Since I am still waiting for the last orders of bottles to release the PLA support solution in our shop, I was trying to design useful things which are printable without support. Sometimes I work in a car rental service in the car wash. The most important tool, the mop, broke one day. 
Not the whole mop at all, but the screw, which connects the shaft with the brushes.
The original screw is made of sintered metal, which is hollow in the inside.
A new one was bought, but one can't buy this screw alone, a complete new shaft had to be payed...quite expensive for a broken screw.
My boss at the car rental service asked me, if I can do things like that, since I have my own prototype manufacturing service.
As PLA is an extreme claimable polymer, it was worth the try to substitute the screw with a printed one.
The thought was to scan the freshly bought one with my 3D scanner and reprint it.
The 3D scan was not that amazing, because I had to scan it in my lunch break and that was not enough time.
But it was enough to redesign it with one of the openSCAD examples in a very simple way.
Then I printed one with 0.4 mm slice thickness, 0.5 infill and many many extra shells - but the overhang didn't look that satisfying although it is fitting.
The reprint with 0.2 mm slice thickness did the overhang almost perfect.
The result is convincing.
I hope it will last a few months. Otherwise, I can reprint it anytime :-)
Maybe someone else also needs exactly this screw. So you can find the stl file on thingiverse: link
Greetings from the lake of constance
Bonsai Brain
