After I have prongs down tight and rounded I further work the
leading edge down firmly against the surface of the gemstone, to
remove any gap at all at this point. This is where customers feel
sharpness and where prongs could catch into fabric.
I made a too from 3mm square steel stock for just this job. Set into
a graver handle and cut to the same length as a graver, this tool in
many ways resembles a graver, but is designed to catch just the very
edge of the prong metal and burnish this area down to close any
remaining gap between metal and stone.
The working edge of the tool is first cut back to make a 90 degree
"wedge shape" with two equal faces. Then one face of this angle is
The other face is hollow ground (using simply a stack of cut off
discs on a mandrel, trimmed to make a small diameter grinding
stone), grinding b= ack from the pointed edge of the tool toward the
handle. This leaves you with a tool very similar to a hand graver,
with a rather blunted, but sharp 3mm wide cutting edge with one
highly polished face.
Under high magnification I take this tool and carefully dig it
lightly into the metal of the prong just above the gap between the
prong and stone, with the polished surface facing the prong. (I am
not pushing down toward the stone surface, this is a steel tool and
any hard pressure at this point would be too risky. I am "cutting"
lightly back toward the base of the prong with very little force.) I
have now made a very small “groove” or bur on the leading edge of my
prong, just above the open gap between metal and stone.
Supporting the thumb of my graver hand against the surface of the
stone I use my tool to gently rock it (left to right around the
surface of the prong), working this small bur forward and down till
it just touches the surface of the stone, continuing my gentle
rocking action so that the highly polished surface of this "graver"
is burnishing the metal at this point and closing any gaps.
It takes a bit of practice to work with this tool, but the trick is
to use almost no force at all and let the cutting edge and polished
face of the tool do all of the work for you. Learned to make this
tool at Bowman Tech over 30 years ago, and use it on every prong I
set, no matter what material I am setting. With practice you can
become very confident with this tool, and it will safely close those
gaps without putting more unnecessary pressure on the gemstone. Have
"cleaned up" behind quite a few other jeweler’s sloppy setting jobs
that customers have brought to me over the years with this tool and
it’s made me look like a wizard to those customers. Hope this helps.