If you ever opened up an old Bulova from the 1930's or so, you may have been pleasantly surprised to find it contained a Cal. 10AN movement, which is really a FHF 3 in disguise (Fabrique d'Horologerie de Fontainemelon S.A. - now part of Eta). These are a lovely little 10 1/2 ligne movement, with individual cocks for the balance, escape wheel, 4th wheel and seperate bridges for the center and 3rd wheel, and barrel bridge. In later models, they combined the escape and 4th wheel cocks into one. Also, you may find a cutaway on the dial side of the bottom plate. This was to allow the movement to be fitted into hinged cases, the cutaway allowing for the hinge under the dial.
The 10AN is fitted with a blue steel Breguet overcoil hairspring, and a cut bi-mettallic balance.
Although these movements are are nicely finished anyway, the ones I have seen have all had an outstandingly well made Lever, of all things. It stands out as even considerably more well finished than the rest of the movement, which leads me to to think that they were outsourced from a specialist lever-maker. I believe that many watch parts were still made by cottage industries back then. The lever is beautifully anglaged and highly polished, with the anglaging taken right down the horns of the lever. The underside is not polished, as is traditional anyway.
To get an idea of size, the lever is only 3mm (1/8") from the staff to the end of the horns, making the quality of finish even more amazing. Even the pallet jewels are nice...they have used deep red ruby, a quality which is usually reserved for the visible top plate jewels.
You would have to go a long way to see a nicer lever than this, parts of this quality are usually found only in very high grade watches. So next time someone says to you "It's only an old Bulova", you know that this is what you may find in it.