Abstract: The present invention relates to inserts for hard facing substrates, and a method for hard facing substrates. An insert according to an embodiment of the present invention may comprise a body of ultra-hard material having a welding node located on a first surface thereof and at least one wire electrically connecting the first surface to a second, opposite, surface. In use, the inserts may be temporarily connected to a substrate by applying a resistance welding electrode to the welding node, thereby causing the wires on the second surface to melt and weld the insert to the substrate. A subsequent brazing step may firmly attach the inserts to the substrate.

Abstract: A downhole tool for incorporation in a drill pipe for selective operation of the tool from surface level when the tool is in a wellbore. The tool comprises a controller electrically powered by a power source separate from surface level, a first sensor of the controller to detect a dynamic variable of the tool in the wellbore and produce an output signal dependent thereon; a second sensor of the controller to detect a mechanical signal transmitted from an operator at surface level; a motor driven by the power source under the control of the controller when said mechanical signal is received; and an actuator driven by the motor to actuate the tool; wherein the controller switches between at least two states in response to changes in said dynamic variable, only in said second state the controller being receptive to said mechanical signal from the operator to drive the motor.

Abstract: An insert (10) for a cutting tool (100) for use down a well bore comprises a body of a hard material (tungsten carbide) suitable for cutting steel. The body is shaped for formation in a mould that comprises a die (70) and first (74) and second (78) punches and arranged so that the first punch can eject the body after formation from an opening of the die closed during formation by said second punch. The insert has first (12) and second (14) ends whose faces are defined, at least in part, by corresponding faces of the first and second punch. Between them is a longitudinal axis (24) of the insert. The area of the first end is less than the area of the second end. The body has flanks (16) that form ridges (18) extending between the first and second ends. The ridges form cutting edges of the insert. They are separated by V-shaped troughs (20) of said flanks. The ridges taper and spiral about the axis.

Abstract: A downhole tool for incorporation in a drill pipe for selective operation of the tool from surface level when the tool is in a wellbore. The tool comprises a controller electrically powered by a power source separate from surface level, a first sensor of the controller to detect a dynamic variable of the tool in the wellbore and produce an output signal dependent thereon; a second sensor of the controller to detect a mechanical signal transmitted from an operator at surface level; a motor driven by the power source under the control of the controller when said mechanical signal is received; and an actuator driven by the motor to actuate the tool; wherein the controller switches between at least two states in response to changes in said dynamic variable, only in said second state the controller being receptive to said mechanical signal from the operator to drive the motor.