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Tension Setting


#1

Dear Abrasha:

Heya. Haven’t seen you in awhile. This is Steve Kretchmer. A
friend forwarded the various discussion about compression-spring
gemstone mountings (tension settings). Johann Exner (president of
Niessing) and I have discussed the origin of the tension setting
and I don’t really know if we agree. He insists that the designer
working for th em created the original tension setting and it was
the ring that looks like a giant jump-ring, the simple round wire.
This is truly the origin of the more contemporary look of the
tension setting, but I do believe that the concept is first seen in
Becker’s work, though his stones were removable. He has died
recently and I was hoping top meet him someday, not only because he
was so innovative, but also to discuss his feelings about this
origin of the tension setting issue.

I stress in all my interviews that Niessing’s work was first to
the market. I hold two patents on Methods for Making Compression
Spring Gemstone Mountings; Niessing strikes (work harden
/mechanical) their alloys to distort the crystal lattice increasing
hardness and elasticity; whereas I blend specific alloys and use
heat-treatments to increase its strength significantly. This allows
for various combinations of techniques (metallurgical means) to be
superimposed on the art object, and creates superior strength, like
steel vs. pounded iron.

Johann Exner and I respect eachother and have agreed to make
arrangements should we feel that our designs come too close
eachother. The tension setting is here to stay and has increased
in production and popularity in Europe. I have no protection there
for my patents that have been published, though I must be very
diligent in protecting my patents in the US.

Having been at the bench for 32 years, working the traditional and
futurisic, I do find that the tension setting is superior in
setting hard stones to other means, though has its design and
servicability limitations.

Examining alloys is one of my passions and after playing with
heat-treatables for awhile, I am working with Hoover & Strong, who
is distibuting two alloys for the market: Plat/SK-1 and
Plat/SK-2. They are heat-treatable, cast well, polish in almost
half the time, and wear much better than Pt-Ir’s, Pt-Co’s, or
Pt-Ru’s, but are general purpose blends, and inadequate for tension
settings. Heat-treating for tension setting is my intellectual
property anyway…at least for the next 11 years until the patents
run out.

Heat treatments have a myriad of uses. Not only for
strengthening, but creating special beautiful precious metal
compounds, including shifting of colors of specific alloys; not due
to oxidation, but because of creating new structures and phases.
Designs are always changing and expanding in our art.

I hope all is well with you and yours and hope to see you soon.

Steve

@Steven_Kretchmer


#2

Mr. K.

Have seen your work. Ingenious. Well executed. Excellent design.
Now, to up the ante. Have you given any consideration to expanding
the concept to larger objects? As in sculpture. As in much larger
pieces . . . three, four, five, six feet, or bigger. How would you
engineer it? Say, using a large, (circular ring, oval, rigid
angular construct) object to grasp a big stone, or other piece of
media. Precious metals would be out of the question. What would you
use? Stainless? Bronze? Polymer-based? How would you treat it? Is
it even conceivable? Does this even pose a challenge to you or is
this pathway irrelevant to your inclinations? Your observations
would be enlightening, even entertaining. Awaiting your reply, with
baited breath.

David


#3

I recently read an insert from Steve Kretchmer regarding tension
setting, I was discussing similar isues with a metalergyst and
he had heard that the alloy was going to be sold to the general
market possibly through hoover and strong. I was wondering if
you can verrify this? It is nice to have such an accomplished
jeweler on line, I have admired youre disigns for years and hope
to hear more from you. Amber Hummel


#4

Hi Amber! Can you tell me where I can find the insert your read
from Steve Kretchmer regarding tension setting. Also do you know if
there is sometihg to read somewhere, may be on the net, about this
alloy.? This is very interesting.

Tanks

Vincent Guy Audette
gaudette@videotron .ca


#5
I recently read an insert from Steve Kretchmer regarding tension
setting,  I was discussing similar isues with a metalergyst and
he had heard that the alloy was going to be sold to the general
market possibly through hoover and strong.  I was wondering if
you can verrify this? It is nice to have such an accomplished
jeweler on line, I have admired youre disigns for years and hope
to hear more from you. Amber Hummel

Yes, It will be available through Hoover and Strong next week. I
have been testing this material for over six months now for Steve
and the results are excellent. I am giving a presentation this
weekend regarding platinum SK and its casting properties. The
response from my clientele has been overwhelming. If you have any
questions feel free to e-mail me. Linus@AuEnterprises.com

Anything I can help with I will.
Linus


#6
Hi Amber! Can you tell me where I can find the insert your read
from Steve Kretchmer regarding tension setting. Also do you know if
there is sometihg to read somewhere, may be on the net, about this
alloy.? This is very interesting.

To read more on tension setting go to the IBM site for searching
for patents at: http://www.patents.ibm.com/patquery.html and
enter the following patent number: 5084108 From Surbhi


#7

Vincent, I read this insert a while ago on orchid, I am sorry, I
did not save it. If I do run across any more info I will let you
know. Amber


#8

Linus, Thank you so much for this info, where will you be giving
this seminar? Do you know where I can get info on how to properly
work this metal? Amber


#9
Linus, Thank you so much for this info, where will you be giving
this seminar? Do you know where I can get info on how to properly
work this metal? Amber

The “seminar” was this weekend in N.Y. at Platinum Day. Hoover
and Strong has a fact sheet on all the properties and how it
works best. If you still have questions feel free to write to me.

linus


#10

I’m sure many of you are familiar with the work of Steven Kretchmer
(http://www.jewelrystudio.com/designer/kreindex.htm). He markets
ring that hold a solitary stone with shank tension.

Does anyone know the proper procedure for tensioning a ring to
securely hold a stone? I am interested in learning this technique.

Randy
@Randall_Brooks2


#11

Dear Randy,

There is a thread in the achives about this and it is mentioned that
Steven K has a patent on this setting. He developed a special alloy
that will keep the tension, copies of this are made but apparently
will not hold the tension over time.

Marta in Sacramento


#12

Randy, First, Kretchmer holds the intellectual patent to this process
and it’s illegal to reproduce it without his permission. Second, the
procedure requires hest treating a special platinum alloy to make it
work, called SK platinum. Kretchmer holds the patent on that, too.
Thirdly, you cannot size one of those rings, as applying heat to it,
ruins the ability of the metal to hold the stobe securely. There are a
few workarounds, and we use them frequently when a customer wants
that “look”.

Wayne Emery
Jewelry Design Studio


#13

I believe that Hoover & Strong sells Steven Kretchmer’s platinum
alloy. Steve.


#14

He hasn’t patented the setting or the alloys, I think… anyway, it’s
quite simple to create a very similar alloy if they are covered.

There are many alloys which are heat treatable. He has patented a
heat treatment method for at least four alloys.

You are free to find your own heat treatment method, and create your
own rings.

  • darcy

#15

So far I’ve made tension rings in 14k pink gold, sterling silver, 18k
yellow gold, and 18k nickel white gold.

All have withstood wearing, though one self destructed under its own
pressure. Time will tell if they will last forever though.

Platinum is not necessary, and I believe that you can get adequate
results with any metal that you can heat harden. You just have to
find the balance point between the force required to deform the metal,
and the force required to securely hold the stone.

That is, if 1 square mm of your chosen heat hardenable alloy can put
forth 10 pounds of pressure before deforming under the load, then
you’ll need 6 square mm of cross section to securely hold your stone.

Over time, I believe, the copper containing gold alloys will become
even harder after mounting the stone, rather than softer. I’m no
metallurgist though.

As soon as I lose a stone, I’ll let you guys know. I’m purposely
experimenting with this stuff, and all have been gifts, so I’m not
gambling with a client’s money (I just do this stuff for fun).
They’ve all been warned too that the stones could fall out :-).

  • darcy

#16
     I'm sure many of you are familiar with the work of Steven
Kretchmer (http://www.jewelrystudio.com/designer/kreindex.htm).  He
markets ring that hold a solitary stone with shank tension. Does
anyone know the proper procedure for tensioning a ring to securely
hold a stone? I am interested in learning this technique. 

I’ve made four so far, basically teaching myself. Here’s a picture of
two:

Basically, if casting, you must:

(a) choose a heat hardenable alloy
(b) cast
(c) squeeze it closed a bit
(d) heat harden it
(e) pry it open on a mandrel 
(f) set the stone
(g) slide the ring off the mandrel

You can use a ring mandrel for tension setting some stones. The
sapphire ring in the picture above is actually done in sterling
silver. I have no clue if it’ll hold long term, but it’s an
experiment. To get that thing pried open, I pushed in a wooden wedge
with hand pressure until the two arms spread open enough to slip the
stone in. So far, it’s been in and worn for a couple of months, so so
far so good. I probably wouldn’t recommend using silver though.

My first ring I didn’t put very much pressure on the stone. It fell
out the next day. I reset the stone with more pressure and it’s held
for 8 months now.

My last ring I worked in white gold, and set the stone with too much
pressure. The ring, even though it was 4mm by 3mm (oval), cracked
under its own pressure. Nickel white gold can exert quite a bit of
pressure it seems :-). The diamond was OK.

I’m entirely self taught, and don’t have any means for measuring
what’s appropriate. I think though, that when I do this again, I will
make the ring to size, squeeze it 2mm smaller than the stone it is
going to hold, heat harden, then pry it open and set the stone. The
nickel white gold ring was closed to 3mm, and it was just too much. I
had a feeling because I’m a big guy (I once bench pressed 315 pounds,
though I’m not nearly that strong these days :-), and I could not get
the ring off the mandrel without a hammer. Previously, I’ve been able
to use my thumbs to push the ring off with the stone in place.

All of the rings I’ve done have notches where the stone fits in.

For setting tips, push the ring up the mandrel until you can snugly
fit the stone in… then you just gently, ever so gently, slide the
ring off. Again, in my last case I had to whack it with a hammer, and
I don’t think that’s a very recommended approach… required some
timing and luck to get it that way :-).

In the last case, even though the ring cracked, and the cracked arm
bent up under its own pressure, and the stone was now at a 30 degree
angle, it still stayed in, and I could not pry the ring open with my
fingers (couldn’t really get them into the ring though, so I couldn’t
apply much strength). Tension rings are pretty solid things if done
right.

I absolutely love the look of the things, and they’re my favorite
thing to make!

  • darcy

#17

Well, I do a lot of lurking and really don�t have enough time to
read Orchid all the time, but I had to say something with this one.

I have been to the workshop in Vreden Germany that made the first
tension ring, designed in the 80�s and marketed by Niessing it is a
pretty cool trick and I must say a lot harder than you might think.
First, the rings from Niessing are not cast but Forged (by heavy
machinery) each and every one, and they can take just about anything
you throw at them, including sized up and down five sizes ten times
with stretching and crushing without breaking (I have seen it, so
don�t any of you tell me it can�t be done) then the area where the
stone will set is removed by a C and C machine and all the parameters
have to be met in a tension testing or the ring is thrown into the
fire and melted back down. Then it is set by one of the setters,
(incredible men that can do really great work) and then tested again.
And in the past 20 years, they have not lost a stone due to
manufacture responsibility or negligence.

The other ring makers make their rings by casting, but Steven
Kretchmer has a patent on the metal. SK-1 or something like that
(can�t remember) and will remain springy and keep the tension, after
reading �theory and practice of goldsmithing� (thank you Charles
Lewton-Brain) I have some idea of how he may have pulled that off.
But there are a few others, but I would not recommend trying it
yourself, you put yourself in the position to loose a lot of stones
from your rings, and we all know that means a lawsuit in California
(not sure where you are)

If you are he11 bent on making one I would make it out of a
stainless steel grade that will take the tension but then you have
the problem of not shattering the stone when you set it. Niessing
will not set any diamond less than SI1 in clarity as it can destroy
the stone. And something like topaz or tourmaline, well you could
just kiss those goodbye and hit em with a hammer rather than ruin em
like this.

I used to work for Niessing and saw lots of the rings set, so if you
have any questions, let me know off the board, I may not get to read
your questions.

Aaron A Tracy
@Aaron