Western Machine Works


Thermal Spray Repair – Hydro Thrust Collar

A public utility with hydroelectric facilities in the West required the rush repair of its turbine shaft thrust collar. Weighing 20 tons, the project required complex setup. After inspection, it was determined that thermal spraying would be the most viable option to meet the customer’s technical requirements and outage schedule. The thrust collar was restored to OEM specifications, repaired and completed within a critical path timeline. Read on for more details about this project.


  • Part: Hydro Thrust Collar
  • Details: 73″ wide x 53″ high; 20 tons
  • Customer: California hydro utility


  • Weighing 20 tons, the thrust collar required special lifting device.
  • Required high-precision machining to achieve .001″ tolerance.

Engineered Solutions:

  • Set up in vertical turret lathe.
  • Inspection and review of prints with customer.
  • Machine the upper and lower ID fits in preparation for metallizing. Surface will be undercut.
  • Thermal spraying of all critical fits using 420 stainless steel coating material.
  • Finish machine to tolerance of .001 and 125 rms finish.
  • Utility QC inspector to verify finish diameter tolerances.
  • QC report and documentation.
  • Prep for shipping. 


  • All OEM specifications were achieved.
  • Completed all machining in 5 working days.
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