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Tricky Layout


#1

I have to make 2 settings for 3 1/2 ct round diamonds for earrings.
8 prongs, tapered. Each prong will be triangular in shape, with the
bases meeting, base angle to base angle, and the tips to be holding
the stones. essentially an eight ray star, folded to a taper. I’d
like to make the rays thicker in cross section at base than at point.
I think that much can be done with a 28 degree bezel block and
punch. I’m not certain of the most precise way to layout for cutting
the prongs. There would have to be eight center lines and sixteen cut
lines on each setting.

If I did the layout first, on flatstock and then dapped, the star
would be uniform and symmetrical but it could easily go off center in
the tapered hole, that has happened before. If I dap a cone first
then scribe layout lines I don’t really have a perfect reference
point from which to begin.

Bright ideas???


#2

That’s a simple job in CAD and a simple milling or growing in CAM.
Call E-Wax, ask for Brant 630-968-6001, fast service, reasonable,
and CORRECT! He also has the CHEAPEST wax tubes and wax specialty
products in the USA…and they are either Kindt-Collins or Mattiello
waxes. Just cheaper than what you are accustomed to, even ones
milled to correct finger sizes, on-center, and waxes for those huge
class-type rings.

Wayne


#3
If I dap a cone first then scribe layout lines I don't really have
a perfect reference point from which to begin. 

Yes, you do have a perfect reference point, it’s your circle. I would
make the cone shape, file the top of it flat, and there’s your
circle. Just use a center finder, and then dividers will turn that
into 1/8’s, marked on that top circle. Then I just make a tiny sawcut
for the 16 lines, partly so they can be seen from the sides and the
top, and take it from there. As you realize, if you premark it, then
it needs to be stamped, marked and domed all precisely on the same
center, which is not realistic with bench tools. Plus your lines will
get erased in the deformations…


#4

I’d not be making this from flat stock pierced or otherwise. I’d
draw triangle wire, or file it from round wire, then filing in the
desired tapers. Precisely measure the required number of lengths so
they’re all identical lengths. Any mating surfaces at the base are
also filed into each prong so they’ll meet correctly. To assemble,
sometimes you can just prop them up on a charcoal block, but I find
it a bit more secure to make a ring of iron binding wire, or by
drilling the correct hole in a bit of sheet steel or similar high
melting metal, and placing that on the soldering block. The ends of
the prongs can rest in there, being prevented from “splaying out” by
the ring. If you have trouble getting them all to rest their bases
together without the whole teepee falling over, another binding wire
ring, about the diameter of the head halfway up the prongs, can just
slip down over the pile, like a belt. A variant would have you shape
the prong wires so the juntion of them all is taller than what the
heat will end up as, coming to a point. A small jump ring is slipped
over the point, and soldered to the heat along with soldering the
prongs together. Then that jump ring is trimmed off with the rest of
the excess. Takes a bit of care to get everyting set up right. If you
get too frustrated, you can always set it up in plaster to solder.
When positioned/fixtured, weld or solder the base joint where
everthing meets. with the hardest solder you dare use. Such a head
will be strongest if you also solder in an undergallery wire, inside
the prongs, but depending on how you make it, and in what metal, that
might be optional. Doing the head like this from seperate wires lets
you be sure the tapers are exactly the same, and if you like,
prepolish the prong wires before soldering together. If you have
access to a laser or any flavor of tack welder, (flash, PKU, etc),
then setting this solder joint up becomes quite easy. The main key
to getting this to come out straight is starting with all wires
exactly the same length, and having them sit on the soldering surface
exactly within the confining circle and evenly spaced. Do that, have
all the points equal in the joint, and your head will come out dead
on
straight.

You can also buy a couple different types of nifty cheating little
jigs that hold wires set up like this, in position for soldering
without such precise positioning needed (the jig does the
positioning. Here’s one such:

the tools are not unlimited, in that the grooves only hold wires up
to a certain size/shape, but when they fit, they’re a cool time
saver…

Peter


#5

I tried a dry run with a piece of scrap sheet. Got a very nice
layout. Eight rayed star with a hole in the center. To my chagrin
when I dapped into the tapered hole in the block the hole in the
setting went from 4 mm to 8!. It came out very uniform and
symmetrical but way too large. So I’m leaning toward making a tapered
tube, sectioning out to the size I need and then eyeball the prongs
in after a quick 8-point reference at the top as suggested by John
Donivan. My first boss would call me ‘the frustrated machinist’. He
might be right but I wonder what he meant by that ;- P


#6
So I'm leaning toward making a tapered tube, sectioning out to the
size I need and then eyeball the 

Yes, that’s the “proper” - most usual, way to do it - make the rough,
and then shape it. One suggested soldering, which is building a
booby-trap with all that solder. You might also try soldering the
base of your cone onto a piece of heavy wire - like brass, so you
have
a handle while you’re carving it…

http://www.donivanandmaggiora.com


#7
8 prongs, tapered. Each prong will be triangular in shape, with
the bases meeting, base angle to base angle, and the tips to be
holding the stones. essentially an eight ray star, folded to a
taper. Bright ideas? 

I would do it the way Peter has suggested, but with one more
suggestion from me - consider making the settings from 4 double
length pieces of triangular wire instead of 8, and make each into a
V shape first, so effectively you are making the setting from 4
double prongs instead of 8. I find this way to be quite quick, but i
must say I do like Peter’s " hole in sheet metal idea" to hold
things, thanks peter i will try this

cheers, Christine In Sth Australia