The z-axis nuts of the printmate are unfortunately only fixed by the weight of the y-axis bar, which holds the Extruder. To fix this problem I designed a "clip" to hold the nut properly in place. This "clip" has a tight fit, so it does not need to be glued or bolted down. And for all those that also have a problem with the filament spool holder of the printmate, this is my solution: https://www.youmagine.com/designs/horizontal-spool-holderThere is a bottom and a top to this model. The top part is the one with the thinner legs (width 3mm) and the bottom part has the bigger legs (width 4mm).