I am setting 2mm faceted stones in a silver tube with 2.8mm OD. I
am able to set the stones in the tube with mostly no problem. When
I burnish the tube over the stone to set the stone, I am getting
imperfections in the, for lack of a better description, "bezel."
First, I want to say that you have exactly the right attitude. One
must strive for perfection no matter how small the job may be.
About your little problem. Most setting issues arising from imperfect
fit of the stone to setting. It would not be exaggeration to say 99%
of setting is to fit the stone correctly. Different stones require
different approach, but in your case, I presume that you have stone
with narrow to medium, sharply defined girdle, which is characteristic
of diamond, or diamond like stone.
Tube setting relies entirely on geometry of the tube. Cut out a metal
disk of some diameter, and measure it. Than tilt it a bit, and
measure it again without changing position of calibers. You will see
that second measurement is smaller. That is the key to tube setting.
The inner size of the tube must be same size, as the smallest stone
diameter. No stone is perfectly round. That does not mean that bur
must be of the same size. Bur must be smaller, usually 0.1mm smaller
than required size. If resulting hole is too small, slight movement
from side to side will fix it.
Stone is fitted tilted and slowly pressed into the seat. Of course,
great accuracy is required, but that is the price of perfection. Once
stone is fitted that way, nothing else is required. It is not coming
out, no matter what. Bright cutting with graver, will also raise tiny
burr, to seal the stone forever. That what creates even, bright
"bezel" around the stone.