RoStrong(er) Delta Printer Corner Bracket

Remix of the excellent RoStrong Delta printer corner. I found the originals to flex a bit when used with 1.5M extrusion.

* Upped the bolt size to M6.
* Added bracing to secure the 2040 extrusion better.
* Increased the size of the V-Slot Rails.
* Increased the overall height and added an extra pair of of bolts.

I printed mine at 75% infill and the frame is now rigid.

More Rostrong remixes coming soon as the build progresses, thanks to Ngarst for the original!