New shapeoko owner, had tried to square it when I got it, but got it “square enough” and came back to it this weekend.
Had the exact same symptom as this post:
Where no matter what I did with the board bolts, and y rail bolts loosened,
one side of the x-z rail did not sit flush when the other side was flush. I loosened all of the x-z bolts to try and shim things, and at very last, loosened the v-wheels.
Aaaaannnnddd then everything could be adjusted to be snug and perfect. No shimming required.
Just thought I would throw that out there for any new shapeokoans.