This is a honeycomb structural shelf bracket using two commonly sourced 23mm wood rods made for 3D filament spools or filament boxes. Originally inspired by a design of Maoirae here on Makerworld, i created my own bracket for my special needs. This bracket allows mounting on wood or concrete beams and leaves enough space for the spools on top (perfect if you have an angled roof..).

It may not be that useful for anybody as its very specifically designed for my room, but you never know..

The diameter of the mounting screw holes is 6mm to allow for 5mm diameter wood screws, i used 5x25mm ones. The hole is chamfered to allow for chamfered woodscrews.
The semicircles for the wood words snap perfectly in place on the rods i was able to source, so no need for an additional hole to fix the rods to the bracket.

The honeycomb structures allows for low material usage while keeping the part strong and reliable.

I used PolyMaker PolyTerra PLA+ and printed 4 brackets holding 2,4m rods. The shelf holds up well even when filled completely with mostly full 1kg spools.