Well here goes... Aluminium frame router design

[mekanik]

Hi Charlie
When you get the carriage cleaned and running smooth, bolt the rails to your Z plate with the carriages installed but not bolted to matting face, offer the carriage/rail assembly up to your other plate and check the matting face with feelers to see if both plates are flat, one or both of the plates might be twisted or something.
Regards
Mike

[CharlieRam]

I've got to get the carriage running smooth first, I tried both carriages on each rail, one of the rails is perfect but on the other rail I have one notchy carriage, that is when i discovered what looks like a ball bearing missing, just wondering if anyone else has had a problem, I can buy some 4mm ball bearings and see if it makes a difference, it definitely doesn't feel right though.
PS. I did remove the rails from the Z axis to check I wasn't twisting it.