Professional Jeweler Archive: Fabricating a Three-Stone Ring, Part 2

January 2001

For Your Staff/Defining Quality


Fabricating a Three-Stone Ring, Part 2

The second part of this three-part series discusses the platinum prong assembly for baguette side stones

by Tom Weishaar, JA® Certified Master Bench Jeweler™ and Shop Manager, Underwood's Fine Jewelry, Fayetteville, AR


This installment – the second in a three-part series on the fabrication of a platinum and gold three-stone ring – focuses on the platinum gallery wires and wire prongs for setting two baguette side stones. Last month’s article (Professional Jeweler, December 2000, pp. 78-82) discussed the platinum prong assembly for the center stone.

For this month’s project, we use two baguettes that each measure 5mm by 3mm. For this part of the project, we use a piece of platinum bar stock measuring 30mm by 3mm by 2mm and the wire left over from the center stone prong assembly.

This platinum and gold ring is one of three projects required for the JA™ Certified Master Bench Jeweler™ practical bench test and illustrates the side stone prong assembly covered in this article.

Steps to Fabricate the Baguette Side-Stone Platinum Prong Assembly

We can’t emphasize enough the importance of planning and layout in successfully fabricating custom jewelry. Here are some key steps in planning, laying out and executing the assembly of the side-stone mountings for this project:

1. The width of the baguette is 3mm (the same width as the platinum bar stock).

2. Start the layout by placing your baguette table- down on the piece of platinum bar stock. Match the end of the baguette to the end of the bar stock. Use sturdy fine-point dividers to measure the length of the baguette, then scribe a line on the stock to mark the exact length of the stone.

Measure the length of the baguette and mark its exact length on the bar stock.
3. Next to the layout for the first baguette, measure and mark the width of a 4/0 saw blade on the stock. Next to that, lay out the second upper gallery “cup” to match the first.
Two upper gallery "cups" with the width of a saw blade in between.
4. Set your dividers to 1mm and scribe a line around the outside perimeter of each cup.
Be sure your wire has some extra length so you can use pliers or small vice grips to hold it while piercing.
5. Once you’ve outlined the baguettes on the bar stock, drill a small hole in the center of each stone’s outline. At that center point, use a fine saw blade to pierce a rectangular slot.
Drill a center hole, then use a fine saw blade to pierce a slot in the bar stock.
6. Use a flat graver and small needle files to bevel the inside edges of the slot, creating a cupped opening for the stone. Be sure the seat is level and without gaps.
The seat should have no gaps or high spots.
7. Next create the lower gallery supports for the baguettes. Using a rolling mill, reduce the remaining bar stock from 2mm to about 1.4mm – the width of the lower gallery wire used in the center stone prong assembly.

8. Repeat steps 1-5, but don’t bevel the inside edges this time.

9. The outside length and width of the upper and lower wires should be about 0.1mm shorter than the overall dimension of the baguette.

10. Once pierced, place the lower gallery supports in a shank-forming block and gently shape them into the expected radius of the finished ring.

11. Finish & polish all sides of upper and lower gallery pieces.

12. The prongs for these baguettes, especially when set in platinum, don’t have to be as thick in diameter as those in our center-stone prong assembly. Take the wire left from the center stone prong assembly and draw it down so its final diameter is 0.7mm to 0.8mm.

13. Cut four lengths of prong wire about 20mm each.

14. Use round-nose pliers to bend each wire into a U-shape with arms of equal length and a gap between the arms slightly narrower than the width of the baguette.

Bend the wire into a “U.”
15. Notch the upper baguette cup and the lower gallery support to accept the prongs.
Use a cylinder burr the same diameter as the prong wire to notch the corners of the upper and lower gallery pieces. The depth of the notch should be one-third the diameter of the wire.
16. Assemble the components, starting with the upper baguette cup.
Fit two of the U-shaped prong wires into the notch you cut into the upper baguette cup. Adjust the spacing between the arms of the U so the cup fits snugly between them. Leave about 2mm of the U wire above the cup. Finally, fit the ends of the prong into your ceramic block and use 1,500° platinum solder to affix the cup to the prong wires.
17. Fit the lower support between the prong wires. Check it against the center-stone prong assembly to make sure the spacing of the upper and lower gallery wires is equivalent. The supports for the baguettes and the center-stone prong assembly should be even with each other.

18. Solder one side of the baguette assembly (one side only) using 1,500° solder.

19. Attach the baguette and center stone prong assemblies.

Solder a light platinum wire loop (1.5 inches will do) to the outer edges of both baguette assemblies.

Adjust the gap between the baguette cups, pinching the center-stone assembly in place.

Solder the baguette cups to the center-stone assembly using 1,500° platinum solder. You can easily remove the wire loop after soldering.

20. It’s time for final adjustments and soldering.
Lower supports should flow together and be the proper radius for the ring size.

The upper baguette cups should flow down at an aesthetically pleasing angle (about 30°) from the upper gallery wire of the center-stone.

Adjust the angles of the baguette cups.

When everything is correct, solder the outer prong wires to the lower supports.

21. After you’ve soldered all the prongs in place, remove the wire holding loop.

22. Cut off the tops of the U, leaving enough wire to set the baguettes. The bottoms of the wires should be flush with the inside of the ring. When you’ve polished the entire assembly, it’s ready to go onto the shank.

© 2000 Jewelers of America Inc. This information is required for the fourth level of the JA® Certified Bench Jeweler™ program.

Illustrations by Lainie Mann – Visual Communications

 

The JA® Professional's Guide to Fine Jewelry Craftsmanship

Fabricating a Three-Stone Ring

By Mark B. Mann
Director of Professional Certification
Jewelers of America

 

Professionally Fabricated Prong Assembly for Baguette Side Stones
A. The upper and lower gallery wires are evenly spaced and proportionate.

B. The assembly is in alignment and conforms to the radius of the inside ring shank.

C. Notches (into which the prongs will be soldered) are burred into the gallery wires at a depth of one-third the wire’s diameter.

D. There is no excess solder at any solder joint nor any cold or incomplete solder joints.

E. Prongs are perpendicular and evenly spaced.

F. Prongs are long enough for stones to be set into them securely.

G. The prong assembly has no tool marks.

Potential Problems to Watch for:
When the stone is set, you should not be able to see the upper gallery wire when looking down at the setting. The baguettes should be equally placed from side to side.
The angles of the upper gallery cups differ from side to side.
The upper gallery cups are attached to the center stone assembly at differing heights.
Excess solder and excessive tool marks are visible in the solder joints – signs of errors in workmanship.
© 2000 Jewelers of America Inc.

This information is required for the fourth level of the JA® Certified Bench Jeweler™ program.

For information about the JA® Certified Bench Jeweler™ program, call JA at (800) 223-0673 or visit www.jewelers.org.

Illustrations by Lainie Mann – Visual Communications


Copyright © 2001 by Bond Communications