Western Machine Works


Engineered Refurbishing – Hydro Servo Parts

Our team completed the refurbishment of a servo part assembly which includes the turbine shaft, piston, and piston rod for a hydro power plant. Several components needed to be manufactured due to severe damage and corrosion. Adhering to stringent technical requirements, all machining, manufacturing, disassembly and assembly were completed within the maintenance schedule. 


  • Part: Servo parts: turbine shaft, piston, and piston rod. 
  • Details: C93200 new bushing material, centrifugally cast 300 or 400 stainless steel for packing sleeve
  • Customer: hydro power plant


  • Custom design and fabrication of 36″ piston ring compressor was needed to prevent ring damage when inserting piston into the bore.
  • Tig welding of packing sleeve to the turbine shaft was required to ensure adequate adhesion at split line.

Engineered Solutions:

  • Dimensionally inspect all critical fits and bearing surfaces on turbine shaft. Lathe check for straightness and concentricity.
  • Non-destructive test of the turbine shaft and packaging sleeve.
  • Hone and polish piston assembly bore.
  • Custom tooling to machine-remove existing bronze bushing and turbine shaft packing sleeve.
  • Manufacture new bushing using C932 bronze material and with proper interference fit to the bore. install bushing and anti-rotation screws. Finish bore the bushing to required tolerance.
  • Tig weld to repair and polish damaged area in the bearing sleeve.
  • Provide centrifugally cast stainless steel packing sleeve material. Rough turn and bore.
  • Machine sleeve material in preparation for welds. Install and weld sleeve to the shaft. Finish machine to OEM specifications.
  • Disassembly of piston and rings from shaft. Dimensionally inspect piston bore and piston shaft. Lathe check shaft for straightness.
  • Manufacture socket and remove retaining nut.
  • Reinstall piston to the piston shaft and retaining nut. Debur grooves as required and install new piston rings.
  • QA and prep for shipping.


  • All technical specifications were achieved.
  • All repairs completed and delivered within the outage schedule.
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