tension settings

[xsscx]

Are tension settings as secure as prong settings? Should I worry about the diamond, a 1.40 square, falling out of the setting?

 

[Rank Amateur]

Tension setting is a tricky thing. I think it's really a compression setting with the band compressing the stone with the squeezing action holding it in place. Service is an issue because checking and re-sizing can't be done by just anyone.

The only advice I would give is to go with an established brand. I believe Steven Kretchmer is the inventer, but keep in mind you'll pay as much for the setting as the stone! There are also some knock-offs which claim to be as sound, but which Kretchmer claims are inferior.

My wife broke a prong on her engagement set and lost the diamond. I suppose that could never happen in a tension setting, so maybe they are MORE secure rather than less!

R/A

 

[justme]

Here is and excerpt from an article about Kretchmer tension settings:

in Kretchmer's designs the equivalent of 12,000lb. per square inch of metallic, springy pressure. Few gems (only those scoring 9 (out of 10) or higher in the hardness scale such as Ruby and Sapphire) can sustain this enormous pressure, first among which is Diamond, the gem of highest hardness (10 out of 10). The exerted pressure guarantees, further, safe setting for longer than a lifetime.

and more

Despite the appearances of "floating in mid air", the mounting is stronger than most conventional prong and bezel settings which tend to loosen with time and use (it enjoys, furthermore, the added benefit of eliminating the unnerving entanglement of prongs in fabrics...). This due to the treated metal springiness and to the fact that more surface is touched by the setting but at points that are optically less critical in terms of exposure of beauty, brilliance and wholesomeness of the Round Brilliant shape: Kretchmer settings hold their diamond solely by its girdle.

The aging and seasoning of the treated metal in Kretchmer's studio furnaces prevent the brittleness that precious metals develop over time and guarantee the treated metals longer endurance and longer retaining of their finish than their standard, untreated 'equivalents'.

Statistically, practically and mechanically speaking a Kretchmer tension setting will never loose its diamond. Only through the use of specialized tool may a Diamond be de-mounted from those settings. Similarly, Kretchmer rings can be set and mounted only in Steven Kretchmer's studios.

 

[justme]

Here's info from a different vendors site.

Tension Settings: Platinum Tension Settings are popular as Engagement Setting and Anniversary Ring. The tension setting concept is over 40 years old. Over 10,000 tension setting diamond rings have been sold. Our tension set diamond rings are manufactured by Gelin and Abaci (G.A.I.) and not by Steven Kretchmer. There have been no known diamond losses due to design or craftmanship. Every tension set ring is closely inspected to ensure it meets the high standards. Each tension ring is custom made for a specific diamond size and finger size. Each tension product is manufactured with special alloys with a sophisticated technique which enables the metal to retain its memory. Tension products have anywhere from 65 to 95 pounds pressure on the center stone.

Advantages: Tension settings are a unique means of showing and selling loose diamonds. Tension mounting is the very best method of showing a stones brilliance. It can enhance the color as much as two grades.

Safety: Tension settings are considered to be safe or safer than a four prong setting. With over 10,000 units sold, there have been no known diamond losses due to design or craftmanship.

Pressure: Depending upon the style tension settings have anywhere from 65 to 95 pounds pressure on the center stone.

Stone Setting: Tension products have been manufactured for stone from 0.10 carats to 8.0 carats.

Stone That Can Be Set: Stones with harness of 8 and up can be set in tension set rings. Stones below hardness of 8 like tanzanites cannot be tension set. Rubies and sapphires as well as diamonds can be tension set. Any stone with surface fracture is not suitable for tension mounting.

Stone Mounting: Due to special memory in tension product all stones mounted in tension product has to be done by us (no exceptions) Any adjustments to tension set rings have to be done by us (no exceptions).

How Long It Takes: Please allow 10 working days for gold tension product and 14 working days for platinum tension products once we receive your stone.

 

[Giangi]

BTW, Gelin and Abaci prefer to work with SI 1 or better stones...