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Anticlastic Forming


Dear Friends,

As I understand, “anticlastic” is in most simple terms the "opposite"
of traditional raising and sinking techniques of forming metal with
hammer blows, etc. From the Internet I am told that “anticlastic
forming” was brought to light by Michael Good,, and by Heikki Seppa.

Are there examples in ancient art and metal work of anticlastic
metal forming? I would be very glad to hear of examples of this
metal forming technique used in times much older than ours




The terms “synclastic” and “anticlastic” are mathematical
descriptions of surfaces. In a synclastic forms [suffix “syn-” from
the Greek, meaning “same”], the X and Y axes of the surface bend in
the same direction, i.e. both go up, down, left, or right. This
gives you a form that is either convex or concave, bowl-like. In
anticlastic forms [suffix “anti-” from the Greek, meaning "against"
or opposing], the X and Y axes bend in opposite directions. The most
common description for this is a saddle form, where one axis fits
around the body of the horse while the other axis sweeps upward to
support the rider. [Mathematically, there are only three possible
forms for a surface: convex, concave, or anticlastic.]

We commonly encounter synclastic forms – bowls, cups, spoons, etc.
– in their pure state, but rarely encounter anticlastic forms used
alone. [Michael Good’s work is the most visible exception.] Heikki
Seppa’s pioneering book Form Emphasis for Metalsmiths provided
inspiration for his students at Washington University in St. Louis
and in many workshops he taught around the world. The book is still
in print and is a wonderful and daunting read. It provided our
modern vocabulary for what Seppa calls “shell forming”. He wanted
his students to explore the possibilities of metal surfaces and
forms independently of any functional goal, so he borrowed heavily
from existing geometric terminology to describe the kinds of shapes
he and his students were making. Betty Helen Longhi did a
presentation at SNAG in St. Louis tracing the influence of Heikki’s
book and teachings in North American metalwork, complete with an
extensive slide presentation of pieces by many artists, some small
enough to be worn and many quite a bit bigger. The Arch in St. Louis
is a shell form, in fact. If you are researching this, I highly
recommend that you contact her and ask about this paper and her
image collection. She, like Michael Good, has worked with Heikki
Seppa; she also teaches excellent shell forming workshops that cover
anticlastic forming.

When you look at metal objects you often see that anticlastic
surfaces and synclastic surfaces can co-exist on the same piece.
Think of the junction between the spout of the teapot and the pot
itself. At that point, their are axes going in opposite directions.
Another commmon example is a ladle or bowl with a pouring spout on
the lip: that little shift on the plane of the ladle is an
anticlast. One of the ways to determine whether a surface is anti-
or synclastic is to see if it will hold water. Only a synclast can
hold water because the axes create some kind of hollow space where
water can pool, although you may have to turn the thing upside-down
to get this to happen. An anticlast cannot contain water regardless
of how you hold it. The transition between these two kinds of
surfaces can be so subtle that you won’t really see it until you
actively look for it – often these transitions are the most
pleasing to both the eye and the hand. This interplay is also a
fabulous playground for design for both functional and sculptural

There are marked differences in the way metal is moved with hammers
to form synclasts and anticlasts. Synclasts are often formed by
raising, which stretches the middle of the sheet and compresses the
edges. One can also make synclasts by sinking and stretching.
Anticlasts are formed by stretching the edges and compressing the
center of a sheet. This is one reason they are difficult to do well
and take a lot of practice and patience. The techniques that you
need to make anticlasts are really quite different than the ones
that you use for raising. Michael Good uses dies and presses to
create his production series work, although he still does plenty of

Anticlastic forms have existed in metalsmithing since we first
manipulated sheet metal with hammers. I think you will find plenty
of examples in ancient work once you look at them in geometric
terms, and once you look for them in the company of synclastic
forms. If, however, you are looking for anticlastic forms used in
isolation, I suspect that you will not find as many, but they are
out there. Bracelets are always worth exploring, as are other
toroidal [doughnut shaped] and torque forms.

If you are researching this in a formal way or for your own
enjoyment, I highly recommend Heikki Seppa’s book because it will
give you clear examples and definitions that will help you in your

Anne Hollerbach

        Are there examples in ancient art and metal work of
anticlastic metal forming?  

There is a person in Co. Wicklow, Ireland who has been doing research
on how goldsmiths used to work long ago - even in times
’prehistoric’. His results are very interesting. He invited Michael
Good to Ireland and they discussed it together - that’s how I found
this (do a search at google for M. Good, workshop, Ireland). They
tried to simulate the old ways of working with metal. The results
were absolutely stunning. Anticlastic raising, for example, was done
using antlers of deer. Best, Will


Dear Ann and Will,

Your posts are well received. I do indeed thank Ann for the very
clear definitions and insight into the perhaps confusing differences
in metal forming technique. Will, thanks for the place to look for
more. Ann thanks for the info on further My work has
been primarily jewelry design and creation, with little of
anticlastic work except by directed accident to achieve a form, not
knowing what to call it except “suited to the design”.

I always respect the work of those who are innovative, creative and
have mastered the basics. The unfinished creations of creative
folks who lack the skill to pull it off disturb me. I want them to
pull it off correctly to the finish.

Some do not know the difference…creativity is not creation, as I
see it, unless the artist is able to finish the job to a level
accepted by peers in that discipline.

I may well explore anticlastic forming. I would hope to finish the
work properly.

Thanks so much! God Bless. Thomas.

   Are there examples in ancient art and metal work of anticlastic
metal forming?  I would be very glad to hear of examples of this
metal forming technique used in times much older than ours

TomDart, I have often wondered if the so-called lunate-shaped
earrings, made of hammered sheet gold, and found in the Royal
Cemetery at Ur (Mesopotamia; ca. 2500 BC) were formed by anticlastic
raising. Could those bulbous, hollow, open crescent shapes have
been formed any other way? Art historians describe them, but they
almost never consult metalworkers for process analysis. Most books
on jewelry of the ancient world will include photos of such

Judy Bjorkman



A year or so ago I looked at the site. I took a pair of antlers and
tried the technique. It works. You ought to see the expressions when
I tell people that one can use deer antlers as a forming tool. I
found the antlers actually more effective than a hammer and stake in
those tight spirals. Amazing.

Bill Churlik

        Are there examples in ancient art and metal work of
anticlastic metal forming?
  There is a person in Co. Wicklow, Ireland who has been doing
research on how goldsmiths used to work long ago - even in times

Brian Clarke is the name of the Irish metalsmith. He does wonderful
work, and gives terrific workshops in his studio in Ireland.
Students stay in his home, and enjoy meals cooked by his wife, and
learn LOTS. The archaeological research that Brian and Michael did
together is quite incredible. They figured out how the ancient
Celtic ribbon torques could have been done using deer antlers as
hammers and stakes. This research was presented at an
archaeologists’ conference in Europe. Here is a link:

I highly recommend taking a workshop with Brian Clarke or Michael


PS. To Anne Hollerbach: nice explanation of anticlastic and


Dear Len and Judy, I found a site with perhaps the earrings to which
you refer:

Are these what you mean? It will take more than my knowledge of
metal forming to answer the question.

I do feel there is little new out there in the basics of such work,
sure improved methods and hydraulic presses, etc. are in use. When
seeing the work of the ancients, whether of UR or of the tomb of Tut
and granulation from the Etruscans…amazement is the word.

Thanks so much for you input. This let me enjoy ancient art not
thought about.

God Bless.


The gold earrings in that picture look fold formed. The metal looks
very thin which would aid the process. I have never heard of fold
forming in ancient times but that is sure what it looks like to me.

Marilyn Smith


What kind of way do you use to hold an anticlastic stake in a vise?
Judy, I take strapping iron and bend two U-shaped forms which have
horizontal flanges extending from the ends of the vertical legs of
the U’s. ( --u–) One is placed towards the front end of the stake
with the belly of the U facing down and the flanges resting on the
top of the vis.e jaws. This cradles the front end of the stake. The
second U is placed towards the backof the stake with the belly
facing up and the flanges catching the underside of the jaws. The
latter U-shape resists lifting of the back end of the stake and the
front positioned U resists downward movement. Another way is to use
two steel rectangular blocks with V shaped grooves running parallel
to the long axis of the stake and place these on either side of the
stake and tighten the vise. It helps if there are horizontal lips on
the outside of the steel blocks to rest on the top of the jaws to
resist downward movement of the stake.

A picture would be more than helpful in this explanation. Joe Dule