Bulova 1927 President Madison
We received this unfortunate Bulova recently and it's hairspring is badly bent, we will see what the result is after we straighten it, or if we have to replace it. I may have mentioned this elsewhere, but under no circumstances should anyone who has not had training try and straighten a hairspring or touch a hairspring. They are easily destroyed, and once straightened do not behave as well as a pristine or new hairspring. Fitting a new one is not as simple as it sounds, the spring must be properly pinned at the collet, with the correct number of coils, cut to length and the balance vibrated to the frequency. Then the balance must be re-set for beat error and in these old watches this is not a simple thing either, as the stud carriers are usually non-movable. All in all, a time consuming and costly repair, even if you can get one already pinned as a spare and authentic Bulova part, sometimes they are not cut.
Ok, rant over......
Patent date stamped 1927 with a square on the movt. The 8AN is the forerunner of the 9AN, although the 10AN was a different calibre ebauche, all by FHF.
I'm thinking President Madison, although I see the one in our db is the 9AN.