These fit on most hardware store conduit. Three sizes available depending on where you live. Check the Outside Dimensions of your local conduit before printing there is 23.5mm, 25mm, and 25.4mm (in). I use the end pieces just to clean it up a bit, you might need to mirror them to keep the style right.
I made this table for the MPCNC and it is surprisingly rigid and much lighter than the old 2x4 table. Little cheesy looking but maybe the next one will look better. You can flip the parts around and easily use the on the inside corner instead of the outside like the pictures.