Flush setting thin cabochons


if i am not mistaken, Rob’s post was along the lines of background removal…on a thin flat sheet or backplate…like excavating a flat bottom of a shallow pool with no opening on the bottom…versus cutting a narrow seat ledge out from the wall on a tube-like setting or one where the majority of the bottom of the seat has been removed…for a small flat cabochon…

like a lawn mower rather than an edger…:rofl::joy:

my brain is leaning toward engraving techniques…like background removal or thise used for metal inlay which is kinda like gypsy setting…

i could be wrong…if so, ignore all my shopping links :rofl::joy:


Julie…While the information about creating a seat for a faceted stone is good information for all of us, you are correct that I am looking for ways to create a straight walled depression in a piece of sheet so that I can flush set a thin cab. I have used the faceted seat tools that I have and they work, but I don’t want to break through the bottom of the sheet the way that I would with a typical setting tool. I have done this with various burs and cleaned out the bottom of the edge with a graver. It is difficult, at least for me, to stay within the outline of the stone. I am just looking for other ideas that I haven’t tried yet. Thanks all for your suggestions…Rob

Hi Rob,

another technique that pops into my head is related to enameling…champleve and basse taille…perhaps enamelers here or an enameling forum could provide insight on how they cut out the cells…

in my experience, what is needed in a rotary bur for this is a non-existent bur!

lift…bur profile angle (like on a tree or cone shape and a very slight curve which results in a more gradual curve into the tip versus a sharper curve into the tip…or a big enough cylinder diameter to provide shaft clearance…but with rounded edges

the bigger the diameter of the bur, the broader the curve, even though the actual tangent point is still small…prevents gouging…like a squat cylinder wheel grinding bur…sharp tips and edges are not good and can dig in if lift angle is raised…

the longer the bur, the more coverage…

to get into any corners, a taper is required on a bigger bur, as the radius on a ball or cylinder will not reach all the perpendicular intersections…

but a tapered bur has a decreasing radius as it goes toward the tip

i feel like…rough it out with a bigger, finer cut ball bur, then go in and smooth and refine with stone burs like ruby points or arkansas points…then sharpen the perpendicular intersections with a square or 90 degree graver

a finishing ball bur will still cut faster than a grinding stone, but will be less aggressive and perhaps have more control on depth…

lets invent the perfect bur!


like these! fir small, medium and large spaces…

like lengths of 2.0mm thru 4mm at .5mm increments…
in 45 degree face angles…

i can dream…


Have you looked at lapidary sintered diamond bits? They may have an appropriate shape, but need to be used wet.

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I do lapidary and have these diamond bits. I haven’t found them to be very accurate to use in silver. I do have an air turbine that uses 1/16 friction bits (much like a dental drill) that does do this job fairly well. Thanks…Rob

Brandi and Julie…Thanks for the great videos!..Rob


maybe…a little mini cnc…look how cute this one is…!

check out instagram account great_cnc…cool stuff!

i know nothing about cnc machines…yet!…:rofl::joy:


Yep. I would still recommend ball burrs or even inverted cone burrs. Adding an inner bezel before attaching the back plate and cut that to the appropriate size and shape before adding that backplate.

Hi Rob,

I was watching a lobster/ parrot clasp video last night on Peter Keeps site


and in it he needed to cut out a shallow depression for the spring wire to seat into…

he modified a 2mm setting bur by using a diamond disc to grind off the top pointed portion, which left him with a sort of wheel bur, but one which was thicker than a normal wheel bur and shorter and stouter than a cylinder bur…it worked well…and i thought of you and your thin cabochon setting question.


Julie…Thanks, I will take a look at it…Rob

Wouldn’t soldering two flat silver or gold pieces together work if the top one has the cutout? Depending on the design, it would protect the cab from a too thin base.

I think that it would work, I just haven’t tried it. It also requires that you know where the stone will go ahead of time. I am not that good of a planner. Thanks…Rob