Thanks Mat,

Is it an X3 you've converted?

I've double checked the ball nut diagrams and read them correctly now I think.

A 1204 with a ball nut height of 30mm would fit within the existing brass nut housing for ease of machining and single ball nut might be a better choice for the Y given the travel issue you mentioned. Just thinking, it could be feasible to have the regular ball nut (or indeed a double nut) mounted backwards on the screw to gain the maximum amount of travel. Would need to offset the BK mounting further forward from the front of the saddle but that should be easy enough with a suitable lump of aluminium. It would protrude more and really necessitate the stepper going off to the side with the pulleys and belt or I'd never get past the thing in the garage .Following on from that it might just be easier to use the same 1204 for the X in that case. I'll have a look at it shortly - the table is already off so should be easy enough to work out. Glad I haven't ordered just yet.

Shows the value of this site and the experience on here again for me..

Not sure if I want to grind my nuts!!