Abstract: A hybrid bit includes fixed blades and wheel support structures. The wheel support structure includes a wheel inserted into a slot between a leading support and a trailing support. One or more shims fill a gap between a flange and the leading supports. An elongated seal between the wheel and the supports is provided to seal the wheel support.

Abstract: A wheel assembly and a method for detachably connecting the wheel assembly to a downhole tool to reduce friction between the downhole tool and a sidewall of a wellbore through which the downhole tool is conveyed. The wheel assembly may include an axle configured to contact a sidewall of the downhole tool, a wheel rotatably connected with the axle, and a fastener configured to extend into the sidewall of the downhole tool to detachably connect the axle to the downhole tool.

Abstract: A rotary drill tool for cutting rock includes at least one journal leg mounting a spindle and a respective rotary cone cutter. The spindle includes a plurality of fluid distribution passageways arranged to provide a supply of a cooling and cleaning fluid to the bearing assembly. Vent holes are provided through the cutter to allow an exhaust flow of fluid and an annular seal is provided at a base region of the spindle to maintain a positive fluid pressure within the cutter cavity to prevent dust and dirt ingress.

Abstract: Embodiments of the invention are directed to compact bearing assemblies configured to operate in small spaces and/or in harsh environments, bearing apparatuses including such bearing assemblies, and method of operating such bearing assemblies and apparatuses. For instance, one or more compact bearing assemblies may at least partially rotatably secure a shaft of a power generation unit to a housing thereof. Also, a first compact bearing assembly may connect or couple to the shaft and may rotatably engage a second compact bearing assembly, which may be connected or otherwise secured to the housing.

Abstract: A cutter assembly, which may include a rotatable cutting element disposable within a pocket of an earth-boring tool, a sleeve configured to receive the rotatable cutting element, and at least one retention mechanism configured to secure the rotatable cutting element within the sleeve. The rotatable cutting element may include a substrate, a table, which may be comprised of a superhard, polycrystalline material disposed on a first end of the substrate, and a recess extending into a second, opposite end of the substrate. The sleeve may comprise at least one radial bearing surface, a backing support sized, shaped, and positioned to extend into the recess of the rotatable cutting element, and at least one axial thrust-bearing surface located on the backing support and positioned to contact the substrate within the recess.

Abstract: The roller cone is retained to the head with axial play taken out of the bearings with a tension rod that is tensioned from the rear of the head and away from the nose bearing region of the head allowing greater resistance to loading in the region of the nose bearing and a reduction in critical stresses. The tension rod has a flat and is oriented for tightening so that the flat faces grease passages to allow grease to gain access to the bearings through the bore for the tension rod and otherwise fill the bore so the tension rod actively supports loading in the head bearing. The nose bearing can be separately supported to the cone directly with a retainer threaded to the cone or a spacer between the bearings can be used so that tensioning of the rod takes out the axial play in both bearings with force transmitted to a retainer at the back of the cone.

Abstract: The roller cone is retained to the head with axial play taken out of the bearings with a tension rod tensioned from the rear of the head and away from the nose bearing region of the head allowing greater resistance to loading in the region of the nose bearing and a reduction in critical stresses. The tension rod has a flat oriented for tightening and facing grease passages to allow grease to gain access to the bearings through the bore for the tension rod and otherwise fill the bore so the tension rod actively supports loading in the head bearing. The nose bearing is separately directly cone supported with a retainer threaded to the cone or a spacer between bearings can be used so that tensioning of the rod takes out the axial play in both bearings with force transmitted to a retainer at the back of the cone.

Abstract: A rotating cone drill bit includes a plurality of mud nozzles extending from the bit body, which are thermally fitted by controlling the temperature differential depending on the corresponding materials, the amount of fit desired, and the diameters of the elements to be fitted and which provide substantially obstruction-free mud paths toward the wellbore bottom. The bit has a plurality of reduced diameter cutter assemblies, each having a journal projecting from a corresponding leg. The journal has at least two cylindrical bearing surfaces and an annular groove formed therebetween and a spindle. An annular retention segment is rotatably mounted in the groove. The retention segment has an outer radial surface engaging a portion of one of the bearing surfaces of the cone, and an energy beam welding area fusing substantially the entire engaging surfaces of the retention segment and the cone.

Abstract: A bearing assembly is for a rotary drill, the drill including a base with a shaft and a bit. The bearing assembly includes a bearing having a central axis and including an inner member disposeable on the shaft and an outer member disposed about the inner member. The outer member is angularly displaceable about the axis with respect to the inner member and having an outer circumferential surface and a recess extending generally radially inwardly from the outer surface. At least one and preferably a plurality of retainer members are each disposed at least partially within the bearing outer member recess and is configured to engage with the bit so as to rotatably couple the bit with the shaft. Preferably, each retainer member includes a generally spherical ball rollable through a passage and into the bearing recess during installation into the recess.

Abstract: A rotating cone drill bit includes a plurality of mud nozzles extending from the bit body, which are thermally fitted by controlling the temperature differential of 300° F.-900° F. depending on the corresponding materials of the elements to be fitted, the amount of fit desired, and the diameters of the elements to be fitted and which provide substantially obstruction-free mud paths toward the wellbore bottom. The bit has a plurality of reduced diameter cutter assemblies, each having a journal projecting from a corresponding leg. The journal has at least two cylindrical bearing surfaces and an annular groove formed therebetween and a spindle. An annular retention segment is rotatably mounted in the groove. The retention segment has an outer radial surface engaging a portion of one of the bearing surfaces of the cone, and an energy beam welding area fusing substantially the entire engaging surfaces of the retention segment and the cone.

Abstract: An apparatus for retaining a roller cone on a bearing pin of a drill bit body that includes a drill bit body; a bearing pin coupled to the drill bit body; a retention member coupled to the bearing pin; a roller cone coupled to the retention member; and a torque transfer member coupled to the retention member and the roller cone adapted to selectively transfer torque between the retention member and the roller cone.

Abstract: A rotating cone drill bit includes a plurality of mud nozzles extending from the bit body, which are thermally fitted by controlling the temperature differential of 300° F.-900° F. depending on the corresponding materials of the elements to be fitted, the amount of fit desired, and the diameters of the elements to be fitted and which provide substantially obstruction-free mud paths toward the wellbore bottom. The bit has a plurality of reduced diameter cutter assemblies, each having a journal projecting from a corresponding leg. The journal has at least two cylindrical bearing surfaces and an annular groove formed therebetween and a spindle. An annular retention segment is rotatably mounted in the groove. The retention segment has an outer radial surface engaging a portion of one of the bearing surfaces of the cone, and an energy beam welding area fusing substantially the entire engaging surfaces of the retention segment and the cone.

Abstract: An apparatus and method for retaining a roller cone on a bearing pin of a drillbit body.

Abstract: An earth boring bit has thrust faces with one of the thrust faces being at least partially tilted relative to the other. The bit has a cone rotatably mounted to a bearing pin of the bit body. The thrust faces are in the cone and on an end of the bearing pin. One of the thrust faces is completely flat and perpendicular to the axis of the bearing pin. The other thrust face has a tilted portion that is at a skewed angle relative to the axis. The tilted portion creates converging and diverging zones between the thrust faces.

Abstract: There is provided an apparatus for preventing displacement of a retainer in a rolling guide by making use of the property of the retainer of moving half the distance of a moving object, such as a table.

Abstract: A roller-cone drill bit in which a double lip seal, made of a self-lubricating elastomer, protects the bearings from the mud.

Abstract: A rotation mechanism for rotating a rotary ring which has the following features: the number of parts it requires will be reduced as much as possible; its configuration will be simple and economical to build; the operating drag of the ring will be low; any distortion resulting from the load or thermal expansion will be reliably absorbed; and the ring will be rotated reliably with a small operating force. This rotation mechanism rotates an annular rotation ring in which two follower links are connected to the periphery of the rotation ring in such a way that they are free to rotate. The follower links act to provide coupled forces to rotate the rotation ring. The central portion of a drive lever is rotatably mounted by an operating pin on the end of an operating lever which rotates on an operating shaft. Two drive links, each of which is connected at one end to a respective one of the follower links, are joined by pins to either end of the drive lever in such a way that they are free to rotate.

Abstract: A roller cone drill bit includes a bit body adapted to be rotated about a longitudinal axis. At least one leg depends from the bit body, and a journal is cantilevered from the leg. A roller cone is rotatably mounted on the journal. A cone retention member is disposed between a first slot in the journal and a corresponding second slot in the roller cone. An access hole runs through the journal to the first slot, penetrating the first slot at a location away from the top dead center of the first slot.

Abstract: A novel split threaded ring bearing member for rolling cutter drill bits with at least a portion of its threads having a different pitch than its mating threads is disclosed. The pitch difference is designed so that the threaded ring can be seated or otherwise located precisely with respect to the other bearing elements within the drill bit to effectively control the axial displacement of the rolling cutter on the bearing spindle within a given tolerance range. Upon assembly, the difference in thread pitch causes the opposite, opposing mating thread flanks to engage, effectively applying a tensile or compressive force to a portion of the threaded ring bearing member, which gradually increases as the assembly is tightened. The result is an improved rolling cutter drill bit with a threaded ring cutter bearing system with excellent resistance to back-off which will not allow significant radial movement between the engaged threads, even if some back-off of the threads occurs.

Abstract: A rotary cone drill bit for forming a borehole having a body with an underside and an upper end portion adapted for connection to a drill string. The drill bit rotates around a central axis of the body. A number of angularly-spaced arms are integrally formed with the body and depend therefrom. Each arm has an inside surface with a spindle connected thereto and an outer shirttail surface. Each spindle projects generally downwardly and inwardly with respect to its associated arm, has a generally cylindrical upper end portion connected to the associated inside surface, and has an inner sealing surface on the upper end portion. A number of rotary cone cutters equal to the number of arms are each mounted on respective spindles.

Abstract: In an assembly made up of a spindle formed integrally with a revolving cutting element, the longitudinal axis of the spindle being the axis of rotation of the cutting element, the spindle is set into a cylindrical bearing. The bearing is fixed in the main body of the bit. The bearing element and a plate form a thrust surface with the end of the bearing at right angles to the axis of rotation of the spindle, which the other end of the bearing element made with the flange projecting outwards is held in the cutting element by means of the retaining ring which is fixed in the cutting element. A thrust surface at right angles to the axis of the rotation of the spindle is created between the top end of the bearing element and the cutting element and another between the retaining ring and the main body of the bit. By maintaining the spindle centrally in the bearing the wear on the bearing is radically reduced.

Abstract: A modular drill bit mounts legs within recesses in a body which are parallel to the central axis of the body using threaded studs with tapered outer portions, in conjuction with an attached pin having recesses therein receiving the upper ends of the legs. The lower ends of the legs terminate in spindles of open face configuration rotatably receiving cones thereon for rotation via a arrangement of bushings, roller bearings and thrust bearings, and a plurality of seals which slide and therefore rotate relative to both the leg spindle and the cone with the help of pressure compensating apparatus. A bushing disposed in the cone-leg spindle interface has oil-lubricated rubber rods disposed in apertures therein to prevent lock-up on an adjacent bearing surface. The cone is held on the leg spindle by a lock nut forming one end of a race for receiving rollers of a roller bearing, in conjunction with a ring-nut secured to an extended portion of the cone protecting the leg from wear and damage.

Abstract: A modular drill bit mounts legs within recesses in a body which are parallel to the central axis of the body using threaded studs with tapered outer portions, in conjunction with an attached pin having recesses therein receiving the upper ends of the legs. The lower ends of the legs terminate in spindles of open face configuration rotatably receiving cones thereon for rotation via a arrangement of bushings, roller bearings and thrust bearings, and a plurality of seals which slide and therefore rotate relative to both the leg spindle and the cone with the help of pressure compensating apparatus. A bushing disposed in the cone-leg spindle interface has oil-lubricated rubber rods disposed in apertures therein to prevent lock-up on an adjacent bearing surface. The cone is held in the leg spindle by a lock nut forming one end of a race for receiving rollers of a roller bearing, in conjunction with a ring-nut secured to an extended portion of the cone protecting the leg from wear and damage.

Abstract: A roller cutter earth boring bit having longer roller bearings recessed into surrounding bit structure for increased load carrying capacity. The elimination of thrust bearing shoulders from the bearing pin structure between sets of roller bearings enables the use of such longer roller bearings.

Abstract: A rotary rock cutter cone is rotatively supported while being axially located and retained on a cooperating cantilevered journal shaft depending from a rock bit body by plain friction bearing means.A primary stationary thrust face is provided by a radially extending surface of the journal shaft adjacent the distal end of the journal shaft.An annular ring, fitted about the journal shaft, forms a gland for housing a grease seal which impinges upon the journal shaft. A radially extending distal surface of the annular ring runs in cooperation with a radially extending stationary thrust face formed by a secondary thrust member. The secondary thrust member is axially secured to the journal shaft thus axially trapping the annular ring adjacent to the supported end of the journal shaft.A radial bearing bore centrally enters the base of the cone and extends to a radially extending primary thrust bearing surface within the cone.

Abstract: A rotary drill bit (10) having a roller cutter (28) retained on a journal (24) by an externally threaded retainer ring (52) mounted within an annular groove (48) in the journal (24). The radii (R1, R2) formed at the inner and outer corners of the groove (48) are designed by suitable formulas to provide adequate strength for the journal (24) including the flange (50) adjacent the groove (48).

Abstract: A roller cutter (28) of a drill bit (10) is retained on a journal (24) for rotation by a retainer ring (82) having external screw threads (88) which are threaded onto mating screw threads (108) on the roller cutter (28) for rotation therewith. The retainer ring (82) is mounted within a semicircular groove (68) on the journal (24) and has an inner periphery formed of a smooth arcuate surface contacting the annular groove at a position spaced at least 10.degree. from the entrance opening of the groove thereby to reduce bending stresses exerted against the root (74) of the groove (68).

Abstract: A retainer for axially retaining a cutter on the journal pin of a rotary drill bit body includes a plurality of arcuate sliding keys and a single initial tensioning ring accommodated astride an annular groove formed in the peripheral outer wall surface of the journal pin and a corresponding annular groove formed in the inner peripheral wall surface of the cutter. When the cutter is mounted on the journal pin, the initial tensioning ring functions to urge the sliding keys into pressured contact with the cutter groove when the two grooves are in registration. Not only is assembly facilitated, but damage to the sliding keys that might otherwise be caused by any excessive axially directed force applied to the sliding keys during operation of the drill bit is prevented by allowing the sliding keys to recede within the annular groove of the journal pin.

Abstract: The present invention is a rotary drill bit locking mechanism comprising a support spindle and a cutter cone with bearing surfaces. Furthermore, first and second annular grooves are formed on the bearing surfaces of the support spindle and the cutter cone that are radially adjacent to each other when the cutter cone is secured onto the support spindle. Additionally, a holding ring having a plurality of segments is assembled into the first and second annular grooves to secure the cutter cone into a rotatable position on the support spindle. Further, there is means for biasing the segments of the holding ring into a ring-like configuration in the annular grooves. This invention thus provides a rotary drill bit locking mechanism for holding a cutter cone onto the support spindle that is easy to manufacture and assemble.

Abstract: An improved apparatus and method for rotatably mounting and retaining a rock bit roller cone on a journal of a drill bit is disclosed. The bit body has at least one depending leg with an outer free end and an inner end continuous with the remainder of the bit body, and the cone surrounds the leg adjacent the outer end, forming an annular space between the leg and the cone. At least two retention bearing sleeves are disposed in the space: a first fixed to the leg and rotatable relative to the cone; and a second, disposed longitudinally inwardly of the first, fixed to the cone and rotatable relative to the leg. The retention bearing sleeves cooperate to prevent relative movement of the second sleeve longitudinally past the first.

Abstract: A thrust bearing and cone locking assembly for rotatably mounting the cutter cones on a rock drill bit is provided. The assembly includes a dual function thrust bearing and cone retainer capable of absorbing radial thrust and axial thrust in opposite directions. One end of the thrust bearing is received in a central channel in a journal leg mounted on the bit body and is secured to the journal leg by a circular cross-section snap ring. The other end of the thrust bearing is received in a corresponding confugured receptacle in the cone and is locked to the cone by a dual function rectangular cross-section snap ring which both secures the cone to the thrust bearing and absorbs axial thrust loads. A separate radial thrust bearing is additionally provided between the journal and the cone. A lubricant supply system contained within the assembly provides lubricant directly to all the bearing structures.

Abstract: A cutting cone on a rotary rock bit is captively retained on a journal pin by an annular array of ball bearings disposed in laterally facing annular races formed in the cone and pin. When a predetermined amount of surface wear has occurred between the cone and pin as the bit is operated, one or more of the balls is caused to axially shift into and become trapped in a small lockup grooved formed in the journal pin and communicating with its race. Other balls become wedged between the trapped balls and the cone, thereby rotationally locking the cone on its pin and preventing further pin-cone surface wear which might otherwise cause cone loss. During operation of the bit, the locked cone produces a readily detectable increase in rotary table torque, and a decrease in bit penetration rate, thereby signalling the driller that the bit needs replacement.

Abstract: An underreamer including a body having a bore therethrough, an arm mounted at its upper end to the body, a conical cutter mounted for rotation on the lower end of each arm, a cup-shaped thrust bearing between the cutter and the arm, means extending through the arm to secure the cutter on the arm including pin elements that extend into a groove in the cutter to prevent rotation movement between the arm and the thrust bearing to lock the thrust bearing to the arm. The arms are pivotally mounted in slots in the body and means are provided for moving the arms to their cutting position with their lower ends positioned radially outward from the body.

Abstract: An improved retainer for a rotary cone rock bit and a method for inserting the same is disclosed. A cone cutter is mounted on a bearing pin of an arm of the rotary cone drill bit. Formed in the bearing pin and the inner wall of the cone cutter is an annular channel that is filled with discs through an insertion cavity and the insertion cavity is subsequently sealed. This enables the bearing surface and the bushing engaging the bearing pin to be substantially longer than heretofore possible and the wobble of the cone cutter about the bearing pin is reduced.

Abstract: There is disclosed a drill bit which is connectable to the lower end of a rotary drill string for use in drilling oil and gas wells as drilling mud is circulated downward through the string, out the bit, and upwardly within the annulus between the string and well bore so as to remove cuttings therefrom. The bit has cones which are mounted for rotation about thrust bearings which extend inwardly from the lower ends of legs which depend from a shank at the upper end of the bit body which is attached to the drill string.

Abstract: A boring drill bit comprises a shank having one end attached to a drill pipe; a plurality of inclined pins extending from the other end of the shank radially and at an inclination toward the ground with respect to the center line of the shank; a plurality of roller cutters mounted rotatably on the inclined pins, respectively. Each of the inclined pins is formed to have a cylindrical side face and has its diameter gradually decreased continuously from the end portion to the root thereof. Each of the plain bearing members, which is divided into a plurality of parts in the axial direction and which is mounted around corresponding inclined pin, has an inner face which engages rotatably substantially all over the surface with the cylindrical outer face of the inclined pin and if necessary, all over the inner face of an opening of the roller cutter which is fitted on the outer circumference of the plain bearing members.

Abstract: An earth boring bit having an improved two piece bearing construction using an internally tapered and threaded, cantilevered bearing lug extending obliquely inwardly and downwardly from a leg carried by the body of the bit. An internally tapered and threaded bearing sleeve is made up on the lug, and includes a mouth that engages a shoulder on a base region of the bearing lug. The mouth of the sleeve has a minimum radial thickness such that the sleeve may be made up to a selected minimum torque. The bearing sleeve has a length greater than that of the treaded portion to define a thick walled inner end region to receive a resilient retainer ring in a groove that provides a minimum section over the threads on the interior of the sleeve. The sleeve is boronized to achieve wear resistance in a manner that does not substantially reduce strength.

Abstract: An improved retention and thrust bearing system for accurately retaining and locating a rotary rock cutter cone upon a journal shaft supported by a rock bit body is disclosed.A rotary rock cutter cone is rotatively supported on a cooperating journal shaft by plain friction bearing means.A pair of complimentary symmetrical and substantially rectangular annularly arranged grooves are formed in the bearing surfaces of both the rotary cutter and the journal shaft at matching positions intermediate the length of the friction bearing.A multiplicity of retention and thrust bearing elements each having a thickness predetermined to substantially fill the mated grooves in intimate sliding relationship thereto, are assembled into the mated grooves via a small bore formed longitudinally within the journal shaft, having an entrance in the supported end of the cantilevered journal shaft and an exit intersecting the floor of the annular groove in the journal shaft.

Abstract: This invention teaches a means to retain a cutter cone onto a journal bearing of an earth boring rotary cone rock bit. Complementary and registering annular grooves are formed in the bearing surfaces of the journal and the cone. A tangential entry groove transitions from an end of the journal to the annular groove in the journal. Simultaneous 360.degree. rotation and axial movement of the cone over the journal, in combination with a ring distortion ramp block in the cone, threads an end of a split cone retention ring through the entry groove in the journal into the registering annular grooves, thereby retaining the cone on the journal.

Abstract: An underreamer, hole opener, or expansible rotary drill bit including a body having a bore therethrough, an arm mounted at its upper end to the body, a conical cutter mounted for rotation on the lower end of each arm, a cup-shape thrust bearing between the cutter and the arm, a bolt through the arm to secure the cutter on the arm and means including a ball and groove between the bolt and the cutter to lock the bolt to the cutter. In the underreamer form of the present invention, the arms are pivotally mounted in slots in the body and means is provided for moving their arms to their cutting position with their lower ends positioned radially outward from the body.

Abstract: Structure for permanently retaining a rolling cutter on a journal pin of a rotary cutter earth boring bit is shown. The structure is defined by opposed, axially aligned, circumferential grooves formed in the mating bearing surfaces of the pin and the assembled cutter. The cutter groove is a single width throughout whereas the pin groove defines a double width for an arcuate extent thereof on its unloaded side. A split snap ring is compressed within the pin groove, with the ends of the ring axially overlapping in the double width portion so that the ring does not extend above the surface of the pin. Upon alignment of the grooves, during assembly of the cutter on the pin, the ring snaps into the cutter groove with the ends in abutting relationship and extends radially into the pin groove to retain the cutter on the pin.

Abstract: A rock bit cone retention means is disclosed which primarily utilizes a series of segmented rings. The segmented rings are inserted into a relatively deep annular channel formed transverse to the axis of either a journal or a cone of a rock bit leg assembly. The complementary channel, shallow in depth, is formed in either the journal or the cone. The cone, when properly positioned on the journal, closes out the channel formed in both the cone and the journal. Upon assembly, the segments are urged within the deep groove or channel in the journal or the cone such that each of the segments do not protrude beyond the bearing surface as the cone is passed over an end of the journal. Means are provided adjacent the cone retention segment to accept a spring biasing means to urge each segment away from the bottom of the deep groove in the journal or cone.

Abstract: A heavy-duty composite radial journal bearing and a method to produce it is described. A pattern of openings is formed through a bearing sleeve representing, for instance, axially aligned metal bars. The openings are subsequently filled wth a metal dissimilar to the sleeve. Filling may be done with the sleeve in place either on a journal or in a housing, in which case the bearing becomes integral to that member by fusion. Alternately, the sleeve may be filled upon a nonwettable mandrel and subsequently used as a floating ring or as a bushing. Final finish machining reveals a pattern which exists throughout the bearing of alternating areas of relatively hard metal and a softer antigalling metal.

Abstract: Disclosed herein is an earth boring bit of otherwise conventional construction except for the bearing and cutter retention. A snap ring is used to retain the cutter, the grooves that receive the ring and the ring construction being such that the ring is forced into the retainer groove when the cone is thrust inward. The ring cannot therefor accidentally return to its assembly position to permit cutter loss. This enables the use of exclusively frictional bearings and retainer means of exceptional strength and reliability.

Abstract: A rotary earth boring drill is provided having a body structure with a plurality of depending cutter supporting legs having integral spindles extending transversely therefrom. Rotary cutter cone elements are supported by split bushings, roller bearings or a combination of the same, on appropriate bearing surfaces defined by the integral spindles. The bushings and cutter cones define mating tapered surfaces having an interference fit that secures the bushings and cutter cone in nonrotatable assembly. Circular locking elements are provided in locking grooves that are defined cooperatively by the bushings and cutter cones. End portions of the bushings extend axially beyond a planar surface defining one extremity of the cutter cone and establishes rotatable sealing engagement with an opposed planar surface defined by the depending leg structure of the bit. This rotatable seal prevents drill cuttings, dust and other debris from entering the bearing support of the cutter cone.

Abstract: A removable ball loading hole plug for a rotary cutter rock drilling bit having an offset head portion to position the inner race end axially and rotationally. A locking groove on the outer surface of the offset head portion coacts with an adjacent end of a threaded retainer for removable locking engagement therewith.

Abstract: A rock bit cone retention means is disclosed which primarily utilizes a series of segmented rings. The segmented rings are inserted into a relatively deep annular channel formed transverse to the axis of either a journal or a cone of a rock bit leg assembly. The complementary channel, shallow in depth, is formed in either the journal or the cone. The cone, when properly positioned on the journal, closes out the channel formed in both the cone and the journal. Upon assembly, the segments are urged within the deep groove or channel in the journal or the cone such that each of the segments do not protrude beyond the bearing surface as the cone is passed over an end of the journal. Means are provided adjacent the cone retention segment to accept a spring biasing means to urge each segment away from the bottom of the deep groove in the journal or cone.