Hi!

I'm converting my mini lathe to a bigger (but still small - 10mm diameter) ballscrew lead screw.

I want to have a double nut back to back configuration for reducing backlash. I've searched a lot for examples and with the standard flange nut, I can screw one ballnut to the nut block, and the other one would be "floating" fixed only by screws on the fixed nut-block assembly, and by means of springs or tightening these screws a preload would be achieved to reduce backlash.

something like this in the first picture:



But as my mini lathe has space constraints, I need to use a flange-less type of ballnut, like this one on the second picture:




So, I thought about creating a balnut block where I could screw one nut on one side, and the other one on the other side, but then, how would I be able to make them a little apart or a little bit closer to decrease backlash?

I thought then about using a belleville washer on one side to act as preload, or spring to make both nuts apart, so backlash would be reduced.

These ideas are drawn below:



My space constraints are tough. I can't mill the nut block to a higher diameter then the outer diameter of the ballnut external case.

In my case I plan to use a 1002 ballnut/screw. It has an external diameter of 19.5mm, and I have 21 mm of height under the lathe's bed only.

Anyone has any ideas if this would work? If not, does enyone has a better idea to couple two flangeless ball nuts in my space constraints?

Thanks for reading!