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Device for making ovals


#1

A while back, I asked about a source for tapered oval mandrels.
Sometimes it’s necessary to build a device to make the parts. Here’s
a work in progress that looks promising.

My need is to be able to form bezel and prong settings that can be
formed over a tapered oval mandrel.

Rod


#2

Rio Grande - Oval Bezel mandrel
http://www.ganoksin.com/gnkurl/rio112364
$24 USD


#3

why not buy a stainless oval mandrel and form the bezels then solder
closed add the prongs by cutting the wiresto equal lengths and
soldering them to the bezel- either cut a notch to hold them or
solder them to the inside or outside of the oval?? I guess I’m not
seeing whay there is the need for the extreme machinery in the you
tube video… that isn’t applicable to bezel making anyway.
Foredom’s Allset system is also a great tool for making, and setting
just about anything, the milling table in the master set will allow
you to set any shape stone in half the time of hand fabrication but
its pricey if you are on a budget…ikohe also has bezel and prong
tools…guess i don’t get the question…rer


#4

Why not just get an oval tapered bezel mandrel from any jewelry tool
provider?

Jerry in Kodiak


#5

Perhaps I’m wrong, but wasn’t the original point being made that the
OP couldn’t find an oval mandrel with the required ratios for the
oval. ‘Oval’ is a pretty generic term… The mandrels out there are
the more common ratios, but I believe the OP had a requirement for a
different ratio and was asking for help to locate one. I gather since
he didn’t get many responces, he did what good jewelers do
(particularly ones with machining/tool design skills) and made his
own. The video is a prototype for a jig to machine a non standard
mandrel for the purpose of truing up non-standard oval bezels.
Virtually any oval can be made with trial and error. The video,
while appearantly not clear to some and likely taken out of context,
is genius.

If you want a job done right, do it yourself.

But I could be completely wrong here. Sometimes the self replicating
machine elves lead me astray.


#6

Scratchbuilding your own oval turning rig: priceless.

(Sorry, just couldn’t resist.)
Brian


#7

I have had to make oval bezels that were too small for any tapered
oval mandrel.

Some oval gems are not the length and width of any mandrel produced.
You can spend as much time as it takes to make an oval bezel trying
to reshape one made from a mandrel.

Once upon a time, there were no tapered oval mandrels. Guess what
they did?

I have used round nose pliers.

Skill, discipline, and patience.

Possibly where the phrase “Third time is a charm”.

Richard Hart G.G.
Denver, Co.


#8

In additon to Richard’s sound advice, here is one more suggestion.
Using a pair of round dowels makes a decent oval.

Michael David Sturlin
michaelsturlinstudio.com


#9
Scratchbuilding your own oval turning rig: priceless. (Sorry, just
couldn't resist.) 

I don’t know about priceless. The design is essentially a simplified,
oversize, and somewhat crude version of the classic engine
turning/rose engine oval chuck, a design that goes back to at least
the early 1800s, and maybe much earlier (not sure exactly when the
first ones became common. I could look it up, I suppose…) But
anyone who’s tried to re-equip an old rose engine will have found
that a good oval chuck costs rather more than pocket change, so if
one has the time and inclination to build one, and it serves their
needs, then it could easily save money, and be fun to build too. Is
it really needed? Um. Do we really have to actually need a cool new
thing in order to justfy the fun of making it?

Just so long as nobody things the design principals of that device
shown on youtube is new. It’s pretty much the same idea as all the
old oval or eccentric chucks were built around.

Peter Rowe


#10
Some oval gems are not the length and width of any mandrel
produced. You can spend as much time as it takes to make an oval
bezel trying to reshape one made from a mandrel. 

Nice modernization of Holapfel’s oval chuck, first off. Or did the OP
invent it anew? To go to Richard’s thought, which I’ve had in mind,
too. It’s one of the goldsmith’s correlations of Murphy’s Law - no
matter what oval mandrel you have, your stone will be of a different
proportion. Get your wire the right length, or nearly, make a perfect
circle in the usual ways, and then squeeze the sides down to your
oval. Squeeze carefully or it will be crooked. It’s way difficult to
make an oval out of a mishapen, soldered wire. It’s easy starting
from a circle.


#11

One thing I have taken to is to not buy stones which have dimensions
that I don’t have a mandrel for. This works when I am designing for
multiples of stones and haven’t yet bought the stones. When I do
have to make a mount for a stone which none of my mandrels will work
I will sometimes simply squish a round mount to the proper shape, if
it is a small stone.

Sam Patania


#12

Hi guys,

Unfortunately, Hanuman or somebody clipped the original message I
was replying to, which said ‘Oval bezel mandrel: $10’ My reply of
"making your own rig: priceless" would have been a lot funnier (and
made more sense) with that in place.

Yeah, I knew it was a big delrin oval chuck. Still cool though.

Regards,
Brian.


#13
It's one of the goldsmith's correlations of Murphy's Law - no
matter what oval mandrel you have, your stone will be of a
different proportion. 

Where does the Murphy lives? Under your bench!

With that observation, since we on the subject of making ovals, I
want to recommend my DVD “Coronet Cluster”

http://www.ganoksin.com/gnkurl/fp

The design is based on 4 ovals, which are fabricated to fit each
other very tightly. If anybody having troubles of fabricating ovals
to precise specifications, after working through the DVD it will be a
walk in a park.

In more general terms, no mandrel was ever intended to be used as
something that conforms exactly. A bezel is formed by utilizing
different areas of a mandrel. Bezel block is where exact form is
achieved, and if particular proportion and/or sizes are not
available, than techniques demonstrated on the DVD, can be used to
fabricate required shapes.

Leonid Surpin
www.studioarete.com


#14
It's one of the goldsmith's correlations of Murphy's Law - no
matter what oval mandrel you have, your stone will be of a
different proportion. 

Same with setting burs.


#15

Hello all,

I have followed this thread with a bit of interest. One way to do
ovals of all different sizes and angles would be a set of templates.
Check out an office supply, craft store, drafting supply. Check the
drafting area. You will see many templates in many sizes and shapes,
elliptical, round, square, hexagon, tryangal.you get the idea. There
is one for about every size and shape you would need. With miner care
they will last forever. The ones I like are the green from, The
c-thru ruler company. I have some of these I have used for thirty
years and stille good. I will lay one on my bench that is close then
slide my stone over it untile it drops into place then transfer that
shape to what ever I am working with. Works great for me.

Rick McC


#16

G, I almost forgot about turned spindles available at home
stores…cheap easily avaialble and castable ( into a metal mandrel
if you don’t want to use wood)…regular baseball bats can be cut into
3 pieces giving you not only a round/ball end, but two additional
tapered mandrels as well if you need bracelet mandrels…I had a
student that coated one with labmetal and it lasted quite a while
longer than wood…( however, once the wood dried the metal "shell"
basically slipped off in one piece… the remaining shell was not so
sturdy for planishing !)…just an afterthought…rer


#17

Hi,

I’m not sure of the size or how many of these you need. But when I
have needed a lot of very small ovals exactly the same size, like for
making chain. I have had some success with using a wood dowel or
bamboo barbecue skewer as a mandrel. I coiled the wire on the skewer
or dowel tightly. Then I run the skewer with the wire coiled on it
through the rolling mill. It compresses the coil on the wood pretty
dang uniformly. Then I just burnout the skewer with my torch. And
voila! You got a nice coil of ovals you can pretty much cut apart as
you would any other coil of wire.

Hope this is helpful.

Thanks,
Aaron
aaronwilloughby.com


#18

We manufacture a set of five different sized oval mandrels for use
with our Jump Ringer. The smaller sizes are always cut on the longer
leg while the larger sizes may be cut on either the long leg or the
end.

Jump Ringers are available from most tool suppliers.

Ray Grossman
Ray Grossman Inc.


#19

June 6 of this year, I asked for any leads to suppliers of small
tapered oval mandrels as my search for a small tapered mandrel for
odd aspect ratios like 8 x 5 mm and 9 x 5 mm was unsuccessful. These
mandrels need to be about 6 inches long.

Since not finding small tapered mandrels, there appeared to be two
options, invest in a CNC lathe or build a mechanical device to make
tapered mandrels. My proof of concept device is working as expected,
although it sure would have been nice if there were plans for such a
device, instead of just books and articles about ornamental lathes.

Thanks for trying to help.
Rod


#20
Since not finding small tapered mandrels, there appeared to be two
options, invest in a CNC lathe or build a mechanical device to
make tapered mandrels. 

There is a third option, which is to become a real goldsmith and
learn how to work with metal.

Leonid Surpin
www.studioarete.com