The backlash on my lovely EMCO has worsened of late, so much so that there is now nearly half a turn on the dial before anything happens, so I resolved to fix it. Copying the nut was straightforward enough, and I found a drawing on the Net just to confirm the finished sizes. A fat piece of brass was found and I was away! I now have just 0.05mm backlash and it is as smooth as silk...
There was the rare option of buying one, but at £72.00...
https://www.ebay.co.uk/itm/235247842218What it should look like!
What I finished up with after two hours work! I bought the length of stainless rod intending to replace the existing one, but it wasn't necessary. I hacksawed the slot using two blades on the frame. Worked a treat.
I cheated and bought some LH taps from RDG Tool. Velly cheep!