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Bezels with 90 degree corners


#1

I am attempting to set my first cabochon with 90 degree corners (rank
amateur). I have read John Cogwell’s “Creative Stonesetting” and he
describes the one approach of removing lots of the bezel at the
corners so the bezel basically is holding on the long sides only. His
explanation for another approach - where the bezel is left at the
same height all around - describes sawing into each corner of the
bezel multiple times to remove the excess material (and working
toward the corners from the sides). (I also read the past postings
on Ganoksin in 2010 by Helen Hill commenting on using sterling and
not fine silver). I am not comfortable with the process of sawing
inward, toward my stone so many times and it just does not ring true
with my past experience (working in upholstery/fabrics). Other
postings suggest starting with the corners and working to the sides.
So: If I use this technique, what gauge should I use for the bezel
and what tool should I use to work the bezel? AND does anyone have
other ideas for making the corners neat and tight? I do not think the
style of what I am trying to accomplish is compatible with changing
the bezel height at the corners. I am trying for a more traditional
and even 'primitive" look. My stone is lapis lazuli and the heighth
of the cab is low. Thanks in advance for anyone willing to advise me
on this. In the past, so many of you have been generaous with your
experience and time. I really appreciate it.

MaryAnn Christianson


#2
describes the one approach of removing lots of the bezel at the
corners so the bezel basically is holding on the long sides only.
His explanation for another approach - where the bezel is left at
the same height all around - describes sawing into each corner of
the bezel multiple times to remove the excess material (and working
toward the corners from the sides). 

I personally don’t like the two approaches above. I feel they look
tatty and I don’t think it is necessary.

I like to carefully close the bezel using a hammer and bezel punch.
As for the gauge to use, I like to use 0.5mm or sometimes even
thicker if the stone is large. Lots of people use thinner gauge in
order to close the bezel using a bezel rocker or burnisher, with
just one hand. Unfortunately, thinner metal doesn’t have the “squish
factor” of thicker metal. Thicker metal absorbs the excess material
as it compresses. If you use thinner metal, you may find that you
push your bezel in at one point, and it springs out at another.

Make sure the bezel is a nice fit for the stone (tight, with no
gaps) and that it is not too tall - this is crucial. If too loose or
too tall, the bezel has further to move and will never close neatly.
And of course your stone may rattle in its setting if the setting is
too big - not good!

My approach to corners (including squares, rectangles, trillion,
marquise and pear shapes) is to first of all, gently use the tools
to partially close the bezel in various places other than the
corners. Then work gently at the corners, pushing first at the
corner then towards the adjacent sides, to avoid too much metal at
the corners. Then go back and push more in the places other than the
corners and finally finish closing the bezel at the corners. The
outcome will be much neater if you do it in “baby steps”, rather
than just a few big pushes (and you’ll have fewer or no tool marks).
When you think you’ve finished, use your X10 loupe to inspect your
work, looking for any tiny gaps to close, where the metal may not be
all the way onto the stone, and go back in and close them.
Personally, I then use sideways motions with the same bezel punch
and hammer, to burnish away any tool marks. If that doesn’t work,
they can be filed afterwards.

Sometimes, the corner may still look “bulky” with excess metal. It
is very simple to take the correct file and file (and sand and
polish of course) your corners smooth/level with the sides. I
personally feel that it gives a much neater and more professional
look than lowering the bezel at the corner or sawing slits into it.

Regarding fine silver vs sterling. I was opinionated on the subject
and I still have the same opinion if concerning bezels made for
rings and bracelets, but would not be so forthright with my opinion,
as that’s all it is - my opinion. It comes from finding that
sterling itself is a relatively soft jewellery metal which dents and
scratches easily, so fine silver, for me (and I have worked with
it), is far too soft.

You could try the above technique and see if it works for you. With
some practice it gives very professional results. Watch you don’t
chip the stone’s corners though! All the best. Email if you’d like,
if you have questions or I haven’t explained enough.

Helen Hill
UK


#3
I am not comfortable with the process of sawing inward, toward my
stone so many times and it just does not ring true with my past
experience (working in upholstery/fabrics). Other postings suggest
starting with the corners and working to the sides. 

Your instincts are correct. Multiple cuts towards the stone is
idiotic. Starting at corners is a bit better, but not for square
stones. It is used when angle between adjacent sides greater than
120, like octagonal shapes. Traditional look is obtained by using
traditional technique.

Start with preparing stone seat. It is important that stone fit like
a glove, or it will break, especially lapis. After seat is done you
should have 4 walls, which will be used to secure stone. Let’s number
them 1 to 4 in clockwise direction. Use 8/0 blade and cut through the
corners to the seat. Cut only once and make sure that cuts perfectly
vertical. While all this is going on, the stone should be out of
setting. Using triangular escapement file 4/0 or even finer, cut
triangular notches in the corners. Since inner surfaces of wall will
touch first when we bend, cuts must be done from inside. Size of
notches are important and determined via measurement and adjustment.

Start by studying the stone. It is advisable to measure the angle of
cut by a protractor. Notches must be cut so when walls bent over the
stone, there are no gaps between them. By starting slowly, cutting
less than necessary, adjusting, and comparing to the stone profile
one eventually will get it right. I am sorry, but I cannot offer any
visual aid which is required here. So one must rely on his/her
imagination.

With stone still out of the setting, bend wall 1 and 2 inwards until
desired angle is reached. Wall 3 and 4 must be bent outwards to allow
stone insertion, but no more! Slip the stone in and verify that it
sits without any movement. It must barely touch inside surfaces of
wall 1 and 2 and be perfectly level. When fit is achieved than close
wall 3 and 4 upon the stone and file to smooth out the setting.

Few points in regards to the technique. Walls (bezel heigh) must be
as low as possible. Excess of height means more outward bending will
be required and therefore more difficulty in setting.

Pliers for bending must of the best quality and only used only for
this purpose.

The best gage for the project is the one that you can comfortably
handle. Working carefully 24 will be fine. 22 may require use of
punch to close the bezel. For fragile stones there is no better
metal than 22k gold.

Leonid Surpin
www.studioarete.com


#4

I’m not sure how “organic” you are trying to be while setting your
90 degree cornered cab. The problem with setting the bezel at the
same height all around is that you are left with extra bezel
material; producing ripples at the corners. If the height of the
bezel on the corners is filed down in a gradual “swoop” using a half
round file from the inside out and then back to full height on the
sides, you eliminate that issue. Your corners are still supported by
bezel walls, but no extra folds or crimps. I normally use fine silver
for bezels instead of sterling because it is easier to push and does
not have that copper memory issue of sterling silver. Once the
corners are GRADUALLY altered, looking at the set stone face on gives
you no idea that the height has been changed- only when you hold the
piece up to eye level do you notice the changes. Another way to help
the issue is to lift the stone underneath with some rubberized cork
and use a taller bezel since you said your stone is rather flat. This
method I call “file setting” gives you a cleaner, more polished
look. It is also a good method to deal with uneven stone heights such
as drusy that has crystals all the way to the edges. I’ve been using
this file setting method for years on square corners, with flat
inlay pieces,watermelon tourmaline slices, drusy, and even oval cabs.
It is a method that I have been teaching my newbie students for a
while now. Using clipped corners on your bezels is not my preferred
method. Maybe that is what you want? Hope this helps.

Ruthie Cohen
Mountain Metalsmiths School of Jewelry & Lapidary


#5

Helens approach sounds a lot like mine. Thicker bezel and a punch
and hammer. Trim metal to look nice. I am much better at trimming
than adding metal.

HeHe… I don’t even own a bezel roller and probably even couldn’t
use one. Too many tools and I still missed one :slight_smile:

Helen is dead right on the fine vs sterling thing. They are not the
same colour and hardly worth the ease of setting. Just wait until you
have to set in nickle white gold. Sterling works like warm butter but
the techniqes are the same.

jeffD
Demand Designs
Analog/Digital Modelling & Goldsmithing
http://www.gmavt.net/~jdemand


#6
I'm not sure how "organic" you are trying to be while setting your
90 degree cornered cab. The problem with setting the bezel at the
same height all around is that you are left with extra bezel
material; producing ripples at the corners. 

This sounds interesting. Would you be willing to do a BenchTube
video on this for those of us who need to see to understand?


#7

My thanks to all respondants. I feel much better armes to make my
decision now.

MaryAnn Christianson


#8
The problem with setting the bezel at the same height all around is
that you are left with extra bezel material; producing ripples at
the corners. 

There is more than one way to skin a rabbit, but I think it’s
important to first assess the shape of the stone in order to deduce
the best method to use.

Cabochons come in all shapes and sizes, and many profiles. If you
look at the side profile of your cab, if the sides dip down towards
the corners, then Ruthie’s method is the one you need (see below),
and probably the only one which will give you the same height above
the stone in all positions around the stone. If you kept the bezel
the same height all around, when the corners of the stone are lower,
it would look very odd face on, even if you managed to avoid crimps
and folds. So:

If the height of the bezel on the corners is filed down in a
gradual "swoop" using a half round file from the inside out and
then back to full height on the sides, you eliminate that issue 

We’re not talking about cutting notches, just filing the profile of
the bezel to match the side profile of the stone.

However, if the side profile of your cab has beautifully even sides,
which are the same height all around the stone, ie not dipping
towards the corners, or if setting a facetted stone, where the
girdle sits nicely on the prepared seat and is nice and level all
round, with the same (tiny) amount (height) of metal to be folded
onto the stone, then the following method is what may work better.
It is what I have worked out for myself by trial and error. Other
methods may work better for you.

If I can explain using words rather than diagrams (not easy!).
Anyone interested may find it easier to draw the following on paper.
Imagine a square, with the centres of the four sides being labelled
1- 4, with 1 being opposite 2 and 3 being opposite 4. Then the
corners being 5 - 8, with 5 being opposite 6 and 7 opposite 8. We
then have eight more areas which need to be labelled, and those are
the areas right next to the corners, between the corners and the
centres of the sides, labelled 9 - 16. Each pair of numbers
straddles one corner, such that 9 and 10 are either side of your
corner labelled 5, 11 and 12 straddle corner labelled 6 (which is
opposite 5), 13 and 14 straddle corner labelled 7, and finally 15
and 16 straddle corner labelled 8 (which is opposite 7). Using baby
steps, use your bezel punch and hammer, and move the bezel inwards
in all places, sequentially from numbers 1 - 16, BUT the important
part is that when moving material in positions 9 - 16, instead of
just moving the metal inwards towards the stone, do inward/sideways
movement, from the corner towards the centre of the adjacent side.
This is what avoids folds and crimps, etc. Work either side of one
corner, then the opposite corner, etc, etc.Then, after partially
closing the bezel by working the areas 1 - 16, start again using the
same sequence. Repeat until the bezel is closed onto the stone
neatly. If your metal is thick enough, the above works like a dream.
Occasionally there may still be some “bulk” left at the corner, but
only on the exterior of the setting, which is very quickly filed,
sanded and polished away, leaving a very neat setting with no
ripples, folds, crimps, shorter bezels or cuts. NB, the above
sequence is also used for the “dipped towards the corners” type
situation, but is obviously done after the bezel profile is filed to
match the stone’s profile.

In summary, you need to look at the profile of your stone, and make
the bezel to match that profile, but only a tiny bit taller than the
side of your cab (where the side changes profile from vertical to
the horizontal top or from steep angle to more shallow angle), or a
tiny bit taller than the girdle if facetted. Notches and slits are
not necessary and give a poor looking finish to a setting. I have
seen otherwise beautiful work done by very accomplished jewellers,
let down by messy looking bezels that have been notched or slit at
the corners - not a good look IN MY OPINION.

Sorry for such a wordy post!

Helen Hill
UK


#9

Thank you very much for the great tutorial. I am anxious to try a
sterling bezel, but I think I need some new tools! Is a bezel
’punch’ different from a bezel ‘pusher’? And can someone please
suggest a vice or ring clamp to use when working with a bezel punch
and hammer?

Thank you, Linda from BC


#10
Thank you very much for the great tutorial. I am anxious to try a
sterling bezel, but I think I need some new tools! Is a bezel
'punch' different from a bezel 'pusher'? And can someone please
suggest a vice or ring clamp to use when working with a bezel
punch and hammer? 

Bezel punch is much, much different from pusher. When using punch
around a stone, one must have very clear picture of what punch
suppose to do! Driving metal perpendicular to the stone ( very common
mistake) will even cause breakage of stones like sapphires, which are
very hardy Metal must be driven at 45 degrees or less to
the side of In case of round or oval it is 45 degrees to
tangent. The idea is to allow metal to slide along girdle of
gemstone, tightening in simular fashion of tangential prong
tightening.

To accomplish all this geometrical requirements, bezel punch is
given shape to make all this automatic. A quarter ellipse face of a
punch does it very nicely if the side, represented by the long axis
of the ellipse, is held parallel to gemstone side for rectangular
stones, or perpendicular to radius of round of oval Such
punch is held at slightly of vertical. If it sounds confusing draw
pictures to help visualizing. For those who took chasing classes,
think of design and use of outliners.

For this type of setting one needs both hands, so piece is secured
on shellack. Shellack must not be brittle, so it must be cooled
slowly ( no water dunking ) and even modified by wax or gypsum or
both.

Leonid Surpin
www.studioarete.com


#11

Hi Linda,

The bezel punch is a wooden handle with a length of round or square
(usually brass) rod protruding from the handle. The very end is flat
and it is a good idea to polish its face so that it is less likely to
leave marks on your bezel. I’m not sure whether "bezel pusher"
describes the above or what is sometimes called a bezel rocker -
something which I’ve never had success with, as I use sterling as
opposed to fine silver, and slightly thicker metal than some.

With regard to holding the work, I simply use a thermoplastic which
can be heated in hot water, which renders it soft so that you can
mount the work in the top, and then mount the thermoplastic in a
bench vice, leaving it to solidify before working on. This holds the
work solidly and keeps both hands free for your tools. After setting
stones, the whole thermoplastic “blob” with piece embedded, can be
heated in water so that it is soft enough to remove your jewellery
piece. I use my microwave to heat the water (which has the
thermoplastic submerged) both before and after stone setting. It is
fine to heat with the microwave after setting also, as the jewellery
piece is under the water so it won’t arc and damage your microwave.
Just take care not to burn yourself if water is really hot - I’ve
done it myself!

Others may have better methods.

Helen Hill
UK