I really appreciate Holger's work & design of the “Yarn cone winder v2 - manual or motorized”
For unknown reasons, the quickchange yarn holder didn't work properly and the hex nut was always slipping through and therefore didn't turn the yarn holder cone.
So, my best approach was to add a hex mount bracket on top, printed in ABS for additional strength and since then, it works perfectly.
Wife is partially happy, she is now complaining only about the diameter of the cone to big…. but that will be another project someday