I made this to replace the hinge thingy on my Yongnuo video light, because I broke it and it had not worked properly anyway. The ridges on this prevent rotation when the screw is tightened even lightly.
The base is fastened to the light with 4 M2 bolts. The swivel part has a 1/4 inch thread that fits a tripod or a light stand.
EDIT: I updloaded a version that has a 3/8 inch thread to fit a microphone stand.

I designed it in Freecad. The 1/4 inch thread was very easy to do - just use the "holes" tool in Part-Design workbench and dial in the needed clearance (in my case 0.4 mm) to compensate for you know what.
This was a quick and dirty design, so don't judge me for the shoddy topology and stuff.