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Die struck bezel cups


#1

Hello! I currently am using a TON of 12mm bezel cups. Right now, I am
using pre-made die struck ones at $2.50 a pop! I am comfortable in
bezel setting free form items, but there is no way I could hand make
as many bezel cups as I am going through. I was curious to know if
you had any ideas about hand made tools, or an inexpensive way to
make die struck bezel cups out of about 30 gauge sheet metal.

Thanks in advance!
Carin Jones, owner/designer
Jonesing for Jewelry


#2

Hello Carin,

Here are three ways I can think of that may help you.

  1. Foldforming Like pastry dough, metal too can be formed over a
    form, in a hydraulic press. You will need to prep a die plate first.
    The die plate can be made by cutting out discs from 3mm high (1/8")
    acrylic sheet or you can get them here,

http://www.ganoksin.com/gnkurl/1hz

You then arrange these discs on a sheet of acrylic glued into place
using acrylic monomer. The dead soft raw material can then be forced
over this dimple covered sheet forming a sheet of road bumps. This
dimpled sheet is then be put into a disc cutter and the individual
bezels are struck and then cleaned up because they will have a flange
off of the bezel wall from the difference between the diameter of the
acrylic disk and the diameter of the cutter used.

As far as how far to place the acrylic dimples apart, this will
depend on the height of wall on the bezels and how much clearance your
disc cutter requires, this tolerance could be as small as 10mm between
dimples.

The largest benefit to this technique is that you are not limited to
using just round discs in one size. You can make bezels for any size
stone and essentially in any shape that you will ever need (odd shapes
will need to be sawn out). Something to think about.

Cost:

Not including the hydraulic press, You will need a disc cutter (in
this case a $25 Harbor Freight cutter will work). You will need 1/4"
acrylic sheet or discs and acrylic monomer, the total cost should less
than $50. You will also need a 1/4-1/2" urethane sheet ($40-50).

  1. Modified Disc Cutter

This idea requires you to use a disc cutter and disc punch that have
been machined for this purpose. You will need a disc cutter that grips
onto the metal (like the Swanstrom disc cutter) and you will have to
have the disc punches specially machined.

You can’t use the Harbor Freight disc cutter because this doesn’t g=
rip the metal so there will be a lot of warping, tearing, etc…, plus
the metal used on H.F tools isn’t the greatest… Example: Using a 14mm
punch, you will need to have the base (3mm from the base, the bezel
wall height) machined down to 12mm diameter. This will form the bezel
cup and shear it off creating a 12mm diameter cup that is 3mm high.
This technique will create a flange that will need to be sanded off
because of the difference between the 12mm “bezel die” and 14mm
shearing punch.

The benefit to using this technique is that your metal can vary up
to almost 1mm thick and still create a bezel.

Cost:

Not including the cost of the hydraulic press. You will need to
purchase a disc cutter ($270-$500), and you will need to have the
disc punches machined for making bezels which could cost anywhere
from $20-? depending on what tools you have on hand, where you live,
and who you know. If you have have this done for you count on it
costing at least $100. You will need a urethane sheet 1/4" thick so
that the cutter isn’t damaged during use ($40).

  1. Specially Made Die and Punch

The only way to get repeatable, perfectly struck bezels is to have a
bezel die and punch specially made. This route will start out at $500
and can easily run into the thousands for a single size die, which may
be an acceptable route depending on the amount you need. A die like
this can allow you to stamp upwards of 10,000 bezels (about 5cents
added to each bezel cost if the cost is only $500) before needing to
be replaced. A older dull die doesn’t need to be thrown away, it can
be re-sharpen= ed and if you have a slightly larger punch made for it
you can make larger bezels for the cost of the new punch. As far as
companies that can do this, good luck! So many either have closed and
the companies that are still open keep raising their prices!

The benefit to using this setup is that you will have perfect bezel
cups that you will not have to fuss with (except to lower the wall
height depending on the stone).

There are all sorts of issues that can encountered by using either
of these methods.

  1. Foldforming

  2. The raw stock will have to be dead soft and even then the cups
    will bow slightly outwards using this technique.

  3. The bezel cups will need to be filed to clean up the edges.

  4. Modified Disc Cutter

  5. The raw stock will have to be dead soft and even then the cups
    will bow slightly outwards using this technique.

  6. Even though you can use this method to strike bezels from
    30gauge to 18gauge thick, with each increase in metal thickness you
    will end with a more pronounced flaring of the bezel wall.

  7. This will put a lot of extra stress on your disc cutter’s
    cutting holes which may render it useless for punching regular discs.

  8. You will not be able to strike bezels using a hammer, you will
    need to use a hydraulic press. The bezel punch will need to be as
    centered as possible when striking because any deflection will require
    the punch to be re-machined.

  9. Specially Made Die and Punch

  10. The cost of this setup can be prohibitive

  11. You will only be able to strike one size of bezel

  12. You will need to use this tool in a hydraulic press, because
    there is too much risk in damaging it using a hammer

Cost Effectiveness of the Techniques

#1&#2 When you do the math using either method #1 or #2, you will
only be saving about 50 cents per bezel cup, plus you will still be
left with clean up which will cost more then 50 cents in labor.

#3 If you go with #3 you will be able to create 12mm bezels that
cost about 40 cents. 30 cents for the silver, 5 cents for the die
wear and tear. This is if you can get the die and punch made for
$500, but plan on it costing around $1,000.00 so you won’t be as
surprised when you hear the cost.

My goal isn’t to deter you, but you may want to stick with your
current supplier, this way you can always be ensured a consistent
supply of a usable product. If they ever supply you with unusable
product, you can always return it for exchange which is a nice fall
back. While $2.50 may sound like a lot for the bezel cups, on paper,
in reality the cost, time and, labor required to make the die and
punch as well as the time and labor required to actually strike the
individual bezel cups may not be cost effective.

Perhaps you can call your supplier and discuss quantity discounts,
they usually require you to buy a specified quantity before any
deeper discounts take effect, but if you buy a specified quantity
over a length of time, they should be wiling to work with you. You
can always threaten to take your bulk business to one of their
competitors.

Speaking of suppliers, if these cups are sterling silver (going from
your Etsy listings), where do you get sterling silver bezel cups for
$2.50? Rio’s quantity discount is like $3 each.

Sorry for the long post!

Take care, I hope I was some help
Kenneth, DynastyLab
http://benchofanapprentice.blogspot.com/


#3
Here are three ways I can think of that may help you. 
01. Foldforming Like pastry dough, metal too can be formed over a
form, in a hydraulic press. 

Wrong term. foldforming is exactly that, literally folding the metal
(usually thin), then manipulating it. Simply unfolding leaves a
raised ridge for example. Forging or stretching or otherwise working
the metal while folded can result in wonderfully organic forms when
then unfolded again. And more variations. It sounds (and in many ways
is) simple, but the potential methods and forms you can generate
quickly this way is nothing short of astounding. It’s one of the few
truly innovative new technical developments in metalworking methods
(as opposed to rediscovering old methods) of the last hundred years
or so. The term, and technique, were pioneered by Charles
Lewton-Brain, one of the people who, after Hanuman, are primarily
responsible for the existance of Ganoksin and Orchid as we know them
today.

The term you were looking for is simpler. Just plain old die
forming, or hydraulic die forming.

In addition to methods Kenneth mentioned, you could also simply
downsize the methods used commercially, and have an actual die made
to die form the cups with a manual press like a hydraulic press or
even a simple arbor press of suitable size. It’s even possible to
make such a die that, with a suitable holding arrangment to hold the
punch and die aligned, you can form such small pieces with just a
sledge hammer. Any good machinist with tool and die experience could
make the tool for you, if you don’t have the means yourself, and a
well made die could last you the rest of your life.

Peter Rowe


#4

Hello Peter,

Check out Charles Lewton-Brains Book “Foldforming” Page 126-127, the
exact term used in the book is “forming block.” This is where I first
learned about it. The example I gave uses the first part of the
technique, up to step 4 as given in the book.

This technique is called by many names, “Forming Block”, “Guerin
Process”, “Rubber Block Forming”

Where Charles Lewton-Brains technique is different is that the shape
is pressed a second time without the form which produces a bezel
edge. This technique is very versatile and yet very few use it.

[]

Let’s have fun and share!

Thanks for the heads up!
Kenneth, DynastyLab


#5

Ok Kenneth - if you would look at the preceding page in Brains
Foldforming book, you will note that the section is on hydraulic die
forming. The pages you reference show extremely irregular forms
pressed with hydraulics. While it is included in the foldforming
book, it isn’t foldforming in any coherent sense of the term. It is
a really innovative use of the press and free form dies.

Managing to create regular and repeatable calibrated bezel cups in
an economic manner would be unlikely or impossible, and to make many
of the same size - to say nothing of the wasted material. How long
would it take you to make 1000 8x10 bezel cups that would exactly fit
an 8x10 stone? If you have tried it, what is your yield?

Judy Hoch