Auto-Leveling Not Working as Expected

This is my second question on Auto-Leveling. My experiment is too complex to describe here so I created a Google Document with pictures stored here.

Please let me know your thoughts.

Please do not post on another platform. There is everything you need here: you can format text, insert pictures, etc… The goal of this forum is to get all the information in one place, not to become a reference to documents elsewhere.

I am confused. I see links to pictures and videos on many sites in the posts with no comments from you.

Here is my attempt to move the information to your platform.

I have adjusted the Z tower to be square to X and square to the Y axis. I also made some spacers to level the X axis to the frame:

X axis Spacers

X Axis Level
3 Black Marks on Glass edge.

My bed has 3 adjustment points, two along the front in the X axis and one in the right rear corner for the Y axis. I marked the auto-measurement points of the BLTouch v3.1 along the X and Y edges of the glass printing bed. I manually adjusted the bed using a metal feeler gage so that the nozzle clearance is identical at the three auto-measurement points, left-front, right-front, and right-rear.



I ran the Auto-Leveling routine and here are the results:


I expected the warping in the bed because of the 96C temperature for ABS filament. However I did not expect the -0.07mm difference between the left and right front corners. Next I adjusted the right-front corner up 0.05mm to see what would happen.

Feeler Gages

The measurements were as follows:


You can see that the right-front corner only changed by 0.03mm. What do you suspect is causing these discrepancies?

It is unmanageable, so I no more accepting this. I have made the necessary so that people can post images directory in their posts.

I will make tests to try to reproduce what you see but I believe that the problem could be this:


It is very unreliable (both the spring and the “wheel”) and on my printer, it move always and not not linearly.

7 posts were merged into an existing topic: Locking the leveling nuts after bltouch

I don’t disagree that this system is not stable. However when I did my experiment to move the front right corner I checked the the gap with the .1mm feeler gage before I changed the adjustment and it did not move.

Have you had a chance to duplicate this?

Salty Doug

Not so far.