A cleaning cutting element includes an ultrahard layer joined to a substrate. The substrate includes a substrate bore formed at least partially therethrough. The substrate includes a plurality of conduits that extend from the substrate bore at a junction. The conduits exit the substrate at an exit opening in the circumferential wall to direct drilling fluid to a feature of the bit to which the cleaning cutting element is secured.

A cleaning cutting element includes an ultrahard layer joined to a substrate. The substrate includes a substrate bore formed at least partially therethrough. The substrate includes a plurality of conduits that extend from the substrate bore at a junction. The conduits exit the substrate at an exit opening in the circumferential wall to direct drilling fluid to a feature of the bit to which the cleaning cutting element is secured.

A reamer drill bit includes a body having an outer surface defining a plurality of grooves, and a cutter arm with an interior surface. Each groove extends from a first end of the body to a second end of the body and has at least one groove recess, at least one groove peak connected by a sloped section, and a track arranged in the sloped section. The cutter arm is slidably attached to the body, is configured to expand radially away from the body, and is configured to slide longitudinally relative to the body along the track. The interior surface of the cutter arm includes at least one arm valley, and at least one arm protrusion. The at least one groove recess receives the at least one arm protrusion and the at least one arm valley receives the at least one groove peak.

A reamer drill bit includes a body having an outer surface defining a plurality of grooves, and a cutter arm with an interior surface. Each groove extends from a first end of the body to a second end of the body and has at least one groove recess, at least one groove peak connected by a sloped section, and a track arranged in the sloped section. The cutter arm is slidably attached to the body, is configured to expand radially away from the body, and is configured to slide longitudinally relative to the body along the track. The interior surface of the cutter arm includes at least one arm valley, and at least one arm protrusion. The at least one groove recess receives the at least one arm protrusion and the at least one arm valley receives the at least one groove peak.

A downhole system may include a downhole drill bit having at least one nozzle bore and a nozzle insert secured at least partially within the at least one nozzle bore. The nozzle insert may include a first radially outer sealing surface sealed against a first inner surface of the nozzle bore via a first seal feature, a second radially outer sealing surface sealed against a second inner surface of the nozzle bore via a second seal feature, and an annular threaded body portion to secure the nozzle insert within the at least one nozzle bore. The downhole system may further include a nozzle pressure chamber formed between the first seal feature, the second seal feature, a radially outer surface of the nozzle insert, and a radially inner surface of the at least one nozzle bore. The pressure chamber is configured to provide a retaining force on the nozzle insert.

A downhole system may include a downhole drill bit having at least one nozzle bore and a nozzle insert secured at least partially within the at least one nozzle bore. The nozzle insert may include a first radially outer sealing surface sealed against a first inner surface of the nozzle bore via a first seal feature, a second radially outer sealing surface sealed against a second inner surface of the nozzle bore via a second seal feature, and an annular threaded body portion to secure the nozzle insert within the at least one nozzle bore. The downhole system may further include a nozzle pressure chamber formed between the first seal feature, the second seal feature, a radially outer surface of the nozzle insert, and a radially inner surface of the at least one nozzle bore. The pressure chamber is configured to provide a retaining force on the nozzle insert.

A nozzle or use in an earth-boring tool includes an inlet having a first size. The nozzle further includes an outlet having a second size different from the first size of the inlet. The nozzle also includes a fluid passage defined in the nozzle from the inlet to the outlet. The fluid passage includes a transition region configured to transition the fluid passage from the first size of the inlet to the second size of the outlet. The transition region includes a first arc curving inward and a second arc curving outward.

A nozzle or use in an earth-boring tool includes an inlet having a first size. The nozzle further includes an outlet having a second size different from the first size of the inlet. The nozzle also includes a fluid passage defined in the nozzle from the inlet to the outlet. The fluid passage includes a transition region configured to transition the fluid passage from the first size of the inlet to the second size of the outlet. The transition region includes a first arc curving inward and a second arc curving outward.

A nozzle or use in an earth-boring tool includes an inlet having a first size. The nozzle further includes an outlet having a second size different from the first size of the inlet. The nozzle also includes a fluid passage defined in the nozzle from the inlet to the outlet. The fluid passage includes a transition region configured to transition the fluid passage from the first size of the inlet to the second size of the outlet. The transition region includes a first arc curving inward and a second arc curving outward.

A nozzle or use in an earth-boring tool includes an inlet having a first size. The nozzle further includes an outlet having a second size different from the first size of the inlet. The nozzle also includes a fluid passage defined in the nozzle from the inlet to the outlet. The fluid passage includes a transition region configured to transition the fluid passage from the first size of the inlet to the second size of the outlet. The transition region includes a first arc curving inward and a second arc curving outward.