Top tips for successful stone setting

By John Shanahan

Ask any experienced jeweler, and they’ll tell you: it takes stones to become a gem setter. You literally have to put hundreds of stones in their place, time and time again, to be able to reach a point of consistent quality. Along the way, as with any aspect of jewelry creation, that repetition leads to finding personalized tweaks to accepted setting practices, the occasional short cut, and new ways to refine and streamline how things get done.

Sometimes, you might even share them.

We asked a handful of jewelers for their tips, best practices, and solid advice on a number of stone-setting types. Gary Dawson, owner of Gary Dawson Designs in Eugene, Oregon, starts us off with a bit of wisdom to keep in mind for any setting job: “Treat every gem like its own setting job. No matter how standardized each situation seems, it’s always different. And if you approach it that way, you’ll have consistently better results.”

Now on to the tips.

 

 

Bezel Setting
When it comes to bezels, David Phelps, owner of John David Jewelers in Durham, North Carolina, has an interesting take on stone setting. According to him, almost all setting is a variation of bezel setting. “It’s just a matter of how many points of contact there are and how wide they are,” he suggests. Whether it’s an actual bezel, prongs, or a channel, a stone gets placed between areas of metal, and the metal is bent around it. There are, of course, bezel-specific tips.

Gerry Lewy, a master gem setter and instructor from Toronto, is a big proponent of bright cutting bezels—but not the way some may do it. “I find it unusual that many setters do not bother to use a simple graver to bright cut a bezel setting,” he says. “If a bezel is going to overlap parts of the stone, you have to bright cut it to give it more brilliance and visually give back what’s covering the stone.”

His tool of choice is a number one or two onglette graver, highly polished with an 800 grit paper. Bright cutting with this after the stone is set allows him to work with very little contact with the stone. “The very sharp side of this tool is basically just gliding over the soft stone-facets, but not digging into them,” he says. “I stop and [check with a] loupe just to examine where the actual cutting is taking place. I could bright cut on a genuine emerald [with this tool] and have no chance of chipping any facets,” he says. He adds that he prefers not to use a flat graver, as that tool tends to leave rippled cutting facets around the inside of the bezel.

Not comfortable with the graver? No problem. Ann Cahoon, a jewelry making and repair instructor at North Bennet Street School in Boston, offers her own graver-free tip: “Pre-finishing the top of your bezel to 800 to 1000 grit, and keeping to a slightly shallower seat depth, minimizes the need for heavy graver use on the inside edge of a set bezel. Sometimes this makes it possible to eliminate it altogether and replace it with a burnishing step, especially in thinner-walled bezels that don’t require hammer setting.”

“Changing the angle of the pressure is really important with any bezel,” says Dawson. He begins with just enough to hold the gem in place, then begins folding the metal in toward the stone. “Visualize a cross section of a piece being set in a bezel. You begin [applying pressure] at about 45 degrees. Once you’ve done that all the way around the stone, you change the angle of attack to maybe slightly less than 90 degrees. Then you want to push the bezel back the other direction to lock it down.” Finally, he says, come at it from about 100 to 115 degrees to bring that lip of metal right up against the girdle cuts. Do that all around, then clean it up with a graver.

A tip offered by both Dawson and Phelps (and which applies to many forms of setting) centered around the analogy of tightening lug nuts when you change a car tire. When you’re putting the tire back on and you begin tightening the nuts, you don’t do them all at once—and you don’t just go around the circle. Same with bezels. Tighten your first spot, then go to the opposite side of the bezel and tighten its corresponding spot. Back and forth this way, work your way around. The idea, Dawson says, is to keep the stone from rocking. Want some help with that? “You can use a little snake of wax that goes over the top of the stone and is pressed into both sides of the bezel to keep the stone from rocking while you set it,” he says. “When the stone is in place, put the wax over the top, then use a 45 degree angle of force to secure the stone all the way around, working opposite sides.”

Prong Setting
Understandably, a lot of prong setting tips center around seating stones properly. That begins with the way you cut the seats. Cahoon recommends you get right in there with your bur and be bold.

“A lot of people tend to run their burs too slow,” she says. “If you run it too slow, no matter how perfect your positioning is, the tool can’t do what it needs to. It’s a fundamental machining concept. Your tools have teeth and [at slow speeds] those teeth are going to grab and spin out. People tend to be timid when they’re learning. You have to brave it out and keep that speed up to moderate or even high as you get better.”

When it comes to selecting a bur, Lewy likes to use a high-speed steel bur when he’s working on a four- or six-claw prong. “It’s got deeper and wider teeth and it’s more aggressive for the initial cutting,”” he says. “A carbide bur has teeth that are smaller and closer together and they won’t be doing anything. I use a bur three-quarters the size of the stone.” He saves his carbide burs for jobs where the high-speed steel burs are too aggressive, such as cluster-tops and gypsy or channel setting.

To help avoid the bur running away when it begins cutting, Lewy first makes a line with a 006 or 007 bud bur. “I make a line from one side of the claw to the other so that when I start to use the high speed steel bur, it won’t rise any further than that bud bur cut. It’s like a speed bump.”

Keeping track of how a stone is oriented in the setting is a vital step toward setting it properly as well as a time saver. “What happens a lot of times, with colored stones especially, is that they are almost never cut with the same pavilion angle all the way around the stone,” Phelps says. “So when I set a stone, I mark one prong with a black felt tip marker and put a spot on the stone so it’s easily indexed, making it possible to orient the stone exactly the same way all the time. I cut each seat individually and put the stone in it and see where I’m off and then measure it and recut a little more. If you always line it up the same way and you cut each prong so that the seats of all the prongs are flush against the pavilion of the stone, you get a stronger and better-looking result.”

Speaking of checking those seats, Dawson can shed a little light on the subject. “To see if a prong is seated correctly and catching the upper girdle facets of the gem, hold it up under your bench light using something white as a backdrop,” he explains. “I have a swing arm bench light with a white reflector around the bulb. I set it up so the white reflector is behind the prong I want to look at, then I hover my finger over the prong I want to look at—not touching it—to shadow it. This will make it very easy to see any gap between the inside of the prong and the upper girdle area.”

And let us not forget the lug nut analogy. “Go around little bit by little bit. Don’t try to set it in one motion,” Phelps says. “If I’m setting a one carat round diamond, I’ll make 10 passes all the way around to get the prongs down. That way you can see how the stone is seating as you go.”

Since you’ve set the stones without busting any, you probably think you’re out of the woods, right? Not so, says Phelps. “Everyone thinks pushing the prongs is the dangerous part, but it’s really when you’re cleaning them up. That’s when you screw up stones.” His tip? The straighter and cleaner you can get things before you press the prongs down, the less cleanup you’ll have—and less risk.

“You can’t touch any stone other than diamond with a tool,” he says. “Before I push the prongs over I’ll shape the ends with files and gravers whenever I can. I’ll polish everything so it’s ready to deliver and then do the stone setting. All that’s left is a little bit of cleanup.”

Flush & Gypsy Setting
Several of the tips already covered could be applied to flush and gypsy settings. According to Phelps, “They’re bezel settings with a really thick bezel. Most people I see doing this have far too much metal over the stone. They hammer it all down and then go back in and try to clean it up with gravers and wheels, but that’s not how to do it.”

Instead, he says, finish everything first. Next, lower the top of the bezel to the desired finished height and bevel the outer edge so it’s easier to hammer over. Finally, polish it inside and out, then hammer down the smallest amount of metal you need to hold the stone in place. “Then all you have to do is touch it up,” he says. “I use a radius flat bottom graver polished with a fine ruby bench stone to clean the inside edge of the finished bezel [first].”

Like a bezel setting, the amount of metal you bring down over the stone will take away some of its brilliance. Lewy’s answer to this is, of course, bright cutting. “You can carefully bright cut the inside of a gypsy setting,” he says. “I use a number one or two graver. The stone that’s been covered with metal will look bigger. It takes me three cuts around the full circle of a 2 mm stone, making sure the width of the opening is uniform.”

When he bright cuts, Lewy holds the graver perpendicular to the metal rather than leaning the graver on the side. This helps make a uniform cut. “My finger will be on the top of the graver,” he explains. “I let its barrel shape give me the desired cut angle.”

Bead & Thread Setting
Preparation is the key to success with these delicate setting techniques. From the way you get the stones prepped to the way they’re put in place, staying a step ahead is decidedly in your best interest.

Phelps starts by heating the surface of his piece and adding a bit of sticky wax. He lays the stones out table down on the metal so they’re properly spaced. Oh, and there’s a tip for that, too: Don’t think in a straight line.

“When you’re laying out a curved surface like an anniversary band, you need to space stones a little further than you think,” he says. “If you draw radial lines toward the center of the ring you’ll see that the lines get closer together the closer to the center of the ring they get. As you drill holes and set the stones down the middle, they’re moving closer to the center. They’ll tighten up. You need to leave a little bit of a gap between the stones.”

There’s no hard and fast rule that applies to spacing, he notes—it’s something of an “eyeballing” thing. “You have to leave that bit of room or you’ll end up with stones touching.” When setting rings, the larger the stones, the more spacing is required because the girdles are set deeper in relation to the surface. Also, the smaller the ring size, the more spacing is required for a given stone size. “Putting 3 mm stones into a size 4 ring will require a lot more room than the same size stones going into a size 10 ring,” he says. “The tighter the radius of the piece and the larger the stones, the more space is required between the stones during the layout phase.”

When he’s satisfied with the layout, he pulls the stones out of the wax and marks the impression with a ball bur. “Then I come back with the dividers and even them up so they’re about the same distance apart, then correct them with the ball bur.” He prefers the bur over using a center punch, which is a common practice. “I can remove the stone and mark the position of the hole in one motion,” he says. “I use the bur to lift the stone off of the surface, then cut a little divot in the center of the depression left in the wax.”

For drilling the holes, Phelps will often take a cone bur and grind the end flat, particularly when he’s setting blind holes (when the hole does not go through the piece to the back side). This allows the bur to cut to the required diameter when it would otherwise be prevented by the point of the bur bottoming out.

“I use it after drilling the holes and before cutting the seats with a setting bur,” explains Phelps. “It’s just easier on the setting bur if I remove a little more metal [first]. Some people use a bud bur in the same way.”

Once again, getting things as close to done before setting helps to minimize cleanup after. “After cutting seats, I’ll go in with a round-bottomed graver about one-third the total width of the seats and cut out the section between the stones.” He starts by polishing the bottom of the round graver with a ruby bench stone. Keeping a 55-degree face angle, he cuts a polished groove between the stones. “By cutting downward from the center on both sides, a peaked U-shaped groove is formed,” he says. “When the top of the ‘peak’ is below the girdles with a sharp upper edge, and the sides of the peak are steep and polished, the metal disappears, just as the edge of a sharp knife doesn’t reflect light and becomes invisible.”

Channel Setting
The rule of thumb for channel setting is the more, the merrier. Points of contact, that is. While the impression of a channel setting may be that of a stone held on either side, having just two points of contact is like inviting the stone to get up and leave.

“With the extreme wear that every piece of jewelry undergoes over time, a stone held by just two points of contact will begin to rock,” Dawson says. “Those points become pivot points and the stone will work itself loose and fall out.”

Dawson suggests cutting a seat for each stone within the channel using a bearing bur that is 10 to 20 percent larger than the stone. “Cut a precise seat that gives two points of contact on each side of the gem. Then it won’t rock.”

If you have your heart set on having just two points of contact at the top of the stone, Dawson suggests making a “donut” to help hold the stone in place. This feature, which encircles the culet of the stone to help prevent rocking, would be built into the model prior to casting.  

To make sure your stones will fit properly in a straight channel, Phelps says it’s best to start in the middle if all your stones are the same size. “Set the stone that goes in the center of the channel, then set one to either side, then go back and forth,” he advises. “You can adjust the ends [of a channel setting] but not the center. If you start at one end and work your way to the other, you might have too much channel left or not enough and have to dig a bunch out. Or you might end up with the center stone not being in the center of the piece. Start in the center and you end up with the stones all in the right positions in the piece and you might have only a little to adjust on both ends.”

For graduated channels, start big and work your way down. “Whenever possible, instead of making a piece to fit the stones I have, I’ll carve the channel then select the stones to fit,” Phelps says. “I cut and set each stone individually to get the spacing right. It’s the most common error I see in channel setting. The gaps between the stones are either uneven or too large. Sometimes they’ll overlap, and that will chip the stones. I set the biggest one first, then hammer it so it’s not moving. Then I’ll measure and cut the seat for the second one, getting it level and straight and flush with the first one.” He continues the procedure until the channel is complete.