The Technique's History
In a previous tutorial, GRS Tools president, D.J. Glaser, showed a setting technique he calls the “Volcano Setting” using a copper bracelet and 3 mm round orange sapphires. But since copper is a soft metal and medium-size round stones are fairly easy to set, some people may wonder if this technique works in harder metals and for non-round stones. To address this, D.J. decided to set an oval 4 x 5 mm natural yellow sapphire in stainless steel. This combines a harder metal with a non-round stone in one setting.
Tools & Materials Used
- GraverMax with Magnum handpiece
- GRS MicroBlock
- Thermo-Loc (Workholding Plastic)
- E-Max NSK Micromotor System for drilling, bur work and some polishing
- GRS-Meiji zoom stereo microscope
- Various modified gravers and burs
The Design & Layout
This particular oval sapphire has a fairly good cut viewed from above, but the bottom is bowl-shaped, irregular and asymmetric. Also, it has a somewhat shallow crown height (the girdle is cut close to the table), so most of its depth is in the pavilion. Many colored stones have cut and shape irregularities like this especially lower cost stones. Experienced jewelers and stone setters are aware of these factors and must deal with them in their work.
This sapphire has a total height of 2.5 mm, while the stainless steel key pendant is only about 1.9 mm thick. Setting this stone without the pavilion sticking through the back side of the metal would be very difficult to impossible with normal techniques. Because the “Volcano” technique thickens the metal around the stone, it provides more options in situations like this.
After marking a 4x5 mm rectangular zone on the top of the pendant, a small round bur was used to drill and enlarge an area in the center of the zone. Care was used not to drill through the metal and not penetrate the back side (this was by choice to leave a smooth back side for aesthetic reasons).
After the starting blind hole was made, the same basic procedure and tools were used to displace metal to the outside as explained in the first Volcano Setting Tutorial. The larger size of the stone and harder stainless steel metal compared to the copper bracelet example required significantly more time to displace and raise the “volcano”.
Step-by-Step Instructions
Step 1.
Here the “Volcano” seat is nearly fully raised and formed to fit the needed 4x5 mm size. The stone (held with beeswax) is placed in the seat to check for proper fit.
Note a black marker dot above the seat and a corresponding black dot on the stone table (somewhat hard to see).
This is to ensure that the stone is oriented the same each time it is placed in the seat.
It’s especially important in this case because the stone is cut asymmetrically by a fair amount.
Step 2.
Because it is difficult to judge the depth and shape of the stone seat in this case, Thermo-Loc heat softening plastic is pressed into the seat. After it cools, it is removed and an exact positive impression of the seat is now available to compare with the stone pavilion shape. It’s good to number these impressions sequentially to make progress comparisons clear and easy to compare.
Step 3.
Once the seat is the proper size and depth, the stone is hammer set in a bezel fashion. Because this stone has such a round pavilion, extra care was used to hammer on opposite sides in small increments to keep it level.
Step 4.
Here is the finished piece and also the view from the back. Notice that the back shows an oval area that is slightly pushed outward due to the forces applied to the piece to create the “volcano” dome on the top. It could be easily sanded flat so the back side would have no indication of the work that was done to the top side.
Final Notes from D.J. Glaser
My purpose was to demonstrate the Volcano Setting in a tougher material and with a non-round stone to show this technique can be used for a variety of metals and stones. Although I got this particular job done, I’m not sure it qualifies as a commercial success because it took a fair amount of time. The stainless steel did work-harden and the stone thickness required a fairly tall “volcano”. At times I needed full power on a Magnum handpiece to make any progress. Jewelers and stone setters should not conclude that this is a viable business use of time to set such a stone in a stainless steel mounting like this. In the future I intend to use this technique for a new project in gold with higher quality stones. When I do (assuming it turns out OK), I’ll add more photos and comments to this tutorial section. If any of you have something like this you would like to show, please let us know by email: grs@grstools.com.
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