Jewel dimensions…

[chris mabbott]

@tmac1956 wrote:

“What have the Romans ever given us? ” MP

The aqueduct, Paved roads, law & order, education, health care… Bloody Romans 😆

[arutha]

Hey guys,
as with anything it takes practice to do these rubbed in jewels. The biggest problem you will find is that if someone has already done it before and they have been heavy handed you have got a real job on your hands. I cant remember the technical names for these tools so lets start with the flat bottomed one you use for moving the brass back away from the edge of the jewel so you can get the jewel out. They come in sets of three flat bottomed and three concave bottomed. The flat bottomed is for pushing that fine lip of brass back over the edge of the jewel. Pick one that fits the jewel but has room to be expanded out, keep it very upright and give four or five twists backward and forwards, undo the thread a touch and then another four or five twists, keep going until you can just see the edge of the jewel. People get lazy and just push out the old jewel, this can damage that fine rim of brass and make it a pig of a job to get the new jewel wiped in. Once you have the old jewel out you need to look at the bottom of the hole where the jewel was resting, if it is at all chewed up it will cause you problems. If it is good then get it as clean as you can. The new jewel needs to be the same height as the old jewel, you can get away with a very slight, and I am talking slight, difference but too much and you will again have problems getting it wiped in. The diameter of the new jewel should be a good fit, a bit of pressure and it goes in, too big and it obviously wont fit or you will break it trying to push it in. Too small and if you do manage to get the rim of brass stretched enough to hold it you can guarantee the jewel hole will be off centre. So you have your new jewel sat in a nice clean flat hole. Now you take the wiping tool( the concave ended one) making sure it is not too big or it wont do anything, and do the opposite but this time you are applying pressure as you are in fact gently riveting the brass over the jewel, you start of with the wiping tool so the outside edge is just a fraction larger in diameter than the rim of brass you are smoothing back over the jewel. A few turns each time and then close it up a touch while applying a little pressure, keep going until you have a reasonable lip over the jewel.
It is difficult to explain without pictures and I have not done one for a while but it takes practice, a gentle but firm touch but the main thing is, like I said at the beginning, if someone has been there before you and carved it up a bit you will not be in for an easy ride. If it is very bad, your only option is to mount the plate on a watch mandrel and turn out the hole to get it tidy, you then obviously have to fit a jewel with slightly larger dimensions.
I hope this help a bit.
Paul.

[tmac1956]

Paul:

I’ve tried this process a few times, and I worked on peeling back the metal for several hours only to find that I still had a long way to go. Perhaps it was because the plate was nickle and not brass…I don’t know, but I wondered why it was so much work just getting the metal off of the jewel. The few times I attempted it, I never got the metal peeled back to the edge of the jewel. I wound up breaking the jewel trying to get it out.

I’ll stick your post in my notebook as I really want to be able to work with these.

Thanks for your post – I know you’ve done several of these before.

Later,
Tom

[arutha]

Nickle is harder than brass, I cant see why they would have used wiped in jewels, if they are just nickle plated it shouldn’t be a problem. The only thing I can suggest is to find an old movement with wiped in jewels that look untouched, get the jewel out and put it back in. You will know then that any issues are down to technique as opposed to any other issues.
Paul.

[tmac1956]

Paul:

I was using old junk plates. I have some more, so I’ll try it again once I get the patience. This is getting my blood up, so I’ll be able to spend some time on it. I’ll let you know what happens.

Thanks!
Tom

[chris mabbott]

Tom, just like I was, you are being Mr nice guy with these 😆 If the old jewel is in place, but cracked, select a flat pusher, same OD as the jewel, or a tad smaller, and push that sucker through, this opens up the rubbed over lip allowing you to insert your opening tool.

Take a toothpick and clean under the lip where the old jewel has sat, then use a small model paintbrush dipped in naphtha and give it a wipe.

Now take the opening tool, gently insert it, loosely, into the hole and adjust the jaws until you feel the nut tighten, slight tension. Keeping your tool perfectly straight, slowly turn it whilst opening the jaws just a tiny bit after each revolution. You only want a small amount. .001 larger than the jewel OD.

Plop in the new jewel, it should JUST fit, so if the new jewel is in place and you turn the plate upside down, it shouldn’t fall out, kinda.
Once that is sorted, make sure it is LEVEL. I use a pump plunger to ascertain this, gently.
Take your closing tool and adjust it to just catch the OD of the opened lip. Use slight pressure, one revolution, then adjust the jaws to close a small amount, complete another revolution. Repeat this process, gently, until the jaws are touching the I.D. of the lip. Your jewel should now be secure and ready to chew gum and keep time, and it’s all outta gum 😆 If you want to get technical, you can burnish the lip and make it all nice and shiny, but be careful because you can burnish the lip away and your jewel will fall out.

To check, I gently give it a little poke with a toothpick, not hard.

Take a jewel setting, a good one, with the jewel installed, rubbed-in, take a macro photo of it and enlarge it on your PC, just sit and stare at it, study it and become one with it, stare at it until you feel that it is a piece of cake, how could something this simple have stumped us, why, its easy 😮

This might not be the correct way but by jesus it works for me and I had to learn it myself which, as you know, is the only way as this is … Secret informations

[tmac1956]

Thanks guys… this is great information.
Tom

[tmac1956]

Hey guys,
as with anything it takes practice to do these rubbed in jewels. The biggest problem you will find is that if someone has already done it before and they have been heavy handed you have got a real job on your hands. I cant remember the technical names for these tools so lets start with the flat bottomed one you use for moving the brass back away from the edge of the jewel so you can get the jewel out. They come in sets of three flat bottomed and three concave bottomed. The flat bottomed is for pushing that fine lip of brass back over the edge of the jewel. Pick one that fits the jewel but has room to be expanded out, keep it very upright and give four or five twists backward and forwards, undo the thread a touch and then another four or five twists, keep going until you can just see the edge of the jewel. People get lazy and just push out the old jewel, this can damage that fine rim of brass and make it a pig of a job to get the new jewel wiped in. Once you have the old jewel out you need to look at the bottom of the hole where the jewel was resting, if it is at all chewed up it will cause you problems. If it is good then get it as clean as you can. The new jewel needs to be the same height as the old jewel, you can get away with a very slight, and I am talking slight, difference but too much and you will again have problems getting it wiped in. The diameter of the new jewel should be a good fit, a bit of pressure and it goes in, too big and it obviously wont fit or you will break it trying to push it in. Too small and if you do manage to get the rim of brass stretched enough to hold it you can guarantee the jewel hole will be off centre. So you have your new jewel sat in a nice clean flat hole. Now you take the wiping tool( the concave ended one) making sure it is not too big or it wont do anything, and do the opposite but this time you are applying pressure as you are in fact gently riveting the brass over the jewel, you start of with the wiping tool so the outside edge is just a fraction larger in diameter than the rim of brass you are smoothing back over the jewel. A few turns each time and then close it up a touch while applying a little pressure, keep going until you have a reasonable lip over the jewel.
It is difficult to explain without pictures and I have not done one for a while but it takes practice, a gentle but firm touch but the main thing is, like I said at the beginning, if someone has been there before you and carved it up a bit you will not be in for an easy ride. If it is very bad, your only option is to mount the plate on a watch mandrel and turn out the hole to get it tidy, you then obviously have to fit a jewel with slightly larger dimensions.
I hope this help a bit.
Paul.

Arutha:

Here is an old plate that I think has rubbed-in jewels.

<div class=”bbcode_quote”>
<div class=”bbcode_quote_head”>Arutha wrote:</div>
<div class=”bbcode_quote_body”>

Does this look like a good practice piece on which to practice your method?

Thanks!
Tom</div>
</div>

[arutha]

Sorry Tom, I cant tell from those pics, they are a bit small. I also didn’t say that it is quite difficult to get a jewel out in one piece, i know Chris just pushes them out but try wiping it open a bit first otherwise you will stand a good chance of chipping or breaking the jewel.

[tmac1956]

Arutha:

I took your advice and used the expandable tool by slowly twisting and increasing the adjustment on the tool. After a few minutes the jewel popped out and stayed in the tool itself. Now I have to try and put it back in. I don’t know how that’s going to go but at least I’ve had a little success.

Here’s a picture and I hope you can see everything.

P.s. That’s one thick jewel!

Thanks for the help…
Tom

[tmac1956]

Removed… duplicate post.

[arutha]

Well done Tom,
make sure the seat is nice and clean and the jewel goes back in level. Some of these procedures do take a bit of practice, the funny thing is once you have done it a few times you start to wonder what all the fuss was about. I had the same issue with balance staffs, I couldn’t seem to make one without over cutting something or breaking a pivot off when I started. I am still not fast at it but I do find it much easier than I used to.

[tmac1956]

Arutha:

I think the problem I was having initially is that the jewels I worked on didn’t have much of a lip above them causing the tool to slip or wobble out the hole. I scratched up many an old plate because of it which was very disheartening. This one had a deeper setting and thus a deeper lip so it kept the tool in the hole better. I have a Seitz jeweling set and a K&D Inverto that both have jewel pushers, so I should be able to get in in level. (Oh yee of great faith)

Again…

Thanks!
Tom

[arutha]

It is a job that takes a certain amount of “feel” and this only comes from experience, again well done and glad Chris and I could help

[Author]

Posts