AS 1187 rate too fast

[DanB]

I've been working on an AS 1187, recently cleaned and lubricated it but no matter what I do, the rate is too high. In the attached photos the movement has the mainspring it came with, and it's older, but I have gotten similar results on the timegrapher when I put in a newer mainspring I got from Otto Frei, MS -711K. Here's what I've done thus far to no avail:

After cleaning the entire movement I cleaned the balance assembly in One-Dip 

End shake seems pretty good from what I can tell, but I'm not very experienced at making those determinations

Banking pins look fine

Checked where hairspring is running between the boot and curb pin. Seems fine. Curb pin seems fine (straight)

Inspected all jewels on bridges, pallet fork, etc. All look good.

What else should I do?

Thanks!

[mikepilk]

With the movement stopped, what do the hairspring coils look like - nice and evenly spaced? 

The amplitude is low which might suggest the hairspring is touching something - is it nice and flat and not touching the cock or balance arms?

Have you demagnetised?

[DanB]

I have demagnetised. I would say the hairspring looks fair, mostly evenly spaced though not perfect, no coils touching. I don't have the skills or equipment (an adequate microscope, a good way to remove and replace the hairspring from the balance wheel to work on it) to improve the hairspring so I would need to source a NOS balance complete. I will give it a closer look though.

[praezis]

John will ask this question anyway: how did the watch run before your service?

[eccentric59]

Those pins look awfully tight. Does the hairspring slide freely between them when you adjust the rate?

 

[nickelsilver]

Can you get a top view with power off, balance at rest? The hairspring could be off center just enough that it is touching something when running (center wheel, stud, regulator). Thing is, on older stuff in particular, if you find a balance complete there's about a 99.99% chance the hairspring of the new balance will need some adjustment to work correctly.

 

Also, not much use getting concerned with the rate until you get the amplitude up.

Edited June 17, 2024 by nickelsilver

[DanB]

Attached is the initial timegrapher reading before working on the movement. The hairspring does move freely when I adjust the regulator. I think I'll try opening up the curb pin to give the hairspring more space. I know that's crazy tricky to do without wrecking the pin (I've tried on other movements in the past) so if anyone has a suggestion on how to do it, I'd greatly appreciate it.

Thanks

[Neverenoughwatches]

35 minutes ago, DanB said:

Attached is the initial timegrapher reading before working on the movement. The hairspring does move freely when I adjust the regulator. I think I'll try opening up the curb pin to give the hairspring more space. I know that's crazy tricky to do without wrecking the pin (I've tried on other movements in the past) so if anyone has a suggestion on how to do it, I'd greatly appreciate it.

Thanks

The pin spacing should be about half a hair either side of the spring when it is still. Tight but not so tight that it crimps up or stretches when you move the reg. arm either way. Really need a downward view picture when it is still so everyone can see how even the coil spacings are. Pictures from any angle are deceptive, like your train picture where the coils are not visible at the top side, are they closer together than the side that can be seen. ?

Hard to see the coil spacings to the left of the stud holder, its a dark area but i thought more would be visible , does it suggest some bunching up at the opposite side ?

[DanB]

I'll get photos looking down later today. I actually have two AS 1187's I'm working on and both have the same problem - running too fast, low amplitude. I'll get a photo of that one as well.

[nickelsilver]

Gut feeling is the pin spacing is fine- don't mess with it. There are other issues to address before adding others.

[JohnR725]

13 hours ago, mikepilk said:

amplitude is low

visually how does the balance wheel look?

1 hour ago, nickelsilver said:

There are other issues to address before adding others.

oh and a note about the amplitude here in the timing machine. For instance the image I snipped out below notice the lines they look? In order for the timing machine to be believed you ideally need to lines they don't have to perfect lines but they should resemble two parallel lines not the snow globe affect as @Neverenoughwatches calls it or like this. Timing machines especially the Chinese one will try really really hard to give you an answer although in this chick a Figure out the rate of all that's why you get the little plus symbols it's out of range or cannot be read at all. But if you have that where we can't figure out what the graphical display is telling us that means the numbers are worthless. So you have to be careful on interpreting timing machines there are definitely some issues going on here.

7 hours ago, praezis said:

John will ask this question anyway: how did the watch run before your service?

yes the standard operating question of background history. It's always nice to have a starting point did the watch run before it was serviced? then in this particular case it would be followed up with how was the watch serviced and in particular how was it lubricated?

4 hours ago, DanB said:

I'm working on and both have the same problem - running too fast, low amplitude.

usually when you have identical problems you look for the common factor for both of them. So the common factor here would be the watchmaker that would be one thing, and that both watches have. This could imply some sort of procedural thing that you're doing it wrong. Or if you're new to watch repair something that you're not seeing especially related to the balance wheel is a lot of stuff like hairspring position that it's really hard to see.

8 hours ago, DanB said:

I have demagnetised. I would say the hairspring looks fair, mostly evenly spaced though not perfect, no coils touching. I don't have the skills or equipment (an adequate microscope, a good way to remove and replace the hairspring from the balance wheel to work on it) to improve the hairspring so I would need to source a NOS balance complete. I will give it a closer look though.

out this is a problem? So hairspring looks reasonably good at least you. I would be concerned about hairsprings that are not flat like isn't touching the balance arm for instance. If you look straight down you're not going to see that you have to look inside ways. Then you want to remove the hairspring to work on it to somehow magically improve it which brings up a couple of problems. We haven't establish that they hairspring is the problem and typically hairsprings out of the watch are just fine the problem is in the watch. It's always best to figure out what the problem is before fixing things.

 

[DanB]

These are the best photos I could get. There's one of the curb pin and it's kinda bent - could that be the culprit? Any observations will be appreciated.

[Knebo]

Difficult to say from these pictures. But here are a few observations.

here, it looks as if there is a possibility of the second coil (counting from the outside / the one that is within the regulator pins) could touch the regulator pins as well when the watch is running. See red arrow. That could effectively increase the rate of the watch (shorter effective length of the hairspring). Have a close look with your loupe/microscope when the watch is running.

 

...but on this picture of yours it almost looks the opposite. Very hard to say.

 

Have you looked from the side to see if the hairspring is flat and not touching anything?

 

 

Lastly, on this picture, you can see that a previous watchmaker has tried to increase balance endshake by creating bumps in the metal under the balance cock. So you know that the watch has been through some things. Possible that someone has replaced the balance staff or even balance complete (in old watches, this can often lead to timing issues when the hairspring is is a bit shorter that the original or the balance wheel a bit lighter).

 

Either way, you'll learn a lot from this one! Good luck!

 

Edited June 18, 2024 by Knebo

[DanB]

Thanks for the reply Knebo. Nice catch about the bumps under the balance cock. I've seen those on the main plate in other watches but not as was done here. I'll do as you suggested and see what comes of it. 

[Nucejoe]

9 hours ago, DanB said:

 

 

 This is not making your watch run minutes fast, but I would unpin the hairspring to repin the stud at the most end point of hairspring.  

When installed the coil looks bad.  I'd be concerned if tg showed this watch running accurate, concerned that my tg might be feeling unwell. 

Rgds

 

 

 

[mikepilk]

As @Knebo suggests, the second coil could be hitting the regulator pin. I also think the coils could be bunched up on the other side to the stud and touching.

I agree with @Nucejoe that it would be sensible to repin the stud nearer the end. It looks odd that there is so much hairspring protruding past the stud.

What I'd do is remove the hairspring from the balance and repin the stud near the end. Then install just the hairspring back on the cock. You can then see if the collet is sat over the jewel hole, and make adjustments as necessary.

(Depending on your skill levels, repinning studs and tweaking hairsprings can be tricky, but it's a good chance to practice and improve)

Edited June 18, 2024 by mikepilk

[RichardHarris123]

I haven't done much hairspring work but isn't the terminal curve incorrect? 

[Jon]

Personally, I would be wary of re-pinning the stud and make the hairspring longer to compensate for the watch running fast, because it is more than likely the balance that has had weight taken from it when the poise screws have been shaved and removed weight from the balance which naturally will increase the timing, thus the index being all the way to one side to slow the balance down, Re-pinning the hairspring is going to change the pinning up point (where the spring passes between the regulator pins), but may also change the vibration rate of the spring slightly, which isn't the correct way to slow things down, unless it was incorrect to begin with, but to know that for sure you'll need a hairspring vibrating tool.

This method will increase the timing, but I doubt it will run exactly at 18000 BPH anymore because of re-pinning the spring where it shouldn't ideally be.

Adding timing washers is the way forward to alleviate this problem and slow the timing down, I believe.

Having plenty excess of hairspring after the stud isn't a problem as long as it doesn't touch anything.

Edited June 18, 2024 by Jon

[Nucejoe]

2 hours ago, RichardHarris123 said:

I haven't done much hairspring work but isn't the terminal curve incorrect? 

Yes its incorrect, thats what throws the coil out of center. 

@DanB  terminal curve is at a radius equal to the distance from balance jewel hole ( or balance pivot) to midpoint of the regulator pin-boot. The coil should remain concentric and unaffected by moving regulator pin along the entire length of the terminal curve, here's how it usually looks.

Good luck.

Edited June 18, 2024 by Nucejoe

[JohnR725]

3 hours ago, Jon said:

I would be wary of re-pinning the stud

in other words it be nice to know what the problem really is before taking a cause of action.

then there is the other little problem all the pictures of the balance wheel out of the watch especially associate with the regulator pins look a bit suspicious but this picture in the watch looks decent? which brings up my complaints of it's hard to tell what a balance wheel is doing outside of the watch because typically it's leaning and not in its natural position like it would be inside the watch where the problem is in the way.

[Neverenoughwatches]

1 hour ago, Nucejoe said:

Yes its incorrect, thats what throws the coil out of center. 

@DanB  terminal curve is at a radius equal to the distance from balance jewel hole ( or balance pivot) to midpoint of the regulator pin-boot. The coil should remain concentric and unaffected by moving regulator pin along the entire length of the terminal curve, here's how it usually looks.

Good luck.

I see quite a few of these end curveless hairsprings, where the next coil touches the back of the curb pin during expansion.  Probably lazy watchmakers fitting a raw spring .

[Marc]

Not all terminal curves look like the one that @Nucejoe posted, which I doubt came from an AS1187.

Below are two examples from working AS1187's which look quite a lot like yours.

I think yours has had its fair share of abuse but it's not so far out of shape.

[Neverenoughwatches]

9 minutes ago, JohnR725 said:

in other words it be nice to know what the problem really is before taking a cause of action.

then there is the other little problem all the pictures of the balance wheel out of the watch especially associate with the regulator pins look a bit suspicious but this picture in the watch looks decent? which brings up my complaints of it's hard to tell what a balance wheel is doing outside of the watch because typically it's leaning and not in its natural position like it would be inside the watch where the problem is in the way.

Surprising how many think if the spring is a good shape out of the watch then it must be ok in the watch, overlooking the fact that is completely free, unheld at both ends. 

2 minutes ago, Marc said:

Not all terminal curves look like the one that @Nucejoe posted, which I doubt came from an AS1187.

Below are two examples from working AS1187's which look quite a lot like yours.

I think yours has had its fair share of abuse but it's not so far out of shape.

Sometimes see 2 knee bends, one at the start of the terminal curve and another to make the hairspring reach the stud.

5 minutes ago, Marc said:

Not all terminal curves look like the one that @Nucejoe posted, which I doubt came from an AS1187.

Below are two examples from working AS1187's which look quite a lot like yours.

I think yours has had its fair share of abuse but it's not so far out of shape.

Would these vibrate better or worse than a hairspring with a definite terminal curve, the kneebend must have some effect over where the spring viibrates from , its a deformity of the spring.

[Nucejoe]

 True, not all terminal curves have a bend  ( the last circle of the coil might be its terminal curve as well) as long as the coil  remains level ,concentric and unaffected as regulator arm is moved through entire length thats needed for regulation.

Rgds

 

 

[DanB]

Does anyone think that the (mis)shape of the pin is a problem (see attached photo)? Looks like at some point in time someone working on the watch tried to make an adjustment to it and it ended up like this. That's not something that's within my capabilities to straighten out.