ETA 2472 - how to tackle this crown and stem?

[Michalzeszen]

Hi there!

I have been servicing an old Technos Star Chief from the 70s, and so far so good, except for the crown and stem.

This is only my 4th or 5th watch service after a year of fiddling with cheap movements, and I'm having a hard time understanding this seting mechanism.

 

1. What is is called?

2. How do I assemble it?

3. Can we confirm all is there?

ps.: bonus pics demonstrating how it was bought and how it is going.

 

[Klassiker]

It's a so-called split stem. I'm guessing the spring is for the screw-down crown operation. I don't think I've ever seen both features together before, but it looks complete. If I'm right, the crown will have an inner thread and the tube a matching external thread. Replace the seals if you want it to be watertight.

If you can compress the spring far enough, slide the two parts of the stem together sideways. If that doesn't work, you should be able to push them back together end to end, the opposite of how you pulled them apart. 

[Nucejoe]

2 hours ago, Klassiker said:

 slide the two parts of the stem together sideways. 

 

 

[Michalzeszen]

17 hours ago, Klassiker said:

If that doesn't work, you should be able to push them back together end to end, the opposite of how you pulled them apart. 

I had a feeling the worst would happen, and it did. The smallest pressure applied to the crown broke one side of its little leg.

I think I'll replace it with a traditional system if possible.

This, I believe. I'm shocked at how expensive the parts for this model are.

[RichardHarris123]

Since the back can be removed, I  see no reason for a split stem. 

[AndyGSi]

The one on eBay doesn't look like a screw down crown. Is the original?

 

[Klassiker]

Richard and Andy both make very important observations, so let's take a step back and see what we are dealing with.

Does the crown tube in the case have a thread on it?

How did you remove the stem? Do you have a photo of the movement in the case?

You might be able to remove the female part of the split stem and reuse the existing crown. Can you see a thread?

There are one-piece stems available for the 2472 for reasonable prices. The split stems I found on ebay for the 2472 are a little more expensive, but have the male and female parts the opposite way round.

[Michalzeszen]

OK. Little panic, but I'm composed now. haha

I need some support on this one, and you guys immediately noticed that. Thank you!

To help us navigate the situation, I recorded a video of the case and crown:

https://youtu.be/tfTLZrLiaqg?si=hIW8Jbmp1DPb9fZC

The measuremen

3 hours ago, Klassiker said:

Does the crown tube in the case have a thread on it?

 

Yes, it does.

3 hours ago, Klassiker said:

How did you remove the stem?

There was water damage, and the two pieces (stem and crown) split up when I removed the crown. I didn't have a chance to see the assembled mechanism, but this eBay ad has the same assembly with adequate pictures.

3 hours ago, Klassiker said:

You might be able to remove the female part of the split stem and reuse the existing crown. Can you see a thread?

I'll try that. Quite afraid of breaking it, thought.

Edited 17 hours ago by Michalzeszen

[AndyGSi]

So the eBay crown won't work with your case.

It's looking like your options are going to be limited with this one.

Edit

Just found this so looks like you can remove the stem part from
the crown but what you replace it with is another question.

Edited 17 hours ago by AndyGSi

[Michalzeszen]

You guys were correct, I can reuse the crown. Now it is a matter of finding the small split steam on eBay!

3 minutes ago, AndyGSi said:

the crown but what you replace it with is another question.

 

Yep, just realized this as well. Now it is a matter of finding the new piece, which will most certainly be a pain

[nevenbekriev]

You best option is t convert it to regular crown with tube sealing. But, the case and the back are totally  toasted, ready for the dust bin.

[Michalzeszen]

2 minutes ago, nevenbekriev said:

You best option is t convert it to regular crown with tube sealing. But, the case and the back are totally  toasted, ready for the dust bin.

Can you elaborate? I'm really new to this. What Case and back are you reffering to?

Edited 16 hours ago by Michalzeszen

[RichardHarris123]

I don't understand why it needs to be a split stem. 

[Michalzeszen]

7 minutes ago, RichardHarris123 said:

I don't understand why it needs to be a split stem. 

From my perspective it doesn't need to be. In this scenario, I'd love some help identifying the correct parts for a conversion.

Oscillating weight, bracelet and crystal are not original, so there is margin for adaptations.

Edited 15 hours ago by Michalzeszen

[nevenbekriev]

What I mean is to use standard tube and crown, like 2.5mm tube for example. You will need to remove the existing tube or in some way to turn or file the part with the thread, then to put in 2.5mm tube and fix it in place. I don't know if the hole will have to be enlarged or if it is possible to just reshape the existing tube by removing the part with the thread from it. The new tube can be press fit wit some locktite for water tightness, or led soldered for example.

I doubt it was a split stem, it has to be just screw-in crown, and the construction is similar to split stem. With standard tube, You will not need split stem, but regular stem that will be shortened to size.

What I meant for the case and back is that watch cases polishing is separate, different craft that is not easy one. In my country only few people are good in this and I am not one of them. The main idea is not to change the shape of the cases, or keep them as close to the original look as possible. This includes never to round the edges and corners for example. Don't take me wrong, if You like it and it brings You joy, this is OK. But, the world is full with examples of not correctly done (ruined) cases. By the way, plated cases are the hardest thing to restore.

[AndyGSi]

16 minutes ago, nevenbekriev said:

What I meant for the case and back is that watch cases polishing is separate, different craft that is not easy one. In my country only few people are good in this and I am not one of them. The main idea is not to change the shape of the cases, or keep them as close to the original look as possible. This includes never to round the edges and corners for example. Don't take me wrong, if You like it and it brings You joy, this is OK. But, the world is full with examples of not correctly done (ruined) cases. By the way, plated cases are the hardest thing to restore.

Looking at what @Michalzeszen has already done with the case and back I don't see a problem with it.

1 hour ago, RichardHarris123 said:

I don't understand why it needs to be a split stem. 

The only reason it's a split stem (of sorts) is because of the screw down crown not having the spring built into it.

1 hour ago, Michalzeszen said:

From my perspective it doesn't need to be. In this scenario, I'd love some help identifying the correct parts for a conversion.

You need to see how the existing tube is fitted in the case.

A photo of the inside would help.

[RichardHarris123]

1 minute ago, AndyGSi said:

The only reason it's a split stem (of sorts) is because of the screw down crown not having the spring built into it.

So not strictly necessary?

[AndyGSi]

1 minute ago, RichardHarris123 said:

So not strictly necessary?

If they want to use the original screw down crown then yes it's necessary, otherwise there's no play from the winding position to screw it down

[Michalzeszen]

1 hour ago, nevenbekriev said:

What I meant for the case and back is that watch cases polishing is separate, different craft that is not easy one. In my country only few people are good in this and I am not one of them. The main idea is not to change the shape of the cases, or keep them as close to the original look as possible. This includes never to round the edges and corners for example. Don't take me wrong, if You like it and it brings You joy, this is OK. But, the world is full with examples of not correctly done (ruined) cases. By the way, plated cases are the hardest thing to restore.

I mean... I'm buying 15-30 USD watches and doing my best to bring them to life. I don't expect it to be perfect, but if you check the YouTube link I provided above, you'll realize I did an OK job bringing the case back to life. Will it be a precious collectible? Hardly. But for daily use, it is awesome.

 

1 hour ago, AndyGSi said:

A photo of the inside would help.

Attached.

 

[AndyGSi]

So to me you'd do more harm trying to remove that existing tube.

Unfortunately nothings coming to mind at the moment as an east fix while keeping the screw down crown.

[Michalzeszen]

1 hour ago, AndyGSi said:

So to me you'd do more harm trying to remove that existing tube.

Unfortunately nothings coming to mind at the moment as an east fix while keeping the screw down crown.

Andy, why you betray me?

 

I may have good news. I'll share later!

I have contacted an old watchmaker from my town, and the guy has it all. He is offline, so no parts are available to purchase, but he offered to send one for less than 10 USD, which is great.

I'm now checking if he has an oscillating weight as well, to close up all that I need to put this movement to work.

 

Thank you all for the support. And if any good soul finds a video of the assembly process of this stem and crown, it would complete my day!

 

[AndyGSi]

Does the watchmaker know it's for a screw down crown and not just a standard split stem as the ones in the photo look standard?

[Michalzeszen]

13 minutes ago, AndyGSi said:

Does the watchmaker know it's for a screw down crown and not just a standard split stem as the ones in the photo look standard?

Yes, we're actively discussing it! I believe tomorrow I'll go there so he assembles it. Better safe than sorry.

Dude is old and experienced.

Now, what it the purpose of the spring?

Edited 9 hours ago by Michalzeszen

[AndyGSi]

The spring is so the crown pops out to the winding position when unscrewed.

[Michalzeszen]

1 hour ago, AndyGSi said:

The spring is so the crown pops out to the winding position when unscrewed.

I see. And is there a possibility to convert it to a springless system by replacing it with a standard split stem model?