Professional Jeweler Archive: Installing a Superfit Shank with Laser-Welding Technology

January 2003

Professional Bench/Welding Technologies

Installing a Superfit® Shank with Laser-Welding Technology

Laser welding improves overall shop proficiency while increasing quality for repair, reconstruction and jewelry manufacturing

Job envelope instructions: Install a 14k yellow gold Superfit mechanical shank onto a customer’s engagement ring. Finished size 6 when closed.

This article describes a bridge-type installation for a Superfit® mechanical shank on an engagement ring using a laser welder. See this month’s Fine Jewelry Craftsmanship (p. 81) covering torch-installation procedures.

The 14k yellow and white gold size 6 ring requires a mechanical-shank device. The ring is 3.6mm wide at the top, 2.6mm at the bottom. The 14k yellow gold Superfit mechanical shank size 6 is 2.5mm wide. (Superfit 2.5mm mechanical shanks actually measure 2.7mm.)

Consideration for Installation

A bridge-type assembly is most appropriate for this project because of the ring’s lightweight and open design at the top. See page 81 for a description of the two methods typically used for installation of rings onto Superfit mechanical shanks.

Preparation Steps for Preliminary Installation

1. Hermanson marks the hinge and latch sides of the Superfit mechanical shank.

2. Using dividers, he locates and scribes the exact top center of the shank.

3. He removes the engagement ring’s shank by sawing precisely at the end of the baguette setting on each side of the center stone.

4. He files each end of the ring top flat then, using dividers, measures to locate the exact center of the top.

5. He positions the engagement ring at the top of the Superfit mechanical shank directly over the marked center location.

6. He measures and scribes guidelines. Using a saw, he removes 1mm of depth from the top of the shank, then files and fits the engagement ring for a precise fit.

7. Once the Superfit mechanical shank is prepared for the engagement ring, Hermanson checks the fit. There’s a small gap between the shank and the ring. The engagement ring is size 6 and is being installed on top of a Superfit size 6, so the radius needs to be slightly larger. The standard difference is about 2mm.

8. The ring is too sturdy to reform simply, so he saws two notches at the base on each side of the center stone setting and reforms it over a ring mandrel. The center arrow indicates the center line of the ring; the outer arrows indicate notches made with a 4/0 saw blade.
9. Hermanson files an open angle around the bottom edge of the engagement ring for better weld penetration (indicated by the arrows). If he didn’t, the welding of the joint would be limited to the surface and would not be strong enough to hold. The angle allows him to prepare a deeper weld joint to permanently bond the components.

Hermanson uses his laser welder.

10. Hermanson scribes alignment guidelines on the ring and shank that he’ll use to properly tack and position the pieces before welding.

11. Next he sets the laser welder at 240 volts, 3.3 milliseconds with a focus of 6 and tacks the two pieces together in several locations and double-checks the alignment.

12. Using the same equipment setting and 28-gauge 14k yellow round wire, he fills and joins all metal in the space between the ring and mechanical shank. (Arrows indicate 28-gauge filler wire and ring being welded to the mechanical shank. Photo taken while work was being done inside the laser cabinet.)

13. As he works, he holds the 28-gauge wire parallel to the open groove that he’s welding. He aims the pulse of light directly at the tip of the wire that’s in contact with the engagement ring and Superfit mechanical shank in the groove. The metal from each of the components is joined.
14. He has successfully welded the ring to the Superfit mechanical shank. Now he sets the laser welder at 300 volts, 3.8 milliseconds, with a focus of 17 to smooth the surface of the welded seam.

Finishing Procedure

15. He performs the finishing and inspection. Two areas require additional welding to fill voids, then he polishes the final assembly.

Procedure Summary

Laser welder settings vary by unit and brand. This bridge installation procedure from start to finish required 1.25 hours.

– by Mark B. Mann

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

For questions related to this process, contact Steece Hermanson by e-mail at shermanson@FTC-I.NET.

Superfit Inc. provided material for this demonstration. For questions related to Superfit mechanical shanks or for a list of distributors, call Gina Alulis at Superfit Inc., (800) 765-7111.

Illustrations by Lainie Mann

Copyright © 2003 by Bond Communications