Quote Originally Posted by biketrialsdave View Post
How hard should it be to push the gantry back and forth on the machine? It takes quite a lot of force to get it going then it still requires a far amount of force to push it...
If you mean with the ballnuts disconnected from the gantry then the gantry should move with one finger. A light shove should see it carry on for a bit and coast to a halt.

If it is hard to move and stops as soon as you stop pushing then either bearings are faulty (unlikely if new) or more likely is they are misaligned relative to each other.

They are very intolerant of misalignment in any plane. This is why epoxy is popular. One side could be higher than the other side, or they could be the same height but twisted, or they could not be parallel etc. etc. I does not take much to make them bind.

Did you set the first rail against a known straight edge?
Did you then use a DTI to set the other rail parallel to it?
Are they at the same level as each other (use straight edge across bearings and check with feeler gauge)

Loosen the bolts connecting the gantry to the bearings on one side, then see if it improves. If it does you have misalignment.

Time spent getting this smooth will pay dividends in the long run.