Gusset plate

2020 Corner Gusset plate with extra hole for Misumi tapped "C" corner bracket HBLFSN5-C. M5 screw holes -> use M5x10 machine screws. Beveled part is shaped for no sharp corners on exterior application. Rotate flat side down to print. Really helps to stiffen up a frame.
Trimcraft RC has very good prices on socket head and button head M5x10 screws. https://youtu.be/VOHdHH8XpUA