Classic combination lock for a safe

This is a combination lock like those you see on a safe - turn left to a number, then right, then left again and the lock opens. The actual combination depends on the position of the drive pins in the wheels, so you can change the combination.

To open the lock, all three wheels must be in the position where the fence rail can drop into them. This allows the drive arm to engage with the rotating drive cam which in turn pulls the bolt open. The fence rail and drive arm is printed as a single piece.

The three wheels each have a pin in one of their holes. The drive cam has a fixed pin - that pin drives the first wheel, which then drive the second wheel, which then again drives the last wheel.

Once all wheels have contact and are rotating as one, you leave the first dish in the correct position and rotate the opposite way to move the second dish to the right position - and then swap direction again and move the last wheel.