My swords keep breaking, why?

A

AresForge

Joined
Aug 15, 2022
Messages
2
Hey guys, I've been making knives and swords at my forge for about ten years on and off but my swords always break when I test them. It's sort of a mystery to me and need help solving it.

I just made a Wakazashi that bent 90 degrees then back with only a 5 degree set and the edge is incredibly hard. I started to abuse it and throw against trees hard as I can, etc. So far so good!

But then I stuck it in the ground point first and started swinging another sword at it. After about 20 strikes and the blade flying 10 feet away with a deafening ring, it finally snapped clean in half. Now I'm open to this being pure stupidity on my part. However, this is why I'm asking for help now. My logic is that swords are supposed to be battle ready, with knights swinging their blades with tremendous force at each other, but maybe I need a history lesson on swords. I just don't know.

Here are the exact specifications and dimensions:

- Blade was forged from bar of 5160, 24" long, flat ground (no fullers etc), 1.25" wide. Handle 10" long and tempered dead soft
- Normalized twice, stress relieved once, heated to non mag and quenched in hot canola oil then pulled out after 10 seconds to straighten, the back in the oil for a minute
- Washed and cleaned and immediately put in oven at 400 degrees for two hours, two cycles
- Used hot tongs to temper the spine, did this twice. It was a deep blue/purple about 3/4 of the way to the edge, the edge kept cool with a sponge and water
- Upon breaking the granular structure was very fine and clean

So did I do something wrong or are swords just not able to withstand that kind of abuse? If they can't hold up to it then why were they used in battle for thousands of years? I must be doing something wrong.

Thanks, stay sharp!
 
Welcome aboard
AresForge said:
Now I'm open to this being pure stupidity on my part. However, this is why I'm asking for help now. My logic is that swords are supposed to be battle ready, with knights swinging their blades with tremendous force at each other, but maybe I need a history lesson on swords. I just don't know.
Click to expand...
I'd say some of your logic follows that you just don't know.

oakeshott.org

Sword Blade Hardness: a Look at the Current Research - The Oakeshott Institute

Sword Blade Hardness: A look at the current research An article by Craig Johnson A bladesmith The possible variables in composition for any given sword blade are often so numerous that they defy counting. It is now understood that this variation is the result of attempts to produce a blade that...
oakeshott.org oakeshott.org

Gus Trim once had a blade of 5160 tested, relative Rockwell of roughly 54 HRC. Bent several times past 90 degrees before taking a set and then bent even further 3 or 4 times before shattering. Start with background heat treating and end up with back yard results. Gus' blades are marquenched at an aerospace heat treating facility but marquenching does work. Guessing at heat treat without controls and salt baths is just that, guesswork.

Start here

Do some studies on how swords were actually used. Swords did get used up but they were not used to strike each other in the manner you seem to imply. The targets were not each other's swords. Nor for bashing armour. You really do need to start all over with what you think to be true.

That first bend to 90 taking a set set up a fracture as the steel piled. Breakage could have somewhat been expected due to your further testings.

Kudos on setting up and working with longer blades. The more you do know will inevitably help with your further endeavors.

Cheers
GC
 
horseclover said:
Welcome aboard

I'd say some of your logic follows that you just don't know.

oakeshott.org

Sword Blade Hardness: a Look at the Current Research - The Oakeshott Institute

Sword Blade Hardness: A look at the current research An article by Craig Johnson A bladesmith The possible variables in composition for any given sword blade are often so numerous that they defy counting. It is now understood that this variation is the result of attempts to produce a blade that...
oakeshott.org oakeshott.org

Gus Trim once had a blade of 5160 tested, relative Rockwell of roughly 54 HRC. Bent several times past 90 degrees before taking a set and then bent even further 3 or 4 times before shattering. Start with background heat treating and end up with back yard results. Gus' blades are marquenched at an aerospace heat treating facility but marquenching does work. Guessing at heat treat without controls and salt baths is just that, guesswork.

Start here

Do some studies on how swords were actually used. Swords did get used up but they were not used to strike each other in the manner you seem to imply. The targets were not each other's swords. Nor for bashing armour. You really do need to start all over with what you think to be true.

That first bend to 90 taking a set set up a fracture as the steel piled. Breakage could have somewhat been expected due to your further testings.

Kudos on setting up and working with longer blades. The more you do know will inevitably help with your further endeavors.

Cheers
GC
Click to expand...

Wow, this was eye opening. I just read the Oakshott Institute article and that just completely changed my understanding of historical blades. I never thought swords were that inconsistent in hardness with sometimes an average of 20 Rc. I'm researching the other links you provided me as well. Thank you very much-- this is exactly what I needed!
 
AresForge said:
Hey guys, I've been making knives and swords at my forge for about ten years on and off but my swords always break when I test them. It's sort of a mystery to me and need help solving it.

I just made a Wakazashi that bent 90 degrees then back with only a 5 degree set and the edge is incredibly hard. I started to abuse it and throw against trees hard as I can, etc. So far so good!

But then I stuck it in the ground point first and started swinging another sword at it. After about 20 strikes and the blade flying 10 feet away with a deafening ring, it finally snapped clean in half. Now I'm open to this being pure stupidity on my part. However, this is why I'm asking for help now. My logic is that swords are supposed to be battle ready, with knights swinging their blades with tremendous force at each other, but maybe I need a history lesson on swords. I just don't know.

Here are the exact specifications and dimensions:

- Blade was forged from bar of 5160, 24" long, flat ground (no fullers etc), 1.25" wide. Handle 10" long and tempered dead soft
- Normalized twice, stress relieved once, heated to non mag and quenched in hot canola oil then pulled out after 10 seconds to straighten, the back in the oil for a minute
- Washed and cleaned and immediately put in oven at 400 degrees for two hours, two cycles
- Used hot tongs to temper the spine, did this twice. It was a deep blue/purple about 3/4 of the way to the edge, the edge kept cool with a sponge and water
- Upon breaking the granular structure was very fine and clean

So did I do something wrong or are swords just not able to withstand that kind of abuse? If they can't hold up to it then why were they used in battle for thousands of years? I must be doing something wrong.

Thanks, stay sharp!
Click to expand...
Hi i can't be of much help for I'm just starting to learn and forge myself, but i think using water to cool the edge of the spine may have created cracks?

I thought having a softer spine with a nice hard edge would be better?

I think swords with longer blades prefer to be softer close to the guard and then gradually get harder towards the front of the blade, so medium hardness in the middle and of course maximum hardness at the tip.

Are you forging from stock steel or drawing out from a block/canister, etc?

I wish you future success and good to see your giving them some hectic testing, I'll be doing the same also but as far as i know it all comes down to the heat treat.
 
my humble 2 cents - 5160 is just not upto the extreme stresses you want out of this use case
no vanadium, nothing to really refine grain structure

try some 80crv2 or something like that .. or the older sword standard, l6

heat treatment will be key, and yeah, salt baths and bainite seem to be a good path if you want to be smashing swords into each other
...
remember the key there historically was to deflect & redirect, never as direct edge on edge test
 
dirc said:
my humble 2 cents - 5160 is just not upto the extreme stresses you want out of this use case
no vanadium, nothing to really refine grain structure

try some 80crv2 or something like that .. or the older sword standard, l6

heat treatment will be key, and yeah, salt baths and bainite seem to be a good path if you want to be smashing swords into each other
...
remember the key there historically was to deflect & redirect, never as direct edge on edge test
Click to expand...
That must be why Zombie Tools uses 5160 on their longer blades. Also why Albion, Arms&Armor and Del Tin use 6150, a chrome vanadium steel. Angus Trim has used 5160 forever in the sword world, with more and more high volume production companies choosing to use it for swords.

80crv2 is a high chrome vanadium steel, so I'm not exactly sure where you are coming from. I guess you are saying the higher content is better.

Cheers
GC
 
not sure what you mean - 'high chrome'? 80crv2 only has a half percent ... (very similar to 5160)
the whole point I was making was that 5160 lacks vanadium, which is a super grain refinement element

the vanadium addition is the key for the added toughness from grain refinement... that's why the old standard, L6 has it
 
Swords are supposed to break. They were fine combat tools, designed to be used in a particular and highly skilled manner. They cut and stabbed through speed, balance and finest. I don’t know where anyone got the idea that we are supposed to hack with them. A sword is nothing more than a thin piece of lightened metal designed to deliver a fine edge to a specific location first. The sword that came in second best was not capable of delivering reliable damage since it’s wielder would have already been gravely injured or maimed. They work best on soft organic material; and are not intended for use against armor, bones, trees or rocks. Some designs could parry, but only with specific parts of the swords that were so designed. They were never a brute force weapon, nor the primary weapon of battle.

n2s
 
The steel used to make a true samurai sword would be "folded" hundreds, and sometimes thousands of times during the forging process to remove impurities and make it stronger. Then the blades were differentially tempered (harder edge, softer back), and yet they were still not indestructible. They were never made for hacking trees, much less other swords.
 
not2sharp said:
They were never a brute force weapon, nor the primary weapon of battle.
Click to expand...
This. You had a LOT of guys on a battlefield with pole arms like spears and such and a bunch with blunt weapons like reinforced clubs and the like. It really depends on the army. An "official" army would have more sword/shield + pike wielders and better armor as opposed to a loosely gathered tribal faction or one fielded from mostly peasants. The trick was to get heavily armored combatants like cavalry and knights off the horse and onto the ground so that the armor could be crushed by repeated blows with war hammers, clubs, etc, or a lucky stab into a less protected area. Even among the samurai duelists the intention was to evade the opponents attack completely while making yours count, it wasn't like rapier fencing with a lot of sword to sword parrying.
 
what a revelation. My understanding of historical blades has radically transformed as a result of reading the Oakshott Institute study. I had no idea that swords' average hardness, which can be 20 Rc, was so variable. I'm also doing research on the other sites you sent me. This is precisely what I needed, so thank you!
 
what a revelation. My understanding of historical blades has radically transformed as a result of reading the Oakshott Institute study. I had no idea that swords' average hardness, which can be 20 Rc, was so variable. I'm also doing research on the other sites you sent me. This is precisely what I needed, so thank you!
 
I was watching a video done by a weapons historian and HEMA practitioner who had some very interesting takes on how swords were used based on the time period. Some of the points he made that stuck out in my mind were that in early medieval warfare sword strikes were most likely short and not full power swings. Before plate armor became common, his idea was that you would want to lead with the blade and keep the hand back away from a strike. Instead of doing a full whip-like strike where you cock back, throw your arm, and snap cut the blade, they would most likely keep the sword arm/hand pulled back and protected either behind a shield/buckler or just out of the line of attack so that the opponent couldn't "take the hand". Also, in a full on scrum, the room in which you would be able to strike would be limited pressed against other bodies. Short strikes, slashes, and stabs would be more common.

The advent of plate armor and gauntlets meant that slashing damage to the hand was mitigated to the point that guarded strikes may not have been needed. This is where the debate of edge to edge and edge to flat/parry defense in medieval combat gets down into the muck and WAY above my academic understanding. But he did make a fair point about sidearm swords like messers having both frontal hand protection as well as knuckle to the side to stop a blade sliding down the flat. The logic was pretty good. People with those types of swords were either unarmored or had a job that required finger dexterity like an archer or crossbowman who could not wear protective plate on their hands.

But I digress. I think a lot of what we see in swords breaking/not breaking is in their design. I also think the truth is mixed in there between the hardness/softness of the blades, the technique and training of the person wielding it, and, quite frankly, the romanticism of the sword as this legendary prized and indestructible weapon that would cleave through foes for centuries when for the most part they were tools. They got beat up, they got fixed, and the people who used them were wealthy enough to just get another one if they were in terrible shape after a battle. I'm also willing to bet that a lot of really good knowledge of how to craft a durable blade has been lost to the ages. I do think that it is unreasonable to expect a sword made for parrying and cutting into bodies should stand up to hacking into trees and the like.
 
This is a revelation. Reading the Oakshott Institute study has totally transformed how I think about historical blades. I was unaware that the average hardness of swords varied from Rc 20 that much. I'm reading the other sites. This is specifically what I needed, thank you!

This is a revelation. Reading the Oakshott Institute study has totally transformed how I think about historical blades. I was unaware that the average hardness of swords varied from Rc 20 that much. I'm reading the other sites. This is specifically what I needed, thank you!
 
OP, it sounds like what you were doing could be expected to damage and eventually break just about any long piece of metal. Better tests for your swords could be to cut with them, through ever more difficult targets, until you start to find the limits of the blades.

Also in case you don't know about it, do a quick study on "stress riser."
 
I'm pretty sure people did not abuse their swords back then.
Film would have you believe 2 combatants would sword fight and be blade to blade fighting, but in reality there would be a lot more light parrying, feints, and avoidance.
Look at American made movies with katanas, in reality those swords would snap. The swords rarely made contact with each other, mostly parry.
 
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