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Tube setting


#1

Hello folks. I just joined a few days ago. I’m a year and a half into
a grad jewelry program, before that being essentially self-taught and
in evening programs.It’s been fun reading everyone’s suggestions. Can
anyone help me with this one? I have my heart set on doing some
sterling tube settings for small facetted stones in some of my
current projects. I know that the usual way is to nest two
closely-fitting tubes together, the inner being recessed and serving
as a kind of nest for the girdle of the stone. But what you do after
that is a mystery…or how you determine the height difference
between the two tubes, how much to allow for going over the rim of
the stone, etc. I saw today that the newest Rio catalog (Gems and
Findings p.317) has some ready-made cast tube settings. (They suggest
using these for synthetic stones only…I wonder why? Too easy to
break the stone?) This seems like a great time saver…but I still
don’t know how to set the stone. Anyone out there know how? Thanks in
advance! Lin


#2

Lin hello!

Your effort to set stones in tube settings is fairly straight
forward. The difficult area is you haven’t had experience doing it.
Not a terribly huge roadblock. Doing things you haven’t done, falls
under the category - challenge.

Decide on whether you are going to purchase or fabricate your bezels.
Purchasing sterling bezels shouldn’t tax even the most frugal, with
expense. If you could make or purchase heavy wall tubing the right
O.D. that would be my first choice. You then have plenty of wall
thickness to work with, can cut your own seat at the right depth, and
have nicer thicker bezel when finished.

The advantage of the readymade is they will already have a bearing or
seat, the proper depth. There is no millimeter depth; that changes as
stones range in size. The depth is relative to the girdle to table
dimension. How the stones are cut, that measurement can vary. Let’s
agree that a 5mm stone has .8 between girdle and table. That is the
maximum depth of your stone seat or bearing. When finished the bezel
should be slightly below the table (if the metal thickness is thin it
will be rather low) and covering very little of the crown facets.
The idea is to surround the stone securely, not to cover anymore of
the stone than necessary.

Whatever material you work with, you then need to cut a seat or
modify the existing seat to the requirements of your stone. You can
use hart burs, setting burs, ball burs, and 90 degree setting burs,
to cut your seats. The basic idea is to use these burs a little
smaller than the stone.You are endeavoring to create a negative space
in the metal that duplicates the size and shape of the stone. Proceed
slowly; work with burs smaller or slightly smaller than your stone.
When your seats are cut the right dimension, at the right depth;
resist the temptation to cut deeper, thereby overcutting your seat.
Instead, remove material from the I.D. with a graver or ball bur,
mabe just the edge of a setting bur. Try to fit the stone often,
removing very little material at each attempt to fit the stone.

Once the stone is resting in the seat, check it for level, and
maintain level throughout the next process. You can use a variety of
hand tools (bezel roller, burnishers, anvil burnisher, even
offsetting a pair of pliers is handy) to move the metal onto the
crown of the stone. Basically you are to move the metal a little at
each pass around the circumference, whatever your chosen tool or
tools… The finished appearrance depends on your discipline. Apply
equal pressure and movement to the entire bezel. Once you have done
what you can with hand pressure it may be necessary to use a hammer
and punch or hammer handpiece if you have one. Use a light touch and
work the entire bezel evenly. To finish the inside edge at the stone,
carefully use a graver to remove a racetrack of metal. Alternatively
you can use a “polished point”. This is nothing more than an old bur
with the head removed. Taper (if it is not already) to a .75 to 1mm
point and high polish. Chuck it into a handle with a chuck. (Great
sentence! eh?) Very carefully and evenly, burnish the metal down to
the stone, and reveal a polished racetrack. You WILL damage the
facets of most stones if you are not careful! Only touch the metal.
The rest is rubber wheeling and polishing. You are on your own there.

Tim


#3

There’s a tube setting trick I learned (can’t remember where) thats
real easy. Pu the tube in your Foredom handpiece #30 and crank it up.
Use a ball bur, a tiny one, mounted in a pin vise and lathe out the
inside of the tube to cut the seat. This usually cuts a perfectly
round seat and is very easy to do…Dave