Friday, April 20, 2007

Norse Womans' Knife

If you have been following this series, you will see that there are three primary topic areas: Viking Age KNIVES / Early IRON SMELTING / Viking Age METALWORK.

KNIVES, and topics related to it, have consumed a lot of effort over the last while. this is primarily because I have gotten a number of commissions for pattern welded blades over the winter. I took the opportunity to start work on a new DVD production - INTRODUCTION TO LAYERED STEELS. Unfortunately, this entire project is now on hold because of massive equipment problems.

One of the simpler projects I'm working on is a Norse 'woman's knife' for a serious re-enactor (from DARC). I decided to create this blade with a considerable eye to detail:

This is the blade at the end of the first polishing step - before heat treating,

Lenght : just over 5" /12 cm
Width (at hilt) : 1' / 2.5 cm
Thickness (at hilt) : 1/4" / 6 cm

These proportions and the overall shape is very close to the 'small tool' samples found at Coppergate in York. The blade also tapers in thickness from the hilt down to the point. The profile also is a V grind. (Most modern blades have a sabre grind - a rectangle at the back with a V below to the edge). Use of these two features radically changes the physical handling of the blade. The weight is moved back towards the hand, resulting in a tip that moves quickly and is easier to control. Ideal for general food preparation or textile related tasks. Another reason you see this profile and cross section used historically is that there is significantly less metal required to forge a given blade length. The long rat tail tang is another example of this conservation. (My work with iron smelting is giving me an ever greater appreciation for the cost and conservation of raw materials in pre-Industrial metalwork.)

For the images, the blade was placed in ferric chloride for a couple of minutes. You can see a dark band along the cutting edge and also along the back. This blade has been forged using another feature seen in a number of Viking Age artifacts. It has a harder carbon steel core, layered between two plates of softer metal (modern mild steel in this case). There are two reasons for this historically. First, that conservation factor, especially for that harder to produce higher carbon metal. Second, and more importantly, there is a significant functional aspect to hard layered inside soft. The core can be made extremely hard, but the softer slabs protect and cushion this also brittle material. As the blade is ground to sharp, the hard layer is exposed along the cutting edge.

The end result of all this shaping and layering is a knife with excellent properties for the end user.

Wednesday, April 11, 2007

On the Sutton Hoo Sword

(from an ongoing discussion with Catherine Crowe on Iron Age artifacts)

> So if all the swords are coroded piles of dust how do
> you know they were pattern welded? ...

If you think of a badly rusted piece of wire cable you might get a picture. The various types of iron alloys used as the layers in the pattern welding degrade at different rates. So even oxidized there is a visual indication. Any real details are reveled by X-rays. They take swords expanded inside bronze scabbards and can X- ray those to show internal details as well.

> ... Or if they had
> designs on them? I found a replica of the Sutton Hoo
> sword - and it had interlacing right on the blade -
> which struck me as fanciful - but maybe I'm wrong?

Absolutely! I've never seen interlacing on an artifact blade.

Sutton Hoo is the most complex sword of all the surviving pattern welded type. Its relative (!) state of preservation also is why it is commonly used as an example.
Although the artifacts are Saxon, take a look at:
Angela Care Evans 'The Sutton Hoo Ship Burial' ISBN0 7141 05449
The book shows the sword (blade x-rays) as well as the cauldron hanger I mentioned earlier, plus that elaborate helmet (the iron base is relatively complex for the period).

I may have mentioned that this sword has eight core rods. Each is twisted right / left / straight in regular sequence. The straights are set on edge so the lines of the individual layers show.
Now the rods are set four on top, four on the bottom. On each of top and bottom, the rods are further set in pairs right and left.The twists are done so as to alternate in a pattern that is matched by pairs, side to side and top to bottom - this diagram as you look at the surface of the blade:

\\\===/// top four

===\\\=== bottom four

This is a repeating pattern down the whole length of the centre of the blade. Notice how the straight sections on the top will match up with twisted portions on the bottom. (For a clear discussion of this see Langton & Engstrom, 'A modern replication based on the pattern welded Sword of Sutton Hoo, ISBN 0 918720 289 X )

There is an argument to be made if this type of elaborate patterning was enhanced by the use of lightly etching the blade. Note that modern practice is to use acids not available before about 1300. At the time of Sutton Hoo (c 625) the choice would be salt water / urine / vinegar. Salt water is really a controlled corrosion and I would suggest not likely for that reason. I have experimented with vinegar and it will produce a slow discolouration of the various alloys in the layers that helps to slightly highlight the patterning. (No - have not done urine - yet!)

Now - there is good archaeological evidence for two other methods to decorate sword blades. That would be engraving, or inlay of other metals. Engraving is cutting into the surface with fine chisels. Inlay is most typically either silver or sometimes gold. An engraved channel is cut and the softer metal hammered into the groove. Most commonly these methods are used to add text inscriptions. This also tends to be only seen on POST CHRISTIAN objects - the texts normally in Latin.
There are sometimes makers marks found on blades. These are usually hot punched during forging as you have seen on my own work. Its safe to say this is not about decoration as much as ownership.

I suspect that what you saw as interlace on that 'replica' was very modern acid etching. You may remember that I have done a LOT of this method in the past! Never to be found pre 1300 because of there being no acids available that would cut the metals.
I further expect that you would not find any kind of interlace etching applied to a real pattern welded blade! It would be like adding gold paint on top of real enamel work. Modern acid etching is relatively easy to do - unlike producing a pattern welded sword which is EXTREMELY difficult. I have also seen modern blades with a photo etched 'pattern' applied to they that attempt to duplicate the look of an etched pattern welded blade.

The price on a modern sword will tell the story here. Real hand forged pattern welded swords cost in the multiple thousands of dollars. Scott Langton, who made the replica of Sutton Hoo now on display in the British Museum, said once that a duplicate would run roughly $25,000 US (thats in 1990 dollars too).

Thursday, April 05, 2007

Pattern Welding Samples

Right now I am undertaking a couple of commissions for pattern welded blades. I'm taking the opportunity to gather footage of the process for another DVD that details the process of layered steels.

A direct scan - about half life size.

Each of these bars started as roughly the same materials. Primarily mix of mild steel and a low nickel alloy called L6, along with a layer of high carbon steel. The L6 simulates the use of meteor material in my historic blades. (L6 is .5 % nickel and a middle level .5% carbon - meterorites are closer to 5 % Ni, but with no carbon). The inital stacks were at 13 layers, these have been welded and folded to four to give a 52 layer bar.

Part of that bar is drawn and cut in two. A piece of high carbon steel is stacked between these and the whole welded to form the cutting edge (at 105 layers) This process was done for both of the billets you see. When forged to a blade and polished, this hard carbon steel is exposed to form a durable cutting edge.

Next the remainder of each billet was pulled to a long octagon and twisted. On the first (top) bar, there was enough to make three twisted bars. On the second (lower) just enough for two rods. These were then squared and welded to the prepared cutting edges. This gives a total count of 261 for the top bar and 209 for the bottom one.

The difference in colour you see is because the pieces were lightly etched in two different acids. The top one has been etched in nitric, which changes the relative heights of the layers, but not the colour all that much. The bottom on has been etched in ferric chloride, which mainly changes the surface colours. Note that the finished blades will be etched in BOTH - nitric to give a durable surface profile (what I call 'topographic') and the nitric after to give the dramatic colours.

Now - if you look at the lower edge of the top (3 twist) bar you will see a slice about mid way - This is marked by a triangle below the image. Now this is a welding flaw - basically a crack in the edge. Its a good 3/16 deep - too much to cut out. What I would normally do is cut the bar at this point and then make two smaller knives (should get two good 4" blades out of that stack.)

Since I required enough material for a 5 - 6 inch finished blade, I made the second bar you see below. It is a good solid weld right across, it is however not as tightly twisted a pattern.

There is always some extra distortion of the pattern - stretching it longer, that occurs during the blade forging. Ideally you want as tight a pitch to the diagonal lines as possible in the starting bar (like the top sample).

Tuesday, April 03, 2007

Iron from Celtic to Early Medieval

I got this request from fellow An Droichead member Catherine Crowe. Since it was going to be easier to just send her the information than reference dozen of fragmentary sources - the following piece developed. (This is a very long article!)

> I am looking for pictures and information
> I am looking for 'Celtic' areas and comparing to
> materials from the Iron age to show development in
> this particular medium (so Europe generally and
> Ireland specifically for 'place' and generally from
> 6th-12thc time wise)
> The materials I am dealing with in my paper are
> bronze, clay, iron, wood, stone, silver and gold. I
> seem only to be lacking in the iron area, probably
> becasue that material is not as 'decorative' in this
> period.

It may not be possible to point you to a single source that will cover the information that you are looking for. The objects and most importantly the mechanics of archaeology are against you. What I know about the following has been pieced together from a lot of individual sources (text, objects, conversations).

In very short hand - iron remains a valuable material. This both because of the raw effort required to create it, plus its utility, thus connection to important objects. Working against this is a preservation problem, further narrowed by the change in burial customs into the Christian era.

Between the Celtic Iron Age and the 'Dark Ages' (post Roman through Viking Age to Early Medieval) there is a general but small improvement in the technology of making iron. (I'm leaving the Romans out of this - there is a jump forward in size and efficiency under the Romans - which drops back after they leave Brittan.) Celtic Iron Age small bowl furnaces with natural draft producing maybe 2 - 5 kg is replaced with a short shaft furnace plus bellows that produces closer to 5 - 15 kg. So the production of iron does increase, but not by a huge factor. (The next jump will come in the Early Medieval period with the application of water power for bellows and trip hammers.) One important limit imposed by hand tools is that the largest width of iron sheet found in any pre Medieval object is about 20 cm.

Iron is prized in both Celtic and Dark Ages for its high utility. This results in a huge range of quality and complexity of objects being made from it. Everything from nails and rivets through to complex cauldron hangers and pattern welded swords. The raw versitility of the material leads it to be used for a wider range of objects than any of the other materials on your list - with only bronze coming close in depth of applications. An axe may range from a simple wedge of plain iron through to an elaborate show piece with inlaid gold or silver.

Unfortunately, to aspects of iron greatly warp any general assessment of the objects made from it. First is its relative lack of preservation. In the presence of almost any water at all, iron reverts from metal to crumbles of iron oxide (rust). With the climate of North Europe as it is - almost any iron object placed into the ground turns into a corroded mass in mere decades. Second is that same utility mentioned earlier. It is quite possible to convert any iron object through the hand of the smith to another iron object. The effort required to do this is so much less than creating new iron from ore. This combination of high utility and ease of transformation leads many iron objects to have been re-cycled into new ones. (You will find the same factors at work for bronze and gold.)

Most importantly, the artifact evidence in the culture and time you have defined is profoundly influenced by the customs of the early Christians. There is a sharp break in availability of artifacts from the pagan cultures who believed in an 'active' after death condition and that of the Christians, who stressed spirit over body. Christians were just not buried with their life goods. This leads to a situation where its much easier to get a picture of daily life for a Norse resident of Ireland than his Celtic neighbors.

There can be an effort made to extend Norse / Saxon cultural practices over into Celtic residents in the same geography. This may not be a huge stretch, as there are many similarities, and certainly the underlaying technologies are very close and the access to raw resources is virtually identical.

So - what does this mean in terms of iron objects?

There is a large volume of iron used for the merely practical. Here I'm referring to boat rivets especially, but also construction nails, simple hooks, straps, hinges and the like. To compare this to the earlier Celtic Iron Age, there would be hardly any use of bronze as a construction material. (Note that wood remains the single most dominant material for all kinds of objects)

Tools of all kinds are made of iron. Obviously this includes cutting edges. Although this is also the case for the Celtic Iron Age, there is a significant improvement in the physical methods used to construct iron cutting edges especially. Wider use of carbon alloy ('steel') is being made. This often is in the form of small pieces of harder steel welded into place to create cutting edges. The raw number and range of iron tools increases.

There are now a larger number of functional cooking tools of iron. This includes both flat dish and 'fry pan' types, spiral cooking irons, and a wide range of spits that range in size and include large forks. In this group of functional objects can be put the large segmented and riveted iron pots and cauldrons. Those range in size considerably. All these objects would have been 'household' equipment. Although cauldrons and pots are also found made of bronze / copper alloy, there is some evidence that there may have been some problems with obtaining this raw material into the Viking Age. In this group could also be placed 'strike a lights' - steel strikers used with flints. These are often overly complex forgings, so appear to be presentation objects. Again these are more likely to be household rather than personal equipment.

Iron is used for jewelery, although not commonly. These will be smaller, less elaborate pieces, more likely to be functional than highly decorative. I have seen bracelets and torcs, mainly formed of twisted square rods. Simple pennaular brooches are also found - there are a number of samples. There is at least one 'charm bracelet' with small iron tokens looped over a twisted iron band. (These all Scandinavian.)

There is only ONE SINGLE iron tripod artifact sample from the Viking Age (the one from Oseberg - c 825). This should be considered a presentation object made for a burial, not a functional tool. For that reason it can be grouped in with the ornamental cauldron hangers. There are a good number of these that have been found, again in association with royal caliber burials. The complex hanger found at Sutton Hoo (Saxon c 625) being the best known example. Hanging in the centre of the hall, these hangers are expressions of wealth and status, both in terms of volume of metal and complexity of craftsmanship. A careful look at the hangers as they would have been used will show that the most complex elements are most often placed at roughly four feet and five and half feet from the floor as they were mounted. This corresponds to sitting and standing eye height - obviously intented for maximum visual impact.

As with the Celtic Iron Age - it is with objects related to combat that the highest value is placed.
Unlike the earlier period, ever increasing use of armour is being made, and more and more that armour includes iron. The technology of iron production, and more important the limits imposed by hand tools, makes the forming of large sheets of iron quite difficult. For that reason, the only armour containing plates of iron are helmets. These are almost always segmented and riveted of smaller plates (construction quite like cooking pots). Helmets are extremely rare in the artifact record, there are only about a dozen surviving from the entire Dark Ages. Use of iron chain maile increased throughout the period. Maile represents a huge investment in skilled labour to produce, but in a way is less technologically demanding that creating plates. Because of this huge labour cost, maile is also seen as a status symbol. (Saga references where leaders boast of their ability to equip a large troop with maile shirts.)
Weapons, ranging from fighting knives through to spears, axes and swords, are found with highly decorated surfaces and furnature. It is important to remember that at core these all remain highly effective combat tools, and function is never scarafised for mere orimentation. Weapons often bore names, and high quality weapons were heirloom objects. It was quite possible for a sword to have a greater reputation than the man who owned it.

It is in swords that the apex of the blacksmiths art will be found in the Dark Ages, most specifically at the hands of the Saxons from southern Denmark c 600 AD. The amazing sword from the Sutton Hoo burial would have be created about that date. The technique of 'patern welding' is first seen in blades from the latter Roman era, about 100 - 200 AD. The technique involves stacking hard steel and soft iron in layers, then welding these into a solid billet. This is then drawn to a long rod, which is then twisted. Several such rods, with twists in opp[ostie directions, are then welded together to form the core of a sword blade. The function of these twisted layers is like a set of coil springs running down the centre of the sword. This creates a blade that is both tough but flexible. The sword from Sutton who is the single most elaborate of the type, with eight core rods which alternate twists and straight prortions right and left / side to side / top to bottom. It is important to note that while pattern welded blades are relatively common during the Viking Age, the technique is essencially lost by the time of the Crusades. Pattern welding is also seen on knives from this era, where is serves no practical function save its decoration and status.

The text references to establish all this will tend to fall into two broad types. You will find topic driven general overviews, which will tend to focus on mainly the high end 'royal caliber' objects. A book with a title like 'Monistaries in Early Ireland' may only have a couple of illustrations of iron objects, and will be unlikely to give much context information for them. More useful to picture a range of objects may be exhibit catalogs, but these often prove very short written details. On the other hand will be the primary documentation of archaeological excavations, which are hard to find and difficult to wade through.

Some texts that you may find helpful for artifact images:

The Sutton Hoo Ship Burial - A.C. Evens (ISBN 0 7141 0544 9)

From Viking To Crusader - Rosedahl & Wilson (ISBN 0 8478 1625 7)

Anglo Scandinavian Ironwork from Coppergate - P. Otaway
(ISBN 1872414 29 X)

It turns out that although there is a huge amount of iron objects from Woods Quay in Dublin (c 900) none of this material has been described in the literature yet.

February 15 - May 15, 2012 : Supported by a Crafts Projects - Creation and Development Grant

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