Rotating ball nut, Ballscrew Pitch, RPM limits, and my particular build pickle

[Muzzer]

I had to do this on one of my ballscrews after The Stupid Fat Bloke managed to get into my workshop when I wasn't looking and rotated the ballscrew too far Wasn't quite as bad as I'd feared in the end.

Best avoided if you can but there are videos out there that show how it's done. There are various methods suggested but this worked for me, as you can screw the ballscrew in as you fit the balls. You could probably do it in 20 mins or so. Or 2 minutes if you are a Chinese factory worker.



Others suggest holding the balls in place with grease or plastic foam and then screwing the ballscrew in place afterwards, which sounds like a recipe for frustration and disaster unless you like that sort of thing.

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Incidentally, at 3000rpm, those balls would be flying through the ballnuts. Try to imagine them being diverted by the plastic guides and ask how long those guides will last. There are max rpm specs for ballscrews and I don't imagine those ones would be very high. Most of the manufacturers publish application notes. Looking at p33 of this one, I'd be surprised if even a top end 32mm ballscrew would be happy at 3000rpm. https://www.hiwin.com/pdf/ballscrews.pdf

A source for better quality parts might be one of the machine breakers. I've bought ballscrews from FA Parts in Korea. https://www.ebay.co.uk/str/industrialpartsshop They stock new old stock (NOS) and used parts from dismantled machines. You might find a decent quality Japanese, Korean etc ballscrew, possibly ground rather than rolled, possibly never used for the same price as a "new" Chinese rolled ballscrew. I got ground Korean 2005, 1090mm long for £109 and a 1205, 500mm long for £51 inc carriage, both delivered within a week - no comparison with the Chinesium ones I got for my Bridgeport conversion.