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Dan Howard




Location: Maitland, NSW, Australia
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PostPosted: Tue 13 Nov, 2012 4:31 am    Post subject: Tofta church mail coif         Reply with quote

Mark Hale posted this in an earlier thread

Quote:

http://www.actakonservering.se/acta/Ringbrynjehuva.html

Rough translation - "In April 2004, found intact in the tower room on Tofta church on Gotland. The hood is unique in view of its exceptionally well preserved and because of its original leather straps remain. The hood was carbon 14 to the 1200s."


Does anyone have more info about this? Overall weight? Link size? Rivet type?
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Peter Johnsson
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PostPosted: Tue 13 Nov, 2012 6:07 am    Post subject:         Reply with quote

Here is a pdf of a report (in Swedish) about the metallography of the Tofta coif:

www.arkeologiuv.se/cms/showdocument/documents...22_gal.pdf

Google-translated snippets from the text:

"The three rings from the ring fabric which have been analyzed are of two different types,
two are complete rings and one is a riveted ring. All three have oval cross sections.
They have all been analyzed in different directions as well as metallographically
chemically. The iron is in all rings mainly ferritic, ie. carbonless
iron. The ferritic iron is much softer than a carbon steel. In the
both the rings, and the rivet, has a phosphorus content was observed.
Phosphorus present in concentrations about 0.15 to 0.20 weight percent. The riveted
ring missing phosphorus, or occur only sporadically in the lower level.
Phosphorus affects iron material properties by increasing its hardness
slightly, but mainly increases its toughness. The latter has often been
coveted feature for wire drawing."

"The results from this study of two different ring types from
ring fabric from Tofta is that the rings are made of a
phosphorus-iron rings which probably has been punched out of a sheet. the riveted
ring shows no clear signs of being manufactured by punching
or from a wire even if the latter is likely. longitudinal
manufacturing traces, which is typical of drawn wire, emerged (according to
from the client) during the conservation process, which confirms
adoption of manufacturing technology. This ring also differs in terms of
composition because it lacks phosphorus, a substance which, however,
present in the spent rivet."

I will edit in more text when I get time to do so.

I also have an essay on this coif by Tommy Hellman who made an analysis of the coif, its pattern and rings but at the moment of writing I am not sure where I have this text. If I find it I shall post further info.
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Mart Shearer




Location: Jackson, MS, USA
Joined: 18 Aug 2012

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PostPosted: Tue 13 Nov, 2012 9:10 am    Post subject:         Reply with quote

Using Google translator to speed the process:

Quote:

Description and sampling
The entire loose ring weighed 0.24 g sampling it has no
varying thickness, probably partly due to the different amounts of corrosion.
The ring (Fig. 2) is not completely symmetrical circular, the outer diameter
varies between 11.2 and 11.8 mm and its inner diameter between 8.5 and
9.4 mm. Ring wire width ranges from 0.8 to 1.4 mm, but is usually
about 1.1 mm. Its thickness is at most 1.2 mm, but significantly thinner
parts of 0.6-0.8 mm are present. When looking at the ring on edge
looks homogeneous and there are no joints, indicating some form of
hopvällning can be seen. It is not possible to uniquely determine the shape of the
its cross section but appears to be rectangular with rounded corners, or
possibly oval. The entire ring is placed flat in the mold. When grinding
and polishing the ring honed the central parts for analyzes.


So, alternating construction of punched and riveted rings (round rivets are clear in the sectioning photographs, Fig.10 & 11) of approximately 1mm thickness, 11.5mm diameter, with a c.9mm hole in the punched rings. Weight of each ring is about .24g, but I don't see an overall weight.

EDIT: The riveted rings are of oval section, roughly 1.5mm wide by .5 mm thick, being wider and flatter in the overlap.

ferrum ferro acuitur et homo exacuit faciem amici sui


Last edited by Mart Shearer on Tue 13 Nov, 2012 5:48 pm; edited 1 time in total
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Randall Moffett




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PostPosted: Tue 13 Nov, 2012 9:45 am    Post subject:         Reply with quote

Very cool find. It is in great condition. I wonder where one can find punch rings of specific designs?

RPM
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Gregory J. Liebau




Location: Dinuba, CA
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PostPosted: Tue 13 Nov, 2012 12:22 pm    Post subject:         Reply with quote

Holy mackerel! I'm in the middle of modifying an Indian-made coif for a 13th century affair, and this is wonderful inspiration. I'm confused about what the leather bit is actually doing, though. Is it holding up a ventail? I can't see any major distinction in the mail bits to tell whether it's solid or separate under the bust's chin. Also, it looks like the cord must be made of rawhide, judging by its color and level of preservation, yes? Thanks for sharing!

-Gregory
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Mart Shearer




Location: Jackson, MS, USA
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PostPosted: Tue 13 Nov, 2012 5:39 pm    Post subject:         Reply with quote

Randall Moffett wrote:
Very cool find. It is in great condition. I wonder where one can find punch rings of specific designs?

RPM


http://www.bokers.com/custom_washers.asp

ferrum ferro acuitur et homo exacuit faciem amici sui
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Mart Shearer




Location: Jackson, MS, USA
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PostPosted: Tue 13 Nov, 2012 6:05 pm    Post subject:         Reply with quote

Gregory J. Liebau wrote:
Holy mackerel! I'm in the middle of modifying an Indian-made coif for a 13th century affair, and this is wonderful inspiration. I'm confused about what the leather bit is actually doing, though. Is it holding up a ventail? I can't see any major distinction in the mail bits to tell whether it's solid or separate under the bust's chin. Also, it looks like the cord must be made of rawhide, judging by its color and level of preservation, yes? Thanks for sharing!

-Gregory


Presuming that it's original to the find, there seems to be a second one at the bottom of the square lappet on the opposite back. This miniature shows thonging on a similarly shaped coif: One to keep the neck tight, and others to keep the square panels over the chest.
http://digital.blb-karlsruhe.de/blbhs/content/pageview/165567


Alternately, the thonging (if that's what it is) could be used to draw the face opening tight over the chin without a sepearate ventail.



 Attachment: 81.57 KB
Karlsruhe 410 fo14v-coif.jpg


ferrum ferro acuitur et homo exacuit faciem amici sui
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S. Sebok





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PostPosted: Wed 14 Nov, 2012 7:59 pm    Post subject:         Reply with quote

The way that coif fits is similar to how mine fits, all the way up to the chin. The way the rings look reminds me of GDFB indian made wedge riveted maille. It looks like it's 9MM in diameter to me.
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Mart Shearer




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PostPosted: Wed 14 Nov, 2012 8:16 pm    Post subject:         Reply with quote

It is clearly round riveted.


 Attachment: 47.82 KB
Tofta rivet section.jpg


ferrum ferro acuitur et homo exacuit faciem amici sui
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Jared Smith




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PostPosted: Wed 14 Nov, 2012 9:17 pm    Post subject:         Reply with quote

That is one of the highest phosphor amounts I have ever seen stated for mail. It normally is about half that, which enhances drawing properties, but can be softened. This would "bake" harden. I would expect it to have high strength after working, but not be very ductile. Are there any other similar period weapons or other objects of similar phosphor content?


http://www.keytometals.com/page.aspx?ID=Check...amp;NM=211

Absence of evidence is not necessarily evidence of absence!
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Mart Shearer




Location: Jackson, MS, USA
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PostPosted: Wed 14 Nov, 2012 10:39 pm    Post subject:         Reply with quote

As Peter quoted:

"The results from this study of two different ring types from
ring fabric from Tofta is that the rings are made of a
phosphorus-iron rings which probably has been punched out of a sheet. the riveted
ring shows no clear signs of being manufactured by punching
or from a wire even if the latter is likely. longitudinal
manufacturing traces, which is typical of drawn wire, emerged (according to
from the client) during the conservation process, which confirms
adoption of manufacturing technology. This ring also differs in terms of
composition because it lacks phosphorus, a substance which, however,
present in the spent rivet."


So the drawn wire rings are phosphorus-free, though the rivet seems to contain phophorus as well as the punched rings. 18th century wire for clavichords and harpsichords (P-wire) is also wrought iron with similar phosphorus levels.

http://en.wikipedia.org/wiki/Wrought_iron

"Coldshort iron, also known as coldshear, colshire or bloodshot, contains excessive phosphorus. It is very brittle when it is cold. It cracks if bent. It may, however, be worked at high temperature. Historically, coldshort iron was considered good enough for nails.

Nevertheless, phosphorus is not necessarily detrimental to iron. Ancient Indian smiths did not add lime to their furnaces; the absence of CaO in the slag, and the deliberate use of wood with high phosphorus content during the smelting, induces a higher P content (> 0.1%, average 0.25%) than in modern iron. Analysis of the Iron Pillar of Delhi gives 0.10% in the slags for .18% in the iron itself, for a total P content of 0.28% in the metal and accounts for much of its corrosion resistance. Furthermore, the presence of phosphorus (without carbon) produces a ductile iron suitable for wire drawing, for piano wire.[15]"

ferrum ferro acuitur et homo exacuit faciem amici sui
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S. Sebok





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PostPosted: Wed 14 Nov, 2012 11:11 pm    Post subject:         Reply with quote

Mart Shearer wrote:
It is clearly round riveted.

Really? The rivets from the pics look square and almost wedge riveted, if it is round riveted that proves that indian made wedge riveted maille is closer to the historical thing than indian made round riveted maille is to the historical thing. Now if only they fixed that.
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Tjarand Matre




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PostPosted: Thu 15 Nov, 2012 12:08 am    Post subject:         Reply with quote

I have been to Tofta church and seen the coif exhibited there. It looks exactly like my Indian maille, especially the wider overlap.
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Dan Howard




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PostPosted: Thu 15 Nov, 2012 12:33 am    Post subject:         Reply with quote

Your indian mail must be different to any indian mail that I've seen.
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Dan Howard




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PostPosted: Thu 15 Nov, 2012 12:58 pm    Post subject:         Reply with quote

Mart Shearer wrote:
Randall Moffett wrote:
Very cool find. It is in great condition. I wonder where one can find punch rings of specific designs?

RPM


http://www.bokers.com/custom_washers.asp


Is Bokers now cheaper than Seastrom? The latter was the cheapest I could find when I went searching a few years ago.
http://www.seastrom-mfg.com/
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Randall Moffett




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PostPosted: Thu 15 Nov, 2012 1:19 pm    Post subject:         Reply with quote

Which ones have you been buying? I am thinking about making a full hauberk and chausses in the next few years so I have been pricing and such but the loose rivets are tricky as they seem to vary batch to batch from what I have seen.

RPM
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Dan Howard




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PostPosted: Fri 16 Nov, 2012 1:02 am    Post subject:         Reply with quote

I've only ever bought washers. The measurements have been virtually identical from one batch to the next. Maybe one in a hundred washers has a curved "bite" out of an edge which rendered it unusable.

This is the last purchase I made.
http://www.seastrom-mfg.com/washerdetails.asp...702-476-30
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Randall Moffett




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PostPosted: Fri 16 Nov, 2012 6:03 am    Post subject:         Reply with quote

Dan,

Thanks. I'll have to figure out what size I need and look at costs. I figure I'll need 10,000s of links in total so likely some 10-20k of solids if I do every other row.

Are these custom Dan?

RPM
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Dan Howard




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PostPosted: Fri 16 Nov, 2012 1:20 pm    Post subject:         Reply with quote

The links I bought were standard washers they already had in stock. I don't think they would have a part number for custom jobs.
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Mart Shearer




Location: Jackson, MS, USA
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PostPosted: Fri 16 Nov, 2012 3:08 pm    Post subject:         Reply with quote

http://www.gnom.dk/projekter/ringbrynjehistorie.pdf
Early Iron, Arne Jouttijärvi
Quote:
The
iron is generally quite homogenous and
contains almost no slag – in other words, it
is high quality. The rings of the Hedegaard
shirt contain 0.2% phosphor. There is no
sign of weld joints, which may be expected
if the rings were made of wire bent into a
ring shape and then welded.
Fig. 2


Quote:
The riveted rings: A horizontal section of
the rings shows that they are also made of
carbon-free iron. The phosphor content in
the Hedegaard shirt rings is 0.1 – 0.2%.


The conclusion made is that this pre-Roman byrnie was manufactured from wire made in north Germany or west Jutland. Certain cities were known for their mail manufacture, and it is possible that these locations had naturally occuring phosphor in their ore, or had learned how to introduce a high phosphor content.

ferrum ferro acuitur et homo exacuit faciem amici sui
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