Abstract: A drill bit includes a floating journal bushing, a seal, a cutter having a seal gland for the seal and a cutter bearing surface proximate to the journal bearing, wherein the cutter bearing surface has a first inner diameter, and a journal, wherein the cutter is rotatably coupled about the journal, wherein the journal bearing is rotatably coupled about the journal, wherein the journal has a seal boss having a first diameter, and a journal bearing surface having a second diameter, and wherein the first diameter is less than the first inner diameter.

Abstract: An insert for an earth boring drill bit, such as a PDC rock bit or a roller cone rock bit, is provided. The insert includes a base integrally joined to a top section, the top section having a first flank that curves in a substantially helical manner about a longitudinal axis of the insert to join a crest.

Abstract: A drill bit having a selected gauge diameter and operable to be positioned within a casing positioned within a rock formation, the casing comprising an casing inner wall having a casing inner diameter greater than the gauge diameter, wherein the positioning of the drill bit within the casing defines a drift distance corresponding to the distance between the gauge diameter and the casing inner diameter, the drill bit comprising a blade comprising a gauge cutter operable to cut an earth formation at the gauge diameter; and a protective insert coupled the drill bit such that a portion of the protective insert extends beyond the gauge diameter by a selected overgauge distance, wherein the protective insert is operable to engage the casing inner wall to substantially prevent the gauge cutter from engaging the casing inner wall as the drill bit is positioned through a selected length of the casing.

Abstract: A drill bit comprising a cutter assembly, further comprising a planar table and a cutter substrate coupled to the planar table, wherein the cutter substrate has a cutter body axis and wherein the planar table is operable to rotate about the cutter body axis. The planar table may be exposed to the rock formation for cutting purposes but may rotate to reduce the time that any specific portion of the cutting edge is exposed to the formation to extend the life of the planar table, among other benefits.

Abstract: The present invention addresses this need in the art by providing a cutter insert comprising a plug section and a cutter pedestal. The cutter insert is preferably formed of tungsten carbide, except for two exterior surfaces covered with PDC. The plug section may be circular or oval in cross section perpendicular to the axis of the insert. The plug section and the pedestal each defines a shoulder which is coated with a PDC layer. In this way, two cutting surfaces are applied to the formation, enhancing the cutting ability of the insert.