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Crown and stem issue Constellation 2852-2SC cal. 501

PatinaPete
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A month of so go I had the crown replaced on my 2852 with a correct for model gold as recommended here. All seemed okay for a couple weeks. Two weeks ago, while winding and setting, I pulled on the crown to set the time, not particularly hard, and the crown and stem came out. I was a little worried so left it as is and took it back to the shop. The watchmaker was there and we discussed as he popped it back in. We tested it there and it seemed fine again and normal action allowed the crown to be pulled to set the time with no issue. I asked if this was something fixable, and basically heard not really - it's an age issue. I wasn't very satisfied but all was well.

Last night, same thing happens again, I do a little winding, go to pull the crown, and it comes out with the stem. I'm about to take it back, but I'm wondering if there's a better reply I can give to "it's an age issue."

When I pull the crown, I'm almost inserting my fingernail gently between the crown and the case. I'm not Hulking it or using my feet as leverage in any way. This watch keeps near perfect time so this is really the only issue and it's only popped up that I'm aware of since I had the crown swapped.

Here's a pic

IMG_0140.webp
 
X350 XJR
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Could be a worn stem and or set lever, both are available new.
 
DON
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Did he just pop it in or did he remove the back and tighten the setting lever?

Setting lever needs to be checked for the under side pin wear or tightness

Stem notch doesn’t appear to be worn
 
PatinaPete
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DON DON
Did he just pop it in or did he remove the back and tighten the setting lever?

Setting lever needs to be checked for the under side pin wear or tightness

Stem notch doesn’t appear to be worn
I should rephrase that section as it is poorly typed and phrased. He was there and was handed the watch, I walked to a display case and he appeared moments later, perhaps 2 minutes? I don't think he would have been able to remove the back.
 
redpcar
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An experienced watchmaker could easily do it in a few mins. We just hope that knowing the stem came out that he would make sure the screw on the set lever is securely tightened. Very common problem on older watches for the lever to wear.
 
X350 XJR
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redpcar redpcar
An experienced watchmaker could easily do it in a few mins. We just hope that knowing the stem came out that he would make sure the screw on the set lever is securely tightened. Very common problem on older watches for the lever to wear.
The 501 does not have a screwed set lever like a bumper movement.
 
hoipolloi
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It will take more than a few minutes.
 
DON
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X350 XJR X350 XJR
The 501 does not have a screwed set lever like a bumper movement.
Ah right. Pin push design. Set lever underside pin needs to be checked for wear
 
Archer
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As noted, there is no screw for the setting lever, so nothing needs to be tightened. There are typically 3 spots that cause this - 2 are easy to fix and one is not.

First is the setting lever - the portion that retains the stem can be worn, so may cause the stem to come out too easily. Setting lever is replaced.

Second is the stem itself - The flange shown on these two stems that is just to the left of the square section, can be damaged and this can allow the stem to be pulled out.

1791751d-0773-4106-908c-559926d6844e.webp


I've seen instances where a part of this flange has been broken off, so if the stem is rotated one way it cannot be rem oved from the movement, but when it has been rotated 180 degrees, the flange is gone and it can be pulled right out. In these cases, the stem is replaced.

The third one is wear to the movement itself. The stem typically goes into the main plate through a hole, and the clearance in that hole has to be reasonably tight. If the hole has been enlarged over the years, it can lead to the stem having so much play in the hole the it can cause the setting lever to lose contact with the flange. This happens when the stem has burrs on it that can cut into the main plate's soft brass - here's an example of burrs on the stem:

4d31aa1b-d0cd-4a80-9ec4-a67a23a0969c.webp


These particular burrs come from someone using a pin vise to clamp down on the stem when changing a crown, but clamping in the wrong location.

This repair is more difficult, and can involve a new main plate, or repair of the plate. In any case it's something that should be able to be repaired.
 
rendo
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@Archer - Al, thanks for the detailed explanation above. Could a deformed pressure spring for the setting lever also cause the stem to come off unexpectedly?
 
PatinaPete
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Archer Archer
As noted, there is no screw for the setting lever, so nothing needs to be tightened. There are typically 3 spots that cause this - 2 are easy to fix and one is not.

First is the setting lever - the portion that retains the stem can be worn, so may cause the stem to come out too easily. Setting lever is replaced.

Second is the stem itself - The flange shown on these two stems that is just to the left of the square section, can be damaged and this can allow the stem to be pulled out.

1791751d-0773-4106-908c-559926d6844e.webp


I've seen instances where a part of this flange has been broken off, so if the stem is rotated one way it cannot be rem oved from the movement, but when it has been rotated 180 degrees, the flange is gone and it can be pulled right out. In these cases, the stem is replaced.

The third one is wear to the movement itself. The stem typically goes into the main plate through a hole, and the clearance in that hole has to be reasonably tight. If the hole has been enlarged over the years, it can lead to the stem having so much play in the hole the it can cause the setting lever to lose contact with the flange. This happens when the stem has burrs on it that can cut into the main plate's soft brass - here's an example of burrs on the stem:

4d31aa1b-d0cd-4a80-9ec4-a67a23a0969c.webp


These particular burrs come from someone using a pin vise to clamp down on the stem when changing a crown, but clamping in the wrong location.

This repair is more difficult, and can involve a new main plate, or repair of the plate. In any case it's something that should be able to be repaired.
This is incredibly helpful. I examined the stem under my magnifier which isn't very strong but I clearly saw something. I tried to capture it with an iPhone here and I think I can see marks on the flange, although I'm not sure if these would have caused problem 2, or 3. It looks pretty beat up. Getting good photos is difficult on the fly, need to get out the camera stand.

IMG_0149.webp
 
Archer
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rendo rendo
@Archer - Al, thanks for the detailed explanation above. Could a deformed pressure spring for the setting lever also cause the stem to come off unexpectedly?
Not something I've seen personally - there would have to be some kind of upwards force from the stem to the setting lever for a weak spring to come into play.
 
Archer
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PatinaPete PatinaPete
This is incredibly helpful. I examined the stem under my magnifier which isn't very strong but I clearly saw something. I tried to capture it with an iPhone here and I think I can see marks on the flange, although I'm not sure if these would have caused problem 2, or 3. It looks pretty beat up. Getting good photos is difficult on the fly, need to get out the camera stand.

IMG_0149.webp
Tough to see much there, but it does look like maybe there is a chunk of the flange missing or it's damaged.
 
PatinaPete
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Archer Archer
Tough to see much there, but it does look like maybe there is a chunk of the flange missing or it's damaged.
There's at least 2 marks like that, and I think it was a vise of some sort like you suggested.
 
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