Landeron 48 running fast

[Bonefixer]

Any suggestions as to cause? I've cleaned and lubricated the movement and it runs ok with a reasonable amplitude. But it's gaining 15 minutes a day, both in real life and in the time grapher. That's with the regulator arm as slow as possible. 
 

I've demagnetised. I've had the balance wheel off to properly inspect the spring and it looks true to me. What else is there?

[AndyGSi]

Can you just refresh on what you've done with this movement.

[Jon]

It sounds to me like the balance is too light because the poise screws have been shaved, reducing the total weight of the balance, thus speeding it up.

I find this to be the case in some vintage watches and the index over to the slow side to try and compensate for the light balance is a dead give away.

If this is the case, I would start by statically poising the balance and add some timing washers for the amount of time you are gaining, then fit the balance into the serviced movement and dynamically poise the balance now, remembering that at 220 degrees of amplitude any poise issues will not be evident. I find it best to poise at a low amplitude, as this shows the error more apparently, but that's just the way I like to do it. You could be there for some time when it comes to dynamically poising!

Let us know how you do?

[AndyGSi]

21 minutes ago, Jon said:

It sounds to me like the balance is too light because the poise screws have been shaved, reducing the total weight of the balance, thus speeding it up.

Looking at @Bonefixer original post it looks more likely that some screws have been completely removed?

[Jon]

4 minutes ago, AndyGSi said:

Looking at @Bonefixer original post it looks more likely that some screws have been completely removed?

That's going to be an interesting project if that is the case, although I would expect it to be gaining more time with a couple of poise screws missing.

Sometimes there are holes for screws but they're not there as they weren't needed for the poise. I'm not totally sure why there would be a hole for no poise screw to be honest

[AndyGSi]

28 minutes ago, Jon said:

That's going to be an interesting project if that is the case, although I would expect it to be gaining more time with a couple of poise screws missing.

Sometimes there are holes for screws but they're not there as they weren't needed for the poise. I'm not totally sure why there would be a hole for no poise screw to be honest

@Bonefixer Be interesting to see a photo of it out of the movement to confirm if this is the case.

[Bonefixer]

1 hour ago, AndyGSi said:

@Bonefixer Be interesting to see a photo of it out of the movement to confirm if this is the case.

Willco. Give me a few minutes  

Thanks for your replies. There are no extra holes for poising screws. 
 

One thing I did think - could the spring itself have been shortened? Off the cock it's perfectly in shape, but when the stud is fixed in place there seems a bit of a stretch on it to the fulcrum pin, as though it could do with an extra half circle of spring. This would certainly explain it running fast, but no idea why this would have been done, except maybe a bodged repair?

Edited February 1 by Bonefixer

[nickelsilver]

Perhaps someone switched the hairspring from another balance. I can see two clearly filed screws at about 3:30 and 5:00, and two that appear to have been unscrewed a bit in hopes of slowing it down at 1:00 and 7:00. The filed screws may be original, not a great practice but have seen it where it had to be "factory".

 

That is a fair bit of hairspring sticking out the stud, don't usually see that aside from really cheap pin levers/cylinder watches. Maybe they got mixed up and shortened the spring in an attempt to slow it down? You can definitely unseat the pin and slide a couple mms out to increase the length (don't forget to adjust the beat). Make sure all the balance screws are tight before doing any adjustments.

Edited February 1 by nickelsilver

[AndyGSi]

Suffering brain fog at the moment but shouldn't the spring have a set before it enters the stud?

Also does look to have an excessive amount from the stud and isn't central.

[nickelsilver]

33 minutes ago, AndyGSi said:

Suffering brain fog at the moment but shouldn't the spring have a set before it enters the stud?

Also does look to have an excessive amount from the stud and isn't central.

There were a number of mid-century mid-grade calibers that had just the slightest offset to the terminal curve to reach the stud, and no real bend or anything at the stud.

[AndyGSi]

7 minutes ago, nickelsilver said:

There were a number of mid-century mid-grade calibers that had just the slightest offset to the terminal curve to reach the stud, and no real bend or anything at the stud.

I've looked at quite a few springs for the 48 and they all appear to have the offset.

Edited February 1 by AndyGSi

[Bonefixer]

I've re pinned a balance spring into a stud once before on a junk movement, and probably not very well. Could anyone guide me as to what to do? Do I leave the stud in place, push the pin out, pull the hairspring through a bit and then put the pin back in? I realise I'll then have to take the wheel off and adjust the collet to centre the impulse jewel. 
 

Is that about it?

[praezis]

With all these shortened weight screws on one side, you can bet the staff was once changed by a specialist (hello punchers!).

In the course of the needed work you should do a static poise test, too.

Frank

[RichardHarris123]

@nevenbekriev, has posted before, if you don't have or can find timing washers, copper wire will suffice  

[caseback]

Working on a 48 now: just a slight offset.

You could move the stud to this position (looks like the original one) and see what happens..

1 hour ago, Bonefixer said:

I've re pinned a balance spring into a stud once before on a junk movement, and probably not very well. Could anyone guide me as to what to do? Do I leave the stud in place, push the pin out, pull the hairspring through a bit and then put the pin back in? I realise I'll then have to take the wheel off and adjust the collet to centre the impulse jewel. 
 

Is that about it?

Sounds like a plan.

Edited February 1 by caseback

[nevenbekriev]

Yes, the first thing to do is extend the hairspring as much as possible from the stud, then show picture to see if it needs correction in order to be centered and parallel to the cock.

Often when the watch has lo amplitude and poor performance, it looses time. Then a clever repairman appears that will shorten the spring in order to increase the rate. Let's hope this is the case.

[Bonefixer]

Thanks everyone. Progress update. I've repinned the hairspring to the stud (lost the brass pin - no idea how or where it went - but had some replacements) and rotated the collet by the same amount. 
 

It now can run fast or slow depending on the position of the regulator, and in the middle it's keeping good time. Beat error is 4ms so I'll need to adjust the collet a bit more, but apart from that I think it's solved. 

[caseback]

5 hours ago, Bonefixer said:

 (lost the brass pin - no idea how or where it went - but had some replacements) and rotated the collet by the same amount. 

Sorry, forgot to tell you that sticking a small blob of rodico on it prevents it pinging away 

[Bonefixer]

3 hours ago, caseback said:

Sorry, forgot to tell you that sticking a small blob of rodico on it prevents it pinging away 

It just evaporated I think. I managed to ease it out, and it was half in position, I could gently slide the spring and it was still there. It didn't ping, it just fell out and went through the hole in my little hexagonal staking block. Then vanished. 
 

I'm quite experienced at losing click springs, pinging tiny screws etc, but this one I've just no idea where it went. I was being really careful and nothing happened. It was just gone. 

[AndyGSi]

2 hours ago, Bonefixer said:

It just evaporated I think. I managed to ease it out, and it was half in position, I could gently slide the spring and it was still there. It didn't ping, it just fell out and went through the hole in my little hexagonal staking block. Then vanished. 
 

I'm quite experienced at losing click springs, pinging tiny screws etc, but this one I've just no idea where it went. I was being really careful and nothing happened. It was just gone. 

It's probably still stuck in the staking block.

[Bonefixer]

3 hours ago, AndyGSi said:

It's probably still stuck in the staking block.

I thought that too - it's not. 

[caseback]

It's probably in that part of the twilightzone where your socks disappear to..

[nevenbekriev]

You guys have no idea how many such pins I have lost in my life. I still loose them sometimes, but don't care much as making one takes 1-2 minutes.

[tomh207]

I just got a funny picture in my imagination of a pile of tapered pins under your bench Nev @nevenbekriev, then I remembered how big stud pins are, the whole pile of many years of losses probably only amounts to 2mm cubed.

 

Tom