La Pavoni/Cremina boiler cap knob and plug

Replacement boiler cap knob for older cremina and la pavoni espresso machines. This model was created from measurements off original knobs from both machines.

The only difference between the cremina and pavoni knob is the size of the square bore that interfaces with the metal stem of the boiler cap, since I've only measured one original of each and the markings on both were the same it's entirely possible this is simply down to a tolerance issue on the original parts not that they were intended to be different, both are included just in case. The plug is the same for both and should also fit original knobs if they're missing their plug!

I've had good results printing these in polymaker HT PLA and I'd recommend you use it as well for this. The boiler cap knobs get quite hot if the machine is heating up for a while to the point where most non engineering filaments will start to soften or melt, even ABS/ASA or PETG. The polymaker HT PLA can handle it pretty well while being affordable and much easier to print than higher temperature engineering filaments, and the extra strength those engineering filaments offer simply isn't needed for this part.

Make sure to print with supports enabled since the original part was molded bakelite and obviously not designed with 3d printing in mind. I've had good results printing on a prusa core one (gen 1) with a 0.4mm nozzle at 0.2mm layer height, 4 perimeters, 25% grid infill. It also works with 2 perimeters but you can feel the square bore flex slightly when you tighten or loosen the knob so I prefer 4 perimeters.

Exact tolerances may depend both your 3d printer as well as your boiler cap, if any of the parts are too loose or too tight for your liking, adjust the fit in your slicer setting using X Y compensation (horizontal expansion in cura).

Any feedback or tweaks are more than welcome!