I’ve rolled and drawn a lot of my own small gauge wire before and
had no problems. Recently though I’ve had the need to do some heavy
gauge round sterling wire and am running into an interesting problem.
Any suggestions would be most welcome.
So, I’m starting with 5mm square silver rod and want 2.5 mm round
wire. I do the usual progressive roll-down on the mill to get say a
2.6+ mm square wire and then take that over to the draw bench. The
problem is that as the square wire is rounded off on it’s way through
the round wire plates I get these wicked burrs. The wire comes out of
my mill as the usual square with the corners knocked off so each of
those square edge gets rolled over by the drawplate to produce a
burr, so that’s no less than 8 full-length burrs per length of wire
drawn!
Of course you need to cut these burrs off before you proceed very
far in the drawing process and that takes a lot of time, at least
doing it by hand the way I have been.
In case anyone is wondering let me be clear: this is not a defect in
the drawing plates (I’ve tried several different plates, some steel,
some carbide). And it’s not a problem with burrs pre-existing on the
milled wire (I’ve checked, several times).
I’ve tried repeated thorough annealings (much more than the wire
itself really calls for), different lubricants (motor oil, wax, soapy
water), larger and smaller draw-down steps, etc and nothing seems to
have much affect. Lots of burrs, lots of nasty work slow-downs and
I’m not a happy camper.
So, what’s the trick here? What am I missing? I’ve tried consulting
the reference books… nothing. I’ve tried searching here at Orchid
… the same. So I plug on trimming off those long, nasty burs but I
do find myself wishing over and over that there was a better way.
So, what's the trick here? What am I missing? I've tried
consulting the reference books... nothing. I've tried searching
here at Orchid ... the same.
When you roll your square wire from 5mm to 2.6mm you folding the
edges. It is not visible right away, but when you draw they separate
and give you the problem you describing.
The solution:
Check you rolls if they mate properly. If it is wear on the rolls,
the only remedy is after every pass examine if any metal was forced
out forming a step. This needs to be filed off before proceeding with
the next pass. If not the protrusion will fold back upon itself
creating the problem in the drawing stage.
I’ve never paid much attention to the burrs along the corners of
square wire that hasn’t yet made it down to round wire while drawing
it – it stands to reason that the first few passages through the
plate will produce them, and I just kept going until the diameter of
the hole was being fully utilized in shaping the wire. Come to think
of it, I carry samples of silver wire that I stopped part way
through, to show my students stages of my wire making, and the one
that’s between rolled ingot and round has got those same burrs on
it.
You could attempt to run the square wire through at a forty-five
degree angle, and make octagonal wire of it. Flattening the corners
would go a long way in the transition from square to round, but it’s
a bit tricky to keep control of the material – it’ll keep trying to
twist itself back to the other orientation. No need for great
precision, of course, you just want the corners to be blunted. Good
luck!
since you have eliminated the drawplate and the material for the
burrs, then the only other possibility is that the problem is in the
rolling operations. My thought is that the first couple of passes
through the roller cause the problem. Those first passes must be
compressing the square corners in such a way that fins are being
forced into the body of the wire. Try filing off the sharp corners so
that the cross section of the wire is closer to the shape of the
roller, then proceed in compressing the wire, carefully and slowly,
as usual.
It sounds like you need an intermediate draw plate to start the
rounding off process. The cheapest way to try this may be to alter a
steel plate by lapping out the corners. Or Start with a larger size
squaring plate first which would leave the corners a bit round on a
first pass. good luck
Thank you all for your feedback on by “square wire makes burrs”
problem. A few of you have suggested that it’s the mill producing the
burrs that are later revealed by the draw plates but I assure you
that’s not the case. My mill is in very good shape, virtually new in
fact, and I’ve examined the wire I roll out of it very closely, even
carved into it to see if anything was hidden beneath the surface. I
am quite confident that there are no sub-surface “fins” or ripples or
anything else of that sort. Given that I can raise the burrs in
question at any time by simply drawing larger gauge square wire
through a round draw plate I am certain that it’s that process that
is causing the burrs, not something that was in the wire before it
went through the draw plate.
It sounds like you need an intermediate draw plate to start the
rounding off process.... Or Start with a larger size squaring plate
first which would leave the corners a bit round on a first pass.
Jesse,
An intermediate plate sounds like an interesting idea (see below)
and I’d very much like to know if that’s the way others have solved
this type of problem. I’m afraid I’m a bit puzzled by your mention of
a “larger size squaring plate” because (a) I’m not using a squaring
plate, I’m running the squared wire that comes off the mill through
round holed plates and (b) I don’t want to make squared wire – I can
get that off the mill – it’s round wire that I’m after.
You could attempt to run the square wire through at a forty-five
degree angle, and make octagonal wire of it. Flattening the
corners would go a long way in the transition from square to
round....
Loren,
Now, that’s an interesting thought, and relates I think to what
Jesse has suggested. I do have hexagonal plates which might be worth
trying. When I think of it that might have some relation to wire
pulling the way I normally do it, which is to run large gauge stuff
through the mill until it is small and then move over to the
drawplates. The upshot of it is that by the time the wire is done in
the mill the proportional difference between one of the squared off
corners and one of the sides is much much less than when you pull the
wire out of the mill when it’s still a large gauge. In other words,
fine wire off the mill is more hexagonal than large wire would be.
It was interesting to read that you’ve basically ignored them and, I
presume, suffered no ill effects because of it. I’m at a loss, and
dead curious, to know more. Are the burs imbedded in the wire but it
just doesn’t matter that much? Does the process at some point correct
itself and the burrs just “go away”? I suppose I could just go ahead
at try some of this to see for myself but I’m reluctant to sacrifice
the metal to find out, though I suppose one need not run a great lot
through in order to see what happens. Still, I am curious on your
thoughts about where those burrs go.
Those first passes must be compressing the square corners in such a
way that fins are being forced into the body of the wire. Try filing
off the sharp corners so that the cross section of the wire is closer
to the shape of the roller, then proceed in compressing the wire,
carefully and slowly, as usual.
When making wire with a rolling mill, as you roll the square wire
down, each pass is made two times at 90 degrees to each other. If you
go down too fast and get a fin, that fin gets rolled over and is not
evident until you start drawing the square wire though the drawplate.
I wrote to Trevor directly and explained my method and ideas about
his burr problem, but after reading the orchid suggestions I thought
I would share my thoughts with everyone. When I was an apprentice I
was told to use a hammer, when shaping square wire to round, before
using the drawbench. Using a hammer and a flat steel plate to shape
the wire.It is easy and most satisfying to shape short lengths of
square wire into round, when the wire is almost perfectly hammered
round, then it is the time to use the drawplate. I agree with others
who have said that the burrs are caused by the corners of the square
wire being folded and creating slight second layers of metal, that
will tear off forming a burr when pulled through the drawplate. Metal
performs different when squeezed in a roller or drawbench, than when
hammered. When hammered metal compresses rather than spreading, which
is why hammered metal becomes harder quicker and needs constant
annealling. I love using hammers to shape metals!
I am suprised how little importance the use of hammers is given in
many modern teaching methods. I think my trade is becoming obsessed
with the use of machinery, don’t get me wrong, I use modern machinery
to make my life easier, but I think when being trained it is
important to be taught the traditional ways of manufacture also. I
also love saw piercing, but over here in the UK, manufactureres are
buying machines that lazer cut metals, so my skills as a saw piercer
are not required. Luckily I have earned my living over the past
thirty years making unique items, single items are not profitable to
be made by machines at the moment.
Last week over here in the UK, we had an auction of Faberge goods at
Christies. The sale prices reached record levels, oh how I wish
these purchasers would commission new goods from current craftsmen, I
know of many goldsmiths like myself who would love the opertunity to
be commissioned to make items like the Faberge’ Easter Egg that sold
for eight million pounds. The experts on our media suggested that
this type of work could not be matched by todays craftsmen, but I
know of at least six goldsmiths who could surpass the quality of the
Faberge workshops. Believe me as I have worked on hundreds of
Faberge pieces in my career as a London goldsmith and I have seen
pieces, made by English goldsmiths, that would make Faberge Eggs look
amatuerish by comparison.
When making wire with a rolling mill, as you roll the square wire
down, each pass is made two times at 90 degrees to each other. If
you go down too fast and get a fin, that fin gets rolled over and
is not evident until you start drawing the square wire though the
drawplate.
Thanks for mentioning that Richard, it’s a good point that often
doesn’t get mentioned. For the record that’s what I’ve always done…
well, ever since I found out what happens if you don’t.
I’ve had a very interesting email exchange with fellow Orchid reader
James Miller in relation to my question and I thought it would be
good to add it to the thread.
James wrote:
What you describe about getting burrs when drawing square wire
into round is a common occurance.... I was taught as an apprentice
to hammer square wire roughly into round wire, before using a
drawplate
I think he pretty much answers my original question and indicates
that this this is a known problem, which is invaluable information
IMHO. I also find the old technique for dealing with the issue most
helpful, as the old ways so often are, especially for a one-man,
low-tech shop like my own.
SORRY ABOUT MY CONFUSION, what I should have talked about was being
careful not to try to do too much at a time. you need to not draw to
a smaller cross section area – don’t try to get a longer wire at all
until you have the shape defined. I think I would start with a
squared plate with rounded sides ( pin cushion shape. ???
When I roll out my small ingot in the wire rolling mill I try very
hard to rotate the ‘now wire’ so that I don’t get the “square burrs”.
Occasionally I need to run the scraper over the edges to remove them,
but not that often. Then I pull it thru the round draw plate. I
haven’t had a problem yet with my wire and I draw down to 30ga most
of the time.
The most likely reason that burs show up on wire that is drawn in a
plate after rolling in a mill, is improper mill techniques. When you
roll wire down in a mill it is very important not to tighten the
wire on one side only as you continue to roll through smaller wire
groves.
This can cause a flange of metal to form on the corner of the wire.
If this flange appear and you are not aware of it and then you turn
the wire 90deg to roll it again - you will compress the flange and
fold it over rather than compress and reshape the wire to a smaller
size. Even if the flange is very slight it can fold rather than
compress. This fold will not be noticed until later when you are
drawing the wire because the pressure of the mill fools you into
thinking the wire is solid and firm. But in fact what you have is a
fold that is only pressed together to form the square wire shape.
Later as you draw the wire and stress the surface these nasty sharp
burs will appear. They are like small cracks and become longer and
sharper as the wire is drawn smaller. This is because the once small
fold is now
elongated and the layers of the fold become thinner as you draw. Be
careful because these can cut your fingers or skin. The worst is
that they don’t show up until after a piece if finished and being
polished. To avoid this - turn the wire 90BA each time it is run
through the mill at the same tightness. Then just tighten a little -
roll and turn - tighten roll and turn. If a flange does appear it
must be filed away before you turn the wire. Otherwise you can roll
and allow the flange to grow and grow without turning the wire. Keep
it rolling on the one side and make sure you remove all the flange
before drawing. This is not the correct method - but it will work.
oh how I wish these purchasers would commission new goods from
current craftsmen, I know of many goldsmiths like myself who would
love the opertunity to be commissioned to make items like the
Faberge' Easter Egg that sold for eight million pounds. The
experts on our media suggested that this type of work could not be
matched by todays craftsmen, but I know of at least six goldsmiths
who could surpass the quality of the Faberge workshops. Believe me
as I have worked on hundreds of Faberge pieces in my career as a
London goldsmith and I have seen pieces, made by English
goldsmiths, that would make Faberge Eggs look amatuerish by
comparison.
I, myself, did not realize until I saw your work that this was true.
The thing to do would seem to be to get a museum or guild interested
in mounting an exhibit that showed the “modern Faberge” type work,
possibly together with the actual Faberge, where they could be seen
and compared side by side.
Far easier to have an idea than to see it realized, of course…
The experts on our media suggested that this type of work could not
be matched by todays craftsmen, but I know of at least six
goldsmiths who could surpass the quality of the Faberge workshops.
Believe me as I have worked on hundreds of Faberge pieces in my
career as a London goldsmith and I have seen pieces, made by
English goldsmiths, that would make Faberge Eggs look amatuerish by
comparison.
A few words in defense of my countrymen. While James is correct that
many goldsmiths surpassed technical standards of Faberge workshops,
work of Michael Perchin is a different story. I have no doubt that it
can be reproduced flawlessly, but the labor cost would exceed the
purchase price of the original.
Another aspect of Faberge work is the superiority of the design. That
is where most of the modern goldsmiths are lacking. That said, I want
to salut to James for raising the subject. Without patronage from
well heeled clientele, the art of goldsmithing is in peril.
I have been reading the postings on getting burs on drawn wire. I
agree that most problems related to sharp “spurs” or burs in the
drawn wire would occur in the rolling mill phase. If the wire ingot
stays in a basically square shape as it is being reduced with the
rolling mill, avoiding any thin “wings” or extrusions from forming
along the corners of the square wire, a good drawn wire should be
assured. That is assuming the annealing of the wire is done with
regularity and the entire wire reaches annealing temperature each
time. The metal should also be soft enough to roll, and not
"contaminated" with a casting-type alloy, which tends NOT to roll or
draw well at all. I cannot stress how important it is to roll this
square wire ingot twice through each groove (rotating the wire 90
degrees each time) to achieve a perfectly square wire before drawing.
Another vital aspect to making good wire is not letting the rollers
come all the way together, touching, while the wire is being run
through the mill. The wire ingot will always expand sideways,
slightly, from the extreme pressure of the rollers, and the wire must
be able to “bulge” slightly outward between the rollers grooves. If
enough room is not left between the rollers (as when the rollers are
touching together), the wire will “extrude” between the rollers,
making a sharp fin. The running of the rollers all the way together
is usually so counter-productive and potentially damaging to the
mill, that I don’t even allow my students to do it in our studio.
Tapering the wire can be quite quickly done with a rolling mill’s
grooves, but that taper MUST be annealed before you can draw the wire
through the drawplate. I have also seen problems drawing wire if the
drawplate is reversed. The wire will always come OUT the side that is
numbered, and go in the larger side, without the numbering.
With reference to Leonid Surpin’s post today, I am one of Michael
Perchins greatest fans, I admire the work he produced at the time he
was workmaster. I was part of a team that made rough copies of the
Perchin Coronation Egg, for use as props in the James Bond film
Octopussy back in 1982. At that time I made an effort to study the
work of Perchin and his workshop. If anyone does not know, the
Rothschild egg sold recently was made at the Perchin workshop, along
with other famous eggs. Perchin’s workshop employed between 30 and
40 craftsmen so their output was quite large. 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. When I was studying the manufacturing of the Coronation Egg, I
found that the interior coach, was made by George Stein at the
Perchin workshop, it took fifteen months to make, at that time
George Stein was being paid 5 Roubles per day for up to a sixteen
hour day, this would have been about a dollar a day back in 1896. I
am sure I could make one hell of a fine coach in fifteen months! I
have made many Easter Eggs in my time and they average about three to
six months to complete. I worked alongside a fine goldsmith back in
the late 1970s, his name is David McCarty,he made an Easter Egg
similar to the Faberge’ Serpent Clock Egg. It was made using
techniques that would have been used in the Perchin workshop and I
defy anyone to say that it was not as good as any Faberge’ original.
I have attached a photo if Hanuman will kindly make it available for
all to see.
It could be that your rollers produce a square bar with sharp
corners, or corners with small bevels or radii. My Cavallin rolling
mill produces a square bar with large bevels on the corners; the bars
can go directly to the drawplate without any problem.
Flashing can happen in my mill but I have to push it… what I do is
pass once, screw the roller down, rotate the bar and pass again; ie I
do not have to pass twice before screwing down except with the
largest groove (5mm to 4mm).
A mill with sharp-cornered grooves needs extra care in rolling to
prevent flashing, and the sharp corners must be removed from the bar
before it goes to the drawplate.
I have been reading the postings on getting burs on drawn wire. I
agree that most problems related to sharp "spurs" or burs in the
drawn wire would occur in the rolling mill phase.
I hear you Jay, but you need to also consider that the problem of
drawing burrs can occur in other ways to. As James Miller has said,
it’s an old problem, and they had specific ways of dealing with it
in the past (hammering down those square edges for instance).
I think one of the things that is getting lost in this conversation
is that I have drawn heaps of wire in the past – the proper way,
doing the 90 degree turn and second runs – and had no problem
whatsoever. I’ve done this with gold, sterling silver, Argentium
sterling, and pure silver so I pretty much know how to anneal
properly and the various ways to botch up the mill rolling if I
really wanted to (fins, single passes, incremental steps too big,
rollers too tight, etc). The key thing in most of my past experience
is that the point at which I made the transition from mill to
drawplate: I almost always only did it with fairly small gauges of
wire, say 1mm or less.
My problem occurred, and continues to occur, when I take large wire,
say 2 or 2.5 mm, out of the mill and run in through the round
drawplate. Now I get the burrs and I’m convinced it’s because the
process of forcing a large gauge nearly square wire through a round
hole will roll over those nearly square edges and thus produce
burrs.
Bottom line: it’s not a milling problem, it’s a drawing problem, at
least with these large gauge wires.
Your work is awe-inspiring. I count you among those who could excel
in the creation of Faberge eggs. Someday, if I’m lucky, I want to
see some of the amazing things you have made.
