Drawing wire, getting burrs

I would just like to putt additional thoughts into the problem. When
rolling out an ingot into square wire stress is caused along the
corners. You have mentioned that you are getting burrs even though
stress fractures haven’t happened along the corners. This doesn’t
mean that the stress along the grain boundaries has not occurred on
those corners.

I have found when getting these burs, it’s usually caused by not
annealing enough, the quality of the ingot, the quality and
cleanliness of the draw-plate, starting and stopping in random
places along the draw, and reducing the roll of the mill too much at
once. This can cause a squeezed corner which is subsequently folded
onto itself when turning and rolling of the metal. To help with all
potential problems, I usually take a little fine grit sandpaper in
my hand and draw the square wire through the sandpaper a couple of
times to take the very corners off before going to the round wire
draw-plate. This eliminates most edges and corners, reducing stress
in the drawing of the wire. Oh, and use lots of oil or burr-lube.

Try this and then work backwards if this does not work. Just some
thoughts.

Jeremy Dunn

When Leonid states that the labour cost of reproducing a Faberge'
Egg would exceed the purchase price of the original, is he
suggesting that the Rothschild Egg could not be reproduced for it's
auction price of 16 million dollars, or does he mean for its
original price when purchased in 1902. 

$16 million is a lot of money for sure. But it is interesting to
examine what would it cost to produce work on Faberge level.

Let’s take a riviere necklace composed of 60 one carat diamonds. I am
using riviere because it technically simple. We have to manufacture
60 settings with built in connectors and a clasp. Each setting would
take 10 hours of labour plus 100 hours for the clasp. Another 40 to
50 hours to assemble and to make sure that everything works smoothly.
Total 750 hours. Jeweler working at this level should be paid no less
than $50 per hours, add to this other expenses associated with
employment and we have close to $80 per hour or the total labour bill
would be approaching $60 thousand.

To manufacture each setting we would have to start with strip of
platinum with dimensions of 21 mm X 9 mm X 1 mm which weigh close to
6 grams or 1/5 of an ounce. So we would need 5 ounces of platinum
sheet plus some wire and solder. I will not be far of the mark
estimating $10 thousand in material.

Diamonds, even is not the best quality, but still have to match and
be of decent colour and clarity, I would estimate another $200
thousand. The expenses so far approaching $270 thousand. Add to it
rent, taxes, salaries of support staff, administrative, insurance,
some profit and it is easy to see that just to stay in business the
necklace cannot be sold for less that $700 thousands.

With some patience, a similar necklace can be purchased at auction
for $70 to $80 thousand or 10 cents on the dollar it cost to make.

Without been tied up to a specific item, I think that in todays cost
environment it makes more sense to buy things at auction than trying
to make them.

Don’t get me wrong. There is nothing I would like more than to
practice the art of Goldsmithing on the highest level possible, but
we are running into economic headwinds which are very strong.

I am still taking orders for Coronets, but I have to do them myself.
It is almost impossible to find a jeweler who knows how to use
jeweler’s saw. I do not know how things are in England, in USA it is
really tough.

Leonid Surpin.

James,

As a goldsmith and an enamelist all I can say is “WOW” your work is
absolutely amazing and gorgeous.

jennifer friedman
http://www.jenniferfriedmanstudio.com

Thank you all for your input on this one. I’m happy to report that
I’ve tried some of the suggestions given and have found a very
workable solution.

It turns out that the idea of providing some transition state from
the squared wire that comes off the mill to the round holes of the
drawplate was the correct analysis of the problem. James Miller’s
suggestion of hammering off the square corners was the solution I
tried: using a forming block that I have that process was easy,
fairly quick and quite effective.

James’s suggestion reduced the burr problem to a mere fraction of
what it had been, less than 5% I’d guesstimate. If I had been more
thorough in my rounding of the wire by hammer before I started
drawing – I had only gone so far as turning the square wire into a
roughly octagonal shape – then I’m sure the burring would have been
reduced even further. Many thanks James for that excellent analysis
and suggestion: any problem that can be solved with a hammer is a
problem well solved IMHO. :slight_smile:

A couple people suggested sanding down the wire a bit before drawing
as a means to get rid of any pointy edges on the wire likely to cause
burrs. I don’t doubt that this would have the desired effect but I’m
sure I’ve read somewhere that this is not a recommended process if
you want to keep your wire clean and your drawplate holes undamaged.
I believe the idea was that bits of grit get lodged in the wire
surface and are then pulled through the drawplate holes which causes
abrasion on the drawplate and imbeds the grit into the wire surface.
Whether that’s a theoretical concern or a practical one I’m
disinclined to find out. Personally I’m happy enough shaving off a
few burrs here and there if and when they form if it means keeping my
wire and drawplates clean.

Finally a comment on the milling process: some of you mentioned that
your mills produced square wire with rounded edges. I’d say count
yourself lucky because those rounded edges probably go a long way to
making this burrs while drawing problem a non-issue for you. My mill
gives the square wire very crisp beveled corners and my guess is
that that’s at least half the problem here. Crisp, squared edges
through a round hole is just asking for trouble and my guess is that
I’ve just happened to find the right combination of circumstances to
make that trouble a reality. Mores the pity but at least a few
minutes with a hammer (one of my favourite tools!) gets me back into
the “happy drawing” zone.

So, there it is, problem solved. Thanks again everyone, your
assistance has been much appreciated.

Cheers,
Trevor F.
in The City of Light
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