My dad wanted a water bottle holder for his exercise machine that could hold his 1L Nalgene bottle (92 mm diameter).
It is held in place with 4 M5 bolts and nuts. You can put the nuts into the recess in the top part.
It is bolted onto the machine on 33 mm diameter metal tubing. We added a small piece of rubber in between the 3D printed parts and the tubing to help make a snugger fit.
I included the .step file if you want to try to modify for a different machine.
The author hasn't provided the model origin yet.