Browny,
There's more than a few different types around. The newer and more efficient designs probably are hard to dig up very much concrete engineering design information on like the screw compressor types. It might take you a lot of digging with Google, But I'd guess there should be quite a bit of information about the "GMC 671 Superchargers". These are a twisted lobe type design. It doesn't take CNC, These were built long before CNC was even close to a reality. It would take a few calculations to figure out the twist ratio and a universal dividing head geared to the X axis feedscrew on a mill though. That and a couple of good I.D./O.D. radius endmills along with some fine handwork should get you what your looking for.
Pete