Burrs used for cabochon tube setting

Help dear helpers,
What burrs have you used to create a flat seat to cut into a tube to set a flat bottomed 5 mm cabachon? I have cut a seat 1st with a ball burr but then I do not like the angle that the traditional faceted stone setting burr gives me.

terryteresa, I always drill my tube for setting before I cut it from the stock using a setting bur. Hold the tube in a small vice with a piece of leather or something soft so you don’t scratch it. Start with a 4.5 mm then 5 mm. I find the seat is flat as long as the bur is used exactly straight into the tube. You will cut it from the stock about 1mm below the seat for what will look close to a totally flat setting. It will be slightly raised by 1 mm. If you are careful, you can go less than 1mm. Sanding it to less than 1 mm might be the better option here.


Rio has some cylindrical burrs, and I’m guessing that’s the “right” tool to use if you’re aiming for a perfectly flat shelf for your cab to sit on. As for myself, I haven’t got any of those yet so I’ve used a shallow-angle Hart burr or a setting bur to do most of the cutting, then used a 2mm polishing pin to touch it up and flatten the shelf. It works reasonably well.

The other way to do this, especially if you need a wider shelf than cutting into the tube will get you, is to use sheet to make another smaller tube to nest inside the outer one. I suppose you could also use square wire or even a slice of another tube that just fits inside.

Cylindrical burrs may help or you can solder a tube in a tube or just form a jump ring and solder that just inside the tube.

If I need a flat surface to set a small cab on I modify a setting burr by grinding off the angled part of the burr leaving it straight sided and cylindrical.
You can then polish the new face so when it cuts it leaves a bright step.
I usually use burrs that are starting to get a little blunt so this eventually gives me a full set of modified burrs.

You can use heart, setting, round, concave burrs. Look at what the job requires and experiment.
Other than that I use an inner bezel for the step but then these burrs can be useful in clean up.

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Interesting! It never occurred to me to do that with my hurts! I recently bought a set of burrs just like that (without the angle & point part)! That’s what I love about this site and the people who participate in it - they’re not selfish about sharing their knowledge to help others. I trained under a jeweler/goldsmith who was very reticent about sharing his jewelry ‘trade secrets’ and for years I kept the same mentality. Thanks everyone for showing me the right way to be a professional!
Paul Smith - dba The GoldSlinger

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Oops! It autocorrected ‘burrs’ to ‘hurts’!!!

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I know where you are coming from. There are probably some secrets I would like to keep, those ideas and techniques that have been hard fought, but I will give them up eventually. But in general if I have an answer or another way of going about something, happy to share.
I have ground round burrs and concave cutters depending on the requirement. It just extends the usefulness of the burrs the most you can get from your tools the better. I maybe preaching to the converted, but try modifying files as well, into gravers, punches, scribes, mandrels for links etc. etc.