This bracket can be screwed into a wooden board to form a secure table on the arm of a sofa.

There is a printed screw that holds it firmly in place.

As you can see from the photo I used two.

The wooden board is an oak chopping board.

I printed it in PETG with extra perimeters at.25mm layer height and its been plenty strong enough.

I've included the .step in case you want to change the size. 

Current size is for an IKEA LANDSKRONA