This appeared at first to be the same as the 1933 Senator, but is dated 1931 and has 17 jewels as opposed to 15J for the others. When I looked more carefully I saw that the case above the 12 and below the 6 is beveled flat not rounded like the Senator. And when I looked even more carefully the stepping continues in the lugs. I entered the inside case number in the form. The outside case number is 218271. Is it common for inside and outside case numbers to be different? Is there a reason for two different numbers?
Great watch, thanks for sharing. Based on the lug to case transition lines, It appears to me to be the same case as this unknown. Your watch appears to have the same 45 degree steps at lug transition to case as the Princeton, but I find no confirmation of an unengraved model, or a Princeton with your jewel count.
Sorry, but 1932 Unknown (based on case s/n) for me at this point.
Inside 7 digit case number is what we go by to determine age of watch. We have yet to determine The significance of the exterior 6 digit s/n. It doesn't appear to be connected to identification or dating of watches bearing 2 numbers from this time period.
You are right. The case and the movement (17J 10AN) do appear to be the same. I did find it odd that the two movements have the same date code (square shield) but the serial numbers are very far apart. Mine at 688674 and the Unknown you mention at 519735. I always assumed that the blued steel hands on mine were not original, and the unknown would appear to confirm that. The numbers on the dials are a different font, and mine has Swiss on the bottom below the sub-seconds, the Unknown does not. I doubt there is any significance, but I did notice it.
It is certainly reasonable to assume that a movement made in 1931 could easily still be available to go into a 1932 case. Having worked for a couple of manufacturers and consulted with others, I would not be shocked to learn that the Unknown with the 1931 movement and the 1936 case actually left the factory together.
I just got a new band for it and thought I'd add this pic.
In reply to You are right. The case and… by Brian Meyer
Hi Brian, I think you're spot on regarding assembling 1931 and 1932 parts. As I've stated dozens of time in the past there is only one day difference between the two years so yes, the likelihood is high that's exactly what happened.
I'm also of the mind that we do not have a proper ID for you watch, so sorry.