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Reattaching Stud and Hairspring


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I removed the hairspring because it had dislodged from the regulator pins. Upon loosing the stud screw, the stud came out but the hairspring separated from it. So I'm trying to figure out how to reattach the two. What is the correct procedure for doing this?

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The hairspring has snapped of very close to the stud.   The brass pin is a tapered wedge and must be withdrawn in order to clear the short broken length of spring from the hole in the stud.   Then, reassemble.  The latter is a bit like the Haynes manual "replace engine in car".   I can talk you through this in detail, if nobody else does.   It's actually not hard if patience and methodology is applied.

Regards

Deggsie

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This is how I do it:  -

 -With the tapered brass pin removed, reassemble the stud into the balance cock and secure gently with the screw. 
- Install the balance wheel complete with the hairspring onto the jewel in the base plate. 
- lower the cock into position, lining up the pivots and install the screws

The balance will now be free to rotate un-tethered by the hair spring, but try to avoid this, as damage can occur to the free end of the hairspring.   Now, carefully rotate the balance wheel so that the free end of the hairspring travels towards its home-to-be in the stud hole.   If all is lined up correctly, the free end of the hair will now go straight into the stud hole, like threading a needle.   Do not try to move the free end of the hairspring with tweezers if its off the target. Its hard work, and ends in tears.   Instead, rotate the balance backwards, thus moving the free end of the spring away from the stud and creating yourself some working space.  Gently tweak with tweezers.   rotate the balance wheel forwards again and repeat process until that hairspring threads itself through the stud with your eyes shut.

Now, with the spring engaged so that its just starting to show on the other side of the stud hole,  you can now reinsert the brass taper pin and lock the hairspring to the stud.   

Note that due to the hairspring now being slightly shorter than before, and all other things remaining the same, in theory the oscillation (vibration) rate will be faster so you will need to regulate the watch again.   Also, the roller jewel will be slightly off center position (watch out of beat).   Does your watch have beat adjustment?  If not and you are really trying to perfect the movement, then you need to tweak the hairspring hub on the balance staff.   Mark Lovic beautifully describes this in a video on here - but I cannot find the link just now.  Can someone assist please?

I hope this helps?

Edited by Deggsie
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Thanks Deggsie for providing this procedure. The watch does not have a beat adjustment but I have seen Mark's video on tweaking the hairspring hub. I just hope I'm able to make it to that point.

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Its not if, but when.  Just take your time and keep a positive mental attitude. I find regular breaks a necessity, even if I want to keep working, I force myself to take a break.  Stroke your cat :)   I do.  He's a handsome moggy you have there!

regards

Deggsie.

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Well, surprisingly I was able to thread the hairspring through the regulator pins, then reattach the hairspring to the stud and finally get the watch back together. I thought I was home free until I noticed that I somehow got the hairspring all tangled up. In an attempt to untangle it, I removed the collet but the hairspring then got detached from it. So my question is how does the hairspring attach to the collet. I didn't see a pin like that used to attach the hairspring to the stud.

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Well, surprisingly I was able to thread the hairspring through the regulator pins, then reattach the hairspring to the stud and finally get the watch back together. I thought I was home free until I noticed that I somehow got the hairspring all tangled up. In an attempt to untangle it, I removed the collet but the hairspring then got detached from it. So my question is how does the hairspring attach to the collet. I didn't see a pin like that used to attach the hairspring to the stud.
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You buy a new spring at this point. I sometimes buy ‘balance wheel complete’ as it can be surprisingly cheaper and you have the added bonus of a new balance wheel


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The spring should be pinned to the collet in the same way as the stud. The taper pins are hard to track down if you’ve lost it. Either make your own or they can be bought here...

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

As Deggsie says, a new balance complete could be an option depending on the calibre?

 

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This is a beater watch so the main reason for repairing it is for my own edification. It seems more practical to me to just order a "balance wheel complete" as Deggsie suggests. However, I was not very successful in finding them on line and those I did find seemed to lack adequate specifications. Where is a good source of such assemblies and what specs should I be looking for?

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Where to look for a balance depends on the calibre.  If you are struggling to identify it, then firstly look for markings on the mainplate, under the balance wheel, or under the dial. If that doesn’t help, then post photos of both sides on here and measure the diameter too.

There is a good listing of makers marks here... http://www.obsoletewatchandclockparts.com/bestfitpages.htm

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I found the symbol underneath the balance wheel. It's an AS 1187/94 but doesn't appear on the symbol list. After an internet search, it turns out to be an Adolph Schild movement circa 1950. I found some technical information at:

http://17jewels.info/movements-en/movements-a-en/movements-a-as-en/283-as-1187.html

There are about eight such movements for sale on eBay but only two that claim the balance is good and these are selling for about $30 US. Is eBay my only hope for finding a balance wheel complete or is it possible to order one now that the manufacturer and model number are known?

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So, you may be in luck, or you may not.

My starting point with a question like this is to go to Jules Borel’s database: http://cgi.julesborel.com/cgi-bin/matcgi2?ref=AS_1187. This tells us that there were 5 different types of balance used (although balancestaffs.com suggests that there are 10 different types of balance staff, as there are 2 different collet diameters). We can discount the Breguet option from the photos you have posted. If it is a shock protected balance then maybe you can identify the type from here http://17jewels.info/movements-en/shock-protections.html. Tapping on each variant at Jules Borel tells you the other movements the same part was used in which can be very helpful.

Unfortunately all my usual sources of datasheet (Cousins, Gleaves), only show a plain balance, so these must be quite early documents and don’t help much. However, what you also see from Balancestaffs.com is that there are in reality only 2 different staff lengths, so it is likely that if you get the right length then they will be interchangeable.

Once you know exactly what you are looking for then it should be easier to find a part - John Senior lists 2 different balance complete assys for AS1187. http://www.obsoletewatchandclockparts.com/721-balance-complete.htm. He is very helpful, so would likely be able to advise on selecting the right one.

 

 

 

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This is getting pretty confusing. The Jules Borel database tells me that there were multiple balance wheel completes used on the 1187 movement but no way to narrow it down to a particular one. The 17jewels website is just as confusing as it shows the 1187 used the Incabloc shock protection, which mine has, but it also states that it's a 15 jewel movement whereas mine is stamped 17 jewels. It also states that Construction is A, HSK, M, F and that Features are SCD but no explanation is given as to what these codes represent.

I think the ObsoleteWatchAndClockParts website may show more promise as it lists two balance completes, one which is used on the 1187 and 1194. The number stamped on mine is 1187/94 so it may possibly work but I can't be sure of that.

     
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The confusion is all part of the fun, but when starting out you will feel like this is so much detective work and you must decide for yourself which sources to rely on for help.

I thought I had posted a link to the parts datasheet from Cousins. This will show you, that the 1187 and 1194 were essentially the same movement with different outer diameters. Hence parts are generally interchangeable.  Look closely at the picture on 17jewels site and you will see both numbers marked on the mainplate... which is odd because that’s  one of the parts which would differ, but it’s telling you where to look for other parts. Yours is marked 1187/94 which is another way of saying the same thing.

https://www.cousinsuk.com/PDF/categories/2449_AS 1187,1194.pdf

The incabloc and other shock protection options are not described here so it’s probably an early datasheet.  However, as we see from other sources, incabloc is definitely an option, and if that’s what you have then you will need the correct balance for that.

Ranfft has one of the most comprehensive databases of old movement images. As you will see here, both 15 and 17 jewel variants are known.

http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&2&2uswk&AS_1187&

The acronyms you describe (A, HSK, M, F) appear to be an explanation of the train construction using the German names for the parts. If you look here you will see that expanded out in German http://www.uhrwerksarchiv.de/movements/movements-a/movements-a-as/282-as-1187.html. Sometimes when hunting on eBay I find it useful to search using the French and German names for parts... Function “SCD” is probably a German description of centre seconds.

Obsoletewatchandclock parts appears to have an inca balance, there is one here https://www.ebay.co.uk/itm/AS-10-11-cal-1187-1187N-balance-complete-watch-movement-part-/272766321667, or here http://www.scotchwatch.com/AS_parts.html. One of the options at Jules Borel says w/screw Inca, but beware this is part number 722 which has a Breguet hairspring so no good for you; you are looking for part 721.

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Thanks, Stuart. This helps considerably. I see that I need to make like Sherlock Holmes to locate some of the parts. The datasheet on the CousinsUK website is quite comprehensive in telling me what to look for. With this information, there are several sources available and I'm more confident that the correct part is will be ordered. Thanks again.

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