Remixed from a 3" version that used M4 screws. Tried to replicate original design as much as possible but made two changes:
1) This now mounts on a 4" pipe (like a PVC radon mitigation system pipe). For some reason, my 4" pipe was actually something like 4.1" in diameter, so this wasn't the perfect size, and the brackets had to bend a bit. However, it still worked.
2) Holes on side are now for a M3 socket cap machine screw. Note - holes were modeled to 2.5mm but were a bit tight - I needed to drill them out a tiny bit with a 2.6mm drill bit
The author remixed this model.
Remixed from a 3" version that used M4 screws. Tried to replicate original design as much as possible but made two changes:
1) This now mounts on a 4" pipe (like a PVC radon mitigation system pipe).
2) Holes on side are now for a M3 screw. (Note - holes were a bit tight - I needed to drill them out a tiny bit)