A.F.W.
144
Here is the info
On the back cover one sees a small screw head about 3 mm in diameter. When this screw is removed one can see another screwhead inside, very small. It is used to free the stem and crown from the case. Once the caseback is opened one can remove the movement. It cannot be removed from the case cover without removing the stem and crown first.
Wrong information provided bt auction houses
I was just doing a little research on the Internet regarding my Patek 3824. I came upon a few Christi's auctions of this model and all refer to the single screw on the back of the case as securing the back... WRONG !! Here is their description: Lot Descri...
Ok, so what does the screw do?
Now I'm beyond curious as I would have also guessed that it secured the back.