Squaring Gantry on Shapeoko 3

I just got my Shapeoko 3 and assembled it as per the Guide. For the most part everything when along as described except for squaring the Gantry.
When I bring the gantry to the front the left side abuts the Y bracket but the right side is about 0.125 in from the Y bracket. When I move it to the rear the right side abuts the Y bracket and there is a 0.125 ’ gap on the left. I followed the guide instructions several times to the letter as described on pg 43 & 44 of the guide. I also loosened all 16 screws in the base, 16 Y rails and 8 X rail. I repeated the squaring recommendations but still not been able to square the gantry as described in the guide.

I checked the Forum and it seems that several have also had the same issue and recommended several fixes ranging from disassembling and resembling to adding foil spacers on y rails.

Has any one at Carbide3d reviewed the problem and recommended a fix?
Or is the 0.125 gap acceptable??
Any one got any recommendations?.

Here are the two saved recommendations from the tech support queue:

Squaring Gantry to Front/Rear Plates
Loosen all of the screws that hold the gantry together (4 on each side), these should still be loose from the initial assembly.
Loosen the screws that hold the Y axis rails in place (16 total). These should also still be loose from the initial assembly.
Slide the gantry to the front, so both Y plates are touching the front plate.
While holding the gantry against the front of the machine tighten the front of the Y rails (8 total)
Now - systematically begin tightening the 8 bolts on the gantry. Work your way from left to right, going back and forth in a X pattern (similar to tightening the wheel of a car).
After the gantry has been secured, slide the gantry to the rear of the machine and tighten the 8 screws while keeping the gantry pressed against the rear plate
Glad you’re making progress!

Being out by as little as 1/16" is about 1/10 of a degree — take out any unsquareness remaining after the above you’ll have to do one or more of the following:

  • clear the powder coat out of the holes
  • drill out / enlarge the holes to allow for adjustment of the plates
  • shim the ends of the extrusion
  • file / machine then ends of the extrusion flat

There’s some discussion of this, and a number of links at: https://www.shapeoko.com/wiki/index.php/Calibration_and_Squaring_the_Machine

That said, if you can get this to occur at the back left corner of the machine it won’t interfere with homing, and so long as:

  • the bed is level
  • the extrusions are level to the bed
  • the Y-axis extrusions are parallel to each other
  • the X-axis extrusion is square to the Y-axis
  • the Z-axis is plumb and square

the machine will run true to itself and cut squarely (given the proper toolpaths and feeds and speeds).