One morning Shelagh Rogers was interviewing a fellow who made baskets on the CBC. From out in the Yukon some place. He told a story about learning to pick ash wood from the bush with his grandfather. The two of them got up at the crack of dawn to hit the trail at first light. As they wandered through the bush, the young man would keep pointing out trees to his grandfather. The grandfather would glance over and say 'No - not that one'. After an hour of this, the young fellow was getting pretty tired of it. 'So grandfather, just what IS it you are looking for'? The old man replied 'I'm waiting for a tree to tell me it wants to be made into baskets'.
Ok - if you look at this one way its a story about First Nations wisdom.
Now, I had a situation a couple of years back where I was putting together a museum exhibit. I had a tent to make and a small house replica to build for this presentation. I had a friend work for a week to help me with a lot of the grunt work and raw labour. The tent had a set of ship oars for the frame. The house needed a large number of poles for the rafters. I walked through the bush with Dave to harvest the required timber. He kept going up to saplings and saying 'what about this one?'
Now, I had seen a particular small grove of pines a couple of years back. One cone had hit the ground and a cluster of trees had grown up. They were too close together, so were growing straight, tall and with few branches. I figured they would be just about the right diameter for the oars. Mind you - I could only vaguely remember where the stand of saplings I wanted WAS inside the forest. So I kept saying 'No, not that one', as I kept trying to remember just where that thicket was.
Now - I'm a western European. So my * explanation * was framed in my scientific descriptions. I told Dave about the ideal sapling for the project, and told him about the special situation which would create the grove like the one I had found years before and how now I was now trying to re-trace my steps. I chose to directly impart the * knowledge * based on my own experience to a younger man.
Too often I personally find that First Nations are attributed with * wisdom * merely because of the method being used to transfer raw information. The young man with his grandfather might not understand what it actually is that the old man is looking for. Since the objective here was basket making, there is no doubt that a set of merely technical requirements were being applied. How old the tree, how straight, condition of the wood, and perhaps its location related to other trees. Maybe the young man would never learn what exactly his grandfather was looking for - the factors he was judging that told him 'this tree wants to be taken'. Its hard not to see this as * reducing * the flow of information, and concentrating it in the hands of people with long experience only. Grandfather appears wise, but how effective is he REALLY at communicating his knowledge?
I was willing to give Dave the full measure of my experience. Of course Dave himself is part of that same European heritage - where information is gathered directly through questions and answers.
I find myself constantly applying direct physical experience, often via the senses not apparently involved in a physical situation. I normally do try to explain directly what it is that I'm observing when asked what the heck I'm doing.
I do have knowledge - but does the manner I chose to educate make me less 'wise'?
Tuesday, February 27, 2007
Monday, February 19, 2007
Norse Weapons - who has what?
(once again modified from a post to Norsefolk)
When you look at the artifacts from the Viking Age, there are quite noticeable differences in terms of 'national preference' against weapon type as found in burials. Viewed as a very rough overall picture (only!)
Norway - swords
Sweden - spears
Denmark - axes
In terms of more of one type that dominates inside the area. All types are of course found, so its not as simple as 'I'm a Swede - so I should use a spear'.
As you might of guessed from the recent series of articles, there are wealth and status considerations to make related to a specific historic character and what weapon to carry. I have not specifically seen any data on the relative frequency of swords in burials overall. Just about everyone had a small tool knife, but my quick gut reaction is to say swords were like modern Rolex watches in terms of distribution through the population.
Generally swords / axes / spears are found only in male burials.
One real big problem with that generalization is the 'male dominant' angle . If there is a weapon found the sex is automaticly determined as male - without further examination into possible gender (converse is glass beads and female). Skeletons are only rarely sexed using methods OTHER than object generalizations as it turns out. There are some obviously female burials which are found with 'male' objects, particularly swords. Are these intended as working tools - or are they instead statements of status (which is more likely)? As I remember , axes are almost never found in female burials for example.
Swords specifically are high cost, special function, tools. Remember than few individuals in Norse society were full time wariors. If you are primarily a farmer who goes on raids a couple of times over your life span, then investing in an axe makes a lot more sense. This would be a tool axe as well - which explains why there are so many more small, multi function head sizes found.
Swords are also herloom objects. So there is scope there to interpet older blades which have been re-hilted. Stories collected on family blades. High quality swords might easily have a larger reputation than the person holding it.
I personally have a real interest in how simple technical factors can combine or interact inside a culture to create the tradtitions and customs that define a people. I think we are seeing how the metalworking problems are shaping the Norse.
(cross posted on the DARC blog)
When you look at the artifacts from the Viking Age, there are quite noticeable differences in terms of 'national preference' against weapon type as found in burials. Viewed as a very rough overall picture (only!)
Norway - swords
Sweden - spears
Denmark - axes
In terms of more of one type that dominates inside the area. All types are of course found, so its not as simple as 'I'm a Swede - so I should use a spear'.
As you might of guessed from the recent series of articles, there are wealth and status considerations to make related to a specific historic character and what weapon to carry. I have not specifically seen any data on the relative frequency of swords in burials overall. Just about everyone had a small tool knife, but my quick gut reaction is to say swords were like modern Rolex watches in terms of distribution through the population.
Generally swords / axes / spears are found only in male burials.
One real big problem with that generalization is the 'male dominant' angle . If there is a weapon found the sex is automaticly determined as male - without further examination into possible gender (converse is glass beads and female). Skeletons are only rarely sexed using methods OTHER than object generalizations as it turns out. There are some obviously female burials which are found with 'male' objects, particularly swords. Are these intended as working tools - or are they instead statements of status (which is more likely)? As I remember , axes are almost never found in female burials for example.
Swords specifically are high cost, special function, tools. Remember than few individuals in Norse society were full time wariors. If you are primarily a farmer who goes on raids a couple of times over your life span, then investing in an axe makes a lot more sense. This would be a tool axe as well - which explains why there are so many more small, multi function head sizes found.
Swords are also herloom objects. So there is scope there to interpet older blades which have been re-hilted. Stories collected on family blades. High quality swords might easily have a larger reputation than the person holding it.
I personally have a real interest in how simple technical factors can combine or interact inside a culture to create the tradtitions and customs that define a people. I think we are seeing how the metalworking problems are shaping the Norse.
(cross posted on the DARC blog)
Saturday, February 17, 2007
Viking Age SWORDS - part 2, ALLOYS
Posted to Norsefolk by Ed Lindey on Thu Feb 15
"Just my opinion but I believe there is sometimes a mistaken impression with
modern people as to what the capabilities of period swords actually were. In
the words of a swordsmith I respect, "A modern alloy sword, properly made
and heat treated, will cut through a period sword without much effort". "
(Once again this, as brief an overview as it is, may be more than many of you wanted to know!)
Ed mentions two aspects, which I'd like to deal with separately. These are technical factors that are most often incorrectly understood - even by many blade makers. To confound this problem, technical language has been increasingly used as mere advertising copy over the last 20 years. This has obscured what was originally precise language - and frankly made it extremely difficult for the layman to figure out just what the heck is being described.
First is 'modern alloy' - correctly identified by Ed (and his swordsmith friend) as being significantly different than historic metals. The metals available in the Viking Age are different from our modern ones in two primary aspects : method of creation and the actual components that make it up.
Iron as a pure element does not exist on the surface of the earth in its pure metallic form (outside of two weird types - which I may get to). Elemental iron reacts relatively with oxygen to form iron oxide - rust. This being the case, to get a bar of metal, you have to take that iron oxide ore and put it into a specially designed furnace and undertake a carefully orchestrated series of steps to reduce the ore and compact it into a mass - a bloom. (Anyone interested in the details should take a look at www.darkcompany.ca/iron ).
The process used by the Norse produces metal which has quite distinctive physical properties (a working texture) and chemical content.
Now anyone who has been reading my past posts will have heard me mention 'wrought iron' any number of times. This is a type of metal made using a process which was largely abandoned by about 1900 in North America. True wrought iron has not been made ANY PLACE in the Western World since about 1975 (outside of industrial museums). (At todays date I suspect it is not made commercially any place on earth - period.) Starting in 1855, an new technology was introduced (the Bessemer furnace) which allowed a quite different material - mild steel, to be made easily and in huge quantities. Our modern world is made of cheap steel in all its variations.
To be more correct, the metal used in the Viking Age is 'bloomery iron' - which although it is much more like antique wrought iron than modern steels, it still has some important differences from even 150 + year old metal. Any of the metals created using the bloomery process always has microscopic layers of silica slag embedded within the structure. This gives the material a fiberous texture, and cause the metal to shear as it is stretched and formed - especially if the metal is pulled thin. (As a side - that is why VA 'currency bars' most commonly have one end flattened to a paddle shape, poor quality shows as de-laminated metal. This is always why things like cauldrons are made of narrow strips, which still remain much thicker than modern versions.)
Modern steel has a fine crystal structure, without the imperfections caused by the slag inclusions inside bloomery iron. Although an ancient sword maker would certainly select the best quality metal (least inclusions) available, the different textures of historic versus modern metals would result in quite different physical properties. At its simplest level, the iron would prove more flexible than the steel. It will be more likely to flex under load. It would prove relatively easy to deform it (bend), but it would take a lot of force to actually get the metal to fail. If stressed to the point of failure, the wrought iron would be most likely to start to de-laminate (splinter). The modern steel on the other hand is more rigid and thus less likely to flex, and even if flexed it would have a greater tendency to spring back to its original shape. It would take much more force to push it to the point of failure. Against that quality, the steel would have a much greater tendency to fail by shattering.
The next factor that will greatly modify the base metal, regardless of what method is used to convert it from ore, is the chemical composition of the material - the alloy. The major content of the metal is iron, which typically is going to account for well over 95 % of the material. The first other pure element which can be added to modify the metal is carbon. The second set of modifiers can be 'anything else' - even small trace additions can have significant effects.
In ancient through to relatively recent historic times, there was absolutely no understanding of how to modify the chemical content of the metal, no real 'science of metallurgy'. Accumulated experience through trial and (much) error would lead to ore from certain geographic locations being sought after as the raw material that would be most likely to yield metal bars of certain desireable qualities. This all balanced against the huge variables inherent in the smelting process and the fact at only ores located in very easy to gather locations could be used at all. Many surface deposits widely used during the Viking Age are various types of 'bog iron ore'. These accumulate relatively quickly (within decades) and thus are most likely to also vary in composition over time. Many of the most common additional elements found in natural combination with the iron oxide are in fact undesirable - and serve to reduce the functional characteristics of the smelted metal.
One major exception relates to one of those rare occasions mentioned where relatively pure metallic iron is found on the earth's surface. These are iron meteorites, which contain a relatively high per cent of the element nickel (generally 4- 5%). This alloy was not attainable in ancient times by any other source, so distinctively marks any object with this high nickel content. Generally most iron artifacts in existence from the Viking Age have NOT been tested for alloy content. so it is hard to know how rare the use of metal from this unusual source actually is. Nickel alloys do show up often enough to prove that this material was in fact incorporated into knives at least. The nickel will change the metal by making it both tougher and more rigid. It also vastly reduces the ability of oxygen to attach to the surface, hence slows the effects of rusting. All desirable qualities in the pre-Industrial world.
The situation for our modern metals is quite the opposite. Small amounts of sometimes quite exotic elements are added to the base of iron to finely adjust the resulting characteristics of the metal as it is produced. These effects are so well understood that commercial iron producers will precisely tailor the qualities of the metals they produce for specific industrial applications. ( Because weight is a factor, the front coil spring on a modern imported car is most likely a different alloy combination than those found on the rear of the same vehicle, for example.) Not only nickel (for 'stainless') but chrome, tungsten, cobalt... and many more are added in extremely small percentages to modern alloys, These additions create metals which may have any possible combination of qualities which the modern blade maker can pick and chose from. In this way a bar of metal that is simply ground or milled into a sword shape can have outstanding handling characteristics. These results would absolutely be impossible for the ancient swordsmith to duplicate.
Of all the possible elements that can be added to iron to change the quality of the metal, carbon is the simplest to combine. Modifying carbon was within the technology of the Viking Age swordsmith, and the effects were at least loosely understood. Additions of even small amounts of carbon (up to 2 %) can drastically change the handling characteristics of the resulting metal. For the blacksmith, useful amounts all range below 1% carbon. As carbon content increases, the metal becomes both harder and more rigid, unfortunately the trade off is the harder material also becomes more brittle. Some useful comparisons: modern mild steel has roughly .2 %, a truck spring has .5 % and a metalworking file about 1%. Comparison uses for those same carbon contents would be: standard table knife (at .2%), a sword blade (.5%) and a skinning knife (1%).
Every blade maker working with historic types of metals (not modern alloys) has to deal with what is called the 'bladesmith's dilemma'. A low carbon metal will be flexible, and thus survive impact, but it is soft and may bend and will not stay sharp. A hard high carbon metal will be hard and stay sharp, but is more likely to shatter on impact. This is why heavy chopping knives and long blade weapons historically have lower carbon contents than small detail cutting tools.
One of the simplest (technically, but involving much skilled labour) is by layering together soft and hard metals so as to lend specific qualities to certain areas within the body of a blade. In the Viking Age, a commonly seen method used for knives is welding a small piece of higher carbon metal to a larger block of soft iron. When forged to shape, the sliver of hard material becomes the cutting edge, in turn supported by the wrought iron. A more elaborate version is piling a stack of plates of alternating carbon content and welding them into a block. The most complex technique is forming several of these layered blocks then drawing them into twisted rods and welding several to form the core of a sword blade. This is the method to 'pattern welding' which creates distinctive herring bone patterns seen on the highest quality swords from the Viking Age. The purpose here is not mere decoration, but a union of hard and soft, rigid with flexible, down the spine of the sword. (There are several commentaries on pattern welding on the blog)
Once the ideal carbon content of metal for a specific type of blade has been chosen, there is yet another way of selectively altering the relative hardness. Any given piece of carbon / iron alloy can be modified down its length by carefully controlled use of the heat treating process.
That is the topic for part three...
"Just my opinion but I believe there is sometimes a mistaken impression with
modern people as to what the capabilities of period swords actually were. In
the words of a swordsmith I respect, "A modern alloy sword, properly made
and heat treated, will cut through a period sword without much effort". "
(Once again this, as brief an overview as it is, may be more than many of you wanted to know!)
Ed mentions two aspects, which I'd like to deal with separately. These are technical factors that are most often incorrectly understood - even by many blade makers. To confound this problem, technical language has been increasingly used as mere advertising copy over the last 20 years. This has obscured what was originally precise language - and frankly made it extremely difficult for the layman to figure out just what the heck is being described.
First is 'modern alloy' - correctly identified by Ed (and his swordsmith friend) as being significantly different than historic metals. The metals available in the Viking Age are different from our modern ones in two primary aspects : method of creation and the actual components that make it up.
Iron as a pure element does not exist on the surface of the earth in its pure metallic form (outside of two weird types - which I may get to). Elemental iron reacts relatively with oxygen to form iron oxide - rust. This being the case, to get a bar of metal, you have to take that iron oxide ore and put it into a specially designed furnace and undertake a carefully orchestrated series of steps to reduce the ore and compact it into a mass - a bloom. (Anyone interested in the details should take a look at www.darkcompany.ca/iron ).
The process used by the Norse produces metal which has quite distinctive physical properties (a working texture) and chemical content.
Now anyone who has been reading my past posts will have heard me mention 'wrought iron' any number of times. This is a type of metal made using a process which was largely abandoned by about 1900 in North America. True wrought iron has not been made ANY PLACE in the Western World since about 1975 (outside of industrial museums). (At todays date I suspect it is not made commercially any place on earth - period.) Starting in 1855, an new technology was introduced (the Bessemer furnace) which allowed a quite different material - mild steel, to be made easily and in huge quantities. Our modern world is made of cheap steel in all its variations.
To be more correct, the metal used in the Viking Age is 'bloomery iron' - which although it is much more like antique wrought iron than modern steels, it still has some important differences from even 150 + year old metal. Any of the metals created using the bloomery process always has microscopic layers of silica slag embedded within the structure. This gives the material a fiberous texture, and cause the metal to shear as it is stretched and formed - especially if the metal is pulled thin. (As a side - that is why VA 'currency bars' most commonly have one end flattened to a paddle shape, poor quality shows as de-laminated metal. This is always why things like cauldrons are made of narrow strips, which still remain much thicker than modern versions.)
Modern steel has a fine crystal structure, without the imperfections caused by the slag inclusions inside bloomery iron. Although an ancient sword maker would certainly select the best quality metal (least inclusions) available, the different textures of historic versus modern metals would result in quite different physical properties. At its simplest level, the iron would prove more flexible than the steel. It will be more likely to flex under load. It would prove relatively easy to deform it (bend), but it would take a lot of force to actually get the metal to fail. If stressed to the point of failure, the wrought iron would be most likely to start to de-laminate (splinter). The modern steel on the other hand is more rigid and thus less likely to flex, and even if flexed it would have a greater tendency to spring back to its original shape. It would take much more force to push it to the point of failure. Against that quality, the steel would have a much greater tendency to fail by shattering.
The next factor that will greatly modify the base metal, regardless of what method is used to convert it from ore, is the chemical composition of the material - the alloy. The major content of the metal is iron, which typically is going to account for well over 95 % of the material. The first other pure element which can be added to modify the metal is carbon. The second set of modifiers can be 'anything else' - even small trace additions can have significant effects.
In ancient through to relatively recent historic times, there was absolutely no understanding of how to modify the chemical content of the metal, no real 'science of metallurgy'. Accumulated experience through trial and (much) error would lead to ore from certain geographic locations being sought after as the raw material that would be most likely to yield metal bars of certain desireable qualities. This all balanced against the huge variables inherent in the smelting process and the fact at only ores located in very easy to gather locations could be used at all. Many surface deposits widely used during the Viking Age are various types of 'bog iron ore'. These accumulate relatively quickly (within decades) and thus are most likely to also vary in composition over time. Many of the most common additional elements found in natural combination with the iron oxide are in fact undesirable - and serve to reduce the functional characteristics of the smelted metal.
One major exception relates to one of those rare occasions mentioned where relatively pure metallic iron is found on the earth's surface. These are iron meteorites, which contain a relatively high per cent of the element nickel (generally 4- 5%). This alloy was not attainable in ancient times by any other source, so distinctively marks any object with this high nickel content. Generally most iron artifacts in existence from the Viking Age have NOT been tested for alloy content. so it is hard to know how rare the use of metal from this unusual source actually is. Nickel alloys do show up often enough to prove that this material was in fact incorporated into knives at least. The nickel will change the metal by making it both tougher and more rigid. It also vastly reduces the ability of oxygen to attach to the surface, hence slows the effects of rusting. All desirable qualities in the pre-Industrial world.
The situation for our modern metals is quite the opposite. Small amounts of sometimes quite exotic elements are added to the base of iron to finely adjust the resulting characteristics of the metal as it is produced. These effects are so well understood that commercial iron producers will precisely tailor the qualities of the metals they produce for specific industrial applications. ( Because weight is a factor, the front coil spring on a modern imported car is most likely a different alloy combination than those found on the rear of the same vehicle, for example.) Not only nickel (for 'stainless') but chrome, tungsten, cobalt... and many more are added in extremely small percentages to modern alloys, These additions create metals which may have any possible combination of qualities which the modern blade maker can pick and chose from. In this way a bar of metal that is simply ground or milled into a sword shape can have outstanding handling characteristics. These results would absolutely be impossible for the ancient swordsmith to duplicate.
Of all the possible elements that can be added to iron to change the quality of the metal, carbon is the simplest to combine. Modifying carbon was within the technology of the Viking Age swordsmith, and the effects were at least loosely understood. Additions of even small amounts of carbon (up to 2 %) can drastically change the handling characteristics of the resulting metal. For the blacksmith, useful amounts all range below 1% carbon. As carbon content increases, the metal becomes both harder and more rigid, unfortunately the trade off is the harder material also becomes more brittle. Some useful comparisons: modern mild steel has roughly .2 %, a truck spring has .5 % and a metalworking file about 1%. Comparison uses for those same carbon contents would be: standard table knife (at .2%), a sword blade (.5%) and a skinning knife (1%).
Every blade maker working with historic types of metals (not modern alloys) has to deal with what is called the 'bladesmith's dilemma'. A low carbon metal will be flexible, and thus survive impact, but it is soft and may bend and will not stay sharp. A hard high carbon metal will be hard and stay sharp, but is more likely to shatter on impact. This is why heavy chopping knives and long blade weapons historically have lower carbon contents than small detail cutting tools.
One of the simplest (technically, but involving much skilled labour) is by layering together soft and hard metals so as to lend specific qualities to certain areas within the body of a blade. In the Viking Age, a commonly seen method used for knives is welding a small piece of higher carbon metal to a larger block of soft iron. When forged to shape, the sliver of hard material becomes the cutting edge, in turn supported by the wrought iron. A more elaborate version is piling a stack of plates of alternating carbon content and welding them into a block. The most complex technique is forming several of these layered blocks then drawing them into twisted rods and welding several to form the core of a sword blade. This is the method to 'pattern welding' which creates distinctive herring bone patterns seen on the highest quality swords from the Viking Age. The purpose here is not mere decoration, but a union of hard and soft, rigid with flexible, down the spine of the sword. (There are several commentaries on pattern welding on the blog)
Once the ideal carbon content of metal for a specific type of blade has been chosen, there is yet another way of selectively altering the relative hardness. Any given piece of carbon / iron alloy can be modified down its length by carefully controlled use of the heat treating process.
That is the topic for part three...
Friday, February 16, 2007
On Vikng Age SWORDS - Design
This is part one of what looks like may be a three part commentary related to Viking Age swords originally drafted for NORSEFOLK:
I ended up posting a number of commentaries on the blog (below) related to knives when that came up a while back. Much of what was said there can be applied to swords as well.
(August 30 / August 18 / likely some other stuff too)
Metals available during the Viking Age are distinctively different than our modern alloys. Too few realize this, and its even rarer to find a modern knifemaker with any historic materials. (Several have commented generally on this.) The physical processes used in the Viking Age also means historic blades will have a different level of finishing than typical of modern makers.
The overall quality of a sword will be determined by three overall aspects:
1) Design:
There will be a balance between width, thickness, length and profile.
The use of groves (fullers) will increase the structural strength but at the same time reduce the volume of the metal in the blade. Most artifact blades will have a wide and shallow simple U shape on both sides running along the centre of the blade, down most of the entire length. Use of a fuller like this will reduce the volume of metal (and weight) by as much as 50% over a simple diamond cross section.
Historically, the fullers would be forged into the bar using a top and bottom tool that would work together to squeeze the metal. This increases the width at the same time. Now, even on a modern anvil with a spring fuller (not used in the Viking Age) - its pretty darn hard to get an even impression with multiple heats and strikes down the length of 30 plus inches.
Next this rough grove would have to be ground smooth and even. Historically this would be done with hand grind stones. A long, difficult and tedious task. I strongly expect that artifact blades would NOT have perfectly smooth and even grooves for this reason.
Modern blade makers will usually grind or mill this fuller into the metal bar. This would not effect the end result. Use of modern powered tools here speeds up the process, and will create a much more even and regular profile than historic practices. Note that the profile of the fullers should always be rounded - not having square corners at the bottom of the grove.
Second is the layout of the tang - most specifically the transition of the full width of the blade into the tang.
Ideally the tang should be as wide as possible. There is a bit of a paradox here, as examination of artifact swords shows that almost all historic blades have relatively thin rod or 'rat tail' tangs. An understanding of the mechanics of the design explains this.
First, the tang should be made of the same bar of metal as the blade is. Most 'cheap' modern swords will reduce the blade to a mere stub - then arc weld a round rod (often threaded) to the blade. This is almost the worst way to construct the tang. The correct way to form the tang is to forge, or possibly grind, down the parent bar into the smaller diameter of the tang (more in a minute).
Next the tang should continue through the entire handle, and extend right through the pommel / counter weight. Historically the guard, handle tube and pommel all had holes in them. These were inserted on to the tang, then the end of the tang peened over to secure the hilt elements. (In some cases the pommel was composed of several elements, with the first element a disk that was peened to the tang. Further elements were then pinned / riveted to this first disk.)
Now, you can actually create a strong design with a thinner tang - if the transition from blade to tang is profiled correctly. Again cheap swords will use simple square shoulders that reduce the width of the blade directly to the width of the tang. The guard is cut so that it fits directly AGAINST this crisp shoulder. This is the fastest way to fit the hilt, but at the same time the WORST way to do this.
There should be ideally TWO changes in dimension between blade and tang. The first should have ROUNDED shoulders. The guard should have a slot cut into it so that the base of the blade and the entire area of these rounded shoulders fits inside the thickness of the guard. These matching areas should be carefully cut so that they fit tightly to each other. There are two purposes here. The rounded shoulders will bleed off stress from the blade down into the tang and hilt. With the incorrect square corners, there is a sharp focuss of stress, the end result being the blade snaps off the hilt when the blade is used.
On historic blades, tangs are usually forged out from the round shoulders (often quite dramatically) into a taper. As long as the SECOND transition in shape is located inside the the handle tube itself, even use of a narrow rod tang towards the pommel is far less likely to result in the handle snapping off. A TIGHT fit to the handle tube will re-enforce the thinner tang material.
The end of the tang should never be threaded. Use of threading of course will further reduce the effective diameter of the tang - and its strength. Threading on the pommel will always result in a hilt assembly that will work loose with time and can not be correctly tightened.
Note here that compression of the hilt tube (assuming use of organic materials) will absolutely result in the hilt elements becoming loose with time and use. With a correct peened over tang, correcting this is just a matter of re-hammering the peen down tighter. Again this was what was done historically. (Owners remember this - even a correctly designed and executed hilt assembly will loosen with time.)
I ended up posting a number of commentaries on the blog (below) related to knives when that came up a while back. Much of what was said there can be applied to swords as well.
(August 30 / August 18 / likely some other stuff too)
Metals available during the Viking Age are distinctively different than our modern alloys. Too few realize this, and its even rarer to find a modern knifemaker with any historic materials. (Several have commented generally on this.) The physical processes used in the Viking Age also means historic blades will have a different level of finishing than typical of modern makers.
The overall quality of a sword will be determined by three overall aspects:
1) Design:
There will be a balance between width, thickness, length and profile.
The use of groves (fullers) will increase the structural strength but at the same time reduce the volume of the metal in the blade. Most artifact blades will have a wide and shallow simple U shape on both sides running along the centre of the blade, down most of the entire length. Use of a fuller like this will reduce the volume of metal (and weight) by as much as 50% over a simple diamond cross section.
Historically, the fullers would be forged into the bar using a top and bottom tool that would work together to squeeze the metal. This increases the width at the same time. Now, even on a modern anvil with a spring fuller (not used in the Viking Age) - its pretty darn hard to get an even impression with multiple heats and strikes down the length of 30 plus inches.
Next this rough grove would have to be ground smooth and even. Historically this would be done with hand grind stones. A long, difficult and tedious task. I strongly expect that artifact blades would NOT have perfectly smooth and even grooves for this reason.
Modern blade makers will usually grind or mill this fuller into the metal bar. This would not effect the end result. Use of modern powered tools here speeds up the process, and will create a much more even and regular profile than historic practices. Note that the profile of the fullers should always be rounded - not having square corners at the bottom of the grove.
Second is the layout of the tang - most specifically the transition of the full width of the blade into the tang.Ideally the tang should be as wide as possible. There is a bit of a paradox here, as examination of artifact swords shows that almost all historic blades have relatively thin rod or 'rat tail' tangs. An understanding of the mechanics of the design explains this.
First, the tang should be made of the same bar of metal as the blade is. Most 'cheap' modern swords will reduce the blade to a mere stub - then arc weld a round rod (often threaded) to the blade. This is almost the worst way to construct the tang. The correct way to form the tang is to forge, or possibly grind, down the parent bar into the smaller diameter of the tang (more in a minute).
Next the tang should continue through the entire handle, and extend right through the pommel / counter weight. Historically the guard, handle tube and pommel all had holes in them. These were inserted on to the tang, then the end of the tang peened over to secure the hilt elements. (In some cases the pommel was composed of several elements, with the first element a disk that was peened to the tang. Further elements were then pinned / riveted to this first disk.)
Now, you can actually create a strong design with a thinner tang - if the transition from blade to tang is profiled correctly. Again cheap swords will use simple square shoulders that reduce the width of the blade directly to the width of the tang. The guard is cut so that it fits directly AGAINST this crisp shoulder. This is the fastest way to fit the hilt, but at the same time the WORST way to do this.
There should be ideally TWO changes in dimension between blade and tang. The first should have ROUNDED shoulders. The guard should have a slot cut into it so that the base of the blade and the entire area of these rounded shoulders fits inside the thickness of the guard. These matching areas should be carefully cut so that they fit tightly to each other. There are two purposes here. The rounded shoulders will bleed off stress from the blade down into the tang and hilt. With the incorrect square corners, there is a sharp focuss of stress, the end result being the blade snaps off the hilt when the blade is used.
On historic blades, tangs are usually forged out from the round shoulders (often quite dramatically) into a taper. As long as the SECOND transition in shape is located inside the the handle tube itself, even use of a narrow rod tang towards the pommel is far less likely to result in the handle snapping off. A TIGHT fit to the handle tube will re-enforce the thinner tang material.
The end of the tang should never be threaded. Use of threading of course will further reduce the effective diameter of the tang - and its strength. Threading on the pommel will always result in a hilt assembly that will work loose with time and can not be correctly tightened.
Note here that compression of the hilt tube (assuming use of organic materials) will absolutely result in the hilt elements becoming loose with time and use. With a correct peened over tang, correcting this is just a matter of re-hammering the peen down tighter. Again this was what was done historically. (Owners remember this - even a correctly designed and executed hilt assembly will loosen with time.)
Wednesday, February 14, 2007
Making a Norse Cauldron?
This modified from a posting to NORSEFOLK - some comments on building a Viking Age cauldron.
(Sorry about the lack of additions the last week - I've been working on the revision to IRON SMELTING and things like digging my truck out from under a snow collapsed garage..)
Artifact cauldrons are all considerably THICKER than what modern metalworkers are generally prepared to work with. This because the sheets of metal had to be hand hammered out. We are talking thicknesses in the range of 3 - 6 mm.
The largest width of any piece is generally LESS than 20 cm. Same reason.
Mild steel as a sub for wrought iron would have to be worked hot at those thicknesses. I have done a couple out of 1/8" plate (a pain to cut) which is still only 1.5 mm thick in comparison.
I personally have been unable to source actual bronze sheet here in Canada. Any USA folks may be able to get it down there. Although you can work bronze hot, it is quite difficult (the stuff has a narrow working heat and gets brittle almost instantly below that temp). Be extremely careful about hot working many bronze alloys, as they can contain some real evil heavy metals. I would NOT recommend working with any scrap bronze that you can not determine the actual content of.
I have had fairly good results with thinner sheet copper and brass. Brass is a ZINC alloy and can only be worked cold. Copper is easily available as thinner sheet (used for roofing) and plate is available, and it is a dream to work hot. Also fairly easy to work cold. Be aware that the prices for industrial copper (and thus brass and bronze) have skyrocketed over the last 6 months (thanks to the Chinese). A full sheet of 3 x 8 feet in 20 ga copper (would make two large cauldrons) runs about $300 CDN new right now. (So figure those prices you saw on my web site - at least $150 of the large copper cauldron is just for the raw metal)
Copper and brass has the advantage of being quite easy to TIN solder the seams after riveting. Purchase a lead free solder used for water pipes (generally a 95 % or so tin alloy) for this.
I have tried bronze braising a heavy forged mild steel cauldron. I have done this three times - and had a real time of it each time. I think it has something to do with the different cooling rates and strengths of the materials (bronze and steel). So I'd say avoid this method.
I have done the cheat of MIG welding the seams of a segmented mild steel plate cauldron to keep it food safe. Takes a good hand with the welder for a clean job. As the seams are on the inside its difficult to impossible to grind them afterwards - so you need your first pass to be perfect. Its also painfully obvious that you have used a modern welding method.
I have had better cosmetic luck welding the OUTSIDE - then taking a fresh cutting disk on my angle grinder and grinding the welds flush. This allows you to leave the 'step' where the plates overlap. Note that this will make the pot water tight - but not FOOD SAFE, there are still cracks on the inside. Once the pot has been put over the fire for an hour the soot pretty much hides the weld and grind. You would have to look at less than 12 inches to tell how it was done (assuming a careful job on the steps required)
If you are on a real tight budget and willing to use a three foot rule for visuals:
Get an old stainless or aluminum cook pot.
Work the surface with a hammer over a trailer ball or even a rounded wood stump to knock off the crisp seams and batter it up a bit.
take an old screw driver or straight chisel and round the edged off a bit. Then work from the INSIDE back on to a block of wood to lightly score a set of lines to suggest the margins of the plates. Lay your lines out with a water based marker before you start. Its best to use a light stroke a couple of times - than hit too hard and risk punching through the metal and making a hole.
Next drill and set lines of rivets next to the lines. As the rivets are set tight - they should seal up again to keep the pot water tight.
Likely you will want to replace the wire bail handle with one forged from a strip of flat metal stock.
Again after an hour on the fire you have something that would be better than average for SCA use. Not good enough for museum work - but since the trade off here is a $5 yard sale pot and an hour's work. - against several hundred dollars for a correct reproduction...
Darrell
PS :
I have made a good number - you can see samples of most of what I discuss above at:
http://www.warehamforge.ca/norsecook.html
Although I think you will find those prices fair and competitive, I give you the link because it also shows you images of a number of artifact cauldrons with the book references.
Be aware that all the UK companies that sell 'wrought iron' riveted pots are in fact using mild steel NO ONE uses actual wrought iron metal. Their pots all leak - there is no attempt to seal the seams (you need to read the fine print to find this out). They also charge as much in Sterling as I'm charging in CDN funds. Do the math...
(Sorry about the lack of additions the last week - I've been working on the revision to IRON SMELTING and things like digging my truck out from under a snow collapsed garage..)
Artifact cauldrons are all considerably THICKER than what modern metalworkers are generally prepared to work with. This because the sheets of metal had to be hand hammered out. We are talking thicknesses in the range of 3 - 6 mm.
The largest width of any piece is generally LESS than 20 cm. Same reason.
Mild steel as a sub for wrought iron would have to be worked hot at those thicknesses. I have done a couple out of 1/8" plate (a pain to cut) which is still only 1.5 mm thick in comparison.
I personally have been unable to source actual bronze sheet here in Canada. Any USA folks may be able to get it down there. Although you can work bronze hot, it is quite difficult (the stuff has a narrow working heat and gets brittle almost instantly below that temp). Be extremely careful about hot working many bronze alloys, as they can contain some real evil heavy metals. I would NOT recommend working with any scrap bronze that you can not determine the actual content of.
I have had fairly good results with thinner sheet copper and brass. Brass is a ZINC alloy and can only be worked cold. Copper is easily available as thinner sheet (used for roofing) and plate is available, and it is a dream to work hot. Also fairly easy to work cold. Be aware that the prices for industrial copper (and thus brass and bronze) have skyrocketed over the last 6 months (thanks to the Chinese). A full sheet of 3 x 8 feet in 20 ga copper (would make two large cauldrons) runs about $300 CDN new right now. (So figure those prices you saw on my web site - at least $150 of the large copper cauldron is just for the raw metal)
Copper and brass has the advantage of being quite easy to TIN solder the seams after riveting. Purchase a lead free solder used for water pipes (generally a 95 % or so tin alloy) for this.
I have tried bronze braising a heavy forged mild steel cauldron. I have done this three times - and had a real time of it each time. I think it has something to do with the different cooling rates and strengths of the materials (bronze and steel). So I'd say avoid this method.
I have done the cheat of MIG welding the seams of a segmented mild steel plate cauldron to keep it food safe. Takes a good hand with the welder for a clean job. As the seams are on the inside its difficult to impossible to grind them afterwards - so you need your first pass to be perfect. Its also painfully obvious that you have used a modern welding method.
I have had better cosmetic luck welding the OUTSIDE - then taking a fresh cutting disk on my angle grinder and grinding the welds flush. This allows you to leave the 'step' where the plates overlap. Note that this will make the pot water tight - but not FOOD SAFE, there are still cracks on the inside. Once the pot has been put over the fire for an hour the soot pretty much hides the weld and grind. You would have to look at less than 12 inches to tell how it was done (assuming a careful job on the steps required)
If you are on a real tight budget and willing to use a three foot rule for visuals:
Get an old stainless or aluminum cook pot.
Work the surface with a hammer over a trailer ball or even a rounded wood stump to knock off the crisp seams and batter it up a bit.
take an old screw driver or straight chisel and round the edged off a bit. Then work from the INSIDE back on to a block of wood to lightly score a set of lines to suggest the margins of the plates. Lay your lines out with a water based marker before you start. Its best to use a light stroke a couple of times - than hit too hard and risk punching through the metal and making a hole.
Next drill and set lines of rivets next to the lines. As the rivets are set tight - they should seal up again to keep the pot water tight.
Likely you will want to replace the wire bail handle with one forged from a strip of flat metal stock.
Again after an hour on the fire you have something that would be better than average for SCA use. Not good enough for museum work - but since the trade off here is a $5 yard sale pot and an hour's work. - against several hundred dollars for a correct reproduction...
Darrell
PS :
I have made a good number - you can see samples of most of what I discuss above at:
http://www.warehamforge.ca/norsecook.html
Although I think you will find those prices fair and competitive, I give you the link because it also shows you images of a number of artifact cauldrons with the book references.
Be aware that all the UK companies that sell 'wrought iron' riveted pots are in fact using mild steel NO ONE uses actual wrought iron metal. Their pots all leak - there is no attempt to seal the seams (you need to read the fine print to find this out). They also charge as much in Sterling as I'm charging in CDN funds. Do the math...
Monday, February 05, 2007
Norse Hammers?
Nickolas wrote:
> I have a question I hope you can help me with. I've been reading about the Mastermyr find, and I'm curious about the hammers. Were they wrought iron, or did they have a wrought body with steel peens and/or faces?
If you are real serious here, you should get a copy of
the Mastermyr Find
Arwidsson and Berg
AlmQuist & Wiksell - 1983
91-7402-129 X
Norm Larson Books in California got the rights to re-publish a couple of years back and was selling these for about $25 US a copy.
According to the report. Only one of the hammers was tested for metal content. That was the large hand sledge (# 69) at 3.3 kg. This shows the PEEN end as forge welded mid carbon steel but welded on to the iron body. Makes some sence if you figure its smaller and thus more likely to deform.
The section on metallurgy mentions most of the hammers are formed of a single mass of iron "..the objects were made from fairly homogeneous iron pieces." (Note that the axes tested have welded higher carbon edges)
If you look at the hammers found, the faces on two of the mid sized tools show significant mushing out at the face, whihc certainly looks like use pattern on softer iron bodies. All show some upsetting at the face - but I personally take this as partially the effect of the original forging to shape.
A fast visual reference : take a look at the blacksmith's shop reconstruction I put together for 'World of the Norse'
> I have a question I hope you can help me with. I've been reading about the Mastermyr find, and I'm curious about the hammers. Were they wrought iron, or did they have a wrought body with steel peens and/or faces?
If you are real serious here, you should get a copy of
the Mastermyr Find
Arwidsson and Berg
AlmQuist & Wiksell - 1983
91-7402-129 X
Norm Larson Books in California got the rights to re-publish a couple of years back and was selling these for about $25 US a copy.
According to the report. Only one of the hammers was tested for metal content. That was the large hand sledge (# 69) at 3.3 kg. This shows the PEEN end as forge welded mid carbon steel but welded on to the iron body. Makes some sence if you figure its smaller and thus more likely to deform.
The section on metallurgy mentions most of the hammers are formed of a single mass of iron "..the objects were made from fairly homogeneous iron pieces." (Note that the axes tested have welded higher carbon edges)
If you look at the hammers found, the faces on two of the mid sized tools show significant mushing out at the face, whihc certainly looks like use pattern on softer iron bodies. All show some upsetting at the face - but I personally take this as partially the effect of the original forging to shape.
A fast visual reference : take a look at the blacksmith's shop reconstruction I put together for 'World of the Norse'
Thursday, February 01, 2007
RRS - whats that RRS?
Although most of my readers will not see this, I've finally switched over to the 'new' version of Blogger. I was extremely resistant to this, as I have no use for so many of the 'services' provided from these Bill Gates style " My Blog" stet ups. I find them invasive and trivial at the least - and usually totally counter intuitive.
We shall see if this has proved a bad idea ...
For anyone internet / computer savvy enough, I have also turned ON the RRS FEED feature for Hammered out Bits. This is supposed to automatically notify a reader when a new post arrives on the blog. Mind you - you as a reader have to go into your e-mail account settings (likely on preferences) and plug in the URL address for Hammered out Bits.
I only vaguely understand this hoodo, my friend Neil walked me through it on a recent visit. It turns out NONE of the blogs I try to follow (only about a half dozen by friends) are set up to send out the automatic notices.
Anyway - if you can set up for the automatic RRS feed notice widget, it will keep you from having to poke in here to see if a post has been added
Darrell
We shall see if this has proved a bad idea ...
For anyone internet / computer savvy enough, I have also turned ON the RRS FEED feature for Hammered out Bits. This is supposed to automatically notify a reader when a new post arrives on the blog. Mind you - you as a reader have to go into your e-mail account settings (likely on preferences) and plug in the URL address for Hammered out Bits.
I only vaguely understand this hoodo, my friend Neil walked me through it on a recent visit. It turns out NONE of the blogs I try to follow (only about a half dozen by friends) are set up to send out the automatic notices.
Anyway - if you can set up for the automatic RRS feed notice widget, it will keep you from having to poke in here to see if a post has been added
Darrell