Simple multi-angle Phone Stand

01.06.2020 update: - Added 10-teeth & 20-teeth versions.

This phone stand suits my need - simple and can change angles.
I designed it really quick.
I'm a novice in both designing and 3d printing so please tell me if there is any problem.

The distance between the outer & inner parts is 0.275mm so depends on your printer's tolerance it could be tight or loose, tell me.
My phone's thickness with case is about 9.3mm, the designed space for it is 9.5mm.