Hi, I already have the mill and use it occasionally. The CNC Fusion kit on order is the 'Small-Mill Deluxe CNC kit with Premium Ballscrews', although there doesn't seem to be mention of the ballscrew accurary: http://www.cncfusion.com/smallmill1.html

The more I read the less certain I am with regards to closed loop. What's the advantage if a servo misses steps but corrects itself, presumably the damage could already have been done?

The single point thread mill looks interesting, thanks.