Lora, the typical setting method is not to trim the prongs shorter
at first. leave them long. it give you more metal to grab when
bending the prongs. After they’re bent over, THEN you trim off the
excess. I usually just use a small, very sharp, pair o flush cut
nippers if i want a square end cut, or even, with stones hard enough
to be safe around saw blades, saw them to length with a 4/0 blade.
Another method is to use standard nippers, which leave a peaked end
to the cut. this takes a bit of practice to be sure the “shock” of
nipping the tip doesn’t damage the stone, or that in nipping, the
scrap end of the tip isn’t bent towards the stone further, which can
happen if the tips of the nippers aren’t sharp all the way to the
tip. If you’re not sure, the saw is often safest, but also hardest
to do.
Before you can set anything, you need to cut a seat for the stone,
unless you’ve bought pre notched heads, and even then, it’s best to
further fit the notches or seats to better fit the shape of the
girdle. Usually this is just a slight notch, cut about 1/4 to 1/3 of
the way into the inside surface of the prong, on which the stone sits
level, without rocking, and with all seats touching the stone. that
both supports the stone properly, and also weakens the prong slightly
at the girdle and above, so when you bend the prong, it defines the
bending point of the prong, rather than forcing the prong to just
bend on account of using the girdle of the stone as a fulcrum. If
you don’t’ cut a seat, the prongs don’t bend cleanly, the stones can
and usually will shift off of level, and there’s a very large chance
of chipping the stone. Commonly, seats are cut with setting burs,
either the 90 degree straight sided ones, or various flavors of hart
bur, which cut an undercut notch in the prong. With experience, and
especially with fancy shaped stones, ball burs and bud burrs can be
of great use to exactly fitting a seat for a stone. After the stone
is seated./fitted to the head, only then are the prongs bent over it,
and trimmed to length. After trimming a file can be used to refine
the shape, or with smaller stones and small heads, often a cup bur
is used to just round over the end of the prong evenly in all
directions. with larger prongs, I prefer a more defined and tailored
shape, still rounded, but mostly on the front and sides, while the
back is left with the curved plane derived from bending it over.
Other tip shapes can be little ‘claws", or “beads”, or almost
whatever you like, so long as it’s secure, and doesn’t catch things
too badly from being sharp. The file you use to clean up the shape
should have a "safe’ edge. Commonly, a barrette file is used, with
the originally sharp edges of the file being polished or sanded
smooth, so the edge riding right at the stone has no teeth, but the
surface facing the prong is still a fine file. One can also use any
of a variety of rubber wheel abrasives to shape and clean up prongs.
which ones depend on the stone type (it’s hardness). Pumice wheels
are common and popular for this…
Hope that helps.
Peter