another split stem issue

[c.kelly]

I have just pieced together another Omega Constellation. Had to replace center sweep pinion, base of rotor, and gear on barrel bridge. Now have watch up and running but can’t keep male part of split stem in. Have completely taken apart setting mechanism and put back together twice. Stem just won’t stay in. It goes in fine enough but when you go to set watch it will slip out from under set lever and come on out. Checked tip on set lever and it seems fine. Have replaced the plate that puts pressure on the set lever with no luck. I can manually insure that set mechanism is working as it should except for holding stem in place. Tried another set lever with no luck. If I put stem in and hold down on set lever everything will work properly. Thought of ordering new stem at dashto but don’t know if that will help. Anyone ever ran into issue like this before?

Thanks,
Charles

[c.kelly]

Earlier I forgot to mention that Constellation was a 1001 caliber. Have again taken it apart and put back together watching stem go in place with dial off. Again when I try to set watch and stem starts to pull back on set lever it just slips out of position and comes on out. Still trying to think of a solution.

[Bob Tascione]

Hi Charles,
Been away for a few days. Good to be back!
If you’re sure that the set lever is secure and that it’s not worn down (sometimes happens with split stems that have been pulled apart often) and that the detent screw is pulling the set lever all the way down and in place then you might check that the stem has very little to no side shake. If the detent is good and secure then the only thing I can think of right now would be that the stem is moving away from the set lever. I’ll see if I have a 1001 or will try to find a pic or drawing of one (a little later tonight) to see if I’m missing something obvious.

’till then
Enjoy!

Bob

[c.kelly]

Hi,
Been playing with this issue for weeks now. Nothing made sense. Finally got another movement that was described as “runs and stops” (had teeth missing on mainspring barrel). This movement however had a very tight winding-setting mechanism. Figured that I would transplant good setting parts off that movement into one I had running well. Transplanted every part just to be sure. On second attempt to set watch the stem pulled all the way out. Then transplanted barrel bridge, thought that might help hold stem up against set lever. No such luck. Last night after work I replaced mainspring barrel on the donor, put all the setting parts back on it as well as dial and hands. Stem will not come out and so far it has ran 8 hours pefectly. I’m wearing it now in fact. Any idea what could have been wrong with first watch plate that would prevent stem from staying in and what fix would be? I have looked under where set lever would set and see nothing wrong.

Charles

[Bob Tascione]

Hi Charles,
Look for wear on the plate where the stem bearing and pilot are supported.
When I mentioned earlier to check for stem shake and

If the detent is good and secure then the only thing I can think of right now would be that the stem is moving away from the set lever

this plate wear can cause this.

Solutions:
Not sure about your movement but often the best repair would be to do what you did and swap plates.

Can also ream, bush winding hole and then remove upper section of bushing if needed. More difficult repair.

Use stem with oversized bearing surface and or pilot. Common and simple repair. Works fine until the next time someone needs to replace stem.

Hope this helps Charles,
Bob

[c.kelly]

Hi,
You know you did mention plate wear earlier and I did go back and check. What I forgot to mention was that when I checked I saw under very close examination that the winding gear on the stem was missing a few teeth in one spot and when winding watch the gears would slip causing the stem to vibrate. At this point I felt that was the problem and quit looking until I got the other movement in and tried those parts. I actually did try another caliber stem from a 1012 movement as I had clutch and winding gear that I thought would work but stem was too large, would not fit through opening in plate.
Now that I know what is going on I still have one other plate that has a few parts. May now try to combine what I have left on that plate.
Thanks,
Charles

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