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

PatinaPete · Oct 28, 2024

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

X350 XJR · Oct 28, 2024

Could be a worn stem and or set lever, both are available new.

redpcar · Oct 28, 2024

Both wear. No biggie. Easy fix.

DON · Oct 28, 2024

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 · Oct 28, 2024

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 · Oct 28, 2024

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 · Oct 28, 2024

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 · Oct 28, 2024

It will take more than a few minutes.

DON · Oct 28, 2024

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

PatinaPete · Oct 28, 2024

You folks are amazing.

Archer · Oct 29, 2024

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.

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:

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 · Oct 29, 2024

@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 · Oct 29, 2024

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.

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:

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.

Archer · Oct 29, 2024

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 · Oct 29, 2024

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.

Tough to see much there, but it does look like maybe there is a chunk of the flange missing or it's damaged.

PatinaPete · Oct 29, 2024

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.

cristos71 · May 9, 2025

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.

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:

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.

Such a great explanation, it never ceases to amaze me as to how seemingly small issues can have multiple increasingly complex causes and solutions!

TIMElyBehaviour · May 9, 2025

Time for a new stem me thinks. It looks kind of beat up. If that doesn’t solve the issue it’s only a few dollars. They aren’t expensive at all.

I’d change it and see.

Archer · May 9, 2025

cristos71
Such a great explanation, it never ceases to amaze me as to how seemingly small issues can have multiple increasingly complex causes and solutions!

Yes - it is the nature of the beast that there can be many different reasons for a particular problem. That's why, when someone new to watchmaking asks a question like "what causes low balance amplitude?" I just have to chuckle...

cristos71 · May 9, 2025

Archer
Yes - it is the nature of the beast that there can be many different reasons for a particular problem. That's why, when someone new to watchmaking asks a question like "what causes low balance amplitude?" I just have to chuckle...

I really do try to understand when my watchmaker explains stuff to me, but my eyes just glaze over and I get brain fog half the time 😅I'm much more design rather than technique led.

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

PatinaPete

X350 XJR

redpcar

DON

PatinaPete

redpcar

X350 XJR

hoipolloi

DON

PatinaPete

Archer

rendo

PatinaPete

Archer

Archer

PatinaPete

cristos71

TIMElyBehaviour

Archer

cristos71

Similar threads

Omega 167.005 new crystal and crown and stem

Cal. 1861 Crown and stem came out when setting time

missing omega crown and stem , seamaster 120

Split stem and crown come out of constellation 167.015

Stem fitment issue - Seamaster 2846/2848 (Cal. 501)

Stem and crown pulled out of SMP300 2552.80