A drill bit including a bit body having an upper end adapted to be detachably secured to a drill string and at least one leg at its lower end, each leg having a downwardly and inwardly extending journal bearing, at least one roller cone mounted on each journal bearing, at least one cutting element disposed on the at least one roller cone; and a hardfacing overlay on at least a portion of at least one of an inner surface of the at least one roller cone and a surface of the journal bearing, wherei...

A roller cutter includes a hub having crushing members mounted on an outer periphery thereof, and a shaft on which the hub is mounted for rotation. Opposite ends of the shaft include respective spigots. Seals are disposed adjacent respective ends of the shaft and are arranged radially between the shaft and the hub for preventing leakage of lubricant. Covers are disposed axially outwardly of respective seals for covering the respective seals. Each cover includes a generally radially inwardly dire...

A drill bit (100) for drilling a wellbore that traverses subterranean formations includes a drill bit body (106) having a plurality of journal pins (112), each having a bearing surface (128), and a rotary cutter (104) rotatably mounted on each journal pin (112), each rotary cutter (104) including a bearing surface (126). A pressure-compensated reservoir (130) is in fluid communication with the bearing surfaces (126, 128) and has a lubricant therein. A seal element (144) is positioned between eac...

A rock drill bit includes at least one leg about which a roller cutter is rotatably mounted. A ring-shaped seal is disposed between an end surface of the leg and a sealing surface of the roller cutter. The seal is arranged coaxially with respect to an axis of rotation of the roller cutter and is formed of an elastic material and a relatively rigid material embedded within the elastic material. The elastic material defines first and second surfaces which engage the leg and the roller cutter, resp...

Intermediate thrust elements are positioned between the cutters and the bearing pins of an earth boring bit. Each intermediate thrust element is located between a thrust surface on a bearing pin and a thrust surface on the associated cutter. The intermediate thrust elements aid stabilization of the rotating cutter, promote cutter rotation and extend the lifetime of the bit.

A texture pattern is applied to bearing surfaces of earth-boring bits, especially the bearings of earth boring bits of the roller cutter variety. The textured surface that may be applied to either or both sides of the thrust washer faces, bearing faces, inlays, or thrust shoulders, or a combination thereof.

An earth-boring bit has a bit body and at least one bearing shaft depending inwardly and downwardly from the bit body. The bearing shaft has a base and a generally cylindrical bearing surface and at least one cutter is mounted for rotation on the bearing shaft. A bearing seal recess is formed generally at the base of the bearing shaft and defines a cylindrical seal face radially recessed from the journal bearing surface. A cutter seal recess is formed in the cutter generally opposite the bearing...

A rolling cone bit includes at least one cone cutter having a gage row of cutter elements and a first inner row of near but off-gage cutter elements that are positioned so as to divide the sidewall and bottom hole cutting duty so as to enhance bit durability, maintain borehole diameter and improve ROP. The off-gage distance of the first inner row of cutter elements is defined for various bit sizes to optimize the division of cutting duty. The distance that the first inner row of cutter elements ...

The preferred embodiments are directed toward methods and apparatus for manufacturing components for earth-boring drill bits. In the preferred embodiments, a portion of the component is coated and the component is exposed to a carbon-rich environment at an elevated temperature. During this exposure, some portions of the component are not coated. The preferred embodiments further comprise coating the areas that were exposed to the carbon-rich environment and exposing the component to an elevated ...

A roller cone drill bit having a bit body with at least one support arm extending from the bit body. Each support arm may have an associated spindle extending inwardly. A respective cone assembly may be rotatably disposed on each spindle. At least one diverter plug may be disposed in a hole formed in each support arm. A void space may be formed between one end of each diverter plug and the bottom of the associated hole. At least one fluid flow passageway may extend from the surface of the associ...