Hi from Hants, UK, and help needed please!

[allactionrob]

Hi, my name's Rob and I'm new to the hobby, and very much enjoying it. I've cleaned and serviced a few Swiss movements so far, but this is the first one that needed a repair. It's a BFG 866 with finger rather than roller, and the hairspring was completely mangled by a previous owner. I bought a replacement '794' part from Cousins, fitted it to the cock (press fit stud), but when the balance wheel is left to rest (pin lever not fitted) the finger is about 180 degrees round from where it should be! Of course it's way out of beat and won't run at all. How has this happened? And can it be corrected without fancy tools?

Thanks for any help, Rob.

 

 

 

[allactionrob]

Oh, should have added two things: the part I bought was a complete assembly (balance, staff, hairspring and finger) so not something I've put together. Also, weirdly, when I compare old and new, the angle relationship between hairspring collet and finger is identical. So if the stud is 180 degrees out, I think that can only mean the hairspring is half a turn too long/short. Right?

[oldhippy]

Thank you for your introduction and welcome to this friendly forum.

We all look forward to your contributions and continued involvement. 

Here is a photo of the same movement. It should look like this, see how the complete balance looks. Can you take a photo of yours and post it please, make sure it is nice and clear. We will be able to help you sort it out. 

http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&&2uswk&Baumgartner_866

[Neverenoughwatches]

57 minutes ago, allactionrob said:

So if the stud is 180 degrees out, I think that can only mean the hairspring is half a turn too long/short. Right?

Eyup Rob. No mate the hairsprings length shouldnt be adjusted, it will already be timed to the balance wheel. Its the position of the hairspring on the balance staff that needs to be adjusted. As OH ask post up some clear close ups pictures. Place the balance cock on its back and zoom in on the balance details.  Then someone can mark out on the photo what needs to be adjusted.

[Nucejoe]

Hi Rob and welcome to the forum.

1 hour ago, allactionrob said:

weirdly, when I compare old and new, the angle relationship between hairspring collet and finger is identical. So if the stud is 180 degrees out, I think that can only mean the hairspring is half a turn too long/short. Right?

The angle relationship between finger and stud is what you want to compare, to adjust either the roller table or hairspring collet must be turned by 180  and if its a fixed stud holder then you are likely to create some beat error. 

By finger do you mean impulse pin is metal ? not jewel.

Too long/ short hairspring means wrong hairspring. 

To turn the collet, insert a razor blade into the seam between the collet and staff, open a gap, work your way around the staff to gradually widen the gap, at some point you can insert a screwdriver into the gap . 

Before attacking,  you should check if the finger correctly engages with the fork.

Good luck pal.

[RichardHarris123]

Hello and welcome. 

[Neverenoughwatches]

2 hours ago, Nucejoe said:

By finger do you mean impulse pin is metal ? not jewel.

 

Hi Nucejoe there is no impulse jewel or roller table. The finger is different component attached to the staff tthat acts on the pin pallet .

Edited April 30, 2023 by Neverenoughwatches
Added photo

[Nucejoe]

2 minutes ago, Neverenoughwatches said:

Hi Nucejoe there is no impulse jewel or roller table. The finger is different component attached to the staff tthat acts on the pin pallet .

 Eyup matey.   

So  only option left would be to turn the hairspring collet. 

This must be the old one jewel version. 

Rgds

[rossjackson01]

4 hours ago, allactionrob said:

Hi, my name's Rob and I'm new to the hobby, and very much enjoying it. I've cleaned and serviced a few Swiss movements so far, but this is the first one that needed a repair. It's a BFG 866 with finger rather than roller, and the hairspring was completely mangled by a previous owner. I bought a replacement '794' part from Cousins, fitted it to the cock (press fit stud), but when the balance wheel is left to rest (pin lever not fitted) the finger is about 180 degrees round from where it should be! Of course it's way out of beat and won't run at all. How has this happened? And can it be corrected without fancy tools?

Thanks for any help, Rob.

 

 

 

New to the hobby? Wish I had your tenacity. Fitting a new hairspring is way beyond my skillset. Got to admire you. Well done. The members here are really good and the skill information is second to none.

Welcome. 

[allactionrob]

Hi everyone, thanks for the welcome and the advice so far. I'll try and answer all the points. Yes it is the 1j version, with a brass finger not a roller jewel. Otherwise yes exact match for the BFG 866 movement in all the photos I've seen on the web, all with the stud at 3 o'clock (assuming pin lever is at 12). Have attached a photo from underneath so stud is on left, and finger clearly pointing 6 o'clock, towards the cock screw.

Yesi was assuming I'd have to rotate either the hairspring collet or finger, just not sure which is easier without the necessary tools to press it back together.

On the old, mangled one, I'm able to force the finger round, just by holding the balance wheel, so I could do that...

 

Oh and yes, if I puff air on it hard enough I can just about get the watch to tick a few times, so the finger does engage with the lever ok.

[oldhippy]

You should move the hairspring round not the finger. 

[allactionrob]

6 minutes ago, oldhippy said:

You should move the hairspring round not the finger. 

Any tips on how to do that with 'beginner' tools? Or should I just forget it and try returning it to Cousins for a replacement? Thanks.

[Neverenoughwatches]

16 hours ago, allactionrob said:

Hi everyone, thanks for the welcome and the advice so far. I'll try and answer all the points. Yes it is the 1j version, with a brass finger not a roller jewel. Otherwise yes exact match for the BFG 866 movement in all the photos I've seen on the web, all with the stud at 3 o'clock (assuming pin lever is at 12). Have attached a photo from underneath so stud is on left, and finger clearly pointing 6 o'clock, towards the cock screw.

Yesi was assuming I'd have to rotate either the hairspring collet or finger, just not sure which is easier without the necessary tools to press it back together.

On the old, mangled one, I'm able to force the finger round, just by holding the balance wheel, so I could do that...

 

Oh and yes, if I puff air on it hard enough I can just about get the watch to tick a few times, so the finger does engage with the lever ok.

Hi. The hairsping needs to be repositioned to bring the balance wheel into beat. Technically its not the hairspring that you are moving, but actually the balance staff and its attached components that you are rotating around the hairspring. The hairspring is held in a fixed position by the stud and its fixed arm and holder so actually cant move at all, it just seems like you are moving the hairspring. So tricky manoeuvre coming up. I do it this way others I'm sure have their own method. With the balance on its back like you have here,  i stick the cock down with some rodico otherwise it moves around and interfers with the operation. I Pick up the balance wheel  turn it to expose the collet and feed a fine screwdriver through the hairspring to reach in to turn the collet ( i said it was tricky ). Tbh yours is so far out that its probably best to remove and replace the hairspring altogether after marking up on the balance wheel its rough positioning.

[allactionrob]

20 minutes ago, Neverenoughwatches said:

Hi. The hairsping needs to be repositioned to bring the balance wheel into beat. Technically its not the hairspring that you are moving, but actually the balance staff and its attached components that you are rotating around the hairspring. The hairspring is held in a fixed position by the stud and its fixed arm and holder so actually cant move at all, it just seems like you are moving the hairspring. So tricky manoeuvre coming up. I do it this way others I'm sure have their own method. With the balance on its back like you have here,  i stick the cock down with some rodico otherwise it moves around and interfers with the operation. I Pick up the balance wheel  turn it to expose the collet and feed a fine screwdriver through the hairspring to reach in to turn the collet ( i said it was tricky ). Tbh yours is so far out that its probably best to remove and replace the hairspring altogether after marking up on the balance wheel its rough positioning.

Wow, that does sound tricky Neverenoughwatches! While you were writing that I think I worked out another way, practicing on the old one. I took the balance off the cock and put it spring side up on a metal block with a hole drilled in (for the staff/finger) so the wheel sits flat. I'm pretty confident I can pry the collet off, rotate it to the right position, and press it back on just using two screwdrivers. Still pretty terrifying tho...

[Neverenoughwatches]

3 hours ago, allactionrob said:

Wow, that does sound tricky Neverenoughwatches! While you were writing that I think I worked out another way, practicing on the old one. I took the balance off the cock and put it spring side up on a metal block with a hole drilled in (for the staff/finger) so the wheel sits flat. I'm pretty confident I can pry the collet off, rotate it to the right position, and press it back on just using two screwdrivers. Still pretty terrifying tho...

Haha yes it is. Its just my prefered way, gives me a good visual of what I'm doing and saves having to unmount the balance each time as it can take a few attempts to get the beat close enough to be happy. Removing the balance from the cock can have its own minor risks as a beginner, so i just carried on with that same method. If it takes half a dozen attempts then thats half a dozen unmounts and remounts, i just got good at doing it this way. I know some do it with the balance hanging from a tack. Nothing wrong with the way you are doing it, two fine sharp oilers if thats all you have under the collet to gently wiggle it off. If you can manufacture something that will fit over the staff and cover the collet, a drill out toothpick could work ? to place it back down

Edited May 1, 2023 by Neverenoughwatches

[allactionrob]

Just one thing I don't quite understand with your way, Never, how do you turn the collet using just a screwdriver? On this one at least there is only one 'slot' on the collet where the end of the hairspring is terminated. Do you jam it in there somehow?

[oldhippy]

No disrespect to you but it is not for someone with little experience. 

This is how to go about the repair.  You need to open the boot red arrow can move the hairspring out the way, now you have a chose you can ether remove the pin from the hairspring taking note of how much is sticking out the end or you can twist the complete piece blue arrow. The balance should now be away fro the balance cock green arrow. Now you need to move the hairspring you can do this with a small screwdriver one that has a blade into the split in the balance be very careful holding the balance and move the hairspring around, with your eyes eye up the finger to the balance cock to the pallets you need to have the hairspring end that is pinned so the finger is in line with the pallets.  You might need to do this a few times. When it is correct and you have power in the movement the balance should auto start. If it has an even tick that means it correct, if it is odd sounding you need to move it a little more.  

Edited May 1, 2023 by oldhippy

[Nucejoe]

On 4/30/2023 at 10:50 AM, allactionrob said:

when I compare old and new, the angle relationship between hairspring collet and finger is identical. So if the stud is 180 degrees out, I think that can only mean the hairspring is half a turn too long/short. Right?

Relation between the  " STUD "   ( not hairpsring collet),  and finger is what matters.

Long/ short hairspring usually means WRNG HAIRSPRING, however, regardless of the length of hairspring the oscilator can be adjusted to be in-beat, by repositioning hairspring's stud.

 

1 minute ago, Nucejoe said:

Relation between the  " STUD "   ( not hairpsring collet),  and finger is what matters.

Long/ short hairspring usually means WRNG HAIRSPRING, however, regardless of the length of hairspring the oscilator can be adjusted to be in-beat, by repositioning hairspring's stud.

 

Also hairspring is bunched up to the side in your picture, which throws the finger off beat. 

[allactionrob]

Just one thing I don't quite understand with your way, Never, how do you turn the collet using just a screwdriver? On this one at least there is only one 'slot' on the collet where the end of the hairspring is terminated. Do you jam it in there somehow?

[Nucejoe]

4 minutes ago, Nucejoe said:

Relation between the  " STUD "   ( not hairpsring collet),  and finger is what matters.

Long/ short hairspring usually means WRNG HAIRSPRING, however, regardless of the length of hairspring the oscilator can be adjusted to be in-beat, by repositioning hairspring's stud.

 

Also hairspring is bunched up to the side in your picture, which throws the finger off beat. 

Is this a fixed stud holder or mobile stud carrier?

[oldhippy]

4 minutes ago, allactionrob said:

Just one thing I don't quite understand with your way, Never, how do you turn the collet using just a screwdriver? On this one at least there is only one 'slot' on the collet where the end of the hairspring is terminated. Do you jam it in there somehow?

Yes but be very careful you do not want to damage the hairspring. 

The stud holder is fixed it is part of the balance cock. 

Edited May 1, 2023 by oldhippy

[Nucejoe]

1 hour ago, allactionrob said:

 On this one at least there is only one 'slot' on the collet where the end of the hairspring is terminated. Do you jam it in there somehow?

Can you show us a picture of the collet?    Perhaps you can find a picture of one similar to yours on internet and give us the link.

I usually remove the coil entirely, put the balance and cock back on the movement, rotate the balance wheel so the finger gets inside the fork horn, ink mark  the point on balance rim thats  in front of the stud holder, reinstal the coil with stud where you have ink marked.

I have never had success trying to zero the beat error.

[Neverenoughwatches]

1 hour ago, allactionrob said:

Just one thing I don't quite understand with your way, Never, how do you turn the collet using just a screwdriver? On this one at least there is only one 'slot' on the collet where the end of the hairspring is terminated. Do you jam it in there somehow?

i wouldn't say jam it in there . This is watch repair, words like jam, poke ,prod ,prise,yank, rive, stick it in, rip it out are all banned . Soooo CAREFULLY PLACE a small screwdriver this might be something you have to dress the tip down to size or an oiler into the slot of the collet and gently turn. I've heard some do it from the side of the collet. The less you have to do this the better as the collet can open up becoming loose on the staff and even potentially break if its weak. Tightening the collet without the correct tools can also break it in half at the pinning point which is its weak spot.  As suggested earlier by me and Nucejoe if its way off like on yours a better approach is to remove it altogether and go for a close reinstall as per Nucejoe's instructions. 

[oldhippy]

Have a look at Marks video. 

 

[allactionrob]

Thank you so much for your help everyone, especially Neverenoughwatches. Using a mixture of 'my' method (set on a metal block, prise the collet off and rotate the whole hairspring around) and your method (reach through the spring whilst it's in situ and turn the slot in the collet slightly) I've done it! Watch all back together and regulated, with only 1.8ms beat error. That'll do nicely. Probably the hardest thing I've ever done. Think I deserve that beer now...