Can't get x-Gantry to be flush

No matter what I try, I just can’t get this to be flush. The opposite side is flush but the front side is not (-y/away from home)

the red lines are equal, the green lines are equal. I’ve tightened and loosened wheels, belts, pulleys, gantrys. What seems to fix it, is if the X gantry is loose, as soon as I begin to tighten it, even a little bit of tension and it starts to do the thing where it backs out and is not flush.

I’m complete lost as to what else to do, besides drill bigger holes into the steel plate that hole the 4 bolts for the x gantry to give it the play it wants to have. Don’t want to do this until I get some sound advice from some ppl who might have had this problem.

I have the base boards off and the router off to lighten the x gantry.

I’m cutting small objects sometimes .1-.2mm at a time, so I need to get everything squared away as close as possible to achieve these cuts. I’m wondering if this little bit off is going to effect that or not. I know someone who has a shapeoko xxl and gets 0.001’’ tolerances cutting aluminum. So I know it’s achievable.


tighten your belt more.

I had the same issue, and it ended up being that one end of my X rail wasn’t square. Took 4 folds of an aluminum can shim to make it right.


Interesting, can you go into detail or a pic of where you shimmed?

Mine would stay flush until I tightened the screws down. Took me longer than it should have to notice it was specifically with the back 2 screws on the right side of the X rail. As soon as I realized, a close look made it pretty obvious that was my issue. I just cut a piece of can as tall as the rail, slid it in between the rail and frame up to the screws, and kept adding layers of can until it stayed flush upon tightening.


oh man, thanks so much! this is exactly what I noticed this morning.

it was fine until i tightened it down. I will try this tonight.

Really appreciate it man, can’t thank you enough!

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Glad to share my experience, hopefully it helped!

I think you have to check the V wheels . There are thicker washers that do not let them work in place.

It’s a bad cut, I think it deserves a guarantee .

Had same issue. X rail ends were not square. Also needed to square the ends of the y axis. I have a post showing the shim stock fix as others have mentioned, too.

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I have had similar issue. In my case the misalignment of the holes was the root cause. I ended up bolting down the MDF on one side, squaring the machine (at this point I had approximately 4 mm difference between the holes on the other side) than I clamped the MDF and the steel plates tightly together and carefully drilled new through holes. The machine works acceptable since but you will realize that MDF will hamper your accuracy/repeatability no matter what you do with it. I am in the process of replacing the hole frame and the MDF with aluminium.


Thanks for the tips guys. I’m waiting for my dial indicator and spindle squaring tool ( Edge pro tram system) to arrive before I shim and re square everything. I also have a 1/4’’ thick aluminum base plate that I replaced the MDF with. I had the cnc drill 5mm holes, with 2’’ spacing (32’’ x 29’’) and tapped them with a m6 drill/tap combo bit. I may have to open up the holes a bit, but I will see what works best, shimming or drilling.

I had the exact same issue as well. I tried clamping the whole thing together and tightening things up, only to have it deflect again once I removed the clamps. My X extrusion is badly beaten-up on one edge as well(L).

All things considered, it is cutting a pretty even square. I ran a path that traced around the entire build area and it is within reasonable tolerance for such a long distance.

I am planning on replacing my extrusion if/when the machine is moved or comes apart for one reason or another.

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Hi, I’m currently assembling a 2019 XL and have the issue with non square gantry ends unfortunately. Can you remember the post title you mentioned describing the shim fix for this? Thanks.

2 set’s of blade type feeler gauges cost about $5.00
Pic’s show where to place them. I think I used a 0.016 on one side and a 0.015 + 0.0005 on the other to rid the 3/16th gap

brought the gantry fairly straight with the frame.

Got it, thank you. For mine it goes out of square as soon as I tighten down one particular screw on each side of the frame ends. Can almost get it perfect if I only tighten three out of the four each side! Can see the slight gap…will try some shims.