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Contouring bezel


#1

Can someone tell me a “simple” method of contouring a bezel to
conform to the curvature for a bracelet? Holding the bezel to the
bracelet keeping it level and immobile while scribing is virtually
impossible. I have been doing the grind and eyeball method for years
but am looking for a faster way.

Thanks for your help…
Richard Langbert


#2

Richard,

I am not sure this is the traditional way, but it is the way I was
taught and it works for me. I have never had a problem with the
bezel being stressed. I leave the top of the bracelet where the bezel
is to go, perfectly flat. In other words I curve both sides of the
bracelet, on a bracelet mandrel, but leave the top flat. My
bracelets are more oval shaped than round. On this flat area I put my
bezel. This has worked for stones around 13X18 mm in size, but may
not work with larger stones. I make sterling silver bracelets, out of
16 or l8 gauge metal—nothing thinner which lessens the amount of
flexing of the top part.

Alma Rands.


#3

Richard- I apply emery paper to my bracelet mandrel and then rub the
bezel bases acroo that. I get a perfect fit every time.

Have fun and make lots of jewelry.

Jo Haemer
www.timothywgreen.com


#4
Can someone tell me a "simple" method of contouring a bezel to
conform to the curvature for a bracelet? Holding the bezel to the
bracelet keeping it level and immobile while scribing is virtually
impossible. I have been doing the grind and eyeball method for
years but am looking for a faster way. 

Crazy glue has helped me with similar tasks. A couple of spots of 5
minute epoxie inside the bezel should help more.

I haven’t tried it but something like JetSet might also work,
probably easier to clean/remove. Hot water vs torching or acetone.

You are still going to have to grind and eyeball for the final fit.

jeffD
Demand Designs
Analog/Digital Modelling & Goldsmithing
http://www.gmavt.net/~jdemand


#5
Holding the bezel to the bracelet keeping it level and immobile
while scribing is virtually impossible 

I take it that the problem is defining the line on the bezel to
which to cut?

Why don’t you try making a template. Screw around with paper,
cardboard, sheet plastic or whatever until you get the contour you
need, then simply overlay the template on the bezel, scribe it and
start hacking away at it. I might scribe some reference lines on the
bezel first so your template will be correctly situated.

If you find you have a lot of cutting to do, you have to decide what
tool to use. I sometimes use a long ring bur and take swiping cuts
rather than try to cut TO line and then follow it. Whittle it slowly,
you can make adjustments as you go rather than finding out…oops you
made the first cut too deep.

If you have a complex crown( curves going in perpendicular
directions for example) Cut to the lowest line first, then kinda
notch in for the opposite crown. Hmmm, could I make that any less
clear?.. Say your bracelet takes the form of a fat round wire bent
into a cuff shape and you want a rectangular bezel perched on top
running parallel. Your complex crown is

  1. the profile of the bracelet when viewed laying on its side, the
    major crown.

  2. Then you have the crown of the wire itself as viewed in a cross
    section, the minor crown. So your procedure would be to define the
    major crown first, transfer to the bezel and cut. Once you’re
    satisfied with the general fit, you now should cut the ends of the
    bezel ‘box’ to fit the perpendicular cross section of the ‘fat wire’.
    Of course, until you actually CUT the minor crown you can only
    eyeball the major crown fit so you might have to go back for minor
    adjustments. If the bracelet is made of flat stock your job is cut in
    half.

Here’s a speedy tip for the not faint of heart…you can make short
work of the major hacking by using a thick cutoff wheel and cut not
with the length but across it. So the wheel is perpendicular to the
surface you want to cut. Make a bunch of plunge cuts to just shy of
the scribed line. If you wind up with what looks like a picket fence
you can simply snip them off with a flush cutter. Then go back in
with a ring bur or whatever to smooth out the ragged edge and fine
tune it. You might like to try stacking a number of cutoff discs
onto a mandrel, true them up with a carborundum stone or even a
diamond edge( I keep a 1/4 ct Old Miner around for just that
purpose). This is basically a custom grinding wheel. Sometimes
grinding is better than cutting with a bur, less chatter and grab. I
say for the not faint of heart because if you make a mistake it could
ruin the piece. But its quick. I like to live on the edge sometimes.


#6

Funny that this post came up. I had a dickens of a time trying to
match a curved bezel to a curved piece to set a pottery shard. Boy,
this is the time that the design/artist goes right out the window and
we don the problem solving hat with lab coat.

There are two things I discovered. One. The standard stock bezel one
recives as mill products was too thin. Thankfully I had some fine
silver sheet and used a rolling mill to fabricate a slightly thicker
bezel.

Second, the shard was placed in the newly formed bezel and I traced
a line with my Sharpie (hmm, I think this company should just pay
jewelers outright), both inside and outside the bezel. Jett Set was
packed in and grinding the bezel to conform to the is working well,
but it is slow. It’s still in process, so I don’t have photos right
at the moment, but this was one way to attack the problem.

The other way, depending on your soldering skills, is to solder the
bezel to a flat sheet of copper or brass with easy solder and slowly
file the conforming side. When a reverse match is made with a good
fit, then heat the bezel and lift it off in one piece. Thicker stock
is better for this if you have a large stone. I might still do this
if the other way doesn’t work.

Many ways to attack a problem.

Karen Christians
Cleverwerx


#7
Many ways to attack a problem. 

The problem is actually quite trivial, if we employ some
mathematics. By the way if math is a dirty word for you, do not
bother to read any further. Only brave, mathematically inspired souls
should venture beyond this paragraph.

Let’s unfold the bezel. What we have is a rectangle. To match the
bezel to the curved surface means to find a geometrical shape where 3
sides are matching the rectangle of the same dimensions, and the
fourth side is defined by a graph of the function of the surface we
are trying to match with.

By saying that we trying to find geometrical shape, we are saying
that we want to know the area of such shape. By phrasing the problem
in this way, we reduced the problem to finding an integral of the
function defining the intersection of our bezel with the curved
surface we are matching to.

Plainly speaking, an integral is simply a sum of areas of
rectangles, arranged in such way, that by varying the height of the
rectangles, the tops are approximating the graph of the surface
defining function. Theoretically, the width of the rectangles is
tends to zero, but for our purposes, it does not have to. We should
choose the width which only provides sufficient accuracy. There is no
reason to bother with smaller values.

Once we understood the mathematics behind the problem, the practical
implementation is quite easy.

Make a bezel equal to required height + maximum height of the
surface, we are matching to. A little bit if extra height would not
hurt. With dividers opened to maximum of the surface height, mark
the line all around the bezel. Take fine snips and divide the marked
off part of the bezel into strips of 1.5 - 2 mm width, same way you
prepare your solder. Do not go beyond the marked line.

Now, the marked part of the bezel is a sum of rectangles that we
talked about. To find an integral all we need to do is simply the
following. Gently tap the divided end of the bezel against the
surface. The portions of the strips that are extraneous, should bend
away. After a few taps, you should have the contour matching the
surface. Open dividers a couple of millimeters and using this contour
scribe another line on the bezel above the contour. Cut off divided
portion of the bezel along this line and we done.

Leonid Surpin
www.studioarete.com


#8

Often times, when faced with applying a bezel, tube or similar
element to a curved or uneven or irregular surface I’ll begin by
making the “bezel” extra tall.

Rather than altering the element (bezel, tube, etc.) to fit the
ring/bracelet/neckpiece, I’ll alter the latter instead by drilling,
cutting or burring out a hole through which the bezel element is
passed. The extra height of this element allows protrusion on the
inside of the piece. In other words, the bezel element passes through
the thickness of the cuff or bracelet, positioned until the proper
height sticks out from the outside leaving an extra bit sticking
through on the inside.

Solder is placed on this inside protrusion and then flowed from
there through the cuff thickness to the outside/top of the cuff. The
excess is then sawn and filed smooth.

This makes a very strong seam and adds the advantage of solder
placement with little chance of flood or accident on the outside. The
con side of this method is that you have to be precise with your
piercing and grinding and there is no room for adjustment should you
change your mind.

With round tubes and bezels it is quite simple.

As with most things in the studio, I find that there is no one
size-fits-all approach. Every situation varies as does my solution to
it. But I find it useful to look at the other side of the equation
when formulating a strategy.

Andy


#9

I made a ring with a curved bottom to fit a ring shank. I made a
taller bezel than normal. Then I used a mizzy wheel and ground a
curve on both edges on the short ends. With the cab in the setting,
I sanded on a round mandrel until the bezel would made a tight fit to
the back plate which was curved exactly like the ring shank I
fabricated. Then I soldered the bezel to the back plate, cut away
the excess metal, sanded and polished the bezel cup, and then
soldered the bezel cup to the ring shank.

This would work for a bracelet, you need a bracelet mandrel, and a
piece of wood curved to the shape would work.

Richard Hart G.G.
Denver, Co.


#10

Send us the length of the bezel and the circumference of the
bracelet and we will send you a drawing of the bezel.

If you have an off size stone take a piece of scotch tape and wrap
it around the stone, mark it with a marking pen, cut it on that line
and measure the length. If it is a millimeter stone send us the
millimeter size.

Lloyd.


#11

Lloyd,

Have done these over the years by fiddling with them on paper to get
the layout, trial and error method. Do you have a better way, say a
computer program for the layout of bezels fitted to a curve. I have
just started Rhino and hope to figure a way to do the layout for any
bezel with that program.

Norm


#12

Hi Norm, it took three of us some time to get the right wording and
the lay out to get the right lay out for oval stones and round
stones, also have found out that with this lay out you can set any
size and shape of stones.

The final printing will be done this week.

Give us your address and will send you a copy.

Not very smart on the computer but will try to send an attachment.

Lloyd


#13

Lloyd,

I would love to have your explanation for layout of bezels applied to
curves. As I said I have done these over the years and it has always
been trial and error fitting. The last one I did which was a large
oval turquoise ring for myself, I did using coral draw to do the
layout and then cut the parts out of aluminum 20 ga sheet and tried
the fit before cutting out the pieces in sterling. The ring worked
out great but took three tries to get it right. It was fabricated in
20 ga sterling two pieces(shank and bezel) bezel sets on shank kind
of like a saddle and is sweat soldered to shank.

I will try and contact you off list to get my address to you.

Thanks in advance
Norm


#14

I want to thank everyone that helped me with the contouring problem.
The varied solutions were all logical and it simply means: Great
minds think diffrently.

Richard Langbert