New Screw

I redesigned the screw.  The overhang should be less  and I made the screw more round with a  Subdivision Surface in Blender. Also I will test here a different Infill speed  now set to 50 mm/s.  And with a small part support material build with a raft  which you can see in the image below.

The infill looks a bit better now...

The print went quite ok. Again some little problems on the right side of the print due to no cooling fan.  In the image below you can see the effect of support material. The raft worked very smooth. First you see the ready screw with the raft still under it.  In the next you see how smooth the raft items came of. 

 Still some disturbance on one side of the screw.

It took 4:19 hour to print it.  Measures are: 5 cm wide at the bottom part and 11.3 cm high.
If you want to create a copy of this screw and you have access to a 3D printer then you can download the file at Thingiverse or from YouMagine.