A true account on the durability of swords
May 13, 2007 3:03:06 GMT
Post by Deleted on May 13, 2007 3:03:06 GMT
A true account on the durability of swords
Once upon a time, in the idiocy of my youth, I decided that it would be a good idea to use some of my swords for a variety of practical purposes. This included cutting exercises, and a variety of non-traditional hard use exercises. At this time I had a number of swords.
I understand that for whatever reason many, many people are interested in the durability of swords, both edge strength and resistance to bends or twists. Even though historically no sword was expected to be indestructable it seems of course to be the preference to get as close to that as possible. And that dream is so close to the forefront of many modern sword collectors that a variety of technologies have been created (or at least promoted)
to address it. It seems that even achieving perfect historical accuracy and balance is of less interest than producing ultimate durability. There is precious little information concerning the durability of swords- only speculation and hearsay. The reason for this, of course, is that no one is willing to damage their sword...but I was.
And for this reason, I would like to share with you what I have learned. I am no metallurgist or sword expert, but I do have actual experience with many weapons under hard use...and not just chopping into wood, which is about as far as anybody ever goes when hard using a sword. I experimented with freak situations that can (and have) occured historically. Mimicking a situation where the sword would unintentionally strike something harder than itself.
Resistance to bend and set
Resistance to bend and set is not that difficult to achieve for modern swordmakers. Good steel and quality spring temper will allow a sword to be bent quite a bit and spring back to true. This means your sword not become crooked from a cut, no matter how bad it is. If this is what you are primarily interested there are a few options. Most notably L6 bainite martensite katanas made by Howard Clark and recently MAS of korea (though lately they fail to mention it on their website, which is fishy) Michael Raw's through-tempered katanas and of course the much, much less expensive 9260 katana from cheness. Additionally, I have found the swords I have had from Cold Steel to have a qualitative enough spring temper to pretty much preclude any bending.
Edge resilience
Now this is the interesting subject. Almost no one, *really* investigates this----because it means sword damage. But at the same time, it is of great importance, becuase I believe people think they are somehow buying more of it when they spend more money...this is not the case. I tested accidental strikes against hard wood, concrete, and even metal--and no, not thin sheet metal signs but a thick metal bar...stupid but very telling.
I believe the strength of a swords edge is basically a compromise of hardness and toughness. Too hard and it will chip...too soft and it will roll. There is also the edge profile and thickness to consider, and this has ALOT to do with it. A meaty edge will do much better against substantial targets, thats why many of the "sharpened crowbar" swords out there are so durable at the edge. It is not that the metallurgy is special, but that there
is alot of material there to support the edge. Of course the tradeoff for this kind of false durability is balance and handling.
This is the basic science of almost every single sword I have tested- almost all of them predictably follow these rules... including the very expensive ones. And it is only after my experiences that I felt I could say that these three simple rules of hardness, toughness, and edge mass are pretty much canon for the swords we can buy today and those that our forebears had...pretty much. You see, there are cases when a wonderful balance of hardness and toughness is produced in the steel. The edge is hard enough to resist deformation and tough enough to resist chipping- creating an edge that is very strong against significant damage save edge on edge with another sharpened and hardened sword. I first read about this in a Cliff Stamp (a guy who has carefully and methodically tested the durability of knives for years) review of some knives and khukuri's. While most of the knives in the test followed the rules (harder ones chipped, softer ones rolled) one particular khukuri did neither...and Cliff mentioned the reason was the combination of attributes this one had in it's edge. Hardness and toughness, together. How is it created? I don't know. Maybe it is a perfect rockwell hardness somewhere between 58rc and 60rc. Maybe it is some
sort of forging trick, I am not sure. But I can tell you that of all the swords I have had, this includes Cold Steel, Windlass, Paul Chen, Criswell, Himalayan Imports and Angus Trim plus a number of customs and ethnographic weapons, only three have ever displayed a significant amount of this quality without the assistance of an overly thick edge. A particular sword from cold steel (one of 4 I have had from them), an antique indian tulwar, and a certain custom sword.
more to follow
Once upon a time, in the idiocy of my youth, I decided that it would be a good idea to use some of my swords for a variety of practical purposes. This included cutting exercises, and a variety of non-traditional hard use exercises. At this time I had a number of swords.
I understand that for whatever reason many, many people are interested in the durability of swords, both edge strength and resistance to bends or twists. Even though historically no sword was expected to be indestructable it seems of course to be the preference to get as close to that as possible. And that dream is so close to the forefront of many modern sword collectors that a variety of technologies have been created (or at least promoted)
to address it. It seems that even achieving perfect historical accuracy and balance is of less interest than producing ultimate durability. There is precious little information concerning the durability of swords- only speculation and hearsay. The reason for this, of course, is that no one is willing to damage their sword...but I was.
And for this reason, I would like to share with you what I have learned. I am no metallurgist or sword expert, but I do have actual experience with many weapons under hard use...and not just chopping into wood, which is about as far as anybody ever goes when hard using a sword. I experimented with freak situations that can (and have) occured historically. Mimicking a situation where the sword would unintentionally strike something harder than itself.
Resistance to bend and set
Resistance to bend and set is not that difficult to achieve for modern swordmakers. Good steel and quality spring temper will allow a sword to be bent quite a bit and spring back to true. This means your sword not become crooked from a cut, no matter how bad it is. If this is what you are primarily interested there are a few options. Most notably L6 bainite martensite katanas made by Howard Clark and recently MAS of korea (though lately they fail to mention it on their website, which is fishy) Michael Raw's through-tempered katanas and of course the much, much less expensive 9260 katana from cheness. Additionally, I have found the swords I have had from Cold Steel to have a qualitative enough spring temper to pretty much preclude any bending.
Edge resilience
Now this is the interesting subject. Almost no one, *really* investigates this----because it means sword damage. But at the same time, it is of great importance, becuase I believe people think they are somehow buying more of it when they spend more money...this is not the case. I tested accidental strikes against hard wood, concrete, and even metal--and no, not thin sheet metal signs but a thick metal bar...stupid but very telling.
I believe the strength of a swords edge is basically a compromise of hardness and toughness. Too hard and it will chip...too soft and it will roll. There is also the edge profile and thickness to consider, and this has ALOT to do with it. A meaty edge will do much better against substantial targets, thats why many of the "sharpened crowbar" swords out there are so durable at the edge. It is not that the metallurgy is special, but that there
is alot of material there to support the edge. Of course the tradeoff for this kind of false durability is balance and handling.
This is the basic science of almost every single sword I have tested- almost all of them predictably follow these rules... including the very expensive ones. And it is only after my experiences that I felt I could say that these three simple rules of hardness, toughness, and edge mass are pretty much canon for the swords we can buy today and those that our forebears had...pretty much. You see, there are cases when a wonderful balance of hardness and toughness is produced in the steel. The edge is hard enough to resist deformation and tough enough to resist chipping- creating an edge that is very strong against significant damage save edge on edge with another sharpened and hardened sword. I first read about this in a Cliff Stamp (a guy who has carefully and methodically tested the durability of knives for years) review of some knives and khukuri's. While most of the knives in the test followed the rules (harder ones chipped, softer ones rolled) one particular khukuri did neither...and Cliff mentioned the reason was the combination of attributes this one had in it's edge. Hardness and toughness, together. How is it created? I don't know. Maybe it is a perfect rockwell hardness somewhere between 58rc and 60rc. Maybe it is some
sort of forging trick, I am not sure. But I can tell you that of all the swords I have had, this includes Cold Steel, Windlass, Paul Chen, Criswell, Himalayan Imports and Angus Trim plus a number of customs and ethnographic weapons, only three have ever displayed a significant amount of this quality without the assistance of an overly thick edge. A particular sword from cold steel (one of 4 I have had from them), an antique indian tulwar, and a certain custom sword.
more to follow