Shauki Bagdadi   http://www.igus.eu/wpck/7975/Zero_Backlash_Muttern check this out for the 1050.

@Shauki http://www.igus.eu/wpck/7975/Zero_Backlash_Muttern check this out for the 1050. there were none local (US)in stock so I will wait a little while for the sample. But I have 3 more 1050 lead screws and 7 regular nuts more. I will build my own spring pre-load x/y ends.