Shelf support for 200x18mm wodden boards - V1

I needed to add some wood shelves on my desk, resting on top of it, so I designed this support. 

It's designed to fit standard wood boards 18mm thick and 200mm depth; the lenght of the wood board can be any. They are very common melamine boards, very easy to find in stores like Leroy Merlin or BricoCenter, typically  600mm, 1000mm or 2000mm long.

The space below the shelf is 170mm and they can be stacked. 

There are two plates, one with 6mm holes and one without. Holes are useful to improve stability when three or more supports are stacked, but to use holes you need to make 4 holes in the wooden board too. Before making any hole in the wood, mount the shelves without and put a mark in the exact hole points, then drill.

They can be put side by side to extend the shelf in lenght. Supports are large 30mm, it's enough to receive two boards side by side without losing stability.

Printed in PLA with 15% infill, they are pretty stable.