Hi,

I brought a pair of used NTN C1 grade ground ballscrews from ebay a few months back and having trouble finding appropriate lubrication.

I've read the previous postings here and I'm assuming that I need something that has very low cst viscosity rating since if I spin the ball nut while the screw is vertical it will move down the length of the screw via its own weight and momentum.

So far I have only been able to find something called "Rocol Sapphire Premier", which at £22 for a 380g cartridge is not cheap, however it seems to fit the bill cst 50 @ 40oC, synthetic oil and lithium soap however it does have PTFE. Some previous posters say to avoid PTFE so I want to make sure I'm not getting something that is both expensive and will damage my screws.

http://www.rocol.com/tsds/live/tds/e...mier%20TDS.pdf