Well, even with it all bolted together properly, my machine will run happily with 0.8mm/0.03" difference in Z across the X-axis travel
I don't think there's any dynamic skew though, as it seems to return to Z=0 with whatever skew it started with after power up.
I do like the simplicity of independent home switches on each screw, but I have been looking and I can't find any precision switches which are rugged enough or have enough overtravel. I think I am looking for repeatibility of about 0.05mm/0.002" which is probably asking for too much.
I am considering fitting digital scales to each screw assembly, so that I could either read off the home errors, or feed them directly into Mach 3, but that would add about £50-100/$100-200 per screw! Anyone else got any good ideas?
Cheers.