Abstract: A method of casehardening an earthboring tool component includes steps of providing an earthboring tool component and providing a semiconductor light emitting device carried by a mechanical arm. The mechanical arm is used to move the semiconductor light emitting device relative to the earthboring tool component. Light emitted by the semiconductor light emitting device is directed to a surface of the earthboring tool component so that it is casehardened.

Abstract: An improved bit body for a tri-cone drill bit has a bit body affixed to a terminal end of drilling string. The drilling string has at least one fluid passageway formed in its wall. The drilling string is dual passage drilling string formed of an inner drilling string and an outer drilling string. The terminal end of the inner drilling string has an area of reduced outer diameter. A cylindrical shroud is affixed to the drilling string and surrounds the area of reduced diameter and an upper portion of bit body, forming a shroud chamber. The shroud chamber communicates the fluid passageway of the drilling string with the fluid ports of the bit body. The lower edge of the shroud is closely spaced to an outer diameter portion of the drill bit body adjacent the recesses. Therefore, the shroud and recesses form fluid ports through which fluid may be directed to cool and remove debris from the roller cutters.

Abstract: A valve-nozzle assembly is disclosed for use in a rock-drilling bit, which assembly utilizes a backflow valve with a replaceable nozzle insert.