Resizing jewels

[Neverenoughwatches]

Hey all watch peeps, hope we all well. Probably discussed this before but i like to re-surface various topics for others that might be interested and not considered, plus I'm sure i will have a few questions that have never been asked. This has come while I've been sorting through selections of jewels bought from ebay and also harvested from old movements. My size variation is quite limited due to to majority coming from the same movements at the moment, the ebay cap jewels are also only 0.1mm incremental ranging from 0.8-1.5mm. So I'm wondering how possible is it to reduce diameter size, obviously only with a lathe, i have seen jewel collets on ebay and wanted to know how usable these thing are ? TIA fellas

[HectorLooi]

The jewel collets are only good for working on the centre part of the jewel, like resizing the hole or oil sink.

I've only tried resizing an endstone which was a little big and thick. I mounted the flat surface of the endstone on a brass rod with shellac. Centering the stone was a real pain. I had to warm the brass rod until the shellac softened, then spin the rod at a low speed on my lathe and used a pegwood to centre it before the shellac hardened.

I reduced the diameter of the stone using a #1000 diamond file. Then worked up to #2000, then #3000.

Similarly, I thinned the convex surface using diamond files. 

Polishing the adjusted surfaces was another pain. I used diamond paste on a popsicle stick to polish the rough surface. It took a really long time. Maybe using the diamond paste on a harder surface like brass might have been more effective. I gave up when the stone reached a semi glossy finish. I figured that the finish of the edge and convex surface of the endstone doesn't really affect the performance.

That was the first and last time I adjusted a jewel. I don't even remember which watch it was.

For hole jewels, I would choose a jewel that has the correct size hole but if it is slightly larger, I would ream the setting hole to fit the jewel rather than try adjusting the diameter of the jewel to fit the setting. 

I still have a few watches with cracked or broken balance jewels. But working with jewels is such a pain that I would rather root canal at tooth. 

Good luck with resizing your jewels.

[Neverenoughwatches]

3 hours ago, HectorLooi said:

The jewel collets are only good for working on the centre part of the jewel, like resizing the hole or oil sink.

I've only tried resizing an endstone which was a little big and thick. I mounted the flat surface of the endstone on a brass rod with shellac. Centering the stone was a real pain. I had to warm the brass rod until the shellac softened, then spin the rod at a low speed on my lathe and used a pegwood to centre it before the shellac hardened.

I reduced the diameter of the stone using a #1000 diamond file. Then worked up to #2000, then #3000.

Similarly, I thinned the convex surface using diamond files. 

Polishing the adjusted surfaces was another pain. I used diamond paste on a popsicle stick to polish the rough surface. It took a really long time. Maybe using the diamond paste on a harder surface like brass might have been more effective. I gave up when the stone reached a semi glossy finish. I figured that the finish of the edge and convex surface of the endstone doesn't really affect the performance.

That was the first and last time I adjusted a jewel. I don't even remember which watch it was.

For hole jewels, I would choose a jewel that has the correct size hole but if it is slightly larger, I would ream the setting hole to fit the jewel rather than try adjusting the diameter of the jewel to fit the setting. 

I still have a few watches with cracked or broken balance jewels. But working with jewels is such a pain that I would rather root canal at tooth. 

Good luck with resizing your jewels.

Thanks Hector, the question was more in relation to cap jewels than bearings. I quite like your idea though for reducing the diameters, i will give that a try. If anything having that option can take the stress away when cleaning a shock setting. 

[JohnR725]

9 hours ago, Neverenoughwatches said:

i have seen jewel collets on ebay and wanted to know how usable these thing are ?

Were probably thinking of two separate things but can you give me a picture of this? This way we all can be on the same page of what you're looking at.

 

 

[transporter]

On 12/1/2023 at 12:15 AM, Neverenoughwatches said:

Thanks Hector, the question was more in relation to cap jewels than bearings. I quite like your idea though for reducing the diameters, i will give that a try. If anything having that option can take the stress away when cleaning a shock setting. 

I have to ask what the stress is with cleaning Shock jewel settings, I would think/know that resizing a jewel is far more difficult. But on pocket watches I was taught to enlarge the setting for a larger jewel if the correct size cannot be found, as long as the pivot hole was correct 

[Neverenoughwatches]

2 hours ago, transporter said:

I have to ask what the stress is with cleaning Shock jewel settings, I would think/know that resizing a jewel is far more difficult. But on pocket watches I was taught to enlarge the setting for a larger jewel if the correct size cannot be found, as long as the pivot hole was correct 

Hi transporter it wasn't a comparison between the two proceedures. Thinking about losing or breaking a cap jewel that you might struggle to replace in good time or at all would be alleviated knowing you can resize one of a different size.

[JohnR725]

1 hour ago, Neverenoughwatches said:

Thinking about losing or breaking a cap jewel that you might struggle to replace in good time or at all would be alleviated knowing you can resize one of a different size.

This is why when we were in school we practiced lots of practice. As far as breaking a Jewel I would be really curious as to how you think you're going to do that I would list that is nearly impossible to do short of whacking it with a hammer. Losing it yes that's easy to do if you haven't practiced enough but in the case of an the stones on modern shock protected watches those can usually be replaced they can be ordered

resizing a jewel can that be done well almost anything can be done but can it be done practically no. In order to resize a stone you would have to mounted in a lathe shellac it in a center position is a diamond file to grind it down a little bit and then hope you get it to the right size but of course your changing things so who knows if it's really going to fit or not.

If you really want to reduce the size of something do with a hole jewel that so much easier often times I've modified modern jewels to knock off the corners so that they can be burnished in the older settings.

On the other hand I suppose you could read George Daniel's book on watchmaking then you can make the whole setting. It would be very practical your chances of succeeding express it with a tiny hole for the pivot and getting it all done perfect would be almost nonexistent but I suppose if you want to sleep tonight you could know that you could get a book and make the whole thing yourself.

[Neverenoughwatches]

1 hour ago, JohnR725 said:

On the other hand I suppose you could read George Daniel's book on watchmaking then you can make the whole setting. It would be very practical your chances of succeeding express it with a tiny hole for the pivot and getting it all done perfect would be almost nonexistent but I suppose if you want to sleep tonight you could know that you could get a book and make the whole thing yourself.

I knew you would have a plan for me, you never fail me