You missed the point here: the new nuts are not available for old SC1 steppies. Ah, sorry. I missed that. Also, one has to look to quality of t...

The backlash goes almost to zero? Maybe the wearing will progressively augment the backlash, but I think it will be limited to few cents of millimete...

What is the benefit of a high quality ball screw (with hardened balls) on a unknown lead screw with technically unknown specs and profile?

Here you go:

So, to my questions : 1) Am i likely right in my hypothesis that this stepper is likely to blame? 2) Should I just replace with direct replacement ...

Aye, worked great. So good that I ordered nuts for X and Z as well. My Z axis has had much play for a long time.

Cool. I want one too...

Thanks jvalencia. I got the same suggestion from StepCraft and Rory from StoneyCNC too. A clip showing how my fix works. I don't consider it perman...

I added a video The white is electrical tape that helped a bit, but still I don't see this working at all.