Abstract: Bucket tip tenons requiring refurbishment are removed from the bucket tips by grinding. Groups of buckets are clamped on a rotatable table in positions adjacent an induction heating coil and a robotic welding arm, respectively. While one group is preheated, the other group of buckets is in a welding location, enabling the welding head on the robotic arm to sequentially apply weld buildup material to the bucket tips. After applying weld buildup material in multiple passes and sequentially to the bucket tips, the buckets are removed, stress-relieved and the weld buildup material machined to provide refurbished tenons. Upon removal of the buckets from the table, the table is rotated to locate the preheated buckets in welding locations and additional buckets are clamped to the table for preheating.

Abstract: Bucket tip tenons requiring refurbishment are removed from the bucket tips by grinding. Groups of buckets are clamped on a rotatable table in positions adjacent an induction heating coil and a robotic welding arm, respectively. While one group is preheated, the other group of buckets is in a welding location, enabling the welding head on the robotic arm to sequentially apply weld buildup material to the bucket tips. After applying weld buildup material in multiple passes and sequentially to the bucket tips, the buckets are removed, stress-relieved and the weld buildup material machined to provide refurbished tenons. Upon removal of the buckets from the table, the table is rotated to locate the preheated buckets in welding locations and additional buckets are clamped to the table for preheating.

Abstract: A machining apparatus is provided. The machining apparatus includes a discharge machining head assembly and a slide assembly supporting the head assembly. The machining apparatus also includes an electromagnet configured to support the slide assembly in a position on a work piece to machine an area. The slide assembly permits linear displacement of the head assembly generally parallel to the supporting work piece surface.

Abstract: Using sinker electrode discharge machining tools, damaged portions of partitions of the turbine which have been removed and replaced with weld material of increased thickness may be shaped and contoured to blend with the suction and pressure sides of the partitions. The diaphragm containing the partitions is located in a tank containing dielectric material. A numerically controlled EDM machine directs first and second sinker EDM tools having surfaces corresponding to designed surfaces of the trailing edge portions of the partitions applied to contour and shape the opposite surfaces of the weld material to blend with the pressure and suction sides of the partitions. A third EDM tool is used to shape the juncture at opposite ends of each partition with the arcuate surfaces of the inner and outer bands.

Abstract: The broach assembly includes alternate spacers and cutters arranged in a sub-assembly having a lead at a leading end and a lag at a trailing end. The cutters have side margins in excess of the margins of the spacers for cutting material from the dovetail slots of the turbine wheel as the broach assembly passes through the slots. The bottom or apices of each spacer and cutter are tapered to form a continuously tapered surface along the bottom of the broach assembly. Upon passing the broach assembly through the slot, the assembly is progressively displaced in a radial outward direction to progressively cut the active dovetail slot surfaces. Shims may be disposed in the bottom of the slot to further displace the broach assembly radially outwardly in multiple passes.

Abstract: A broach assembly includes an elongated base having a central upward projection and a pair of side flanges and a tapered undersurface. Releasably mounted on the projection are multiple tool holders spaced along the length of the base. The tool holders mount cutters for engaging active surfaces of the wedge slot as the broach assembly is passed through the wedge slot. Shims may be interposed between the tool holders and base to increase the elevation of the cutting surfaces relative to the undersurface of the base to progressively increase the bearing pressure of the cutting surfaces against the active surfaces of the slot during multiple passes of the broach assembly through the wedge slot.

Abstract: An automatic machine for peening the tenons on bucket cover plates to secure the cover plates and adjacent buckets of a turbine wheel to one another is provided. The machine includes a fixture having stepped surfaces for locating the freely suspended fixture and peening tool relative to the bucket tips and cover plates and clamping the tips and cover plates to the fixture surfaces. After peening a first tenon, the fixture and tool head are displaced relative to the fixed cover plate and bucket tip to register the tool with a second tenon. An actuator displaces the suspended system to compensate for the movement of the fixture and tool relative to the turbine wheel. A counterbalance is provided to accommodate fixtures of different weights when peening the tenons of covers in different turbine wheels.

Abstract: A broach assembly includes an elongated base having a central upward projection and a pair of side flanges and a tapered undersurface. Releasably mounted on the projection are multiple tool holders spaced along the length of the base. The tool holders mount cutters for engaging active surfaces of the wedge slot as the broach assembly is passed through the wedge slot. Shims may be interposed between the tool holders and base to increase the elevation of the cutting surfaces relative to the undersurface of the base to progressively increase the bearing pressure of the cutting surfaces against the active surfaces of the slot during multiple passes of the broach assembly through the wedge slot.

Abstract: The broach assembly includes alternate spacers and cutters arranged in a sub-assembly having a lead at a leading end and a lag at a trailing end. The cutters have side margins in excess of the margins of the spacers for cutting material from the dovetail slots of the turbine wheel as the broach assembly passes through the slots. The bottom or apices of each spacer and cutter are tapered to form a continuously tapered surface along the bottom of the broach assembly. Upon passing the broach assembly through the slot, the assembly is progressively displaced in a radial outward direction to progressively cut the active dovetail slot surfaces. Shims may be disposed in the bottom of the slot to further displace the broach assembly radially outwardly in multiple passes.

Abstract: The broach assembly includes alternate spacers and cutters arranged in a sub-assembly having a lead at a leading end and a lag at a trailing end. The cutters have side margins in excess of the margins of the spacers for cutting material from the dovetail slots of the turbine wheel as the broach assembly passes through the slots. The bottom or apices of each spacer is tapered and extends beyond the corresponding surface of the cutter to progressively displace the assembly in a radial outward direction to progressively cut the active dovetail slot surfaces. Shims may be disposed in the bottom of the slot to further displace the broach assembly radially outwardly in multiple passes.

Abstract: The broach assembly includes alternate spacers and cutters arranged in a sub-assembly having a lead at a leading end and a lag at a trailing end. The cutters have side margins in excess of the margins of the spacers for cutting material from the dovetail slots of the turbine wheel as the broach assembly passes through the slots. The bottom or apices of each spacer is tapered and extends beyond the corresponding surface of the cutter to progressively displace the assembly in a radial outward direction to progressively cut the active dovetail slot surfaces. Shims may be disposed in the bottom of the slot to further displace the broach assembly radially outwardly in multiple passes.

Abstract: An automatic machine for peening the tenons on bucket cover plates to secure the cover plates and adjacent buckets of a turbine wheel to one another is provided. The machine includes a fixture having stepped surfaces for locating the freely suspended fixture and peening tool relative to the bucket tips and cover plates and clamping the tips and cover plates to the fixture surfaces. After peening a first tenon, the fixture and tool head are displaced relative to the fixed cover plate and bucket tip to register the tool with a second tenon. An actuator displaces the suspended system to compensate for the movement of the fixture and tool relative to the turbine wheel. A counterbalance is provided to accommodate fixtures of different weights when peening the tenons of covers in different turbine wheels.

Abstract: A method of removing a pin from a hole including a) drilling a first hole of a first diameter in the pin a selected fraction of a length dimension of the pin and attempting removal of the pin; b) if the pin cannot be removed, drilling a second hole of a second diameter smaller than the first diameter an extended fraction of the length dimension of the pin; and c) removing the pin.

Abstract: A method of removing a pin from a hole comprising a) drilling a first hole of a first diameter in the pin a selected fraction of a length dimension of the pin and attempting removal of the pin; b) if the pin cannot be removed, drilling a second hole of a second diameter smaller than the first diameter an extended fraction of the length dimension of the pin; and c) removing the pin.

Abstract: An automatic machine for peening the tenons on bucket cover plates to secure the cover plates and adjacent buckets of a turbine wheel to one another is provided. The machine includes a fixture having stepped surfaces for locating the freely suspended fixture and peening tool relative to the bucket tips and cover plates and clamping the tips and cover plates to the fixture surfaces. After peening a first tenon, the fixture and tool head are displaced relative to the fixed cover plate and bucket tip to register the tool with a second tenon. An actuator displaces the suspended system to compensate for the movement of the fixture and tool relative to the turbine wheel. A counterbalance is provided to accommodate fixtures of different weights when peening the tenons of covers in different turbine wheels.

Abstract: An automatic machine for peening the tenons on bucket cover plates to secure the cover plates and adjacent buckets of a turbine wheel to one another is provided. The machine includes a fixture having stepped surfaces for locating the freely suspended fixture and peening tool relative to the bucket tips and cover plates and clamping the tips and cover plates to the fixture surfaces. After peening a first tenon, the fixture and tool head are displaced relative to the fixed cover plate and bucket tip to register the tool with a second tenon. An actuator displaces the suspended system to compensate for the movement of the fixture and tool relative to the turbine wheel. A counterbalance is provided to accommodate fixtures of different weights when peening the tenons of covers in different turbine wheels.

Abstract: A method has been developed for removing turbine buckets that have become stuck to a turbine rotor wheel. This method includes making two or more first cuts to the base of a female dovetail of the turbine bucket. Two or more second cuts are also made to a lower neck of the female dovetail. The blade of the bucket is broken off at the first cut, which breakage also splits the base of the dovetail into two sections. These sections are pressed down along the second cuts so that they may be removed from the wheel.

Abstract: A method of brazing a plurality of copper strands to a buss bar includes: a) cleaning the buss bar and the copper strands; b) positioning a filler shim on the surface of the buss bar; c) placing a copper strand on the filler shim, the filler shim and the strand having substantially equal lengths; d) stacking additional copper strands on the buss bar, with a filler shim between each adjacent pair of strands; and e) heating the filler shims utilizing an induction brazing coil to a temperature sufficient to cause melting of the shims and to thereby form a brazed lap joint between the copper strands and the buss bar.