I have an LR2 (no I’m not upgrading to the LR3 yet for reasons of my own ).
I just built a new table for it that is square with in a 1/32 of an inch, corner to corner, and have just finished setting it up.
the table is 65" long by 38" wide.
The issue I’m having is that as it travels it veers off to one side or the other.
Is it possible that the side plates/wheels are out of square to each other? is there an easy way to check for that?
My last table I used 3/4 x 3/4 rails to help keep it strait - for the same reason.
I’d prefer to not have to use rails again if possible.
Generally, the belts and paired Y motors should keep the gantry square, or at least as square as the machine starts.
It is possible that the wheels get enough traction to pull the gantry to the side, but that should be limited to the play between the table and the tubes at worst, and even then, most builds don’t have that problem. Also even if it’s got some wander along the Y axis, the gantry should still remain square to the table if the Y motors remain in synch.
Check your table for anything that might catch on the Z tubes, listen for skipped steps. Check your Y motor grub screws! Check your Y motor wiring, and any connectors that might be in the track for anything loose. You can check the wheels for steering by rolling the gantry along with the Y belts disconnected
The forums are very big and it isn’t always easy to know what to search for. So I expect repeat posts with similar problems. We don’t shame people for asking repeat questions. In fact, the more annoying problem is when someone says, “I have the same issue” without giving any details at the bottom of a dead posts.
You may not have meant that to be snarky. It is hard to tell with only the text. But it could definitely be read as a RTFM comment.
Thank you for linking the other post though. That is helpful advice.
Oh no no no… Sorry! I did not mean this like “OMG yet another post about this!”
I have been through this many times. Another way to formulate it:
“I have been through this exakt issue that you have so many many times with my own machine!”
Read the thread, and this post Another way to formulate it:
“Read this thread about what my issue was, and how I solved it. Maybe you can find a solution for your machine in there!”.
We are in this together! And I am down there with you! Trying to solve whatever issues we have!
Thanks for the feedback everyone!. I’m going to pick up some angle aluminum this weekend and start there. I’ll run a square/circle test to check and see what else might need to happen.
Which solution are you going for with the angle aluminium?
My advice would be to not get tracks for the wheels just yet. Try to find other causes first! I made some tracks for my machine and they just caused more confusion
Have you measured the wheel shafts like I did in my thread? It would be interesting to know if your machine has the same issue.
OK, so I did some checking. I have a feeling it is a similar situation that @dailybombs had with the alignment of the wheels. I’m thinking I might need to try his idea of a metal fixture that will keep them aligned.
I did install 3/4 aluminum angle along the inside of the wheels for now but have not yet tested anything. I still need to finish my wire set up for my Y (short) axis before I do.
@dailybombs , I saw you had a holder for the tape measure cable chain idea. did you find that on thingyvers or is that yours.
First square test is complete. I jogged a 400x400 square and did this twice with the same resulting measurements.
corner to corner I get Yellow 564mm and red 568mm
the magenta box exaggerates the issue.
Based on this, I need to push my top wheel (physical endstop) forward a small amount - light blue line - right?
start point and end point align perfectly.
@SupraGuy thanks, that was spot on.
I measured equal distance corner to corner.
the next issue…
I ran the pen roughly 900ish mm down the x and the result was like the red line.
I’m guessing maybe my pen was too low and flexed.
However the pen ended in the exact same spot as I started.
there was also a distinct “kinK” in both directions.
thoughts?
Make sure that your Z axis starts level to the table. If you are not using endstop switches, this can be done by putting equal length supports under the bars at both ends.
I don’t remember who offhand, but someone posted that he uses soup cans. These are actually really accurate… I had a pair of 3D printed supports with indents for the X rails.
I think what is happening is the entire machine is drifting to -y as it travels forward. Remember my y axis is the short axis.
As it travels is drifts until the far side Z rails rub along the side of the table.
jogging back to 0 this reverses and drifts in the +y until the near size z rails rub long the side of the table.
Thinking back to @dailybombs post and his solution to make a steel bracket between the wheels might be what I need.
I can actually flex the mdf and move the leading wheel. the steel bracket will stiffen that up.
But even if I do that how do I check for alignment between the -y set of wheels and the +y set of wheels?
I never did that actually. I just made sure that both sides was OKEY. The “alignment between -y and +y wheels” is made sure by making sure that Y pipes (???) is square.
Have u measured the shaft points on one side to see how much the wheels are off?
@dailybombs , are you meaning this measurement from you post?
I have not yet. but the fact that I can flex the MDF and move the wheel is telling.
I’m going to check and see if someone in my neighborhood has metal fab skills that can help out making a bracket out of 1" steel angle.
).
We are in this together! And I am down there with you! Trying to solve whatever issues we have!
false alarm then. 
