@Solla-topee I have the same question/problem. I adjusted the angle of my c120 camera yesterday and it's now loose and angles down over time. Just need to tighten the screw in the hinge, but it doesn't seem to be a standard size.

Here's the screws we are talking about. The one I want to tighten is the one closer to the camera, but both screws in this picture are the same odd size.