Luthier CNC

[Voicecoil]

there is a little patchiness to the motion - there are occasional slight sticking points which require a bit more force than just two fingers can apply

BTW, did you check the ballscrew for smoothness throughout its' length before mounting it?? As I mentioned in my thread here: http://www.mycncuk.com/threads/12524-gritty-ballscrews , although Fred tries hard to please, his engineers don't always seem to adhere to the old saying "cleanliness is Godliness" when it comes to machining ballscrews. Even the replacement parts he sent me needed a clean, strip down, flush through and re-grease before they were acceptably smooth. Try running (twisting) the sticky portions through a piece of clean tissue and then examine under magnification to see if there's any small flakes of swarf.