Customizer shaft collar

Say you have a gear spinning around a shaft. Printing the gear takes a long time and the shaft connection is the hard part to get right. Makes sense to print the bit next to the shaft separately and then screw it onto the gear. You might want to do the same.

UPDATE 2019-01-08: added a small adjust between the contact faces and a chamfer (ish) cut on the inside corner to get better grip on the shaft inside the collar.

examples:
https://www.instagram.com/p/Bppv1YmhSMT/
https://www.instagram.com/p/BpqEr2XhSDU/
https://www.instagram.com/p/BppxjhUh2Ev/
https://www.instagram.com/p/BqBksYSH87E/
https://www.instagram.com/p/BqfdchRH_jM/

You can customize:
- the inner diameter (sane values < outer diameter)
- your printer adjustment (in case ID is overtight)
- opening cut angle in the collar
- screw diameter
- screw head diameter
- screw head offset (distance from cut to the flat where the head sits)
- number of nut sides (in case you want square nuts)
- axial holes (0