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How can I reattach the hairspring to the stud?

scholzie
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scholzie New Member

scholzie

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While disassembling a Unitas 6497 (or during subsequent reassembly) I slightly deformed the hairspring, and to fix it I removed the wheel from the balance cock and then the hairspring from the wheel. The balance cock is of the Etachron type, so the index pin is simply clipped into the stud support. The spring sits inside a notch on the underside of the pin, and is secured in place with some sort of gummy, flexible adhesive (instead of a tiny pin, as I've seen elsewhere).

Anyway, I had a lot of trouble getting the spring stud back into the stud support, and after about an hour of man-handling the glue finally gave out and the spring came loose. Now I have a spring (in perfect condition, thank you very much!) and stud I need to reattach to each other.

What kind of adhesive is this? What are some accepted ways of reattaching the spring? I saw someone on the internet use shellac, but 1) I don't think that was the correct thing to do (this stuff was flexible, and probably for a reason) and 2) I don't have shellac or know how to use it regardless.

Thanks for reading, and thanks for any help you can offer!

Here are some pictures to help visualize what I'm talking about:

IMG_5434.thumb.jpg.656c6d05c568ddd68651c7c30d5ab815.jpg

IMG_5436.thumb.jpg.130688aa87342ba5b35dbf1b4d7a2903.jpg

Edited by scholzie
oldhippy Distinguished Member

oldhippy

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Posted

This is not a fitting that uses pins. The hairspring is held in place by that greenish stuff in the slot. I would clean out that greenish stuff first, I think a tiny drop of Loctite should do the trick as this is commonly used to bond metal so there shouldn't be any problem in it affecting the hairspring.

 

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Mark Distinguished Member

Mark

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10 hours ago, clockboy said:

Can to attach with a normal hairspring pin. If so it's much easier than messing with glue. 

 

https://www.cousinsuk.com/product/hairspring-collets-pins-pocket-watch

This particular one is not possible to pin unfortunately. The best remedy is to clean out the old adhesive and apply new. I would use a slower drying epoxy (very very small amount applied using a clock oiler for example). Apply when the glue is tacky enough to hold the spring in place so you can test if it is correctly positioned. Once you are convinced of its correct position along the length of the end of the spring then leave it to set.

Do this with the stud re-attached to the index but the hairspring not attached to the balance staff so that you can check the position of the hairspring collet being directly over the pivot hole. This will make it easier for you to observe that the spring is straight and true on the stud.

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scholzie New Member

scholzie

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This particular one is not possible to pin unfortunately. The best remedy is to clean out the old adhesive and apply new. I would use a slower drying epoxy (very very small amount applied using a clock oiler for example). Apply when the glue is tacky enough to hold the spring in place so you can test if it is correctly positioned. Once you are convinced of its correct position along the length of the end of the spring then leave it to set.
Do this with the stud re-attached to the index but the hairspring not attached to the balance staff so that you can check the position of the hairspring collet being directly over the pivot hole. This will make it easier for you to observe that the spring is straight and true on the stud.

Thank you Mark! Any particular brand or type of epoxy you'd suggest, or can I use any slow drying epoxy made for metals?


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clockboy Distinguished Member

clockboy

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Posted

The two part Araldite that comes in a twin tube should be OK. It sets quickly  but stays tacky for a long while before hardening. 

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Mark Distinguished Member

Mark

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What @clockboy said.

Just avoid 5 minute epoxy as it may not give you enough time should you place the spring incorrectly.

 

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scholzie New Member

scholzie

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Hot glue probably would have worked a charm, actually. I used a Devcon epoxy with 60m working time, applied with the tip of a sharpened x-acto blade. I don't have spare oilers like all you old timers :P. I'm brand new to this hobby so I don't have spares of anything!

 

The epoxy seems to have worked fine. And by some grace of His Noodly Appendage, the hairspring collet sits nearly perfectly centered over the pivot hole on the balance cock even after all it's been through.

 

I'm going to remove it one last time, give it a rinse in naphtha and denatured alcohol, and put it all back together.

 

 

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Federico Member

Federico

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Posted

Glad it worked out. I am not sure what the roller jewel is attached with but denatured alcohol will thin shellac if any is present.


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scholzie New Member

scholzie

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The balance wheel is not attached. I'm just cleaning the hairspring since I'm sure it picked up some gunk along the way.


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  • 1 year later...
Colditz WRT Addict

Colditz

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Posted

just wanted to thank you guys for this post. I have exactly the same problem on a Seiko movement. I think  the cleaning fluid removed / degraded the fixing. I now have to reposition the hair spring to the stud. What is your opinion on using superglue? I think I will use Devcon epoxy 60 min.

Colditz WRT Addict

Colditz

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Hi all. Just wondering is there any videos on the Etachron balance that I could refer to?

I really want to get this right.

Edited by Colditz
Forgot to tick notify me of replies
Nucejoe Distinguished Member

Nucejoe

Posted
Posted

 I wouldn,t glue anything unassembled. Since as the glue dries out, you are facing a set  HS- STUD  position which may render the HS unlevel, coned .. once assembled.

So, once I position the collet right over the jewel hole and regulator pin along the lenght of HS end checks alright. I assemble the HS on the wheel ,run HS through slots in regulator and stud and install on mainplate with the cock screwed tight.  Everything positioned right as should be . I will then place the mainplate on a level surface. cock facing down, Stud slot facing up. What I see is what I get if I glue at this time, since the glue dries out holding the HS at this position where we know the pivots ( final position ) are inside the jewel hole and approved the configuration and levelness of HS etc before applying the glue.

To apply the glue, put only as much as you need(  to fill the slud slot)on flat face of your screwdrive tip, lumped as wide as the stud slot. No more, excess glue runs and ends up where not welcomed. The stud slot was faced up, if faced down even small amount of glue  can drip out of the slot and end up on BW.  The next day you find everything exactly as you approved,  I remove the cock-Hs  rinse ready for assembly. 

Should there be a need, I removed  and soak the Stud-HS section in acetone or burn the glue by heat with soldering gun.

Regards

 

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Colditz WRT Addict

Colditz

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Thanks Nucejoe.

I think I will follow your advice. I'd rather have the balance in position and stable on the plate than floating around. I will let you know how it goes and I will try and take pictures or a short video.

Can I upload a video to here?

 

Nucejoe Distinguished Member

Nucejoe

Posted
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Hi colditz,

As long as you pick small amount of gule and on one side of screwdriver only ( avoid having glue on both sides of the blade) and ofcourse not runny glue, you are likely to get near perfect results.

Facts are, we don,t have a full top view of HS when installed even less in motion, even if we did, manipualtion is limited to external section of HS. All is most reachable when outside. So why risk damaging the perfecrion we worked for, glue the perfection in. No need to spend hours, days to master installed HS manipulation.

Furthuremore I shim the external circumference of bridge to lower the bridge jewel, so it keeps the balance wheel from turning as turning  may let the HS to slip out of glue before it dries.

Regards

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Nucejoe Distinguished Member

Nucejoe

Posted
Posted
9 hours ago, Colditz said:

Thanks Nucejoe.

I think I will follow your advice. I'd rather have the balance in position and stable on the plate than floating around. I will let you know how it goes and I will try and take pictures or a short video.

Can I upload a video to here?

 

I think you can upload, see others done.

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Colditz WRT Addict

Colditz

Posted
Posted
On ‎3‎/‎14‎/‎2019 at 12:26 AM, Nucejoe said:

I think you can upload, see others done.

Hi Nucejo

I have purchased a new digital microscope so we will see what is can do. Cheers

nichod WRT Addict

nichod

Posted
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45 minutes ago, Colditz said:

What is denatured alcohol?

 

I suspect that is only available in the U.S.A.   They change the nature of ethanol into a poison substance so we cannot drink it and cheat our rulers out of their proper taxes!

Nucejoe Distinguished Member

Nucejoe

Posted
Posted
42 minutes ago, Colditz said:

Hi Nucejo

I have purchased a new digital microscope so we will see what is can do. Cheers

Hi, I shim the cock outbound ( pig,s ear with a piece of aluminum foil) to temoprarily lower the cock jewel so to prevent the wheel from turning. And mix the epoxy( not runny) after all is set up, smother the expoxy( using a safety razor) on a flat surface( piece of cardboard or glass etc) thin like .25 mm or less, all this just to have good control over the amount of epoxy you pick up,  avoid picking excess epoxy ( so if your hand moves/ shakes no expoxy would be on the sides of the blade to get on other parts. Apply the glue and leave stud slot face up. You should have some acetone ready, to immediately  rinse if any part get messed up with epoxy. Some epoxy may inevitably ran down the slot, which can later be scraped off.

You should expect perfect results. No hard task for a horologist.

Regards

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