Cheers, I've just looked through the thread and noticed there's no good images of the back of the machine. There are two steppers on the x-axis, they are set down a little and then connected by short belts to the screws. It allowed the machine to be a little more compact.

This build has, indeed, taken a really long time for a variety of reasons, just over ten years at this point I think. I'll get there eventually.

I don't suppose you know a good source for ball screws do you? The ones I bought originally have seized. Somehow condensation must have formwed in the ball nut and they have rusted solid to the screw. I thought my workshop was dry and warm enough for that to not be a problem.