Qtdragon_hd Zero button not zeroing

yes I bet that's it. I notice you are using metric, so .006 is pretty small.
I'll try to track down where the rounding error comes from.

Thanks Chris,

I also notice previously I had 0 as deadband and the steppers all worked well. With 0 now they hunt 0.000 to 0.001 so are contstanly vibrating. I had to set the deadband to 0.001 to stop it. There are 6400 pules per rev and each rev is 5mm.

If you need anymore info please let me know.

Regards