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Controlling Proper Mandrel Expansion with the GRS ID Ring Holder (#004-735)


Thursday, July 12th, 2012 Published in: Tech Tips & Tricks

The GRS ID Ring Holder (#004-735) is one of the best holders for working on rings. The sturdy steel frame uses a double expansion cone system designed to securely hold rings from the inside for secure stone setting and engraving.

Normally, the ring should be placed in the center of the mandrel (plastic collet) so that it expands and grips the ring evenly. However, some jobs require the ring to be located at the outside end of the mandrel. The following tip will show you how to control proper mandrel expansion in these situations.

Normally, locate the ring in the center. Note how this provides equal expansion of the mandrel on both sides of the ring.

Normally, locate the ring in the center. Note how this provides equal expansion of the mandrel on both sides of the ring.
If the ring is moved to the outside end of the mandrel, note how unevenly the mandrel expands.

If the ring is moved to the outside end of the mandrel, note how unevenly the mandrel expands.

When engraving or stone setting on the side of a ring, you want maximum clearance to do the work. In order to get a good hold on the ring, you will find that the ID mandrel will not expand properly when tightened.

This is easily fixed by creating a balance of pressure to keep the expansion gap even across the mandrel. A set of Finger Gauge Rings are relatively inexpensive and will work well for this application. If you do not have a set, you can use a ring of similar size to control the mandrel expansion. Be sure to use ring gauges that are strong and well-built. The wider sets are often better for this.

Here is an example of a wide band Finger Gauge Ring. The diameter matches the ring we are working on.

With the proper ring diameter matching both rings, you are ready to position and clamp the ring.

Now you can see that the mandrel is evenly supporting the ring without undue expansion.

Move the holder fixture to where it is comfortable for you to work as needed.