How to check a populated gantry for square

Okey so I have done some metal work.

I made one for each side. And they should hold the wheels axis perfectly parallels to each other. At least that is the theory.

I have done some 40x40cm drawings again and this time the pen tip stops exactly where it started!


But it still doesn’t draw 90 degrees angles. The square is not square. It is still a parallelogram. It has gotten a bit better tho. But not enough.

So my guess: adjust physical end stops until square is square.


Even tho my metal brackets put them in parallel. The bearing on the Z axis doesn’t touch the pipes anymore. @vicious1 should I be worried about this? The machine runs true now, but as you see on this image, one of the bearings doesn’t touch the pipe anymore.

I am not great at helping with the bearing/mechanical questions, so I will skip that

But to make it square, you probably have it right. The motors need to start square and then they will travel in lockstep and be fine. I have some chunks of wood I clamp down and I hole the machine up against them when I power on the machine and I send a movement away from the blocks to start the machine.

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Okey. So I did some more test runs.

I haven’t adjusted the physical end stops because I knew I made sure to put those end stops as square as possible when mounting them… So I tested with them as is. And prayed.

And the machine now runs true!! At least when I draw a 40x40cm in the middle of the table. :smiley:

So the issue in this case was that all my wheels was pointing in different directions so I needed to force them into alignment with a metal bracket. Maybe I should make a tutorial of that for others in need too.

@jeffeb3 thank you for spending time and keeping me going on solving this issue. I didn’t do the guide rails even tho I had the material. Amazing to brainstorm with u. Thanks!

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Could be several things.Your Z rails might not be parallel, see if the gap changes from all the way down to all the way up. You might have the Z clamp flipped, one side has a small lip, or you could be above the lip causing a tilt.

Just a heads up, you can mount those angle brackets along the backside of the MDF plates. I had to do that on mine. I also have one bearing that is not touching but it hasn’t been a problem. I run mine along tracks as well and fine tuned the spacing/wheel to track clearance with washers behind the wheels.