Ed, Thanks so much! That sounds like a very plausible explanation. Much appreciated! Sorry, don't see how to load a pic of the model. But it could well be the problem you describe. I was wondering if the narrow base, required by specs, might also lead to some oscillations, even though the long axis ...

I need some help please! I am using an M2 with V4 head, run by Simplify3D software and with PLA filament. I've have a lot of print time on this machine and am fairly familiar with some basic maintenance issues. My problem is that even after a very careful bed leveling, the hot extruder head will cra...