Herewith a tool-less, snap-fit enclosure for your LM2596 buck/step-down converter. This enclosure also allows you to keep your wires separate via the outside channels or together in one via the centre channel. This enclosure can be print with clips to attached to an extrusion or without clips if you would rather use double sided tape or need to attach it in a different way.
Images: (Click on images for larger view. )
The STL files for this project is available HERE