I just recieved my 6040 frame, however, I took most of it apart to see what I'm dealing with, and ignored my better judgement with ballscrews.
Eventually, I put all the balls back into the internal recirculating nut, and as a note I did notice a space in each raceway which is about one ball width but a final one wouldn't fit. I'm guessing that's how it's supposed to be and I didn't lose any balls.

I didn't apply any lube, and actually stripped all the grease off with solvent. Later on I added some engine oil to keep it from rusting but know it won't work for operation.

What is an ideal lubricant for ball screws in a wood dust filled environment?

Also, what is good for those generic linear bearings found in the 6040 Chinese machines?

Thanks in advance!

Josh