Luthier CNC

[bluesking]

Lee, you are a legend, thanks for all the detailed and helpful responses. I will be sure to post a vid showing some of the machine motion once its rebuilt.

Machine is currently in pieces because today I have disassembled all 3 of my ball screws. Cleaned every part with naphtha and relubed with lithium grease (thanks AndyUK - I just smeared about 3cm^3 on the screw and ran the nut over it, repeating until none was left collecting on the rubber seals at the ends of the nut).

Counted the ball bearings - exactly 51 in each ball screw and I managed to get exactly 17 back into each track when reassembling. I reassembled them dry, using the ballscrew itself to guide the balls into their channels. Found this easy and I think its less messy than using grease to stick everything in place. I used the method in this vid to repack the balls https://www.youtube.com/watch?v=GXdt5M8ZeoE

All I have to show for my work is the following vid. Shows all the nasty stuff left floating in the naphtha after cleaning each ballscrew:
https://streamable.com/up3n4

End result certainly feels subjectively smoother - will only know for sure once the machine is rebuilt. One thing I've noticed is that after cleaning the nuts do not spin as easily - though they do spin much more smoothly. I put this down to increased viscosity of the lithium grease compared to what was in there from the factory.