The present invention relates to a downhole tool (23), for removing sections of metal tubing, comprising: at least one conductive element (1) being arranged to corrode a section of metal tubing using an electrolytic process, said conductive element (1) being a tube or a pipe which is made of electric conductive material, an apparatus (4) to establish a connection to the metal tubing (2), and a milling apparatus with cutting or abrasive elements (3) arranged to remove byproducts from the electrolytic process. The invention also relates to a modular downhole tool (45), comprising an elongated main shaft (8) with several modules for insertion in a wellbore.

A light weight component, the light weight component including: a metallic foam core formed into a desired configuration; an external metallic shell applied to an exterior surface of the metallic foam core after it has been formed into the desired configuration; an inlet opening and an outlet opening formed in the external metallic shell in order to provide a fluid path through the metallic foam core; and a thermoplastic material injected into the metallic foam core via the inlet opening.

A dielectric gel for use in electro-discharge machining. Aspects of the dielectric gel include a liquid solvent phase entrapped in a three-dimensionally cross-linked fibre network.

A cutting electrode head for a handheld electrical discharge machining (EDM) device comprising: a housing; a cutting electrode supported in the housing, and configured to move from a retracted position to an extended position along an electrode axis (C) to cut a workpiece; and an actuator supported in the housing and movable along a movement axis (E) which is at an angle to the electrode axis (C), wherein movement of the actuator along the movement axis (E) causes the cutting electrode to move between its retracted and extended positions.

A method is provided for removing a fastener having a longitudinal shank from a workpiece using electro-discharge machining, EDM, the method comprising: contacting a portion of the fastener or workpiece with an EDM fixture, thereby: locating the EDM fixture and an EDM electrode relative to the fastener in a lateral direction; and establishing an electrical ground connection to the fastener via the EDM fixture; and eroding the fastener using the EDM electrode.

An electrode guide assembly for an EDM process includes a guide tube having a first end and a second end, a fluid feed portion, a fluid return portion, and an electrode. The guide tube has a set of at least two supporting protrusions, with the protrusions projecting radially inwardly from an inner diametral surface of the guide tube. The electrode is slidably accommodated within the guide tube, with an outer diametral surface of the electrode abutting against the set of supporting protrusions. The first end of the guide tube is in fluid communication with the second end of the guide tube to thereby provide a fluid feed channel, and the second end of the guide tube is in fluid communication with the first end of the guide tube to thereby provide a fluid return channel.

A process for forming a single crystal superalloy wave spring is provided. In one embodiment, the process may include machining a wave spring from a single crystal superalloy slab after optimizing its orientation using diffraction techniques so that the wave spring will exhibit optimal spring properties.

EDM assemblies mount on a machining surface and discharge rotating sub-electrodes against the surface. The sub-electrodes can also revolve about another shared axis while discharging. Rotation and revolution may be achieved with planetary gears fixed with the sub-electrodes and meshing with a stationary sun gear. Several sub-electrodes can be used in a single assembly. Downward movement of the sub-electrodes from a central shaft on the mount allows several inches of the surface to be machined. Assemblies are usable in a nuclear reactor during a maintenance period to machine a hole for a replacement manway cover underwater in the flooded reactor. The differing rotational movements and vertical movement can be independently controlled with separate motors in the assembly. Power and controls may be provided remotely through an underwater connection.

An electro-discharge machining (EDM) device comprises a housing, an erosion electrode, a ground electrode, and a dielectric inlet. The housing is configured to be positioned on a surface of a workpiece and proximal to a fastener to be eroded. The planar erosion electrode is positioned at least partially within the housing, with the erosion electrode being movable relative to the housing in a first axis. The first axis is substantially normal to a longitudinal axis of the fastener.

The ground electrode is conductively connected to the fastener. The dielectric inlet is configured to deliver a dielectric fluid to a region between the erosion electrode and the fastener.

EDM assemblies mount on a machining surface and discharge rotating sub-electrodes against the surface. The sub-electrodes can also revolve about another shared axis while discharging. Rotation and revolution may be achieved with planetary gears fixed with the sub-electrodes and meshing with a stationary sun gear. Several sub-electrodes can be used in a single assembly. Downward movement of the sub-electrodes from a central shaft on the mount allows several inches of the surface to be machined. Assemblies are usable in a nuclear reactor during a maintenance period to machine a hole for a replacement manway cover underwater in the flooded reactor. The differing rotational movements and vertical movement can be independently controlled with separate motors in the assembly. Power and controls may be provided remotely through an underwater connection.