The rotor hub in ductile cast iron forms the interface between the rotor and the drivetrain. Bolted onto the rotor hub are the blade bearings of the enormous rotor blades. While the rotor hub is part of the rotor, functionally, it is closely associated with the mechanical drivetrain. All rotor forces and torques are virtually concentrated in just this one important component. The stresses to which the component is exposed to are correspondingly high.
We have the metal cutting tools for machining components like these.
Here is a selection: