Precision balancing air shafts that end up on the Boeing 787 is an art. The corrections are made in a milling machine using carbide end mills with very specific corner radii. The part is gripped on one end in an index head and is supported in a lathe steady rest to mill to precision requirements. These parts are extremely delicate and have fragile labyrinth seals that can be destroyed with a very light bump. The value of the shaft as you see here is over $10,000 USD.
