Longines Comet mystery dial problems

[Yamagata]

Hi, I have two troublesome Longines Comets.

Back in the mid-1980s i purchased two comet movements with “dials” (minute, hour, and chapter ring). Last year, I purchased two NOS cases with crystals already in them from Switzerland and gave them to my watch repairer to clean and assemble. After a cleaning, the movements run perfectly, until they are mounted in the cases. The outer ring and chapter ring come in contact and stop the watch. This happens with both cases, and both movements, and both minute rings. (We’ve tried all the combinations.).

We’re not sure if there’s supposed to be a spacer in the case, or if the minute wheel may have swelled over the years, or what. We’re stumped. These are such cool watches, I’d like to get them running on the wrist! Any ideas about what could be causing this? Or any recommendations of where to look for help on this problem?

Thank you in advance! 

[JohnR725]

It would help if we had a picture of the case?

[anilv]

Check if the outermost (minute?) ring is touching the case when movement installed in case. I would imagine that part of the movement or a movement ring should butt up against the inside of the case to ensure the ring does not touch as that would definitely affect timekeeping.

Interesting watch, well worth saving.

Anilv

[anilv]

One check you can do to see if you are missing a spacer/ring is to eyeball the stem hole thru the case tube. If it is perfectly centred then the problem is elsewhere. If the movement stem hole is a bit lower than the casetube then a spacer/movement ring is required.

Anilv