Haha my Tree is described as "ultraprecision". That just seems to mean it has good quality bearings and ballscrews (all HSK) and the bed / frame is solid cast iron but still there is no means of compensating for any backlash after the ballscrews other than rely on the quality of the parts to minimise it.

I swapped the original 4000rpm 5HP DC spindle motor and drive on the Tree for a Yaskawa VFD and 3000rpm 4kW TEFC induction motor which work nicely with the Acorn using the 0-10V analog output. My Shizuoka mill came with a nice 6000rpm Hitachi induction machine, an ancient VFD and a 2 speed gearbox. With a modern Yaskawa VFD, this works fine up to 7500rpm with the Acorn. And despite being intended for industrial use with a wide speed range, the motor has no separate cooling fan. unlike the Tree which has a little blower on the side.