Abstract: A portable lathe for machining the end of a pipe workpiece for butt welding, having a cylindrical shroud with a collar for receiving the workpiece and three equiangularly spaced, hydraulic clamps mounted on the collar for clamping the pipe workpiece therein coaxial with a rotary cutting tool support of the lathe. Three equiangularly spaced, hydraulic actuators provide for axially feeding the tool support during machining and are hydraulically interconnected for damping an unbalanced machining reaction force on the cutting tool support.

Abstract: An orbital welding apparatus for butt welding tubular pipes includes a non-consumable electrode for establishing an electrical arc and means for storing and dispensing consumable weld wire through an aiming conduit. The weld wire is a solid monofilament wire helically coiled into a plurality of closely spaced convolution having a hollow core to provide minimum bending stiffness and a low constant spring rate in the bending mode so that it can negotiate sharper bends without permanent deformation. It is stored around a spool which is rotatably mounted in a non-rotatable magazine having a fixed block at one end. The fixed block supports a friction member formed by a plurality of axially projecting spaced loops of resilient filaments which engage the smooth end of the spool to provide a low uniform frictional drag balancing the low spring force of the weld wire as it is uncoiled from the spool and is fed to the aiming conduit by a pair of powered feed rollers having a resilient outer periphery to grip the wire.

Abstract: A TIG pipe welding method which employs two sets of machine guide surfaces on the pipe ends. First radially inner guide surfaces cooperate with a sensor coupled to the welding torch to continuously monitor the arc gap between the welding electrode and the weld puddle as the welding electrode moves around the circumference of the pipe. The second set of radially outer surfaces cooperate with a welding carriage to guide the carriage and welding modules around the pipe joint. The carriage is constructed to provide a sealed welding chamber surrounding the electrode. An additional flow of shielding gas is provided around the torch electrode of a TIG or hot wire TIG welding module to augment the normal gas shield.