Hi All,
Been working on a Bulova 7AK wristwatch recently. Cleaned and oiled. replaced mainspring but with all that watch would still run and stop. Before I put hands on you could not keep it stopped. In any position you could stop balance but as soon as you removed pressure it would start right back up. With hands and cannon pinion it runs and stops. Hands were not touching dial and not hanging on each other. Last night was doing some more checking and found that if I tried to set watch counter clockwise that the sub second hand would stop and even move backward a bit. Took dial off again and without hands I decided that setting gears seemed way too tight. Put another cannon pinion on and eveything loosened right up. Watch no longer stops when set counter clockwise and as of now hasn't stopped at all. I'm guessing maybe someone before me put wrong pinion on it. Could sure tell difference when i put the one I had on it. Setting was much easier. I'm now trying to work out in my mind exactly why a tight cannon pinion would stop watch. I can see it when setting but in normal operation it seems to me as if pinion is supposed to be held by shaft it is placed on by friction? Why would too tight stop watch? In this particular watch I know balance is good, hairspring looks fine under 16 power.
I am still trying to learn how to figure out issues of watches that aren't running and get them going again and would appreciate any thoughts.