Machine Voltage/Phase Mismatch and Retrofit 3

[MitchusMaximus]

Good day, I am helping a machinist getting some equipment operational that he has purchased with mismatched voltages. I'll lay out what he has:
-240V single phase power
-51kVA 230 - 460 step-up transformer
-12.5HP 460V lathe
-3HP 575V mill
-A tight budget

My plan is to use an oversized 480V drive to feed the lathe, and tap off the output to feed a step-up autotransformer to jump from 460V to 575V, and use the transformer output to run the mill. I would use interlocked contactors for selection, so only one motor can be energized at a time, but my transformer selection raises a question I haven't run into before. Autotransformers by default seem to be Wye-Wye connected, with a neutral terminal for the line and load side. If I am feeding this transformer off a VFD I don't have a neutral to work with, is it possible to make this wye connection work? Or should I opt to try and get a custom delta-delta transformer built for this application?
Thanks for the help, it is shocking how often people will buy auction equipment without considering a means to achieve the power requirements. If you weren't looking for it, it's not a good deal.

 

[BrianPetersen]

The Italian machine probably uses a motor with an IEC frame size.

https://www.baldor.com/~/media/files/brands/baldor-reliance/resources and support/backcover.ashx

The Chinese one, who knows, but perhaps it's worth checking dimensions against the IEC chart.