Channel Setting Round Stones Knowing how to set melee diamonds demonstrates another aspect of quality in your shop by Mark B. Mann Director of Professional Certification Jewelers of America This installment begins a new format we think you’ll like more illustrations, fewer words! Designed as a visual, user friendly introduction to the topic featured in the JA Quality Assurance Guide that follows, these two pages in non technical terms offer the sales associate, store manager and bench jeweler information that’s useful in their work: inspections, customer communications, problem solving or repair techniques. Besides discussing ways of manufacturing different types of jewelry, these pages provide an overview of some common problems associated with improper repair or manufacture methods and how to avoid them! We encourage and feature input from JA Certified Bench Jewelers and will bring you their stories, their experiences and their recommendations. Periodically, these pages also will feature a workout area, a sidebar photo op you can use as a training or refresher exercise to test and expand your own or your coworkers’ knowledge. It will picture a piece of poorly crafted jewelry and give you a chance to use the related JA Quality Assurance Guide to locate and identify the problems inherent in its craftsmanship.
Bench jewelers channel set round stones in a variety of methods. Let’s take a look at some ways to ensure it is done correctly and the results are successful. Here are eight essential points to consider when channel setting the small round brilliant diamonds known as melee.
1. Typically, an individual seat is used for each stone.
Stones are set into seats individually cut into the opposing walls.
It’s essential the seat or notch accommodates the girdle thickness and fits the crown and pavilion angles at the point of contact for each stone (usually 72º to 78º). The stone will loosen quickly if the seat angles are larger than the stone dimensions.
2. Each stone is secured between two opposing walls, not resting on an under gallery.
Channel set stones should not be “trapped” on lower support rings or bars. Foreign matter could be trapped between the stone and the ring, making it very difficult to clean and service.
3. Support bars or rings beneath the stones connect the channel walls, stabilizing them so they don’t drift apart and let the stones loosen or become dislodged.
4. Metal from the opposing walls covers 10% to 15% of the stone’s overall diameter – without any visible gaps. Further, the top of the stone is even with the top of the walls into which it’s set. A good rule to follow: about 10% to 15% of the stone’s total diameter is secured with metal from the sides. The top of the table is even with the top of the wall.
5. All stones set at the same overall height.
It’s considered an error in workmanship to have groups of stones set at different heights. The example shown above is how a bench jeweler lays out the stones before setting to ensure they are all of the same make. If the stones have varying crown heights or proportions, the bench jeweler can compensate by burring the seats at slightly different heights.
6. The tables of all stones are level and even.
7. All stones are close to each other and evenly spaced.
The spacing between stones is a design consideration. But channel set stones generally look best when set fairly close together. However, they should not be so close they touch or overlap; that could cause damage in the setting process.
8. When sizing is determined to be feasible, it’s recommended that rings with channel set stones be sized in steps or increments. For example, if a ring needs to be sized down with the channel stones in place, a suitable approach is to remove one quarter size at a time, each time rerounding the ring and tightening any stones that may have become loose. Repeat the process until you reach the desired size.
Proper Channel Setting of Round Stones
1. The stones are close to each other, evenly spaced and not overlapping or touching.
2. About 10% to 15% of the stone’s total diameter is covered by metal from the two opposing walls.
3. Individual seats are cut for each stone.
4. No gaps are visible at the junction of the metal and the stone (use a 10X loupe).
5. Individual notches are cut directly across from each other into opposing sidewalls and are placed at nearly equal depths.
6. Tables of all stones are level and set at equal heights.
7. There is a bar between each stone or a “ring” below each stone so the walls don’t drift apart.
Potential Problems When Channel Setting Round Stones
Walls too close together
No more than 15% of the stone’s diameter should be secured; more than that makes the stone look small and risks damage in the setting process. This is the result of errors in workmanship.
Walls too far apart
Less than 10% of stone ‘s total diameter is “embedded” in the sidewall, risking loss of the stone. This is a result of errors in workmanship.
Noticeable gaps at each seat
There are noticeable gaps between the stone and the wall of the ring. This stone will loosen very easily and eventually fall out. This is a result of errors in workmanship.
Lacking structural support
There are no rings or bars beneath the stones to connect the opposing channel walls. They may fan out (moving out of parallel) or drift apart, loosening the stones. This is due to errors in design and manufacture. This illustration shows proper support.
Stones set at differing heights
Stones with different crown heights could have been adjusted while being set. This is a result of errors in workmanship.
Stones unevenly spaced
The space between stones should be equal. This is a result of errors in workmanship.
This ring has a continuous channel cut the entire length of the channel. There are no support bars between the channel walls. The stones are sure to loosen and become dislodged through normal wear. They should be removed and the channel wall rebuilt or replaced, or the ring should be remade from scratch and each stone reset individually.
Stones are not level
The table of each stone must be face up and be set level with the top of the channel walls, as shown here.
© 1998 Jewelers of America Standards as described for the JA® Bench Jewelers Certification Program(TM)
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