Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4858243.

I am using the nice enclosure provided by 3d upfitters and I wanted to improve a little bit the air management system (fancy name for number of fan) of the enclosure.

To do so I need to find a way to add a second fan but the only way to do it was to use the grommet holes available on the back/top of the enclosure.

So, I made up an adapter for a 60mm fan to the 49.5mm diameter hole. It is simply a screw/nut solution.

The nut has a grid for safety purpose. I also add a grid for the fan itself. We never know. As per mounting instruction you should first mount the fan to the adapter and then screw the whole assembly with the nut to the enclosure wall.