I designed a corner bracket that supports three faces.
Over the past few months, I’ve seen many designs of this type, but none matched the design I had in mind, so I decided to make my own.

In other designs, when one face is placed flat on the build plate for slicing, the remaining two faces end up with layers stacked horizontally relative to the build plate, making them weak along the layer lines. To solve this problem, the bracket was designed to align the layers of all three faces, ensuring uniform strength throughout. This increases the cross-sectional area of the layers on all faces, improving layer adhesion and enhancing overall strength.

This is a truly strong corner bracket.
 

For reference: Does Angled 3D Printing Really Make Parts Stronger? by CNC Kitchen

Notes:

• The size is 50×50×50 mm, with a thickness of 4 mm. It’s designed for 3–4 mm screws.
• This design includes a built-in brim to improve first-layer adhesion. Please trim it off as needed.
   

• Added 20x20x20mm size, 3mm thick version.