a function of the axial thrust applied to a pilot bit located in front of the helical cutting system.

Abstract: An underreamer which may be mounted on a core drill to allow single phase underreaming or creation of a bore hole of larger diameter beneath a pilot hole. A plurality of levers are powered by a plurality of corresponding jacks which are adapted to exert pressure on the levers in order to cause them to extend beyond the periphery of the expander body. Each lever contains at least one roller-cutter rotatably mounted to the lever so that when the levers are forced outward, the roller-cutters crush rock beyond the periphery of the expander body and thus underream the bore hole.

Abstract: A pilot bit for use with an auger bit in an auger bit assembly secured to the downhole end of tubular drill stem for drilling boreholes in earth formations comprises a tubular pilot bit body having a downhole end and an upper end at the axially opposite end of the body, the body being dimensioned to be telescopically received within an axial bore of an auger bit and being releasably connectable to the auger bit against axial and angular displacement, an axial throughbore extending through the body for telescopically receiving an earth sampling tool, a closure device secured to the downhole end of the pilot bit for opening and closing the throughbore, and pilot bit cutting teeth secured to the closure device.

Abstract: A multi-bladed reaming apparatus for enlarging a subterranean borehole, the apparatus having a tubular body with a plurality of longitudinally-extending, circumferentially-spaced, generally radially-extending blades carrying cutting elements, the blades being unequally spaced about the body. The cutting depth of the cutting elements on at least one of the blades is adjusted to modify the distribution of the depth of cut (DOC) among the cutting elements to substantially equalize the volume of formation material removed by the blades. Wear is reduced and the potential for premature failure of cutting elements on any single blade is alleviated.

Abstract: A device for augering a conical hole in a solid medium that includes a first elongated member that extends along a longitudinal axis and a cutting blade having a cutting section and a non-cutting section coupled to the first elongated member. The rod is adapted to be rotated about the longitudinal axis. A motor is coupled to the first elongated member which rotates the cutting blade about the longitudinal axis. A shroud is provided through which the first elongated member passes. The shroud attaches to a hydraulic unit. Activation of the hydraulic unit causes the first elongated member to move in a longitudinal direction, which causes the cutting blade to move in a radial direction thereby forming a conical hole in a solid medium. The device is used for forming holes used in foundations and anchors. Also disclosed is a method of operation of the device to form a conical hole in solid media.

Abstract: A down-the-hole drill tool comprises a one-piece shaft and pilot bit. The shaft is adapted for connection to a down-the-hole hammer. A reamer and a guide body are detachably mounted to the one-piece shaft/pilot bit. The guide body has a downwardly facing shoulder for pushing a casing tube downwardly along with the tool.

Abstract: A drilling tool for percussive and rotary drilling in advance of a trailing casing tube (20) has a reamer (15) pivotally journalled and an eccentric shaft (12) rearwardly of a centric pilot bit (11). The reamer (15) has an eccentric portion (32) carrying axially directed hard metal button inserts (36-40) grouped within an arcuate angle (V) of a circle sector centered on the drilling axis (C). The inserts comprise primary inserts (36-38) with a radial reach defining the full diameter of the drilled hole and inner secondary inserts (39, 40) closer to the shaft (12). The reamer (15) is pivotable on the shaft (12) between a projected and a retracted position. When projected, the group of button inserts (36-40) ream up the hole from the diameter drilled by the pilot bit (11) to the full diameter of the hole enabling the casing tube (20) to advance. In the retracted position, the drilling tool (10) can pass through the casing tube (20).

Abstract: The invention, which can be applied to both starting mills and window mills for use in sidetracking a cased borehole, makes use of carbide discs as cutting elements and the geometrical disposition of blades on which the discs are mounted to enhance cutting efficiency. The blades are angularly offset with respect to the tool centerline in a variety of configurations.

Abstract: An auger cutter head includes a rotatable body that is mountable on an auger and a plurality of cutting assemblies spaced about the outer wall of the rotatable body to drill a hole in the ground as the auger cutter head is rotated and advanced into the ground. Two of the cutting assemblies include outside chisel bits positioned to ream or gauge the hole as the cutter head is rotated and advanced. All of the flighting sections, bit, blocks, and blade assemblies provided in the cutting assemblies are offset in a radially inward direction relative to the two outside chisel bits to reduce the wear and tear on those components. Each of the chisel bits is oriented to rotate relative to its bit block about a predetermined axis of rotation to reduce wear caused by uneven loading on the rotatable chisel bits during drilling of the hole.