I needed a simple 30x30 to 20x20 reducer to mount my replacement flight control. I couldn't find what I was after so designed this. I have now changed the mounting for the 20x20, you will need 4x m2 self tapping screws but this is much stonger than the previous option.

I've managed to utilize the design to incorporate a slight amount of dampening by the little pegs that join the two parts together and this could possibly be increased by printing the top section in tpu or similar filament.

A simple print and click design no need to supports and a 20% infill seems to surfice.I hope this helps somebody out.