With the gantry mounted and the rails bonded in place, I was able to fine tune the X axis rail alignment. I loosened the linear bearings on one rail and attached a dial indicator to the gantry at that same end, reading to the reference edge of the profile rail. I ran the gantry back and forth to see how far out it was across the whole range of motion. Most of the rail was within +/- 0.001” parallel to the opposite rail. Toward the end there was a 6 inch section that was out by 8-10 thousandths. I loosened those rail mounting bolts and applied some pressure on the rail by hand to bring it back to zero before re-tightening the rail. After rechecking the whole rail it still needed some minor adjustments. After a few rounds of this I am happy with the straightness. Next up will be mounting the X axis drive assemblies.