20x20 aluminum extrusion corner bracket and/or feet with recesses for M4 screws.
While building a enclosure for my 3D printer I got tired of the 20x20 aluminum extrusion scraping up my wood topped work area. So I decided to create feet for the bottom that could be attached and also help strengthen the corners. There are recesses for the M4 screws so they would not scratch the wood and also keep the weight of the enclosure on the flat of the part. Additionally this will give my enclosure a small gap at the bottom for air to flow in while being drawn out through my fan/filter at the top. If necessary I will model/print 'gap' fillers to limit the amount of air drawn in but I don't think it will be necessary.