Professional Jeweler Archive: Bead- and Bright-Cut Setting Rounds in Platinum Using Triple Corner Beads

October 2003

Professional Bench/Defining Quality


Bead- and Bright-Cut Setting Rounds in Platinum Using Triple Corner Beads

Knowing this stone-setting technique demonstrates another aspect of quality in your shop


This demonstration features Steece Hermanson using the bead-and-bright-cut technique to set a 5.2mm round diamond in the top of the platinum ring illustrated below. He uses a triple-bead cluster, with two securing the diamond and the third one adding a decorative finish to the setting.

Creating the Bearing

1. Hermanson constructed this ring using PT950, a platinum ruthenium alloy. The final step is setting the center diamond, which measures 5.2mm. Here is his procedure.

2. He drills a pilot hole measuring half the diameter of the diamond. Shown in this illustration, Hermanson uses a 5.0mm bud bur to enlarge the pilot hole.
3. For the final step in creating the bearing, Hermanson selects a 5.2mm (or slightly smaller) setting bur to create the bearing. “If the bur is even 1/10mm too large, the stone will never be secured tightly in the setting,” he says. “It should bite into platinum when being pushed into the bearing.”
4. The depth of the bearing is 90% of the total crown height. The diamond should fit snugly into the bearing.

Preparing the Plate for Setting

5. Using fine-point dividers, Hermanson marks guide lines that are parallel to the outside edges of the plate and that touch the circumference of the bearing.

6. Without the diamond in place, Hermanson uses a 3/0 point graver powered by the GRS Graver Max to cut fine “thread” lines along the guide lines he scribed in step 5. To ensure good control and the cleanest work, he cuts the thread lines in steps. The first cuts (eight in all) are made starting 1mm to 2mm from a corner up to the bearing (the graver should just break through to the inside of the seat). Next, these lines are extended just to the corners, working in the opposite direction (eight more cuts). Several passes are made with the graver until the depth of the thread lines is level with the position of the girdle.
7. Using a #2 knife graver, Hermanson cuts the outside edge of the two beads closest to the bearing. He removes the small amount of metal outside the line using a flat-bottom graver.
8. Next, Hermanson defines the corner junctions of the plate. He uses a 3/0 point graver to make a cut from the corner of the plate to the base of the corner bead. He repeats this cut on the three remaining corners.
9. Hermanson begins the bright cutting on the sidewall using his #2 square graver. He positions the graver 25% of the way down one side going toward the corner and cuts metal away. His goal is a wall evenly bright cut at 45.&Mac251; He’ll make the final bright cuts after he’s set the stone.
Tool Note

Hermanson has relieved his #2 square graver on the bottom or belly side by 5&Mac251; to 10&Mac251; (A). The belly is polished to a mirror finish using a ceramic lap on the GRS Power Hone. As a final step in polishing the graver, he coats a leather strap on one end with green rouge and on the other end with white rouge. He drags the belly of the graver backward down the green rouge side three or four times and then on the white rouge side. The graver is mounted in a quick-change unit for the GraverMax handpiece. “When setting stones in platinum,” Hermanson suggests, “it’s very important to polish the bottom side of all gravers used in the process. When done, there are no fewer marks, and the final polishing is less time-consuming.”

Final Preparation, Bead Forming and Setting

10. Gently rebur the bearing using the same setting bur to remove all rags of metal. Use a brass pusher to firmly seat the diamond in its bearing. Ensure the diamond is level. “Remember, the diamond should grip or bite into the bearing wall at this stage,” he says.

11. Using a 52 round bottom graver with a 50&Mac251; to 55&Mac251; face, Hermanson pushes the beads slightly onto the diamond. He partially moves all eight beads onto the diamond, working opposite corners.

12. With the diamond only partially set, Hermanson completes the final setting and bead-forming simultaneously. Remember, the corner bead is for decoration, but it will need shaping at this stage. He pushes the two adjacent beads from different angles onto the diamond. This technique also forms the rounded bead shapes. Again, work the beads on opposite corners.

13. Remove any burs or unwanted pieces of metal with the 3/0 or #2 flat graver.

Burnishing the Beads

14. Hermanson uses a #10 beading tool for final formation of the .75mm beads. Too small a beading tool would leave flanges around the beads; too large a tool would cut into the back of the newly formed bead or the plate.

Final Steps

15. He uses the #2 square graver for the final bright cutting.

16. With the tool work completed, he does final polishing.

17. As the last step, he selects an appropriately sized fine milgrain tool. Applying even pressure, he gives the top edge a finished beaded appearance that will wear evenly. Hermanson likes the edge that’s being milgrained to be slightly rounded, fitting the milgrain wheel. “When the edge is too sharp, the metal mushes over, giving a crude appearance,” he says.

Procedure Summary

Setting the center stone took Hermanson 2 hours. For questions, contact Steece Hermanson at shermanson@ftc-i.net or Mark Mann at mark@visual-e-communications.com.


Professional Setting for Ovals in Partial Bezels

A. The beads are evenly shaped. They also generously secure the diamond and are free of tool marks.

B. The bright cuts are angled at about 45,&Mac251; highly polished and free of tool marks.

C. The corners of the bright cuts above the beads are sharp and well-defined.

D. The side of the plate is polished and free of tool marks.

E. The milgraining is applied evenly and consistently.

F. The stone is centrally set in the top plate with even space around it on each of the four sides.

– by Mark B. Mann

Technical contributions by JA® Certified Master Bench Jeweler Steece Hermanson of Galloway & Moseley, Sumter, SC

Illustrations by Lainie Mann
©2003 Visual Communications

This series is sponsored in part by Jewelers of America, (800) 223-0673

Copyright © 2003 by Bond Communications