ETA 2824 Hairspring

[Scouseget]

Hi all from frigid Edmonton; currently minus 30 degrees - but it promises to warm up around May so it's not too bad really!

I'm currently working on an ETA 2824-2 movement and removed the hairspring to untangle it (another story for another day), which I managed to do successfully. Unfortunately I'm having a real problem reinstalling the hairspring back on the cock as the stud is actually held in a really tight fork, rather than by the more normal method of locking the stud in with a small screw. The fork is really tight and I'm sure they use a special tool at the factory for this, one that expands slightly to spring the fork open a bit. Alas I have no such tool and despite my best efforts, cannot persuade the stud to seat itself back into the fork without the risk of doing irreparable harm to the spring. FYI, I was able to wedge the stud out of the fork by judicious use of tweezers but no such option is available for reinstalling it. 

As always, your help will be very much appreciated. 

 

[JohnR725]

A similar subject has come up before unfortunately it involved the removal aspect. If the link doesn't help just do a search for Etachron there are quite a few other discussions somebody probably has how to put the stud back in without bad things happening.

https://www.watchrepairtalk.com/topic/997-stud-removal-techniques-for-the-eta-chron-system-eg-2824-2/

[jdm]

In the past I have mentioned this problem in relation to the system used by Seiko, which is is virtually the same. I've got various suggestions about the tool to use but none risolutive. Seiko manual recommends "sturdy tweezers" with the cock installed, but that proved very difficult for me. I imagine that a special fixture which holds the parts precisely is used at the factory. Sorry if I can't be more useful but that's still an open issue for me too.

[ecodec]

Hi, I do not have an easy answer but I have fixed a Seiko by juduciously and very carefully using a fine screwdriver to expand the fork  with the cock installed after tearing my eyes out to sort the hairspring,  de-gauss straighten,   etc. The bead did seat OK when the fork was released a little. That is all I can offer. there are people here that will offer advice I expect but it is a "hands on" job. Regards, Mike.

[clockboy]

I have seen a vid (forget where) & the guy uses a small screw to open the fork installs the stud & just unscrews to release the fork.

[jdrichard]

  On 12/30/2017 at 8:06 PM, clockboy said:

I have seen a vid (forget where) & the guy uses a small screw to open the fork installs the stud & just unscrews to release the fork.

Great trick


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[wls1971]

  On 12/30/2017 at 8:06 PM, clockboy said:

I have seen a vid (forget where) & the guy uses a small screw to open the fork installs the stud & just unscrews to release the fork.

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I think that's the vid for vostock hairspring removal, but no reason why a small screw couldn't be adapted and used for ETA movements,

 

[dieale2]

  On 12/31/2017 at 1:55 AM, wls1971 said:

I think that's the vid for vostock hairspring removal, but no reason why a small screw couldn't be adapted and used for ETA movements,
 

Why do manufacturers use this system? A screw is simpler imo.

Maybe it's easier to automate manufacturing if you remove sideways screws? So you can jig the part and do everything on one side.

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[JohnR725]

  On 12/31/2017 at 8:10 AM, dieale2 said:

Why do manufacturers use this system? A screw is simpler imo.

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They use a system like this because it's much much easier to adjust.

So Seiko makes it look so simple it probably Is not really that simple. So I'm attaching a Seiko Tech guide Page 15 shows reassembly. Pages 24 and 25 terminology and how to adjust. Then Seiko is assuming that the balance wheel didn't have the hairspring untangled and things might get more interesting if everything isn't exactly where it's supposed to be. In other words the kind of things that happen when untangling a hairspring Is very likely going to make this much more complicated.

 

seiko_02036R20A.pdf

[jdm]

  On 12/31/2017 at 9:03 AM, JohnR725 said:

They use a system like this because it's much much easier to adjust.

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Adjustment is done on the regulator only, but we're talking about the end stud, which in theory does not need to be touched ever after assembly. Nothing but cost reduction would prevent it being kept in place with a screw.

[rodabod]

  On 12/31/2017 at 1:55 AM, wls1971 said:

I think that's the vid for vostock hairspring removal, but no reason why a small screw couldn't be adapted and used for ETA movements,

 

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I really do appreciate it when people share videos to help others, whether it be watch repairing or otherwise. However, some of the American ones are so incredibly slow to get to the point! You use a screw to force open the stud holder. Got it!