Connector for 101818 aluminum profile

I needed an enclosure for my 3D printer to use the ABS decently so having inside 18.5 x 18.5 aluminum profiles I thought to create a plexiglass case to hold the printer.
This is the corner that I created for the construction, soon I will publish other T, L and Star shape connector too.

If you want to use them you have to thread the hole in the profile from each side with possibly M5 thread and use bolts with hexagonal head, 3 for each corner with this connector like in the photos.

Good Wo