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Ancient coin technology


#1

Greetings, This post may be off topic somewhat, but I thought this
would be the place to get some learned opinions on a question I have
on the technology necessary to produce ancient coins. This is a
mystery that scholars have not been able to answer. By 450 BC the
Greeks had adapted their classical sculpture for use on coins. The
coins were standardized in weight and fractionals began to be
produced. Many of these small silver fractionals were under 9 mm and
some were 5 mm (you could not afford to have holes in your pockets).
A couple examples of the artistry can be found here:
http://www.people.memphis.edu/~tjbuggey/kyzikusboars.jpg My main
question to those experienced in engraving is:

  1. Could 8 mm dies with beautiful, realistic images be done today
    completely by hand and without magnification?

No one is sure how the dies were rendered nor what types of tool
were used. I imagine a micro chisel would be needed.

Thanks for any help you might offer in solving this ancient mystery.

Dr. Tom Buggey
The University of Memphis


#2

Dear Tom, I don’t know what technology the Greeks had. Did they make
steel? Have bronze metal working tools been recovered?

Looking at the coins pictured I would go about working in the
positive rather than the female part of the die. I would carve in wax
, to be cast in bronze, a male or positive punch and use it to stamp
into what would become the actual coin making die. That would be the
quickest and easiest way to produce. Carving into metal, engraving,
at the depths these coins are stamped would be very time consuming
and much more difficult than making a punch to make the die to make
the coin. Then bits of silver or what ever metal the coin was to be
made with could be produced by pouring metal into a mold, cooled
weighed and adjusted for weight by filing to remove weight or
remelting and adding more metal, and set onto the die and hit from
the back with another die or a flat hammer or chisel. Wax casting is
an ancient method of production and would be a familiar technique for
tool production. Sam Patania, Tucson


#3

Dear Dr. Tom,

As a part time lover of archeology I can across an article several
years ago regarding a find in the middle east. It was a hoard of
river polished clear quartz stones. Hundreds of them if I remember
correct. The amount in the find would not have been possible in
nature. Several reasons were submitted for discussion. My own opinion
is that indeed even back then craftsmen and artists needed
magnification. At a lecture I attended on ancient granulation I
submitted the thought to the presenter and he agreed with me that
some magnification must have been used. I suppose ancient tools like
this were rarely found along with the products they produced. Just a
thought…

Best Regards,
Todd Hawkinson
T.R. the Teacher
www.trhawkinson.com
www.ajt-online.com
www.mctc.mnscu.edu/jewelry


#4
    I don't know what technology the Greeks had. Did they make
steel? Have bronze metal working tools been recovered? 

Bronze yes. Steel, no. Not till the romans.

   Looking at the coins pictured I would go about working in the
positive rather than the female part of the die. I would carve in
wax , to be cast in bronze, a male or positive punch and use it to
stamp into what would become the actual coin making die. That would
be the quickest and easiest way to produce. Carving into metal,
engraving, at the depths these coins are stamped would be very time
consuming and much more difficult than making a punch to make the
die to make the coin. 

Sam, I think I’ll disagree with you here. From the greek coins I’ve
looked at, the designs seem to me to be more likely cut directly into
the female die, which I expect was either bronze, or perhaps (and
here I dont’ know) maybe stone. Also, looking at the way many of the
coins have cracked edges, I’d guess these are struck coins, not just
cast. The dies might have been cast, but i’d bet the work hardening
obtainable by forging would have suggested forged bronze, then
engraved in much the same manner in which the fine examples of greek
intaglio gem carvings were done, or perhaps made with chasing tools,
or stone chisels, or something (remember, no steel chisels, or files,
yet). I’d expect too, that the planchets would be carefully weighed
amounts of metal, melted into buttons and hammered somewhat to shape
before being struck between the dies for the designs. Since often
the designs are not quite centered on the coins, this too suggests
die striking rather than casting, either into the bronze (or stone)
dies, or via lost wax.

While modern coinage dies are indeed made by carving, engraving, or
otherwise producing a male hub, (actually, modern dies start with a
large clay, wax, plaster, or other such model, usually about a foot
in diameter, which is then pantograph reduced by machine to produce
the male die) from which the female coining dies are then produced,
actually engraving a female die directly isn’t as time consuming as
you might expect. I’ve done small dies that way, though not for
coins, over the years, and you can get surprising depth without too
much trouble. And I was doing it in steel, not softer bronze. But
of course I did have access to modern tools to do it.

But we really aught to ask Jack Ogden, who I believe reads Orchid,
to comment on this. he’s the expert on ancient technologies, or so
his wonderful books on the subject have led me to believe…

Peter Rowe


#5

I have heard speculation that myopia was the original magifying
tool, and that this apparently dysgenic trait was at one point in
our history very desirable amongst the artistan class, which
explains the prevalence of myopia in our current gene pool. I know
for a fact that my own bad eyesight is actually the equivalent of a
2x or 3x loope- to do detail work, or check out the polish of a
stone, I do not normally need my optivisor- I just take off my
bifocals…

Lee Einer


#6

Dear Dr Buggey,

I was very interested in your post to the Orchid group. I was also a
little startled by your statement that “no one is sure how the dies
were rendered, nor what types of tools were used”. While the
technological developments of the Industrial Revolution may have
obscured the details of primitive die and mould making, many of the
core techniques of those earlier Greek coin makers are being
practised to this day by hand engravers and medallion die-sinkers.
Examination of the original artefacts by a trained and experienced
eye - such as any competent engraver or die-sinker possesses -
reveals clues to technique and method of manufacture about which
others may be ignorant.

In Australia I tutor master classes in hand engraving where the
participants and I research and explore these techniques and
reproduce them in real-world practice. Although I am not employed in
academic research, I have been able to easily reproduce these items
(to ‘coin’ your phrase) “completely by hand and without
magnification”.

that many of these early coins were pressed from molten metal
between two moulds. I have done this by melting metal to a molten
"button" on top of one mould, then pressing the obverse mould down
upon it. The top mould, being cold, rapidly cools the liquidus of the
button of metal into the form against which it is pressed. This
produces a simalacrum coin with the same characteristics of the
original.

No rocket science required, just patience to make the moulds/dies in
the first place, and I’m certain they had plenty of that. A
metamorphic rock would do for both moulds, with perhaps a fine
dusting of releasing agent such as fine clay or talc ground from
readily available soapstone. Stone moulds were used long before the
Greek era.

Our reliance and trust in modern technology may blind us to the
simpler forms of genius exercised by our ancestors. I hope that your
interest is rewarded by other experiences. It is a fascinating
subject for both researcher and practitioner.

Kind regards, Rex Steele Merten


#7
    http://www.people.memphis.edu/~tjbuggey/kyzikusboars.jpg 

Indeed the abiulity to engrave small items existed in the roman
times. If i had a guess i would think they used either a small
diamond or other hard stone fragment fused or soldered onto a shaft
of bronze. I rarely use magnification when i engrave as I feel my
way more than see it. I have made small motorcycles that are
1\4"x3\32" that have engaved motors ect, Nothing
is impossible given the desire toi accomplish… Ringman


#8
    From my own research and practical experimentation, I would
suggest that many of these early coins were pressed from molten
metal between two moulds. I have done this by melting metal to a
molten "button" on top of one mould, then pressing the obverse
mould down upon it. 

Rex, Your classes sound fascinating. Now, in your coin-making
experience how does striking when hot compare with pressing when
molten? By hot I mean hot forging (say) silver at dark red heat. I’d
imagine that melting the silver to a button on top of the bottom
(bronze) mold would generate a lot of oxides. Striking the silver
coins by hot forging seemd to me to be how they were done.

And what metals were favoured? Was there a certain amount of copper
in the silver and gold coins?

Brian
B r i a n A d a m
e y e g l a s s e s j e w e l l e r y
518 South Titirangi Road
Auckland NEW ZEALAND
www.adam.co.nz


#9

Hi I assume that the earliest gold coins (ie Lydian) were stamped or
pressed in a semi-molten state which explains the edges and (??) the
apparent structure. Presumably there was some link between alloy and
means of production - some alloys would provide such a semi-molten
state. Engraved coin dies were made from a copper tin alloy (there
are surviving ancient examples) and perhaps iron. Wrought iron came
into some use for tools in some parts of the world before 1000 BC but
only became more prevalent after about 800 BC. There was steel of
sorts (but not cast steel, which had such an impact on jewellery
technology after its introduction in the 1740s). Those who doubt the
ability to cut iron dies in antiquity need only look at the superb
engraved iron rings of the Hellenistic Greek and Roman periods.
Indeed I think that some changes in jewellery production after about
800 BC lie in the introduction of iron tools - not so much in their
use for working the gold, but for their use in producing tools - such
as dies and implements for making decorative wires. My guess is that
the earliest coin dies were ‘chased’ and that true engraving of dies
came in a bit later.

On the other hand copper-silver alloys can be of considerable
hardness and have been used for jewellery dies in Iran etc in recent
times. These were cast and then ‘sharpened up’ with an engraving
tool. Use of copper-silver alloys for tools in antiquity needs more
analysis work, but gold-copper alloys can also be extremely hard and
the ancient gold-copper alloy tools from South America and Sumeria
might well have had a practical more than ‘symbolic’ function.

Ancient coins were not cast - indeed casting is rare for coinage
throughout history (except, for example, such things as the Chinese
cast iron coins, ancient ‘fakes’ and some medals). One thing that
coinage requires - and which casting cannot provide - is production
to precise weight standards. Forgeting modern methods, it is
impossible to produce a mould that provides a final object of
pre-determined weight. Having said that, the individual ‘flans’
(disks of metal the coins were struck from), could be made by cutting
sheet to size (later using a cookie-cutter punch) or by melting small
bits of weighed metal, or even by gently pouring molten metal onto a
flat surface (experiment shows that accurate weights can be judged
with experience).

Best etc
Jack Ogden
www.osmiridium.com


#10

Dear folks, Thank you for these thoughtful and insightful responses.
There are a lot of other interesting things to learn here. I am a
carver and my wife a stained glass artist. But, back to the coins.
Let me comment on some of the comments.

=95 Crystal magnifiers have been found. Two specific finds are
particularly noteworthy, one in Egypt and one at Pompeii. One was
found in an artist studio, the other in an engraver’s workshop. I
have that journal article.

=95 Metals: The Romans had a crude steel, but in terms of hardness and
strength it wasn’t much better than the bronze.

=95 The myopic theory is quite plausible as almost all mint work was
done with slave labor. I guess they had vocational “counselors” back
then too. I guess they had an ancient Snellen Chart eye test as part
of their screening.

=95 From what I have read and been told, the flans of the coins were
prepared separately and then either struck cold or heated. This may
vary between bronze and silver (and I assume the softer gold). I
have several silver coins with double strikes.

=95 Quantity: Hard to imagine, but the Rome mint alone produced
several hundred million coins a year at it height in the 3rd
century! And, there were mints from London to Shanghai. (That’s
partly why for the price of a 1909 VDB penny I can buy 300 late
Roman Bronze coins in nice condition - and all hand struck.)

=95 There must be some connection to intaglio carving.

=95 Hardly any remains of mints remains. There are a few dies and
almost nothing in print. They must have been very protective of mint
secrets.

Once again thank you so much for your comments. I am kind of
obsessed with finding out as much as I can about this lost process.
For your viewing enjoyment let me link to my site on the Most
Beautiful coins of Antiquity. This is page two - just eliminate the
2 in the url and you can view the first page if you like. It is the
bottom coin on page 2 that fits into this discussion = 10 mm and .3
g. http://www.people.memphis.edu/~tjbuggey/beaut2.html

Thanks for a 3rd time,
Tom


#11

Hello Lee Einer,

 I know for a fact that my own bad eyesight is actually the
equivalent of a 2x or 3x loope- to do detail work,  or check out
the polish of a stone, I do not normally need my optivisor- I just
take off my bifocals... 

Yup. Me too. I work naked (sans corrective lenses, that is) when
making jewelry. Bummer to wake up and not be able to see the clock
face if it’s more than 24 inches away, though. Judy in Kansas

Judy M. Willingham, R.S.
Biological and Agricultural Engineering
237 Seaton Hall
Kansas State University
Manhattan KS 66506
(785) 532-2936


#12

This discussion is really fascinating. I love this, I have wanted to
make coins in the ancient style as jewelry elements. I would love to
hear from Jack , and know what books are available about ancient
technologies? Can you give me some titles Peter? Or Jack?
Sam Patania, Tucson


#13
 copper-silver alloys can be of considerable  hardness and have
been used for jewellery dies in Iran etc in recent times .... 
gold-copper alloys can also be extremely hard .... 

Sounds fascinating Jack ! What were the compositions of these
alloys?

Allan Heywood


#14

Hello, If I might step in heRe: Here are some overviews of ancient
minting techniques that are available on the internet:

http://www.culture.gr/nm/presveis/Pages/info/Reference/Production1.html
http://www.pcgs.com/articles/article1350.chtml
http://www.arch.ox.ac.uk/ccindex/ccindex.htm
http://www.geocities.com/Athens/Troy/7551/MintProcess.htm

And an article, if you can find it. American Numismatic Society
Museum Notes, Volume 32, 1987. Composition and Technology of Ancient
and Medieval Coinages: a Reassessment of Analytical Results, C.
Morrisson, J. Barrandon, C. Brenot.

The most cited work on ancient coin minting processes is Wayne
Sales’ Ancient Coin Collecting Volume 1, which I believe one can get
for about $20 at Amazon or the like.

The metallic composition of coins varied widely. Bronze alloy Coins
of Amisos, Pontos on the southern coast of the Black sea have a gold
look to them and often have no patina. This was due to the local ore
used that was high in nickel. The Orichalum (A coppery appearing
bronze alloy) was used extensively in minting the Larger Roman coins
of the first two centuries AD. These bronze alloys were allowed this
variance in composition because the bronze coinage was akin to paper
money in that these never were worth their weight. Greek silver
coins were relatively pure, but in Roman times, beginning with Nero,
silver began to be debased in a show of true inflation/deflation
until by the late 3rd century silver accounted for only about 4% of
the metal content. Most of these coins became silver plated or
washed using a method which is also not clearly understood.

I hope this is useful. Do jewelers tend to be myopic? I find this
fascinating and may represent a tradition extending back 3000 years.

Regards,
Tom