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Prongless Setting


#1

If you want a prongless setting, you may want to consider duplicating
Steven Kretchmer’s process of compression setting. (I think we can
expect a flame for this) He has patented the process. If you are
interested in his version of this process go to the US Patent Office
online and query his name and you will get the details which I assume
are accurate.

The only drawback of a tension setting is that the band must have a
pretty large diameter cross section that may be uncomfortable to the
wearer, especially on petite fingers. This is the primary reason I
gave up on the idea. Still, the design has its merits. The setting
provides for maximum exposure of the girdle.

You may also consider making the ring with a small bridge across the
underside of the stone, small enough to not be easilly seen. This
solution solves the problem of patent infringement; thus avoiding
Kretchmer’s wrath, allows the band to be made narrower
cross-sectionally and asures that the diamond wont pop out.


#2
   If you want a prongless setting, you may want to consider
duplicating Steven Kretchmer's process of compression setting. (I
think we can expect a flame for this) He has patented the process.
If you are interested in his version of this process go to the US
Patent Office online and query his name and you will get the details
which I assume are accurate. 

You get the synopsis, not all the full details. For that, you’d have
to order a copy of the full patent papers.

Keep in mind that the shape itself, thick cross section included, is
incidental to what Steve’s real techical contribution is here. A
number of people have copied the design itself, usually with
unsatisfactory results, since even in thick metal, rings made this way
with our normal jewelry alloys won’t be strong enough to stay tight.
Steves rings stay tight and secure because he’s using specially
developed alloys which can be heat treated to greatly increase hardness
and elasticity well beyond what’s normally possible with your regular
standard gold or platinum alloys. The result is that his rings not
only look like they are holding the stones under tension, they
actually do. They function as highly engineered compression springs,
and if spread apart a little, loosening the stones (this takes a
surprisingly large amount of force, by the way, with his rings), the
rings snap right back into shape, again holding the stones when you
release the metal. It’s this characteristic that makes them not only
safe, but probably safer than most of our more conventional methods of
setting diamonds. It’s damned hard to get his stones out. He’s not, by
the way, the only legal producer of this type of setting. Only holds
the U.S. patents on it. The german manufacturer, Nissing, also
developed the process, and produces similar rings in europe.

 You may also consider making the ring with a small bridge across
the underside of the stone, small enough to not be easily seen. This
solution solves the problem of patent infringement; thus avoiding
Kretchmer's wrath, allows the band to be made narrower
cross-sectionally and asures that the diamond wont pop out. 

Kretchmers solutions, however, is far, far stronger than the common
design mentioned above with a bridge under the stone. The trouble with
the bridge is that in this design, the weakest point is that bridge.
If you bend the shank out of shape at all, such as is easy to do with
the suggested thinner and narrower bands, then the bridge becomes a
hinge, easily allowing the shoulders to spread apart a little, thus
loosing the stone… with Kretchmer’s bands, you simply cannot bend
the metal out of shape like this. Plus, his metals are hard enough to
allow them to wear much better than is normally the case.

Steves specially developed platinum alloys, in particular, are of
interest, since conventional platinum alloys are noted for their
softness. With these alloys, you can make your piece with the metal in
the soft state, then heat treat to harden afterwards. Big difference in
the durability of the piece. While the specific high
hardness/elasticity alloys that Steve developed for his tension rings
have been kept secret, he has marketed somewhat less critical versions
to the trade, though Hoover and Strong, who sells the platinum alloy as
"Platinum SK ™". The heat treat cycles for this are considerably
easier to perform than his own tension ring version, and give many of
the same advantages, for normal fabrication work.

And finally, as you’ve expected Flames for suggesting that we copy
Steve Kretchmer’s work, I’ll be happy to comply. SHAME on you.
Really. I know we’re in an industry where many people have no respect
for the creative efforts of others, and are happy to be leeches,
profiting from other’s idea with no respect for either the copyright
or patent laws, nor for the common decency of respecting someone elses
work. Knockoffs are everywhere. But the prevalance of this dispicable
practice does not forgive it, or make it right. Nor is there any
increased excuse for doing it yourself just because some others do so.
I’m all for eagerly examining what Steven Krechmer has achieved with
his work, and learning from it. I’m sure he doesn’t mind our study and
our attention. He has, after all, learned much from other jewelers
who went before him. But this is different from taking someone elses
idea and stealing it. He owns the patent. and the copyright.
Respect that, please. His work easily stands apart from that of
others as a creative body of work worthy of respect and honorable
treatment on the part of his fellow jewelers.

But of course, I know that the above paragraph is of academic value
only, since I’m sure nobody with enough brains to be on this list would
ever dream of stooping so low as to be knocking off someone elses
creative work, now would we? Certainly not the poster to whom this is
a response…

Peter Rowe