This fits the buck converter from https://a.co/0PotDp1 the board is 62*38*14mm. 

There are two versions, one that has a solid hex lid and one that had some extra holes cut out so that you can access the screw and buttons a bit easier. It's loosely remixed from the model I linked.

To assemble, sandwich the buck converter between the base and the box, and secure with small m3 screws.

Also uploaded my Sketchup file in case anyone wants it.