I bought two ballscrews on ebay. Both are nice looking NSK parts. One is silky smooth and the other is slightly gritty. Is is possible/advisable to disassemble, clean and relubricate the gritty one? Any suggestions on the best grease to use?
Dented races from overstress can cause a 'gritty' feel; hope it's not that, but just some dirt.
Find a fitting and force lube into it until the grit washes away. It's NOT recommended to disassemble (sometimes those balls are installed in oversize/undersize alternation, and it's hard to reassemble correctly... disastrous to reassemble the other way).
If there's a preload adjustment, it might pay to loosen it while the gritty one is getting flushed.
If you can, find out from NSK what the recommended grease is. Grease is cheap.
My solution for cleaning ball nuts is to wipe axle grease on the screw, run the nut across the screw, wipe remaining grease off other side of screw. Observe rag for shiny flecks, if visible, repeat process. This has worked quite well to clean out several ballscrews that were of the kind that could be quite difficult to disassemble and reload the balls into.
Jon
DON'T TAKE THEM APART!!! Wash them out repeatedly or send them out.
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