IKEA Kallax Built-In Adapter

The piece can be pushed into Kallax boards and gives them a bit more support at their flimsy open ends. A short sill supports the boards from underneath.

Openings for screws to mount it to a wall have been prepared.

The print is not meant to hold loads of weight!

Due to the size of the boards, hardly any 3d printer can print it in one piece.

I've made partial prints in PLA to check for the dimensions. 3 walls made it pretty sturdy already.