Ambiano small box fan I got from Aldi.  I wanted to ceiling mount it for use in my home gym.  Be careful how tight you tighten the ring screw on the ceiling mount, the threads can/will break off.  This mount holds the fan easily at slight angles (enough to face down towards a stationary bike or treadmill):

4-5 walls

30% infill

Normal supports- Snug

I used a drywall screw to attach the shaft piece to the main mount after attaching the screw ring piece.