Automatic watch weight not spinning freely

[jpewslgl]

I have not had this issue come up more than once on two different watch movement styles / manufacturers.

I've dis-assembled, cleaned, re-assembled and oiled the watch movements and the automatic winding weight does not swing freely over all 360 degrees. It seems to have a hard spot where it stops or slows way down when it is turned. I don't have anything that I can find in the way, like a screw or something on the movement being raised as to drag on the bottom of the weight, so I'm assuming it is in the winding mechanism.

Any ideas on what might cause this problem? Have I missed some oil/grease somewhere down in the winding gears?

Any help is greatly appreciated. If it were a single case, I'd chalk it up to a cheap movement or something similar, but now it's on more than one movement and one is a high quality watch, so I'm leaning towards having done something myself along the way.

Thanks!
Jimmy

[Bob Tascione]

Hi Jimmy,
If everything is seated down and meshed correctly (VERY IMPORTANT and a common problem) then it sounds like sticky reverser wheel/wheels (not sure if it has one or two without knowing what movements they are) caused by dirt or incorrect lubrication might be at fault. Correct lubrication is also VERY important. Also possible that there's some dirt caught between the teeth or even some damaged teeth in the autowind gearing.
When manually winding the movement when held in the vertical position does the rotor rotate at the same time? It's common for a rotor to wiggle a little when manually winding but should never actually rotate. If it does then problems with the reverser wheel/gear would be suspect.

After thinking about it for a bit since it's happening on each rotor revolution you may want to try assembling just the rotor without the autowind gearing to see if it spins freely or if there is a problem with the bearings or somewhere else. You can then repeat the assembly process, each time adding another component to see if you can pin point the culprit.

Bob