Gear-operated mechanical box

I created a small mechanical box as a personal project to explore gear mechanisms and glue-less assembly using Fusion 360. The lid opens and closes through a system of interlocking gears, and all parts are designed to snap-fit without adhesives.

I used ESun PLA matte black and Esun PLA Silk copper.

Assembly Instructions:
 

Step 1: Attach the large gears to the Lid
Slide the large gears onto both sides of the lid.
The fit is intentionally snug so the gears rotate the lid without slipping.

Step 2: Align the smaller gears
Position the two smaller gears over the holes on the sides of the box, as shown in the reference image.
If alignment is difficult, gently rotate the large gear on the lid to align everything correct.

Step 3: Install the gear arm
Carefully place the gear arm over the gears, ensuring it's aligned properly.

Step 4: Lock the gear arm from the outside
Hold the arm in place while sliding the small locking piece over the big gear, like in the reference image.

Step 5: Lock the gear arm from the inside
Carefully open the box.
Slide the largest locking piece over the largest pin on the gear arm. This step may require some finesse.
Ensure the printed side of the locking piece aligns flush against the side of the box. The chamfered top edges are designed to fit snugly over the chamfered pin.

Slide the small locking piece over the small pin in the same way.

Step 6: Repeat for the opposite Side
Follow steps 3–6 for the other side of the box.