Machining before CNC/WW2 tech
I've recently been in awe at WW2 technology and the massive piston aircraft engines, it got me thinking how were things like centrifugal compressor wheels for turbos/superchargers made back then. All compressor wheels today seemed to be machined by CNC.
How did they machine such complex surfaces back then? I can't figure it out and it is annoying me.
Many thanks