Invisible stone setting basics

Jewelry Discussion
21 
I know that there is a Blaine Lewis tutorial in the Orchid
archives that gives an illustrated step by step of the invisible
setting procedure, at least one method. It's worth a look.

That is exactly what I mean. All tutorials uses pictures made by
computer. I want to see photos of the process made by human hand.
Where can I see that?

I am sorry to come across so distrustful of fellow goldsmiths, but
methods illustrated require precision, which can be achieved in
setting one or two stones, but if you have to set 50, even tiniest
errors will accumulate until subsequent stone couldn’t be set.

Here is an experiment that you can try:

Take 20 calibrated stones. Make sure that they are all cut well.
Measure on stone and multiply measurement by 20 ( number of stones ).
Make a box with inside exactly corresponding your calculation and see
if you can fit all 20 stones in this box.

The rail method has no margin for error, not even slightest. In real
world, it is not achievable. All the techniques that I know, and I
know some elaborate ones, there is always a compensation system to
account for inevitable tiny mistakes. I cannot find such system in
the rail method. If someone knows of one, I stand by to learn.

Leonid Surpin

22

when you heat a ring the hole gets bigger. This works even if the
hole is in a piece of plate. If you shrink a pin by freezing it you
can put in into a hole that is too tight when it is warm.

This works all the time… I don’t know how Leonid thinks… His
comments on brass don’t fit reality either,

jesse

23

Leonid

Take 20 calibrated stones. Make sure that they are all cut well.
Measure on stone and multiply measurement by 20 ( number of stones
). Make a box with inside exactly corresponding your calculation
and see if you can fit all 20 stones in this box.

In commercial production of invisible set jewelry, the stone setter
cut each stone to fit. They don’t use calibrated stones… Go and
visit some factories in Thailand to see how it’s made…

24

Leonid,

I am afraid but hole does get larger upon cooling. If you think
about for at least 10 seconds, you would understand why.

Take a piece of 1mm flat brass and drill a 6mm hole in it. Measure
is exactly. Now heat it up. Measure it again. You will notice it is
larger when hot…I promise you. I have just done that and the hole
increases in size by .3mm And if I leave my digital caliper in the
hole as it cools down, I can see the numbers go down as it shrinks.

Cheers, Hans
http://www.meevis.com
http://hansmeevis.blogspot.com

25 
I suggest you think about it for more than 10 seconds then. Take a
sheet of metal, scribe a circle on it and heat the sheet. The
sheet expands of course, but what happens to the circle? It expands
too, obviously.

That is correct but it does not apply.

When stones are cast in place, a hole never existed in cold state. It
is created hot and when it cools off, the metal shrinks away from
stones, and hole is getting larger.

Leonid Surpin

26

I have got a lot of email on the subject, but examples with taking a
hole which was created cold, and heating proves nothing.

I am going to write a long dissertation to show why holes is getting
larger. Starting with basics:

Metal, like any other substance is simply a bunch of atoms held
together by force very similar to gravity. When we heat metal, the
heat energy is absorbed by atoms and they begin to move faster and
faster. The more we heat the faster they move. Since mass of atoms
does not change, but speed of motion does, the distance that they
cover is getting larger and we observe that metal is expanding. If we
continue heating, the distance between atoms becomes so large that
forces of attraction cannot maintain shape anymore and metal become
liquid.

Upon cooling a reverse is taking place. As temperature decreases,
atoms receive less and less energy and the distances between them
shrinking and therefore the whole piece of metal shrinks as well. The
largest amount of shrinking will take place where the largest
concentration of atoms is. And it is stands to reason, since every
individual atom will contribute equal amount of shrinkage. Round
holes actually become ovals if distance between them less then the
edges. Anybody who ever made a model for pave in metal, knows this
phenomena.

When piece is cast with stones in place, the hole does not know it’s
cold state. The hole is created when metal is liquid. Upon cooling
metal will shrink away from stones thereby creating holes which are
larger then stone dimensions.

Leonid Surpin

27 
When piece is cast with stones in place, the hole does not know
it's cold state. The hole is created when metal is liquid. Upon
cooling metal will shrink away from stones thereby creating holes
which are larger then stone dimensions.

Leonid Leonid…even if its true…We were talking about Invisible
stone setting not about cast in place stones… I am not sure why
you are spinning the subject…A simple “I was wrong” would do just
fine…:-)) It takes a great man to admit his mistakes

Cheers
Mark in waking Prague

28 
The rail method has no margin for error, not even slightest. In
real world, it is not achievable. All the techniques that I know,
and I know some elaborate ones, there is always a compensation
system to account for inevitable tiny mistakes. I cannot find such
system in the rail method. If someone knows of one, I stand by to
learn.

But there IS a little compensation available in the rail system,
Leonid. Remember that in invisible setting, though the stones look
like they are in contact to the naked eye, if you use a good loupe
and examine such work carefully, you’ll find there remains a tiny
gap between stones. Each stone is fitted and pressed in individually,
so the seat can be slightly adjusted as neede for each stone, with
the exact fit determined when you actually push or “click” the stone
into place. And tiny differences in accuracy can be taken up in tiny
variances in that little gap between stones. If the stones were
actually in direct contact with each other instead of only the
metal, they would never be completely tight, and would be at great
risk of chipping. The same tiny bit of leeway also exists when
invisible set stones are placed into individual “box” seats instead
of just two rails. The metal, which isn’t visible of course, is what
takes up any bit of slack in exact measurements.

Peter

29

Basic annealing principles at work here. When heat is applied
molecules separate causing expansion. When cooled they are contracted
causing shrinkage. Quenching however adds a different element all
together… cracked stones! LOL. Steve I can’t see how a hole gets
larger and stays larger, unless the piece stay hot. Not a Scientists
by never have seen it.

30

I am sorry Leonid, but you are wrong this time ! Metals - and
jewellery metals are no different - expand when heated and shrink
back when they cool.

At my day job we work with engine flywheels sometimes, replacing the
ring gears, they are made much smaller than the flywhhel, then
heated to a certain temperature, this expandes them so they slide on
easily, when they cool they are tight ! I have a friend who has done
this with a stone and a silver ring - no pushing a bezel over, just
really tight !

Best wishes,
Philip Wells in Nelson NZ

31

Leonid,

hole which was created cold, and heating proves nothing.

If what you propose was true than a cast ring size would be larger
than the wax which it is cast from, which it is definitely not.

James Binnion
James Binnion Metal Arts

32 
In real world, it is not achievable.

Oh? That’s the problem with jewelry schools in general - students
walk out of them thinking they are jewelers. 90% of goldsmithing
isn’t taught in schools, it’s learned by process. There are no
tutorials or photos of invisible setting (that I know of) because
they’re not in the school business, they’re in the jewelry
manufacturing business. Most stuff is like that…

Invisible setting is really a variant of baguette setting, in terms
of fitting, which I can assure you is quite achievable. One stone at
a time…

33 
When stones are cast in place, a hole never existed in cold state.
It is created hot and when it cools off, the metal shrinks away
from stones, and hole is getting larger.

NO! the stone is captured in the metal in compression.

jesse

34 
Go and visit some factories in Thailand to see how it's made....

Related to the topic… One prevalent model of jewelry in the USA
these days is a person sitting at a bench. That person very often
has just enough training to do what they do, but largely have never
actually worked outside, much. And very often those people are
idealists, because they are working by rote - “It’s not ~a pinch~ of
salt, it’s 1/32 of a teaspoon…” And work is done by recipe -
just the cleaning methods for soldering in some books take up whole
chapters, especially the 60’s academic books.

As the saying goes, If you ever went in the kitchen, you wouldn’t
eat in the restaurant. Nobody in a jewelry factory cares whether you
use a pinch or a 32nd teaspoon, nobody thinks about whether metal
expands or contracts (unless it’s a genuine factor). That is, unless
you’re doing it just plain wrong, and wasting time and resources.
The only thing that matters is the result that you hold in your hand

  • that is the product of what you did to get that result, yes, but
    I’ve worked in shops where the white people are sawing handle down,
    and the Asians are sawing handle up. Nobody cares, it’s the work
    that matters.

Invisible setting is a melding of lapidary and goldsmithing much
like inlay is. They call the lapidaries “diamond cutters” because
it’s a specialty of lapidary, but it’s still stone cutting. One of
the big problems is no different than any other setting: You set a
diamond in prongs, cinch up the stone, and then you CUT THE PRONGS
OFF… The metal that you had in manufacture is no longer there
in a repair situation. And it’s much the same in invisible setting -
the manufacture is a process, and it’s just not repair friendly
after it’s done. The stones aren’t supposed to fall out, it’s not
designed to be worked on if they do.

Many, many diamond designs are made in such a way that diamonds MUST
be soldered on to execute the design - it’s common practice. I know
many repair people and novices here shudder at the idea, but in a
manufacturing situation it’s routine - it’s just another tool in the
toolbox.

Jewelry isn’t made by theory or idealism, it’s made by skilled
craftpeople, with their hands. You take two hours to bend some thing
into a shape, I pick up a hammer and go THWACK - they are identical
to the eye. That’s how it is…

35

Hi Leonid:

Have you ever done any cast-in-place work? I’ve seen CZ’s shatter
after casting from the pressure of the [contracting] hole. They
cooled down and divested just fine. They blew up minutes to hours
later, long after they’d hit room temp. Just sitting around waiting
for the tree to get trimmed. The wrong little shock, and ‘snap!’. Off
they went.

Leonid, you sound like you’ve been around lathes and machine-shop
sorts of work. Have you ever done a shrink fit, or bored a hole to
really tight tolerance? (By dial-turning, none of this CNC frippery.)
If you have, you should remember that you don’t do the final cuts on
the bore until the piece has cooled down from all the heat of the
initial cutting. If you try to bore it to final size while it’s hot,
it’ll end up under-sized after it cools. You can verify this
yourself, any time you like if you have access to a metal lathe.
Start with a 1.5" diameter rod of aluminum, about 4" long. Leave an
inch or two hanging out the front of the chuck. Center drill it with
a.875" drill, and bore up to 1.000" from there. Make sure that you
mike it carefully, and bore to an exact bore diameter of 1.000".
It’ll be hot as hell from the center drilling. Wait for it to cool,
and I guarantee it won’t still mike out at 1.000". Probably somewhere
in the .996" range, at a guess.

The fact that hot holes expand and cold holes contract is the basic
principle which makes shrink fits possible. I believe you would
agree that shrink fits are possible, and are in fact performed daily
in machine shops around the world.

Regards,
Brian.

36 
But there IS a little compensation available in the rail system,
Leonid. Remember that in invisible setting, though the stones look
like they are in contact to the naked eye, if you use a good loupe
and examine such work carefully, you'll find there remains a tiny
gap between stones.

It is true. I have seen some work on jewellery shows where there is
much more than a little metal showing. But I also have seen work of
Van Cleef and Arpel. I am in New York, so I have an opportunity to
attend Christies and Sothebys auction previews, where you can
examine pieces very closely. There is no gaps. It looks like a single
stone was cut to imitate many small stones. How this level of
precision is achieved always have been a great mystery to me.

Leonid Surpin

37 
I can't see how a hole gets larger and stays larger, unless the
piece stay hot.

You have stone set in wax. Model is invested and wax burned out. We
left with stones held in place by investment with spaces between
them. We pour liquid metal which fills these spaces. So stones
surrounding is created from metal where distance between atoms is
quite large. Metal begins to cool; distances between atoms start
shrinking and therefore the metal itself occupies less space when it
is cold, than when it was hot. We have a situation where there is
not enough metal to fill the void between stones when metal is cold,
because this void was filled by hot metal and hot metal takes more
space then cold metal. This what is responsible for making holes
larger.

Leonid Surpin

38 
If what you propose was true than a cast ring size would be larger
than the wax which it is cast from, which it is definitely not.

This is true of course, but that is because while the inside of the
ring is getting larger, the ring itself is getting smaller due to
shrinkage. So outside shrinkage compensates for inside shrinkage and
the net effect of this is that the wall itself getting thinner. If
you
would measure inside of the ring as a proportion of the outside,
after
casting that relationship would change with inside been relatively
larger than outside.

Here is an example from real life. Bronze sculpture is cast hollow.
The core of investment is supported by metal pins. The hollow wax
model is pierces by many metal pins in different places. The pins are
sticking out on the inside and outside. When model is invested and
wax
burned out, these pins support the core at fixed position. Than metal
is poured and pins are removed by the chaser while finishing. These
pins are pulled out very easily with small pliers and sometimes with
bare fingers. If the holes after casting were getting smaller, it
would be impossible to remove these pins and the technique of cire
perdue would not be possible.

Leonid Surpin

39 
It is created hot and when it cools off, the metal shrinks away
from stones, and hole is getting larger.

Every jeweler who’s actually worked at the trade knows better than
that. Sometimes what we say reveals more than we wished.

40 
In real world, it is not achievable.

In my opinion, the greatest compliment I can get from a fellow
goldsmith is “Wow! How’d you do that?” I love to try the impossible,
and encourage everyone to try to achieve the unachievable at least
once. You just might surprise yourself.

I don’t have a lot of experience with invisible setting, but I have
been talked into doing a bit of it and associated repair work. Here’s
how I do it, and from my limited experience how most people do it.
For a two row setting, the girdles of princess cut stones are grooved
along one side (for rails) or three sides for (square holes). The
settings usually are square holes that are azured on both top and
bottom forming a sharp edge that fits into the groove, with the
outside channel prepared much the same as a baguette channel. The
seat is carefully cut for the stone, one at a time, the stone is
fitted into the hole with the grooves fitted onto the azured edges.
The outside girdle is then lowered into the seat on the outside
channel, and the outside channel is then hammered down, just like
setting a baguette into a one-sided channel. A flat graver is then
used to press the azures into the grooved girdle and the next seat is
prepared and the stone is set, permanently holding the azure pressed
into the first stone by the graver. The process is repeated until the
final stone is set, usually hammered down on two adjacent sides, the
outside channel and the end of the row, just like a baguette or
princess, tightening up the entire row.

For three or more rows, it’s done the same way, except the stones in
the center row are grooved on four sides, and the stones are set from
the center out. The pressure from each stone holds the azure on it’s
adjacent stones in place. Don’t know about cast-in-place, but I would
expect a bunch of chipped corners and loose or missing stones.

The reason it gives people such fits is that the seats are
absolutely unforgiving of even the slightest errors in layout or fit
before or after setting. Any single error or poor fitting seat is
multiplied, and affects all the adjacent stones, which in turn
affects all of the stones. It is also quite a pain to have to reset
stones that fall out and nigh on impossible to tighten stones that
get loose without unsetting adjacent stones to allow access to the
loose stone’s seat, which will more than likely require rebuilding.
It is not unusual to find that invisible set stones are glued to stop
them from rattling (gee, I haven’t seen that since this morning). The
best way to avoid trouble with invisible settings is to assume they
are poorly set and glued, clean them very gently and quickly (don’t
use the ultrasonic if possible), never steam them from the back,
never heat them any more than absolutely necessary (or more than you
can hang on to with unprotected fingers - the heat can burn glue or
distort the seats during expansion and contraction which can cause
loosening), and be very cognizant of the reshaping of the piece that
will be caused by whatever you are being asked to do, like sizing.
Then tell the customer there is no guarantee whatsoever. Then tell
them again, and maybe one more time just to make sure they
understand. It is also helpful to charge exorbitantly so that if they
do say OK, you will have the time to fix it if things don’t go well,
or enough money to send it to someone that can fix it for you.

Invisible setting isn’t impossible or even all that difficult if you
can successfully channel set baguettes. It just requires extreme
precision and attention to detail at every step to be done well.

Dave