I've now got my Optimum BF46 running with 3 Step/Dir open loop stepper motors on Kflop. I'm currently using the original ACME leadscrews with about 0.25mm / 0.01" backlash. Whilst the backlash compensation does a good job of reducing the effect of this, I suspect that I will want to improve the precision long term.
The question is, would I be better off fitting ballscrews, or adding linear glass encoders and changing to closed loop in the Kflop? Since this is a hobby machine, doing both will require a more convincing justification to my "finance director"