inset stones in wood?

[scottp55]

Hey all. 15 years ago I inset a piece of agate into padouk by scribing and chiseling by hand an undercut pocket until with oil and beeswax and a modicum of pressure it passed the thin grain on the lip and was held in with with no adhesives. It took HOURS.
I carve freeform opals and I'd like to set some in ebony and rosewood the same way. Ironstone matrix opal so not as fragile as other opals. Have all my old Leigh dovetail bits(still unused). Opals are all different but a good average is 3/4" and up.
I've thought about scanning them on my flat bed and then starting undersized with the smallest dovetail bit and cutting inside the line and gradually increasing my negative offset until it ALMOST goes in, and touching with sandpaper until it does.
Has anybody done anything like this? Helpful hints on scaling irregular shaped objects into my drawing?
Wood will most likely be a shade over 1/4" thickness and VCarving a complementary design and cut out shape after stone is set.
Apologize for poor pic.

[chiloquinruss]

I have been dabbling with 3d printing and 3d scanners for awhile now. The current state of the art in home style 3d scanners is pretty weak. However for your particular task, they may work out just fine. The issue currently is lack of picking up fine details, but in the case of a stone, may be good enough. Aspire already allows you to bring in an STL which is the output from most 3d scanners. This would allow you complete control over depth, placement, etc,. Just a thought. Russ

[scottp55]

Thanks Russ, No Aspire and no money for a scanner. Think I'm going to eyeball it and play around a lot with scraps and cheaper stone until I get a method down. I was hoping not to have to re-invent the wheel---Oh well:)

[Burkhardt]

Maybe I don't understand the idea completely but I suspect a dovetail bit may create more undercut than you can use. When pressing the stone in, the protruding surface edge might just chip or break.

I would try a close-up photograph of the stone on a white background, import in Vcarve, convert to a vector outline and scale it to match 2 points that you can measure with a caliper. Then you can cut a slightly undersized straight pocket with a 1/8 or 1/16" end mill and press/pound the stone in so that the interference fit holds it in place.

[scottp55]

G, If anything I remember undercutting more than my dovetail will give me. A small strip of beeswax goes into the concavity before the stone is pressed in to keep it from moving and provide a barrier against full direct contact, so it's kind of of floating. Same reason jewelers use epoxy when full bezel setting, it doesn't hold the stone in, it supports it. Opal is basically a silicone glass made of spheres so direct pressure or point load pressure causes conchoidal fractures.
Just trying to have the bot do 90% of the work:) Will try both scanning and 90 degree picture and try to get 2 defined points. Thanks