Schaublin 125-CNC retrofit.

You're very welcome; I'm glad I could help in some small way. The breakdown of the components into different places/pages was new to me too, until I started using QElectroTech (I didn't have previous experience with wiring diagrams). It's great!

*lol* For a moment there I thought you were about to open that long package with the bandsaw.

Good idea!

To late ... already seen it !
Thank you.

Time flies. I again forgot to upload a link.

I would like to say "do not use the variator" or "do not use a VFD" or "get rid of the gearbox", but knowing what a POS i am there is no way, so use all and try to make all automated from LinuxCNC !
I know i would ...

  personally I would have all three under linuxcnc control. That way you can have the speed and torque control you need . Their's a reason
modern automatic car/truck transmissions have so many gears. That said dialing in when to favor which method will take some
 experimenting.

I am thinking that most turning cuts, the gearbox range set first, then set a standard frequency like 50Hz, and use the variator to set the desired RPM.

For facing, set the gearbox range, then the variator slow, and use the VFD to control up to nearly it top frequency, and then do one full variator move, with the VFD compensating to maintain target CSS rpm.