An electrical tool including: a cutter bit assembly, a driving mechanism for providing a power to the cutter bit assembly, and a flexible transmission mechanism, which is connected at one end thereof to the driving mechanism and connected at the other end thereof to the cutter bit assembly; the flexible transmission mechanism is twistable and bendable, and is configured to transmit the power provided by the driving mechanism to the cutter bit assembly.

A method includes positioning a cylindrical tool having one or more rows of blades within a cylindrical bore having a surface, forming annular grooves and peaks into the surface with the grooving blades when the swaging blades are in the retracted position, and translating the swaging blades from the retracted position to the extended position to deform the peaks. The one or more rows of blades includes fixed grooving blades and translatable swaging blades having retracted and extended positions.

A hollow spring includes a steel tube in which the average of surface roughness is smaller than 10 μm across the entire inner surface of the steel tube and/or compressive residual stress is given to the entire inner surface of the steel tube. The hollow spring may be manufactured by a step of polishing the inner surface of the steel tube by flowing a viscoelastic abrasive medium (200) within the tubular member (10), between a first opening (11) and a second opening (12) of the tubular member (10). The abrasive medium (200) may include a viscoelastic base material and a granular abrasive. The inner surface of the steel tube is polished evenly to reduce the surface roughness and/or is given compressive residual stress to increase the fatigue life of the hollow spring.

A hollow spring includes a steel tube in which the average of surface roughness is smaller than 10 μm across the entire inner surface of the steel tube and/or compressive residual stress is given to the entire inner surface of the steel tube. The hollow spring may be manufactured by a step of polishing the inner surface of the steel tube by flowing a viscoelastic abrasive medium (200) within the tubular member (10), between a first opening (11) and a second opening (12) of the tubular member (10). The abrasive medium (200) may include a viscoelastic base material and a granular abrasive. The inner surface of the steel tube is polished evenly to reduce the surface roughness and/or is given compressive residual stress to increase the fatigue life of the hollow spring.

A center shaft machining apparatus includes: a grinding structure that moves on a machining central axis while rotating about the machining central axis and machines an end surface on one end side of a workpiece arranged on the machining central axis; an end portion support structure that supports an opposite end side of the workpiece; and a shaft portion support structure that supports a shaft support portion set at an intermediate portion of the workpiece. The end portion support structure includes an eccentric mechanism capable of supporting an opposite end of the workpiece in a state where a workpiece central axis of the workpiece is eccentric with respect to the machining central axis.

A center shaft machining apparatus includes: a grinding structure that moves on a machining central axis while rotating about the machining central axis and machines an end surface on one end side of a workpiece arranged on the machining central axis; an end portion support structure that supports an opposite end side of the workpiece; and a shaft portion support structure that supports a shaft support portion set at an intermediate portion of the workpiece. The end portion support structure includes an eccentric mechanism capable of supporting an opposite end of the workpiece in a state where a workpiece central axis of the workpiece is eccentric with respect to the machining central axis.

The present disclosure is directed to a surfacing tool for repairing a sealing surface on a fitting. The surfacing tool is defined by a tool head and a tool head guide having an internal bore sized to receive the tool head. The tool head is includes a reverse flare working surface positioned at a first end thereof. A threaded element is positioned at one end of the tool head guide to threadingly receive a threaded flare fitting. The tool head being rotatable within the tool head guide while engaging and grinding the sealing surface on the fitting to a desired finish.

The present disclosure is directed to a surfacing tool for repairing a sealing surface on a fitting. The surfacing tool is defined by a tool head and a tool head guide having an internal bore sized to receive the tool head. The tool head is includes a reverse flare working surface positioned at a first end thereof. A threaded element is positioned at one end of the tool head guide to threadingly receive a threaded flare fitting. The tool head being rotatable within the tool head guide while engaging and grinding the sealing surface on the fitting to a desired finish.

A tire pre-conditioning system includes a first mandrel, a second mandrel spaced apart from the first mandrel, and a controller in communication with the first mandrel and the second mandrel. The first mandrel is fixedly attached to a first shaft and including a first tapered sidewall. The second mandrel is fixedly attached to a second shaft and including a second tapered sidewall. The controller is operable to axially move the first mandrel and the second mandrel toward one another until the first and second tapered sidewalls are opposing respective beads of a tire, and supply pressurized fluid into an internal cavity of the tire to inflate the tire. The inflating causing the beads to move relative to mandrels while contacting the opposing respective tapered sidewalls to burnish the beads of the tire.

A tire pre-conditioning system includes a first mandrel, a second mandrel spaced apart from the first mandrel, and a controller in communication with the first mandrel and the second mandrel. The first mandrel is fixedly attached to a first shaft and including a first tapered sidewall. The second mandrel is fixedly attached to a second shaft and including a second tapered sidewall. The controller is operable to axially move the first mandrel and the second mandrel toward one another until the first and second tapered sidewalls are opposing respective beads of a tire, and supply pressurized fluid into an internal cavity of the tire to inflate the tire. The inflating causing the beads to move relative to mandrels while contacting the opposing respective tapered sidewalls to burnish the beads of the tire.