Yes, I am a little concerned about stripping this all down. I've heard people say that all the ball bearings can fall out if you're not careful.

I posted this same question in a Facebook group which is all about motion control, it's full of people with lots of experience building motion control video rigs. It's called DIY motion control for those interested. Anyway, the consensus there seems to be that this is quite common at particular speeds when using ball screws for motion control and is a resonance thing.

Now, I don't know if they're correct and I'll still be investigating this but it's interesting that they all seem to think this is normal. I wonder if using this for motion control video has an impact. For example, in that use case I think, and correct me if I'm wrong, that it would be more likely to use a ball screw at this slow speed and at more speeds in general; fast, slow etc. Whereas cnc users would generally be going a bit quicker?

I'll pop you a separate message Jazz. Would love to chat