I created in Blender this screw. It was a test. The design is good and has no problems. But the printing on my ultimaker gave some overhang problems as you can see in the image.

It took me about 4:39 hour to make it. The hight is 11 cm and at the bottom it is 5 cm wide.
In the bottom part on the image you can still see the support material. I removed that later...