Well the parts have started to trickle in. I am still waiting for the printer but I got some of the hardware I ordered from Amazon. I have watched the build video from TronXY meticulously and many times and didnt see some of the hardware I am familiar with using on aluminum extrusion so I added that myself. The corner supports are for the bottom and maybe the top. The sides will be open squares with no corners. It is gonna look flimsy. I'm not even gonna use them angled side supports. But I am gettting ahead of myself. Check out this hardware. Aside from the corner supports that go inside the extrusion and a bunch of m5 screws There is also a bunch of sliding T slot nuts for all the horizontal beams and spring loaded sliding T slot nuts for the verticals. I do not use drop in nuts..