The original driving shaft broke in the middle of the screw part. I printed it in PETG according to the instructions, but apparently the walls are too thin.
So, I created a remix, which has a reinforced screw and the "top" end of the cone.
I printed it with 25% Gyroid infill and added a modifier at the bottom, specifying that the teeth section is printed with 100% Concentric infill (as per the original).
Update 20231228: Added image of the broken original driving shaft.
Update 20240501: Added STEP file.
Update 20250127: Reinforced version of the driven shaft is also available.
The author remixed this model.
Remix of the driving shaft with reinforced screw part and the "top" end of the cone.