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Longines Balance staff pivots - are they too flat ?


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10 minutes ago, JohnR725 said:

Pivots burnishing it all down so as nice and even isn't that going to shrink the size of that pivot? Then with shrinkage of diameter isn't that going to be a problem?

It was adding pressure to try to burnish it flatter was what caused my mistake. But now I'm going to have a new balance staff, and new jewels !

Out of interest, does anyone know why top cap jewels are thicker than lower, when they use the same chaton?

Top jewel is 121.11 thickness 0.27mm and bottom 122.11 thickness 0.18mm.  Why not use the same jewel?

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23 minutes ago, VWatchie said:

Not sure how that works for a balance staff though as you would need a same-size chaton with a smaller jewel hole!? If you need to change the diameter of a staff that much I guess it is better to replace it.

That's easy, the chatons are 111.xx where xx is the hole size. These are 10, so I could go to 09

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The story I heard on the thicker top cap jewel (cock jewel) was after lots of practical study, they found that that jewel saw the most impact, so it made sense for it to be thicker. But in reality, I have never ever found a cracked cap jewel on a shock setting, so it seems to have been overkill. But you can't replace it with a thinner one, the spring won't hold correctly- or vice-versa, the spring won't go over the jewel without damaging it.

 

On Jacot too use-

This is a tool I use frequently enough I keep one set up in a vice all the time. I also see young watchmakers who supposedly learned to use it in school come to the shop and are useless on it. Aside from typically using far too short of strokes on both burnisher and bow, they always want to have their face right in the tool with a loupe while using it (possibly why the super short strokes). As I was taught, and continue to do, I get the pivot in place and runner adjusted, checking with a 10x loupe. Then, I get my burnisher in place, and from there it's almost like John said "eyes closed in the dark", that is, I'm not peering at what's going on, just focusing on keeping the burnisher in contact with the pivot (i.e. level and to the left), and listening to and feeling what's going on. I'm sitting in a normal position, looking at the tool, but not up close. Usually pinky and ring finger are resting on the right of the tool, burnisher held the same as one would hold a pen. Pressure is between 250g-1kg, depending on the pivot. It does take some practice to develop a bit of feel, but I have shown folks in 10 minutes how to use it and they are successful.

Edited by nickelsilver
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8 minutes ago, nickelsilver said:

The story I heard on the thicker top cap jewel (cock jewel) was after lots of practical study, they found that that jewel saw the most impact, so it made sense for it to be thicker. But in reality, I have never ever found a cracked cap jewel on a shock setting, so it seems to have been overkill. But you can't replace it with a thinner one, the spring won't hold correctly- or vice-versa, the spring won't go over the jewel without damaging it.

For this movement 30L, the chaton is the same top and bottom 111.10, and the springs are the same 170.03. But the block is different, hence the need for different cap thicknesses. 

(Why do the French have such similar words for top and bottom, (dessus, dessous). Surely at sometime in history a simple typo must have caused disaster?)

Incabloclongines.thumb.gif.bce40f4ecb9d2a1fe6a8941037f47aa4.gif

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On 2/12/2024 at 10:15 AM, nickelsilver said:

On Jacot too use-

This is a tool I use frequently enough I keep one set up in a vice all the time. I also see young watchmakers who supposedly learned to use it in school come to the shop and are useless on it. Aside from typically using far too short of strokes on both burnisher and bow, they always want to have their face right in the tool with a loupe while using it (possibly why the super short strokes). As I was taught, and continue to do, I get the pivot in place and runner adjusted, checking with a 10x loupe. Then, I get my burnisher in place, and from there it's almost like John said "eyes closed in the dark", that is, I'm not peering at what's going on, just focusing on keeping the burnisher in contact with the pivot (i.e. level and to the left), and listening to and feeling what's going on. I'm sitting in a normal position, looking at the tool, but not up close. Usually pinky and ring finger are resting on the right of the tool, burnisher held the same as one would hold a pen. Pressure is between 250g-1kg, depending on the pivot. It does take some practice to develop a bit of feel, but I have shown folks in 10 minutes how to use it and they are successful.

Great advice.

I found an old scrap balance to practice on, and re-dressed my cheapo burnisher,

I too was making the mistake of trying to work looking through the microscope. Following your advice - once set up, sit back and feel and listen to what's going on. You can feel and hear what's happening. I found shaping the end quite easy - as the pivot is sat in a hole in the disc, there's no chance of the balance escaping and getting damaged.  I was so pleased with the pivot end shape and finish I'm not going to bother getting the Bergeon tool.

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On 2/12/2024 at 4:15 AM, nickelsilver said:

The story I heard on the thicker top cap jewel (cock jewel) was after lots of practical study, they found that that jewel saw the most impact

This kinda makes sense.  The top jewel is facing outward from the wrist.  You slap a wall with your wrist going around a corner, the force is toward the top jewel and strong.  On the other hand (same hand actually), if you slap your wrist on the table (when ordering a beer!), your body is part of the shock proofing so less force is seen on the bottom jewel. 

That is my theory and I am sticking with it!

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On 2/12/2024 at 11:15 AM, nickelsilver said:

Usually pinky and ring finger are resting on the right of the tool, burnisher held the same as one would hold a pen.

Probably just me (perhaps I haven't woken up). Anyway, I try to picture how/where you keep your pinky and ring finger (you're right-handed?) and if by "tool" you mean the burnisher (I would assume) but I don't quite get it. I hold the burnisher as I hold a violin bow (was aiming to become a pro when young), which is mostly with the thumb and long finger opposite one another and the other fingers more or less just used to guide the burnisher.

Perhaps you could ask someone to record a short video of you using the tool and publish it on your Instagram. That would be gold!

On 2/12/2024 at 11:15 AM, nickelsilver said:

Pressure is between 250g-1kg, depending on the pivot.

Oh yeah, this is important and took me the longest to figure out!

As can be seen in this video I have my face right up in the Jacot but I will definitely try to just go by feel and the sound to see what it does for me. Thanks for the tip, much appreciated!

 

Edited by VWatchie
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Great, I have to try that! I couldn't figure out your description either. That looks like it could work, it's a bit like playing the guitar, I often support my picking hand with a pinky resting on the body. I guess having played for 30 years helps with fine motoric skills needed in watch tinkering.

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Just to end this thread - I put in a new balance staff and shock jewels. After having 12 hours to run in, on a full wind,  the numbers are :

DD 290°    0s
DU 284°  +7s
CD 235°  +2s
CU 227°  +2s
CL 228°  -5s

After fitting a new staff, I thought I might need to tweak the balance, but I'm more than happy with the numbers.

I think one reason for the good performance is, all the pivots in the gear train are beautifully polished, AND the shoulders of the pivots are polished. Not something I've noticed on other makes.

The original poor performance was due to lack of end shake between the barrel arbor and bridge.

 

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57 minutes ago, mikepilk said:

The original poor performance was due to lack of end shake between the barrel arbor and bridge

But that cannot have impact on performance. The arbor moves when winding only.

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26 minutes ago, praezis said:

But that cannot have impact on performance. The arbor moves when winding only.

Well spotted @praezis - just testing you 🤣.

There was also no end shake in the barrel, which is what was causing the problem. 

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  • 2 weeks later...
On 2/19/2024 at 4:17 PM, mikepilk said:

Well spotted @praezis - just testing you 🤣.

When I make a mistake as a teacher (programming, not watch repairing)and one of my students catches me, I usually say it's my way of checking that they haven't fallen asleep. Of course, I make sure they understand I'm only joking and thank them for their help.

On 2/12/2024 at 10:44 AM, mikepilk said:

That's easy, the chatons are 111.xx where xx is the hole size. These are 10, so I could go to 09

That is valuable and new information to me. Much appreciated!

It wasn't intuitive to find some on CousinsUK, but I found them after a while.

https://www.cousinsuk.com/product/inca-jewel-holes

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On 2/14/2024 at 10:38 AM, nickelsilver said:

I hope this works!

 

 

Jacot.gif

Oh yes, it works! I've practised this approach and technique now and it works very well, better than anything other I've tried.

In the beginning, it feels very scary, much like crossing a busy road with your eyes closed, but after a while, you start to trust the process. Without having analyzed it, it also seems to be a safe method. I spent a great deal of yesterday practising and didn't once destroy or damage any wheel pivot (knock on wood).

One question I have is if you have unusually large hands. I think it looks like that. I tried to hold the fingers of my right hand in exactly the same way as you do but noticed that my hand became quite tense. You probably have to adjust the way you hold the burnisher to some extent depending on the size of your hand. It's crucially important to be able to be relaxed, like with everything else when working on watches, and you look super relaxed.

I'm also wondering if you hold the tip of your index finger right in the middle of the burnisher and if the middle finger is hanging freely in the air, or if the index finger is slightly to the left on the burnisher to make a little room for the left side of the middle finger so that the middle finger can support (press on the right side of) the burnisher? Watching the video it's a little hard to tell.

(OT: Should we be crying or laughing?! I mean no disrespect.)

Edited by VWatchie
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You did better than me, I broke a pivot 🥴

Just to finish the thread @VWatchie. The pivots on the new balance were just as flat, I assume to make horiz and vertical rates more equal. As I posted elsewhere, I stopped short of perfect balancing, but got close. After a weeks tweaking the timing the results look good to me. I wind each morning and wear for about 10 hours a day, recording the error from true time 3x/day.
After 1 week I'm with 1s, and the error was never more than 4s.

When on the timegrapher fully wind DU, it's about -3s, which goes to +ve after about 24h. Which goes to show that the timegrapher is just the starting point.

 

image.png.771e56c909f84da510f4a628491483d2.png

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4 hours ago, VWatchie said:

One question I have is if you have unusually large hands. I think it looks like that. I tried to hold the fingers of my right hand in exactly the same way as you do but noticed that my hand became quite tense. You probably have to adjust the way you hold the burnisher to some extent depending on the size of your hand. It's crucially important to be able to be relaxed, like with everything else when working on watches, and you look super relaxed.

I'm also wondering if you hold the tip of your index finger right in the middle of the burnisher and if the middle finger is hanging freely in the air, or if the index finger is slightly to the left on the burnisher to make a little room for the left side of the middle finger so that the middle finger can support (press on the right side of) the burnisher? Watching the video it's a little hard to tell.

(OT: Should we be crying or laughing?! I mean no disrespect.)

I don't have small hands, I suppose they are normal size for a 183cm/6ft man? Tip of finger is right in the middle of the burnisher (width-wise). Middle finger is there, kind of in opposition to the thumb, but not really doing much.

 

Tensing up is probably more an issue of your hand being in an unfamiliar position. I shot some arrows last week with some watchmaker friends; never got into archery but had a cheap fiberglass bow as a young teenager, so like 35+years since I held a bow. I was surprised how spastic I was! Arrow flopping around on the bow, a mess. I did finally manage to make some good shots, but I imagine it would take a number of sessions before the motions become natural.

 

One thing that watchmaking schools (used to) do that's great is making you spend hours and hours filing and sawing, eventually turning in the lathe with handheld gravers, making your own tools. The dexterity and muscle memory from the increasingly fine work really does translate over to things like the Jacot, or manipulating hairsprings. I can tell the fellow in the vid linked (I Shoot Watches) hasn't done much filing, haha!

 

 

 

 

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Edited by nickelsilver
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Just to note- I know folks who can put the pedal to the metal on Jacot use who don't anchor with ring/pinky, or even have a similar overall grip on the burnisher. But this is how I was taught, and have demonstrated to absolute greenhorns who within minutes are successfully using the tool. Honestly I think the burnisher "grip" is less important than getting your head away from the tool and going on feel and sound. I just did a really short length balance staff (1.95mm) with 0.07mm pivots and it was with me sitting normally and going on feel and sound. Wouldn't do it any other way. Loupe to line things up, sit back, and go. On that staff it was like 8 strokes.

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On 3/24/2024 at 12:21 PM, nickelsilver said:

Ha, for erasing pencil! Don't know why it's there (I'm not super tidy)

Aww! I thought I was going to get a game-changing super-secret hot tip. Couldn't you make something up just to stop me being so disappointed?

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