Professional Jeweler Archive: Channel-Setting Round Diamonds in a Multiple-Level Ring

December 2001

Professional Bench/Defining Quality


Channel-Setting Round Diamonds in a Multiple-Level Ring

Knowing how to accomplish this task demonstrates another aspect of quality in your shop


Multiple-level stepped rings, those with channels descending down their sides, are among the more difficult setting projects for bench jewelers. This article will describe how to do the job in a professional manner.

Multiple-level stepped channel rings are difficult setting projects because there’s only one exposed channel wall to work with when tightening the stones. Precise seat cutting is essential, especially on the inside channel walls.

General Channel Setting Guidelines

1.

When channel setting round stones less than 10 points or 3mm diameter, the width of the channel should be 90% of the stones’ diameter.


The proper inside channel width for a 2.5mm diamond is 2.25mm. This width provides adequate support for the stone and reduces the amount of metal you will have to cut away to set it.

A channel wider than 90% of the diameter of the stones will not adequately support them.

Narrow channels have too much metal to remove and will interfere with the seat cutting and setting process. Narrow channels often result in scalloped walls or damaged gems.

2.
  • The channel should not be more than twice or less than three-quarters of the depth of the diamond.

  • Overly deep channels will weaken the strength of the channel walls.

    Shallow channels will cause the stones’ pavilions to sit on the base of the channel – trapping the stones.

    Trapped stones often have ragged finishing around the girdles and are more difficult to clean.

    3. Use a 70° bearing bur to cut bearings or seats for stones.

    45° bearing burs cut too shallow a bearing.

    70° bearing burs are ideal.

    90° bearing burs remove too much metal and cause excessive gaps between the bearing and the stone.

    Remember the most precious metal that bench jewelers work with is often cut away.

    Steps to Channel Setting a Ring with Multiple Stepped Levels

    1. Every stone-setting procedure, no matter how simple, requires proper layout.

    Place the stones table down and mark their lateral locations. This can be done by direct measurement or by fixing the stones to the top of the channel wall with sticky (boxing) wax.

    Next, mark the depth of the seat cuts on the inside channel walls. The top of the table should be even with the top of the channel wall.

    If channel-set too shallow, a stone will have insufficient metal coverage.

    If channel-set too deep, a stone will be difficult to tighten.

    Always take into account variations in individual stone thickness and place the seats so all tables will be level and even with the top of the channel wall.

    2. The bearings are cut differently for channel setting stones in multiple stepped levels than for channel setting in a single row.

    Use a 70° bearing bur. The bur's diameter should be slightly less than the width of the channel.

    Cut the bearing inside the channel wall, making sure it’s level. If it’s not level, a wider bearing will be required to make it level. If you remove too much metal from the bearing, you’ll have trouble tightening the stone in the final step. After the inside wall is prepared, repeat the procedure for the outer wall.

    After preparing opposing bearings for each stone, cut an angle from the inner lip of the top of the outside wall down to the girdle line of the seat.

    Slide the diamond into the inner seat first. Once the girdle has cleared the lip of the outer channel wall, it can slide down and into the seat of the outside wall.

    Tighten all stones in a row at one time, starting with the central portion and working to each outer edge.

    (A) Bevel the outer channel wall. Use a hammer tool to lightly tap the channel wall down onto the stone, securing it in place.

    (B) Use a small needle-type burnisher to push extra metal over the stones if the bearings are too large to hold them tightly.

    Solder shouldn’t be necessary. If you have to use solder to fill gaps, you need more practice in channel setting.

    When all of the stones are tight, file flat and polish the outer channel walls.

    By Mark B. Mann, Director of Trade Programs, Jewelers of America

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

    ©2001 Jewelers of America Inc.
    Illustrations by Lainie Mann – Visual Communications


    The JA® Professional’s Guide to
    Fine Jewelry Craftsmanship

    Channel-Setting Diamonds into a Multiple-Level Ring

    By Mark B. Mann, Director of Trade programs, Jewelers of America

    Professional Multiple-Level Channel Setting

    A. All stones are tight and secure.

    B. All stones are level and evenly spaced.

    C. Individual bearings or seats are cut for each stone.

    D. The tables of all stones are at the same height and even with the channel wall.

    E. 10%-15% of each stone’s total diameter is covered by metal from the two opposing walls.


    Potential Problems to Watch for

    Channel Wall Is Too Wide

    Not enough of the stone is secured by metal from the opposing walls. These stones will become loose and can be lost during normal wear.


    Channel Walls Are Overly Deep

    The stones are set too high in the channel wall. Overly deep channels are weak and don’t offer needed security for this style of setting.


    Many Stones Are Loose in the Channel

    Care wasn’t taken when cutting the bearings, so the stones aren’t tight in the channel setting.


    Stones Are Set at Differing Heights; Some Are Not Level

    Care was not taken when cutting the bearings.

    This information is required for the second and third levels of the JA® Bench Jeweler Certification™ program.

    © 2001 Jewelers of America Inc.
    Illustrations by Lainie Mann – Visual Communications

    Copyright © 2001 by Bond Communications