Broom screw

Painting my home, with my limited skills, I've pushed the roller too much and the shaft screw broke so I've designed and printed a replacement.
I was unable to figure out wich kind of thread it is, but it appears to be the standard for brooms here in Italy. So I've measured a bunch of thread and I've modeled my one from scratch.

Printing the part vertically is not the right orientation to give good resistence but it's a lot easier and cheaper so I've decided to go this way.
I've added a hole on top of the model to add a screw so strenghten the layers adesion and prevent snapping.
The round marks on the shaft are suposed to hammer some indents in the metal shaft to fit everything togheter firmly. Due to the brittle nature of PLA those are needed. In my case the connection was already extra tight and I've skipped this part.