I guess you weren’t around a year ago.
I’m not sure, I haven’t tested that. What surely does affect auto calibration is that it’s done with a cold bed. I’ve confirmed that a heated bed changes the leveling. They need to change it so you can heat the bed before doing calibration. (Yes, you can heat it first and then do the auto leveling, but it is then starting to cool off and that changes the level)
Currently I think using my “Check Level Hot.gcode” file above and tweaking the individual mesh points is the best way to get an accurat…
Heating the bed is a known workaround for the thermal expansion of the platform, and is an essential part of the calibration workflow for some people here on the forum.
Here’s my results on the matter. For me, thermal expansion was much smaller of an issue than the deformation in the webbed platform.
Tony’s spreadsheets are a wrapper that helps generate the syntax for the M421 command. Where the data comes from is not terribly important as long as the measurements you take are at the same place the firmware thinks it is.
G42 can be used to move the head to mesh coordinates from 0…4 in I and J (firmware’s names, not mine). It you took manual measurements with a paper card, that’s great. If you took measurements with a dial indicator, that might be better.
I took measurements on my board wit…