Mega XL assembly - squaring gantry to T-slot bed bed

[stevew]

So I am a total noob, so my apologies if this is already spelled out in another thread, although search didn't find anything when I searched for "Mega XL square gantry"

Anyway, when mounting support extrusions to T-slot joiner, I tried to make overhang equal on both sides.   Once I got the Y rails/gantry bolted to bed, sliding gantry all the way to the front, right Y rail wheel hits front support first and the left rail wheel is about 2mm away from front support.   I am thinking they should touch the front supports at the same time.  No clue how to make them equal while it is in the assembled state and not that keen to dismount the Y rails/gantry from bed and adjusting left extrusion that way, but I am suspecting that is what I need to do.   Be nice if assembly video showed the best way to do this from the start.  Thanks.

Steve

[Derek the Admin]

Hey. It could be a couple of different things. One rail could be very slightly longer or there could be a bit of an angle on the end of the gantryy rail. If it is the latter, a bit of shim stock (a piece of cut feeler gauge works well would push it around. I would recommend cutting a square thougg and measuring the cut piece before messing with it though.

[pony]

I had this issue also and in rechecking everything I found the bottom axle/bolt for v wheel was loose to the gantry plate ever so slightly. Backed off adjusters on top wheels and tightened all axle bolts. Reset adjusters on top wheels. It seemed to have rectified the issue.

[rwdiehl]

I am having a similar issue. The gantry is not square. The left and right side are off by 3/8".
I loosened all of the wheels, let everything settle, then re-tightened and set wheel tension. Same problem.
The 2 side rails are square and they are the same distance apart at front and back. The gantry just 'prefers' to sit at an angle and I can't figure out how to adjust it.

I can pull it straight, power on, and the steppers hold it. I can jog back and forth and it stays to within 1/16". But as soon as you power off, you can see the gantry move back to its original angle.

Any suggestions?

Rob

[Bruce]

rwdiehl, what machine do you have?

[bob]

I had about 1" difference in which both wheels hit the wall. Machine not square. I loosened all of the screws, both hex heads and allen wrench screws. Both sides. I ran the router arm up and down and adjusted the squareness of the machine with taps. Once square was attained, I lightly tightened all screws (one on the left, then one on the right ... back and forth working to the front of the machine). Final tightening in the same sequence. Now my machine is square. motors mounted, motor floor plate adjusted and tightened so the the motors run up and down the arms with little resistance.
On the the next step (following YouTube video 2).