Thermal shaft

Thermal shaft

Alloy steel


Thermal shafts are fitted in steam turbines. They are often around 10 metres long and weigh over 100 tonnes. It often takes months to machine them, with up to 20 t of chips being produced. Machining this type of stainless-steel shaft is generally considered one of the most demanding machining tasks.

This particularly applies to milling the precision mounting grooves. As a result of a component-specific machining process developed individually for the user, Walter ensures that machining is both accurate to size and cost-efficient. This is implemented in production with our highly precise special tools for milling and drilling.

Back counterboring the coupling holes

Our solution:
Walter back counterbore

  • Customer-specific, custom-designed tool solution for back counterboring shaft couplings
  • Available as back counterbore or circular interpolation technology
  • Also available as a manual solution for unfavourable ratios, either with ScrewFit, shell or bayonet interface

Benefits for you:
Custom-designed solution. Flexible tooling system with process reliability.


Machining fir-tree grooves

Our solution:
Indexable inserts for semi-finishing and finishing face milling cutters

  • Cost-efficient semi-finishing and finishing of fir-tree grooves
  • Finishing profiles up to a profile tolerance of ±10 μm
  • No regrinding for solid carbide and shorter machining times
  • Available for various profile shapes

Benefits for you:
Cost-efficient machining of fir-tree grooves with process reliability. Faster machining times and no additional regrinding costs compared to solid carbide tools.

Rough milling of straight fir-tree grooves

Our solution:
Form slotting cutter

  • Design: Modular cartridge system
  • Equipped with Tiger·tec® Silver standard indexable inserts
  • Roughing the grooves in the most effective and cost-efficient manner
  • Maximum number of teeth and optimum chip clearances ensure maximum cutting performance and chip removal

Benefits for you:
Tiger·tec® Silver standard indexable inserts for maximum cutting performance and process reliability.


Finishing fir-tree grooves

Our solution:
Solid carbide and HSS finishing face milling cutters

  • Particularly well-suited for smaller fir-tree profiles and tighter tolerances
  • Rounds off Walter's product range to allow all customer and tool requirements to be processed in full

Benefits for you:
Increased accuracy on the component and complete machining from a single source.