This secret box contains a mechanism with a gear and two racks that make lock bars to protrude on the sides.
It is made from 3mm plywood for most of its parts an some 5mm with a laser cutter.
Step 1: Sanding and Testing the Mechanism
The tolerances are quite tight, the moving parts were tested and sanded until they slided easily. It is necessary to sand them slimer, even if the thickness is a bit more than 3mm.
Step 2: Closing the Mechanism
I used a wooden skewer for the axle of the gear.
Be careful not to glue the moving parts at this stage.
Step 3: Glueing the Illustration
The box I made was Harry Potter themed (copyrighted design not included in the svg files). Before varnishing everything, I rubbed the burned parts to avoid it to become dirty. This box could be improved with a better lower part for instance.