How to Tighten Princess Cut Diamonds?

The ring that we used to practice this type of setting was the
exact same four-prong setting we used for a round stone. 

Actually, I spoke with a friend today who went to Blaine’s stone
setting course, and the head Blaine uses for that demo is definitely
NOT the same as the one used for a round. It’s what we call a
4-prong, peg base (or not) die-struck head. But the one Blaine uses
is a 4 prong, die stuck, alright, but it’s made for princess cuts.
It’s prongs are thicker, shorter, and splay out at a lower angle.
Check the Stuller findings catalog and compare #21343 (the one Noel
refered to called the “True Seat”) with #411. The desing allows the
culet to rest just above the bottom of the head, and the extra
thickness of the prongs allows for the cutting of a groove to seat
the four quadrant pavillion facet junctures. In that setting, the
stone would be secure enough that should a prong or two bend away,
the stone, by its geometry, couldn’t escape. I still am not crazy
about that head, I rather like the extra protection to the points
that a “V” prong head provides.

David L. Huffman

Hi Leonid,

Princess cut, in my opinion, is an obscenity which has been
perpetrated on the public by the "industry leaders". 

That’s a shame, it happens to be my absolute favourite cut of
diamond. I’m not alone in this view either as most of my girlfriends
also share the same opinion.

For me, apart from the obvious difficulty of setting them, they are
the prettiest of all the cuts. I was under the impression that cuts
like the princess, marquise, pear, oval and the like were all
modified brilliants, ie. designed to maximise the return of light -
but as you know I’m often wrong. Obviously, I’m NOT disputing what
you say about it allowing cutters to save material and therefore
charge more, as that’s obviously the case due to its shape being so
close to the rough crystal - but I still think it’s damn pretty.

Yes, even though a novice, I too have had a few nightmares setting
princess cut stones and have broken a couple this Christmas (not
diamonds fortunately). I’m still in the heavy handed, hammer
weilding bezel setting stage with a view to moving onto prong setting
soon so no doubt I’ll be breaking a few more!

I’m watching this thread with great interest.

Helen
UK

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.

Princess cut, in my opinion, is an obscenity which has been
perpetrated on the public by the "industry leaders". 

Helen, that’s Leonid’s personal opinion. It doesn’t necessarily have
any validity in the world of aesthetics. Perhaps he’s speaking simply
as a stone setter although ‘obscenity’ is a bit much.

KPK

Hi Drew;

It all boils down to what the customer wants, obviously.... Whether
it looks "right" is up to the payee. 

Without going further into the merits or aesthetics of this type of
setting, I wish you would re-think that statement. I appreciate your
dedication to pleasing the customer, but, as I’m fond of saying,
“Anything looks possible to a customer who doesn’t know any better”.
(I stole that from my employee actually). What I mean is, when a
customer doesn’t know the risks, it’s up to us “experts” to try and
convince them to do things in the best manner. Personally, it felt
like a luxury, indulging in a bad attitude, when I began to refuse to
do things I thought weren’t well thought out, but now I realize it’s
an uphill battle even when you do. The sooner one gets used to it,
the better. You will find it is harder to make money struggling to do
things one way when you know a better way, and these kinds of
situations can come back to haunt us. The customer won’t remember you
saying that you had concerns about the stone coming loose or
breaking. And they’re right… because, in the final analysis, it was
your decision. And again, the guy I talked to said that Blaine was
using a Tiffany head proportioned for a princess cut.

I have a client, an “estate” jewelry guy, who always pressures me to
find some way to “cobble” things together, do it on the cheap. I keep
telling him, I can’t remember if I forgot how to do that or I never
learned. That’s not saying I don’t have a few tricks up my sleeve.
Maybe I just worry that I’d be handing over an opportunity for some
jeweler to feel smug when he sees hack work.

David L. Huffman, wondering why I’m doing this after riding my bike
home in a snowstorm with a flat tire. Most people would have cracked
open the JD hours ago.

I would recommend the princess cut setting video by Blaine Lewis. I
bought it 6-8 months ago, and the methods it teaches are and focus
strictly on princess cuts.

Best money I’ve spent!
Gerry Aubin