This is a small desk decoration of an open differential that I made. The model is intended to visualize how an open differential works.

Creality

Ender 3

Doesn't Matter

Yes

200

15

5mm diameter rods:
1x 50mm rod
3x rods of minimum 50mm length

Connecting bottom and back casing:
6 M3*10mm screws
6 M3 hex nuts

Connecting top and back casing:
6 M3*10mm screws
6 M3 hex nuts

Connecting top and bottom casing:
8 M3*10mm screws
8 M3 hex nuts

Build the core of the differential by placing an axle gear and the two differential gears on the gear holder as shown below. Make sure the holes of each gear aligns with the holes in the gear holder.

Place a 50mm segment of 5mm diameter rod through the hole in the gear holder, ensuring the differential gears are attached freely to the rod. Glue the rod in place to the gear mount, but make sure the differential gears are still free spinning.

Place the remaining axle gear on top of the differential gears and slide the assembly into the bottom of the case. Make sure the holes in the axle gears align with the holes in the case.

Slide two 5mm diameter rods into the holes on either side and glue them to the axle gears. The axle gears must be glued to the rods to work properly.

Slide the driveshaft gear into the position shown below and glue the last 5mm diameter rod, attaching it to the rod, but free of the case.

Using 6 M3*10mm screws and nuts, attach the back of the case to the bottom.

The top of the case can also be permanently fixed by screwing it to the bottom and back parts of the case, similar to step 6. The top of the case can also be loose for a removable section to look inside the differential.

Print two disc brakes and glue one on either axle for a better gripping surface and to better visualize the rotation of each axle. Attach each brake through the centre hole.