How to check a populated gantry for square

LowRider CNC Troubleshooting
#21

Okey so I have done some metal work.

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

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

Success!

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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.

Maybe?

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.

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#22

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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#23

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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#24

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.

#25

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.