IKEA Lixhult Air Hole Grommets

I bought a Lixhult metal cabinet from Ikea and wanted to place backup hard drives inside the cabinet. In order to ensure proper cooling of the drives, I needed to make some air holes in the front of the cabinet. These air hole grommets fit over the holes I made in the cabinet sheet metal, allow airflow, but hide the sharp edges around the holes. There are two air grommet designs: small for the front (12mm) and large for the back (31.75mm).

The holes on the front of the cabinet were made by fi