Making a Corinthian Helm?

[Paullus Scipio]

Kineas is pretty well right on the money when it comes to how Corinthian helmets were made. D ........as he points out, all 'ancient bronze' began as being poured/cast either into an ingot or some other shape ( see conclusion below), since there was no rolled/sheet bronze back then.

A Corinthian helmet from Olympia in the manchester museum was suspected on various grounds of having had a "reproduction" noseguard added to it, probably in the 19 C when found and "restored" - it was evident the cheekpieces which had been ritually flattened had been bent back into their original position.

A non-destructive examination using X-ray fluorescence revealed the materials used and crystallographic texture data obtained on a neutron diffractometer revealed how it had been made......

Here is the conclusion:

"Neutron and synchrotron X-ray analytical techniques were used to characterize a Corinthian-type
bronze helmet in the Manchester Museum. The alloy of the helmet consists predominantly of Cu(copper)
with a varying Sn(tin) content between 11 and 12 wt %. The neutron data contain clear indications of
the working processes involved in the production of the helmet. The observed degree of
microstrain broadening hints to repetitive annealing-hammering working cycles in order to harden the alloy.(elsewhere the report refers to hammering over a rod-type stake/anvil, just like those shown above in this thread. ) The last step was most likely a hardening step.(cold-working/hardening)
The preferred orientation of grains, as displayed in the texture maps, agrees with hammering in one direction. The object was more than likely cast as a ‘skull-cap’, then beaten and heated in an iterative cycle and dressed down to its final thickness and shape to fit the customer’s head.
Considerable effort was undertaken by the makers of the helmet to harden the alloy. Hence, the
object was surely produced for battle rather than just cast for ceremonial purposes.
The nose guard of the helmet is made of a different alloy, namely Cu/Zn. (a modern type brass, of similar colour/appearance to ancient bronze - which is very different from modern "bronzes")
One can assume that the nose guard, being made of a different material, is most likely not part of the original helmet
but is a later replacement, maybe by the 19th-century finder of the object. This confirms earlier
suggestions that the shape of the nose guard is unusual and that the present angle at which it
is set is not functional and therefore not authentic, and that the edges of the nose guard itself and
of the holes for fixing the lining are much sharper than on the rest of the helmet."

[caiusbeerquitius]

t has been hypothesized--repeatedly--that smiths poured their sheet on slate. That is to say, they heated slate to a relatively high temperature--they could so this simply by building a fire on the slate and then sweeping it clean--and then poured newly mixed bronze straight onto the slate, in effect pouring "sheet." The sheet, as poured, would be subject to all sorts of possible flaws, but as bronze can be re-cast several times before it gets wonky (not a technical term ) a craftsman could make a pouring error and simply re-melt and recast.

And why would he do that, if he can start with a domed form already with basically the same amount of work? I mean, once you cast already, why make a flat form and convert it to a dome when you can cast a dome and save all the work. Casting a simple dome was certainly not beyond their skills.

in effect, all bronze began as "cast." Then it was "worked. If it was not "worked," the wearer would end up with a heavy helmet that offered no protection.

That is exactly what i have been saying above, on page 1 of this thread:

Especially in regard of the huge differences in thickness on most Corinthians, I suggest that they were originally cast, and then the cast object was worked over.

and

The chiselling is something you find on bsically all larger cast objects, so that doesn´t come as a surprise, the skull, the cheek guards and the neck are most certainly hammered after casting. Let alone to make the bronze denser, hence better suited for protection. Nothing new either, though.

I wonder when brazing and/or riveting became sufficiently facile for Classical craftsmen that they could make multi-piece helmets?

There are loads of 8th century BCE helmets which are multi-part constructions.

[Paullus Scipio]

Christian wrote:

There are loads of 8th century BCE helmets which are multi-part constructions.

.....but not 'Corinthians', which is the subject here.'Kegel',the short-lived 'Insular', and early 'Illyrian' helmets were two-piece, but even the very earliest 8 C BC 'Corinthian' types ( e.g. those from Argos museum) were one-piece, and one-piece rapidly took over - the'insular' and 'kegel' types disappeared, and the 'Illyrian' became one-piece, like the 'Corinthian', though it retained the two crest/comb ridges which had previously protected the seam/joint of the earlier two-piece type....

[caiusbeerquitius]

.....but not 'Corinthians'

Nobody said so.

This:

There are loads of 8th century BCE helmets which are multi-part constructions.

was a direct reply to this:

I wonder when brazing and/or riveting became sufficiently facile for Classical craftsmen that they could make multi-piece helmets?

simply stating that the technical abilities (at least for riveting) were there before the Corinthian design. If one looks at Hallstatt findings, where there is a lot more published on metallurgy, one could make the same point for brazing...

[Kineas]

Well, if you are saying and I'm saying it and Paul is saying it, there's some possibility it will turn out to be true!

Pardon me if I misunderstood. Seriously--the electronic media can be the most remarkable forum for misunderstanding....

[PMBardunias]

.....but not 'Corinthians', which is the subject here

I have an image of a corinthian helm that is two halves riveted together down to the nasal. I can't access it now, but its so common I'm sure you've seen it. Was this a repair of some sort rather than initial construction?

[Giannis K. Hoplite]

Paul,are you talking about the one in the osprey "Greek Hoplite" book,the one that doubles on the nasal to give it double thickness?I think it says it was restored in several spots in antiquity.
How about this one? Restoration or not?

[Paullus Scipio]

I think restoration.......a probable explanation is that it is a 'trophy' which has had its cheekpieces bent out, and someone has tried to bend them back, likely resulting in cracking or breaking, hence the need for the repair at the obvious place where metal fatigue would cause cracking/breaking. Look at the altered eye shapes, caused by the need to overlap the repair.This could have occurred in antiquity, or be a modern 'restoration' following excavation/discovery......

[Matthew Amt]

Khairete!

Nasals up to a *centimeter* thick?? *Average* thickness of 6 to 7mm?? My big question is, Did the author actually handle the piece and measure the thickness with calipers? And not just at the edge! Cuz this is what I noted on page 1:

A few years ago I was looking at a Corinthian (much like that Manning piece pictured above) in the University of Pennsylvania Museum, and noted that the edge around one eyehole and the nasal was clearly turned back and not cast to that thickness because it was COMING OFF. It was separating right along the angle, though I could not tell if this was due to stress/corrosion/etc., or if that turned-back strip was a separate applied strip. It was clearly NOT a thicker cast area!

Since the book is presumably in German, which I can't read, I'll have to depend on others to pass along pertinant bits.

I'm still having a problem with thickness and weight even IF the face area was cast thick and the rest hammered thin. Again from my post on page 1:

My own Corinthian (also by Piela) was forged from bronze sheet no more than a millimeter thick, probably less because a lot of scratches had to be sanded off (ah, cheap scrap metal!). It weighs 5 pounds. I have yet to see statistics for ANY Corinthian helmet weighing more than 4 pounds, and most are about 3 or even less. So we're talking half a millimeter thick on average, yes?

I've also seen the Corinthian helmet riveted entirely together in two halves, left and right. The seam is a little wavy, and runs right down the nasal. Very neat job, but visible. It's not a really late style, kind of in the middle. There are also a couple early Corinthians that were made in multiple pieces, with the bowl riveted to the bottom half. One was in the Keinbusch collection in Philadelphia, as I recall. These all looked like original construction, not repairs. Ah, here's one:

http://www.ancientgreece.com/media/publ ... les/a2.jpg

Huh, a little Googling turned up this image:

http://humanities.uchicago.edu/orgs/ist ... -hlmts.jpg

Never seen those before! Love to see the BACKs...

Other very minor metallurgical quibbles, I don't *think* cast bronze is quite so soft that a spear will go through it easily--it's metal, after all! Kineas, can you tell me more about what you said you've done? I'm curious! I am told by Neil Burridge that the thin bits of flashing around the edge of a newly cast piece are very malleable, even when the tin content is high, because they've just gotten a very good annealing (getting the piece out of the mold often involves dumping it in water, which anneals the hot bronze). So the finished hammered sheet can be quite hard, but any part left in its cast state, especially if it's over 5mm thick, should be PLENTY protective!

...one of them being that the ancients didn't know that tin and bismuth were different metals, so that they might easily end up with cast brass--which is unworkable.

Huh, I've seen analyses of any number of Bronze Age items, and if bismuth shows up at all it's only a trace element. Same with zinc. Though of course the Romans used plenty of brass (copper and zinc) for making helmets and other stuff, so it's clearly workable. I believe bismuth makes lead more brittle, though, so you're right that it's not something you want a lot of, but it seems the ancients didn't have any general problem with it.

Like I said, though, minor quibbles! I'm more interested in the "proof" from this new book.

Thanks!

Matthew

[Giannis K. Hoplite]

Matt,i have to disagree on nasal thickness. It's 100% certain that this thickness was not achieved by turning the edges. This was done partially to the eyw holes,though those do not show as great thickness and actually they are not turned,just a ridge is chiseled to create the inner edge of the raised area around the eye holes.
I have seen nasals from the back. They are all plain. When the nasals have an edge,this is usually no more than 0.5 mm.

I can provide photos of nasals that are clrearly solid and not edges turned.

I also don't believe the frontal area was cast. The decoration on it,be it brows above the eye holes or flowers on the forehead or sculpted scenes on the cheeks is visibly beaten from the inside. I have also noticed that only the nasal is very thick and this thickness in most examples(especially the later ones) is decreasing emediately next to it so the eye holes have a much smaller thickness and the decoration around them can be beaten (and not cast).
This is visible from fragmentary examples.
Like the others,i believe a small part of the original cast thick bronze sheet (or whatever shape it might had) was left thicker in the area where the nasal was estimated to have been cut.
Khairete
Giannis

[PMBardunias]

Hey guys, none of those was the one I was thinking of and now can't seem to find (funny how I would always come across it when I didn't want it). It had a line of rivets going from just right of the nasal back over the top of the crown as though put together in two halves like an Illyrian, but offset to the right. I did come across this helmet, which is similar to the one Matt posted above. Its from Axel Guttman's collection.

[hoplite14gr]

Thickness of noseguard.
If you think its too much there are 2 helmets in National Museum and 2 in the War Museum.
Kind regards

[Gaius Julius Caesar]

It looks to me that the earlier style of corinthian all seem to have a thin nasel, while the more refined style have a thick nasel.
I would imagine some would see that as an over simplificatin, but I have seen nothing to make me think otherwise.
Perhaps that there are a number? of the earlier type with broken repaired nasels, would point to the thicker nasel being a logical
solution to a common problem?

[PMBardunias]

This may be the back of the helm I am looking for!

[PhilusEstilius]

I have been going through this topic and have found many of the points of view very interesting, I would of course go along with Christian where he says that various helmets may well have been cast.
Infact in the Connoly book Greece and Rome at War there is a very nice picture of just such a cast one, but apart from that I would like to show just a couple from a few that I have made myself over the years and must point out that these have been beaten out in parts and braised together. Indeed having looked at some in the BM it becomes evident that originals were also made in parts where some are riveted and others braised together.

http://www.northumberland-computers.com ... oman12.jpg