2020 / 3030 cube corner

As mentioned with the earlier jig, here are permanent corners for easy aligning and fixing of extrusions.
The small corner doesn't have any holes so just relies on the corner brackets. It allows quick assembly, uses about 6m filament per corner and prints in a little over one hour per piece.
The larger corner (pictured) adds holes for extra stability. Use M5 bolts, 7 or 10 mm long with the usual (bought or made) profile nuts. There's also a hole in the underside if you want to bolt into the extrusion centre. Allow 10m filament and 2.5 hours printing time per corner.

20x20 and 30x30 profile .stl corners included, or you can play with the scad files

Manuel García's 2020 extrusion model was used as a check for 20x20 extrusion
https://www.thingiverse.com/thing:136430
30x30 was modelled allowing for 8x6 rib