Professional Jeweler Archive: Efficient Prong-Setting for an In-Line Bracelet

May 2005

Bench | Fine Jewelry Craftsmanship

Efficient Prong-Setting for an In-Line Bracelet

Knowing efficient setting techniques for multiple round brilliants demonstrates another aspect of quality in your shop

By Mark and Lainie Mann

This article covers automated setting procedures using Foredom’s AllSet® Master Stone-Setting Kit. By using this equipment and these procedures, you will increase your setting efficiency and decrease overall labor while guaranteeing consistent quality. The featured procedure is efficient to use when setting one or multiple gems in prong settings.

JOB ENVELOPE INSTRUCTIONS: Set 46 matched 3mm round brilliant moissanites in a 14k white gold in-line bracelet.

1. The featured bracelet provided by Stuller, Lafayette, LA, (#BRC12, 800-877-7777, holds 46 3mm round brilliants.

For this demonstration, I’m setting moissanite, created by Charles & Colvard (800-210-4367, Moissanite is cut to exacting proportions, making it a good candidate for automated setting procedures.

2. The bracelet is cast, assembled and expertly prefinished. The prongs are square, sturdy and sufficient in length. The first step in the setting procedure is to make sure all prongs are spaced evenly and appropriately.

I want to remove about 40% of the prong thickness to create the bearing for each stone. To do this, the distance between the prongs should measure about 2.35mm. In this photo, I’m making a setter’s punch to reflect this measurement.

3. I insert the setter’s punch in each setting and lightly tap it to spread the prongs evenly. This procedure is done over the anvil part of my bench top.

4. Next I use a cup bur to shape the tops of all prongs. Notice the prongs on the left are slightly rounded and the ones on the right still have to be rounded. I hold the bracelet in my hand for this procedure.
5. To create the bearing in each link, I use the Foredom AllSet and a non-aggressive tungsten-vanadium steel setting bur with a 3/32-in. shank (page 106 of the current Stuller tool catalog).

The setting bur measures 2.95mm and is slightly smaller than the stones. For instructions on preparing and setting-up the AllSet, see Tool Tips (page 96). The AllSet systematically controls the depth of each bearing cut, allowing me to work quickly. Note I’m holding the bracelet with my fingers, allowing each setting to move and align itself as the prongs come in contact with the guide and bur.

6. After creating the bearings in each link, I use a flat-bottom graver to remove the flashing of metal created on the sides of the prongs.
7. Next I use half-inch, extra-fine abrasive snap-on discs to refinish the sides of the prongs. Before setting, I prepolish each link.
8. For setting, I place a stone in its bearing, picking it up with a piece of utility wax. After placing the stone, I will set it using a prong pusher.
9. This photo shows the prong pusher made for this setting procedure. It’s modified from a 42 flat-bottom graver. I created a notch in the tip of the graver using a coarse diamond disc, giving it a desirable rough surface.

The rough surface inside the notch helps keep the prong pusher from slipping off the prong when you exert force.

10. To bend the prongs, I place the tip of the prong pusher on the side of the prong at the height of the girdle. I raise my elbow and bend the prerounded prong over the crown of the stone. Then I bend the opposing prong using the same technique. Next I bend the opposite two prongs.

To bend the final prong, I place the pusher on the top of the prong as shown and rock from side to side. For these steps, I support the link on a narrow part of my bench pin.

11. I polish and finish the bracelet. The stones are level and set at an even height. I use a cup bur on the prongs and prefinish them before creating the bearings, and I bur each link with the AllSet.

Photos by Mark and Lainie Mann
Illustrations by Lainie Mann
Visual Communications, Inc. © 2005

This information is provided without warranty, either expressed or implied. The procedures can be harmful if not executed properly and are undertaken at the reader’s own risk. The author and publisher are not responsible for injuries, losses or other damages that may result from use of this information.

Professional Setting of Multiple Round Brilliants for an In-Line Bracelet

By Mark B. Mann

A. All gemstones are evenly spaced, are set at equivalent heights and are level.

B. The prongs are shaped evenly.

C. The tops of the prongs are even with the top table of the stones.

D. No more than 40% of each prong is removed.

E. No flashes of metal are left from creating the bearings.

F. There are no visible tool marks.

Illustrations by Lainie Mann
Visual Communications, Inc. © 2005

Copyright © 2005 by Bond Communications