Adjusting only one Z axis so that the bed is more level?
I just upgraded to the MK3.5 and ran a bed visualizer test.
If I'm reading this correctly, it appears that the left side of the bed is lower than the right side. If so, then wouldn't the proper way to fix this be to twist the left Z axis up?
When the printer does Z calibration, it seems to level the two axes by the top of the printer rather than on the bottom. This never made any sense to me. Wouldn't it make more sense to adjust the two Z axes so that the extruder is at the same height as it moves from left to right?
RE: Adjusting only one Z axis so that the bed is more level?
It does Indeed make sense to level the x-axis at the top of the x-axis. Unfortunately, depending on the tolerances, it is not clear, which spot of each side hits first. If you add a vertical screw on each side of the upper z-stops, you can fine adjust each side. I modded the original Prusa z-axis-top parts left and right (see github.com/prusa3d/Original-Prusa-i3) by just adding a cylindrical hole. I then cut an M5 thread by hand. I deliberately used a larger thread so that the frontal area of the screw is not too small when it makes contact with the upcoming x-axis-ends. On the underside, usually only the screw on the higher side protrudes just the height difference you measured. That way you do not reduce the nominal available z-troke that is checked by the firmware during calibration. On top I have counter nuts. At the end you will be able to move the extruder from left to right at the same distance to the bed. Works like a charm for years.