The dreaded..........."Backlash"

[Robin Hewitt]

Thanks for that. By "springing" 2 nuts together, is that as obvious as it sounds?

Hi Paul

Put two ball nuts close together on the same screw, arrange it so neither can turn but one can slide. Add springs to push them together or apart.

I use Belleville washers and preload them to about a quarter of a ton, so I get zero backlash up to that point.

Obviously this won't work with ordinary nuts, they'd just seize, has to be a rolling contact.

I also spring the thrust races holding the ball screws in place. It's complicated to do but solid as a rock

Robin