I designed this very simple fan adapter because I wanted to have something a little bit sturdy to mount my larger fan on the enclosure.
Simply print with standard settings with filament of choice.
Be careful to print the fan grill in the right orientation.
Use fan grill as template for marking the new larger hole.
Carefully cut the larger hole with an exacto knife.
Drill the 4 mounting holes for M4 bolts.
I cut some threaded rods for mounting everything together.
Bolt lengths depend on the 120mm fan you use.
Grill goes on the inside, fan and adapter go on the outside of the enclosure.
The author marked this model as their own original creation.