I suspect Nick was on the sauce last night ;-)

But his point was if the basic machine can't hold tight tolerances, then everything is else is superficial.

Shielding is not as big a problem as people often think it is. None of my Denford machines came with anything shielded other than two sensors on the Triac mill. Everything else, including the spindles (VFD on the Cyclone lathe, and DC spindle on the Triac) used unshielded wiring, but then they're not using TTL level logic for inputs.