Boy, this thread sure morphed.
My own opinions aside (which would be anything that works,
works…but what’s your definition of ‘works’?) this would be how I
would approach the problem of a customer owned ring as mentioned.
You say there is a small hole drilled to accept the point of the
stone. I hope this doesn’t mean the hole was drilled thru to the
outside of the prong, which I have seen once or twice. If all you
want to do is tighten, and a remount is out of the equation(my own
preference, since once you touch it you may become married to it,
but)…loupe the prong tip, is there enough metal to do something
with or has it been polished to death before it came to you? Is there
light coming thru between pavillion and prong? What I’d be looking
for here is enough metal overhanging the crown to get a bite on the
stone. If there is some metal first thing I’d try is a setting plier
held in such a way as to put the force in the inboard edge of the
tip. Try to curl the prong down. Be careful you don’t mangle the
prong away from the stone if it slips, which is a good possibility
with this angle of attack. I modified a plier once by grinding a hook
in the top jaw so that the pressure was only on the inboard edge. You
can find very small (3 inches?) channel lock pliers that will do
much the same work but the serrations mark the heck out of the metal,
but I didn’t tell you that and keep them out of sight.
You might also try a beading tool and burnish the metal over the
crown some more.
Another thing that has worked for me is to use a short jawed plier
and squish the prong sideways. This is real hard to describe, much
easier to show but I can’t. Grab the prong so that the side opening
of the jaws is parallel to the apparent direction of the prong tip.
Your pliers will point to the center of the stone at an angle similar
to the crown angle. Get as close to the pivot point of the plier as
you can, multiplying the mechanical advantage. See I told you its
hard to describe. What you are trying to do is force the metal
sideways out of the jaws and therefore down onto the crown. Don’t be
a gorilla about it though. This may work under the stone too, raising
the seat up to meet the stone, but tool marks here are much harder to
remove.
If the stone does not have a decent seat to start with, change the
head.
I’d be real hesitant to add solder to the tip as you mentioned
someone said. Not from a purist’s point of view, we each make our own
decisions on that. But from a liability perspective. If there’s a
hole behind the point of the stone its quite likely there’s dirt or
rouge too and you cannot guarantee you’ll get every speck out before
heating the stone. You run the risk of discoloring the diamond.
If this were my problem I would explain to the customer the
limitations and risks involved in trying to fix someone else’s work
but for $X I can do the job right(by using a new head).
I believe someone in this thread mentioned polishing off the sharp
corners of the princess. This is most excellent advice. All corner
chips I’ve seen emanate from the very tip simply because the tip
basically tapers to zero and trauma concentrates there, but even
repolishing carries at least some risk.