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margolisd

Pallet Stone Wear

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Hi folks. Ive got an Omega that's showing occasional beat errors in certain positions and only on one side. It's very intermittent and I can't work out what's causing it. Because it's just on one half of the reading (lower) it made me think one of the pallet stones could be damaged or dirty. I just put them both under the microscope to see how they're looking. Is this a normal amount of wear for a 50 year old watch?

 

 

 

 

stone2.png

stone3.png

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That might also work, but you need to be careful if you mess with the over all geometry.

You can buy pallet jewels, so you could remove the old ones (heat the shellac, remove the jewel), then fit new ones, assuming you can source the correct jewel,  but you do need high precision to get this to work. I have no doubt that someone here could advise on this, better than I can.

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11 minutes ago, margolisd said:

...Or change the pallet fork height by a few microns so the escape wheel touches a fresh area on the jewel.

Being a micron one milionth of a mm is virtually impossible to do that, and not just for a beginner amateur like OP is. Suggestions given should fall in the realm of the doable. 

Edited by jdm

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A micron is one thousandth of a millimeter and a commonly used unit in watchmaking, I have a stack of prints on my desk with tolerance callouts in +- 2 or 3 microns. Moving a pallet stone in or out a few microns is frequently done, on small calibers a shift in position of 0.005 microns is considered large.

Measuring this can be tricky, true. For measuring pallet jewel movements I use a toolmaker's microscope. If shifting a fork on its arbor 0.005mm is easy to read on a good jeweling tool. Is it really 0.006 or 0.004? At that point it doesn't really matter.

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My Seitz jeweling tool has a fitting for this very purpose. I might try this just for fun. I'm still going to replace the escape wheel as it's super worn and the fork for the sake of good craftsmanship. I found them new on eBay for a few £s so it seems sensible.

Here's a question, with a 1970s Omega, how likely is it I'll need to adjust the pallet stones on the new fork? I know the parts are less interchangeable on very old watches. But I'd presume parts from this era are made with high enough precision so it should in theory just work(?)

Has anybody used the Begeon Pallet Alignment Tool or similar? I'd love to know how it works.

 

 

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on small calibers a shift in position of 0.005 microns is considered large.
 

I presume you mean 0.005 mm ( i.e. 5 microns) - 0.005 microns is pretty small, bearing in mind that the wavelength of light falls in to the 380 to 740 nanometers range, so adjusting to 0.005 microns would require super human vision.

Shifting by 0.005 mm means a shift of roughly a third of the width of a human hair, but at the scale of small watch calibers, human hairs are like scaffolding poles. :D

Edited by AndyHull

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on small calibers a shift in position of 0.005 microns is considered large.
 
I presume you mean 0.005 mm ( i.e. 5 microns) - 0.005 microns is pretty small, bearing in mind that the wavelength of light falls in to the 380 to 740 nanometers range, so adjusting to 0.005 microns would require super human vision.

Shifting by 0.005 mm means a shift of roughly a third of the width of a human hair, but at the scale of small watch calibers, human hairs are like scaffolding poles.
Ha yes of course

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On ‎4‎/‎15‎/‎2019 at 8:01 AM, Tmuir said:

If he can measure it I would like to know how, as I doubt I could.

   vernier calipers.  but do those jewels wear?   I don't think so, just get out of alignment?  

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Being a micron one milionth of a mm is virtually impossible to do that, and not just for a beginner amateur like OP is. Suggestions given should fall in the realm of the doable. 

I'm going to be pedantic again...  a micrometer or micron, is an SI derived unit of length equalling 1×10−6 metre (SI standard prefix "micro-" = 10−6); that is, one millionth of a metre (or one thousandth of a millimetre, 0.001 mm, or about 0.000039 inch).[1]

.. in other words, it is a millionth of a meter not a millionth of a millimeter, it is a thousandth of a millimeter.

This is the sort of scale that you find on features on silicon wafers, which typically range down from a few tens of microns to the nanometer scale for non high power devices.

A nano meter for completeness, would be a millionth of a millimeter, and a pico-meter would be a thousandth of that, which is sub atomic in scale (and since an atom is between 62 and 520 picometers, we are talking pretty small). 

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8 hours ago, AndyHull said:

I'm going to be pedantic again...  a micrometer or micron, is an SI derived unit of length equalling 1×10−6 metre (SI standard prefix "micro-" = 10−6); that is, one millionth of a metre (or one thousandth of a millimetre, 0.001 mm, or about 0.000039 inch).[1]

Of course, my mistake. Nevertheless in watchmaking the use of the hundredth of mm is commonly used, where the first digit after the decimal point indicate microns. E.g. SeikoHeights.thumb.PNG.eec8ba760bd9cb7252c8bc1f07438cde.PNG

Bonus info: the table above shows a fact little known: the very popular SII NH36 is actually available in two heights, and the numbering of the relevant parts.

 

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I hope my previous post didn't come across as being picky, but I felt it was important to understand the relative physical scale of what we are  dealing with in order to better understand the problems involved.

The face of that jewel for example is probably of the order of perhaps 1mm x 1.5mm, and the wear, I would estimate is probably of the order of around 1/10 to 1/20th of that in width, and roughly the same depth. i.e. of the order of a tens or hundreds of microns. This is sufficient to have a very measurable effect on the performance of the watch. Shifting the height of the pallet fork by a few tens or hundreds of microns would be possible (assuming the geometry of the pallet fork allows this, without snagging on other components), so this might be a feasible, if tricky solution.

Automated manufacturing to 1/100 mm or better is relatively easy, however hand working and machining to this kind of tolerance takes considerable skill.

For example most low cost FDM 3D printers (the plastic squirting kind :P) are only accurate to 1/10mm at best (and that, typically only in the Z axis).  For comparison, a state-of-the-art ultra-high-resolution laser lithography 3D printer is typically capable of layer thicknesses and detail sizes well below 1 micrometer. So if you wanted to 3D print these watch parts, it would be technically possible, however, probably not in a suitable material. The technology is fast evolving though, so perhaps in a few more years, those unobtanium parts for rare watches will be a mere click or two of the mouse away.

For comparison, the legs of this 3d printed object are approximately the same width as the wear pattern on that stone.

3dp_nanoscribe_detail_2.jpg

Edited by AndyHull

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51 minutes ago, AndyHull said:

I hope my previous post didn't come across as being picky, but I felt it was important to understand the relative physical scale of what we are  dealing with in order to better understand the problems involved.

The face of that jewel for example is probably of the order of perhaps 1mm x 1.5mm, and the wear, I would estimate is probably of the order of around 1/10 to 1/20th of that in width, and roughly the same depth. i.e. of the order of a few microns.

No pickiness, your is exactly the correct approach. Now, I don't know what Omega the OP has, but a Seiko 12 lignes pallet stone has a section side of (about) 0.2mm, that's 20 hundreds, or 2,000 microns. I'm happy when I can handle and fit the entire fork correctly, let alone manipulate the stones. Pictured below next to a medium size pin.

P4170717.thumb.JPG.e182417975bb7bbefa08dd770953b52c.JPG 

Edited by jdm

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If the Omega palette is similar in dimensions to the Seiko one i.e. 1/5mm across, then my estimate of the wear pattern as about 20 microns is probably off by a factor of 5, so the wear is more like the fluting on those columns in the Brandenburg Gate model. So more like a couple of carbon fibers width than the width of a single a human hair. :P

Edited by AndyHull

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On 4/15/2019 at 3:41 AM, margolisd said:

Omega that's showing occasional beat errors in certain positions and only on one side.

out of curiosity how much beat error are you getting? 

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12 hours ago, JohnR725 said:

out of curiosity how much beat error are you getting? 

It was very erratic and hard to quantify. But I'd say around 10% of the beats were completely wrong.

The replacement escape wheel and pallet fork arrived. Fitted today and wow, what a difference. I put the escape wheel under the microscope to compare it to the old one and yeah it was completely worn. Thanks everyone for the advice. 

IMG_1506.png

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On 4/16/2019 at 3:49 AM, margolisd said:

Interesting. I normally use a little 9010 on the pallet cock jewels :phew:

Thank you marg for sharing, I had just heard about it, never seen an actual case and them pallets jewels sure tell the story and TG says something possetive has happened, perhaps by chance.  :lol:

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