That is definitely not a calibration procedure that should be expected to work. We would recommend that you follow the procedure from the user guide instead — start with the pen up, and make sure that it has enough vertical range to touch the paper everywhere.
The AxiDraw’s cantilevered geometry means that there is no guarantee of a consistent height between pen and paper over the entire plotting area. Even if your paper is perfectly level, the AxiDraw may not be, and it can even lean forward a bitThat’s one of the main reasons that we have the “floating” Z stage, which is tolerant of a variable Z height. The floating Z stage *does not* apply a different amount of pressure depending on the pen-down position. It applies exactly the same amount of pressure whether you have the pen-down height set at 55% or at 25%.
