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June 1998
For Your Staff:Selling Quality
JA Quality Assurance Guide
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. |
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| 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. |
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| 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. |
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| 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. |
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| 6. The tables of all stones are level and even. |
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| 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. |
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| 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
- The stones are close to each other, evenly spaced and not overlapping
or touching.
- About 10% to 15% of the stone's total diameter is covered by metal
from the two opposing walls.
- Individual seats are cut for each stone.
- No gaps are visible at the junction of the metal and the stone (use
a 10X loupe).
- Individual notches are cut directly across from each other into opposing
sidewalls and are placed at nearly equal depths.
- Tables of all stones are level and set at equal heights.
- 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
| 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. |
| 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. |
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| 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. |
| 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. |
| The table of each stone must be face up and be set level with the top of
the channel walls, as shown here. |
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© 1998 Jewelers of America
Standards as described for the JA® Bench Jewelers Certification Program(TM)
Copyright © 1998 by Bond Communications.
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