Something I have been wondering is why my three cal 861 watches all have different reserves and very different no's of turns to full wind. If I run them all down, then: Watch 1 (1980's) takes 40 turns to full wind & will last 40 hours; Watch 2 (early 70's) takes 26 turns & will last approx 52 hours; Watch 3 (early 70's) takes 80 turns before I get nervous about winding it more (even though the others come to a hard stop) but lasts under 24 hours. Watch 3 spent a long time run down & I have recently been winding it daily. The other two are usually given a 20 wind top up every morning and run all the time. Does anyone know if there is a simple explanation for all this ? Or does it indicate that something might be wrong with Watch 3 in particular ? Thanks
All other things being equal, it's the condition of the mainspring. Watch #3 probably has a broken mainspring. I used to get 46-ish hours out of my De Ville 861, and 51-ish from my Seamaster 321.
True, the trick is getting it apart and putting it back together without having any bits leftover, then you can call yourself a watchmaker lol
Actually that would be OK and correctable. The real trick is getting it almost all back together and not be missing a part.