Sizing a flush set gold/diamond ring

I had this ring made many years ago & it’s been tucked away. I’d like to wear it but it’s a bit tight now. I can get it on but I need it to be just a tiny bit bigger. It’s 10k with a decent diamond in the blowhole. This may be a stupid question, but can it be annealed on one side somehow? Thanks.

be careful of heating a diamond… the temperature at which it quickly turns into graphite can be lower than the stated 1,700C… which is still high (about 3000F)… the shank is thick and gold conducts heat very well, so thermal shock cracking is a risk… the shank can be stretched on a mandrel by gently tapping it with a rawhide hammer or hard rubber hammer…that avoids creating hammer marks., hitting too hard risks loosening the stone or mechanical shock cracking.
I don’t think that it would be possible to soften the shank by annealing before working it since it’s thick, the rest of the ring is thick and gold is a very good conductor of heat… does anyone else have any ideas?

Thanks. I had tried with the mallet but it didn’t help much. It just occurred to me that given the nature of the design I think if I just saw at one end of the whale & finish the ends nicely I can make it look like it was actually meant to be an open ring. Cheerio

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that’s a great idea! problem solved!..

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Here is another idea…

Is it possible to tap it a bit at the bottom quad with a goldsmiths hammer to stretch it a bit…and/ or file/ grind a bit away from the inner diameter…


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I hadn’t considered grinding. That’s seems like a reasonable option as well, thank you.

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There are mechanical devices that will stretch your ring. Kagan has made one for years and you can be specific where you roll so as to avoid damaging any area that you would like to preserve. As for the peril in annealing with the stone still in place, I have to leave that to others as I don’t work with faceted stones. Good luck…Rob


I think I’m going to go with the opening up idea. I can make it look good, and then as necessary (age, arthritis) I can it adjust down the road.

the other option is to take it to a professional jeweler and have them stretch it for you using specialized equipment. if it is only slightly too tight, then filing off some of the metal on the inside could work also…

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If the diamond is very clean first, and coated with boric acid to prevent contact with atmospheric oxygen, then there is no reason why only a portion of the shank cannot be annealed. Or one could safely anneal the whole thing. Annealing can be done as low as 900 F, where the gold will be only just starting to glow dark red visible in a darkened location. Even many gold solders won’t be flowing at that temp. The diamond should not be heated enough for it to glow much more than that either, but the boric acid or borax coating will protect it so long as there is no dirt or oil on the stone. Gold itself is a pretty good heat conductor, (not at all as good as silver, or aluminum, or graphite, to name a few better ones) but in general, it’s alloys are only fair thermal conductors. Many commercial jewelers, needing to protect heat sensitive stones in a light weight gold ring, while sizing it, will just hold the ring with their fingers at the stone set top, while quickly coming in with a fairly hot flame to flow the solder in a sizing seam, or even just fusing (welding) the seam. Then quickly onto a mandrel to let it cool. Stones and fingers remain comfortably cool. You just cannot be timid and slow. In till it melts, then back off again. 3- 5 seconds. The ring in the OP’s photo needs to be held in tweezers because it’s heavier, but soldering a piece in to size it up is a pretty simple and worry free job. If still worried about the stone, then submerge the top / diamond portion in a small container of water while soldering the seams

I would Not risk stretching this with a standard wedding band stretcher. All the stretching will concentrate on the thinnest / weakest spots, including prior solder seams, and often, the sides of the drill hole the diamond is set in. The hole becomes oval, no longer holding the stone properly.

If the shank at the bottom is a suitable match for profile shape with one of the ring shank roller type sizers, which stretch only the portion being rolled up, the you can use that.

But if it only needs to go ip a smidge, then anneal the shank if it needs it, and be gentle with a light weight hammer. This may end up slightly thinning the shank more than other means, since then the hammer marks need to be filed or sanded away. But in any case, there are many ways to do this. And in commercial shops, this is considered a basic, almost beginner level job…

agree with your assessment. graphitization of diamond occurs at much higher temperatures but oxygen in the air must be excluded… no matter what, oxygen must be completely excluded as it it does lower the graphitization point by causing nanoscale nucleation centers for graphite to grow. the main risk is thermal shock cracking. I believe that it was 10k which isn’t nearly the conductor that silver or higher k gold is… people should know that any stone that gets hot is at risk… that’s the main point… then comes how best to “open the shank up”… many suggestions have been made and many have merit…

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Have you tried a jeweler that has a vertical piece of machinery to stretch a ring slightly?

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If you only need to make it a pinch larger I would definitely just sand the inside , keeping the integrity of the ring intact.

You could try covering the diamond with an insulating gel such as thermo gel. This keeps the stone and the relevant shank area cool while the rest of the ring is annealed.

No one has mentioned this method yet, but it works great if you just need a little bit of size enlargement. If you dapping tools with their nice long one that is half the size of the interior of the ring. Just roll it back and forth only on a small space where no stones are located. It happens fast so check after a few rolls and see if it is enough. No need to anneal it for this method. It only works on less than a 1/4 size differential. If it is rounded on the outside as well, just use a flex shaft with a bur that is round. take a piece of wood and make a small line with the burr. now do the roll in that space to keep the round on the outside from flattening out. I learned this in a workshop over 30 years ago. I kept thinking someone would have chimed up with it before me, so I never posted it.