C13th "chopper" ?

[leonardo daneluz]

Oh yes, modern and soft sae 1010 steel, who knows how thick and the helmet flyes which what energy?Is the flying helmet wasted energy similar to the wasted energy by human head and neck? In which position?

On the other side

http://www.shinkendo.com/kabuto.html




Ancient steel , work hardened, realistic thickness.

Skip the unsolvable problem of the possibility of doing that in battle and just look at how different both pieces of steel behave. They are both steel, both convex but a huge difference in every other aspect.

[bigdummy]

Regarding piercing mail with arrows, one guy did a test to evaluate the practice of wearing textile armor OVER the mail as we so often see in period art especially from the 13th and 14th Century, like here:



Here is the guys description of his test:

Chuck and I have tested our jacks against period arrows loosed from an 80 pound bow. We tried broadheads, swallowtail, needle bodkins, and regular bodkin points. Chucks jack is 25 layers of linen and mine is 15 layers with maille under it.

We used hay bails as a rest and loosed from 20 and 15 yards.

Only the bodkin points would go in the others bounced off the jacks. The bodkin point did not penatrate Chuck's jack and it tip barely came tough mine, maybe 1mm, and did no damage to the maille under it.

Images of the bodkins sticking in the jacks and the tiny holes it made on the outside:

I also loosed a few arrows on a 16g breastplate that is unfinished at a demo last year; it had no backing just siting on a little hill. The breast plate swayed a little when hit and got dings but a dead center hit shattered my arrow and bent the arrow head. This was at about 30 yards with an 80 pound bow.

Of course an 80 lb bow is weak by historical standards, but the use of the textile over the mail, which seems counter-intuitive to modern eyes, seems to have made a huge difference. Which is interesting.

BD

[bigdummy]

Oh yes, modern and soft sae 1010 steel, who knows how thick and the helmet flyes which what energy?Is the flying helmet wasted energy similar to the wasted energy by human head and neck? In which position?

On the other side

http://www.shinkendo.com/kabuto.html




Ancient steel , work hardened, realistic thickness.

Skip the unsolvable problem of the possibility of doing that in battle and just look at how different both pieces of steel behave. They are both steel, both convex but a huge difference in every other aspect.

Yeah I've seen that before, I'm not convinced, I think it's a gimmick. The idea of cutting helmets is a fetish with Japanese fencing people based on legends going way back of guys supposedly cutting through dozens of helmets, and as far as I recall, most of the modern tests done to emulate this failed, ending up with damaged or broken swords and intact helmets. Even this one didn't cut all the way through the helmet the way the test is supposed to work (and as we see depicted in the Maciejowski bible). I don't remember all the other details but I do remember this test was fishy. But obviously armor vs. weapons arguments can go on into infinity. It's enough for this thread that you believe one thing, and I believe another, and we can present our evidence. No way we can settle it.

BD

[leonardo daneluz]

I would like to see the same test against mail alone, if the arrow point bent I would think it was totally useless for the test. An arrow point is something easily hardenable while mail and breastplates not. The case of hard bodkin point against soft mail would make a difference.


Anyway I forgot to tell that the M1s I used to punish were surplus of the army used to test different grades of ammo (7,62, 5,56). The pattern on soft steel of a piercing shot is one of deformation in the edges like the bullet marks in breastplates, just that modern bullets pierce thicker plates.

But the patterns on the m1, which were obviously work hardened manganese steel, were just like this japanese helmet: cut, ripped. The steel was hard and didn´t yield by deformation, it got cut. By a greater force, for sure, but got cut. Modern M1 helmets were obviously made with the same stress on mind that this japanese helmet and unlike the repro in the video you posted. To glance off blows with a minimun thickness.

[leonardo daneluz]

Oh yes, modern and soft sae 1010 steel, who knows how thick and the helmet flyes which what energy?Is the flying helmet wasted energy similar to the wasted energy by human head and neck? In which position?

On the other side

http://www.shinkendo.com/kabuto.html




Ancient steel , work hardened, realistic thickness.

Skip the unsolvable problem of the possibility of doing that in battle and just look at how different both pieces of steel behave. They are both steel, both convex but a huge difference in every other aspect.

Yeah I've seen that before, I'm not convinced, I think it's a gimmick. The idea of cutting helmets is a fetish with Japanese fencing people based on legends going way back of guys supposedly cutting through dozens of helmets, and as far as I recall, most of the modern tests done to emulate this failed, ending up with damaged or broken swords and intact helmets. Even this one didn't cut all the way through the helmet the way the test is supposed to work (and as we see depicted in the Maciejowski bible). I don't remember all the other details but I do remember this test was fishy. But obviously armor vs. weapons arguments can go on into infinity. It's enough for this thread that you believe one thing, and I believe another, and we can present our evidence. No way we can settle it.

BD

I have pictures of similar test in Japan, and they have smaller cuts but got too
My point is how the steel behaves, not if a head can be cut with one of this helmets protecting it.
It´s obvious that the Maciejowski exagerates, but the pattern of behavior may be just right.
Work hardened breaks that way, as in that picture, as in the maciejowski bible, if a mail can be cut, can be cut with a wide, thin blade with a hard edge, like the 13 chopper because.
Soft untreated steel behaves as in the video. We can settle this, I can work harden a piece of steel and show you. May be tomorrow I´ll have the time.

[bigdummy]

So you are telling me that you spent a bunch of time trying to hack up a US army helmet with a Samurai sword?

BD

[bigdummy]

If you can temper a piece of medium steel that would be more interesting. But any testing of this sort is cool in my book. Even with Kattanas

BD

[admin]

Taken from another poster on your crossbow thread on MyArmoury:

Of the 22 pieces of fourteenth century ‘German’ armour (they are northern european pieces of armour, Williams couldn't be positive exactly where they were from) tested by Williams only half are made of steel, and only a few of them were tempered in any way. KATBF 331-332

It would be good if someone could actually write some kind of summary and stick it online, because different people writing about that book seem to emphasise different things to suit their argument. I guess that is always the problem with a large book and a bunch of statistics.

[admin]

Regarding your assertions about medieval v modern steel, BD, I like Owen Bush's response from MyArmoury:

http://www.myarmoury.com/talk/viewtopic ... c&start=80

I must jump in here in defence of modern steels . the idea that old steel is better for making swords or crossbows of any kind is simply not true.
and I may hasten to add that I am someone who is much enamoured by ancient steel and spends a lot of time making the stuff from ore and carburised wrought iron in order to re visit these old steels. They are beautiful materials and you can make good weapons with them but.....
The reality is that modern steels are in every way better and if you replace "washing machine" and "I beam" with "jet engine components" and" racing car suspension" you will see modern steels performing in ways simple wrought steel will never manage ,no matter how they were treated.
The same goes for heat treatment , in the modern world it is both repeatable and precise.

[bigdummy]

Taken from another poster on your crossbow thread on MyArmoury:

Of the 22 pieces of fourteenth century ‘German’ armour (they are northern european pieces of armour, Williams couldn't be positive exactly where they were from) tested by Williams only half are made of steel, and only a few of them were tempered in any way. KATBF 331-332

It would be good if someone could actually write some kind of summary and stick it online, because different people writing about that book seem to emphasise different things to suit their argument. I guess that is always the problem with a large book and a bunch of statistics.

Here is your summary: In the 14th Century, this is true. At that time only Milan and Brescia were consistently making steel armor. By the 15th Century this practice had spread to southern Germany, and by the second half of the 15th Century both in Italy and Germany tempered steel was the norm. By the 16th Century the Italians stopped tempering their armor due to more of an emphasis on gilding (i.e. with gold). The Germans in Ausgburg and some other towns somehow figured out how to do both, and continued making tempered steel armor. By the latter half of the 16th Century royal armouries in Austria had recruited the best urban craftsmen from Ausgburg and established their own high standard for tempered steel armor at Innsbruck. Henry VIII also apparently established a similar high quality Royal armory at Greenwich, recruiting armorers from Landshut, Bavaria. According to Williams, both of these centers were producing tempered steel armor with a hardness of 500 VPH or more well through the end of the 16th Century.

Armor production in the rest of Europe in the 15th and 16th Century remained at 14th Century levels. But the industry was dominated by the regions of Lombardy and Swabia in the 15th C, and Swabia and Austria in the 16th, if you wanted good armor that is where you got it. The other critical factor is the income of the people who fight.

For example in the Baltic in the 15th Century, as well as Poland and Bohemia, the militias of the richer towns and almost all the mercenaries and the knights were buying and using Milanese or Swabian harness. They list the prices for these seperately from armor from other regions. There was also a local arms industry based in Krakow in Poland which produced middle and munitiions grade armor (most of which was either iron or low-carbon steel).

By the 17th Century, as Williams points out and for which I also have a lot of other data to corroborate, the pay of urban militia, mercenaries, and even knigths had declined dramatically, to the point that only Princes could afford the good armor, and regular soldiers hated wearing their very heavy iron armor so much they had to be paid extra to march in it. The Polish Hussar armor Williams tested was low carbon steel with a lot of slag.

BD

[bigdummy]

I would like to see the same test against mail alone, if the arrow point bent I would think it was totally useless for the test. An arrow point is something easily hardenable while mail and breastplates not. The case of hard bodkin point against soft mail would make a difference.

That was the point of the test, IIRC the arrows went through the mail alone fairly easily. With the textile on top the mail was undamaged.

BD

[bigdummy]

Taken from another poster on your crossbow thread on MyArmoury:

I take it as a HUGE PERSONAL COMPLIMENT that you are reading my crossbow thread. I hope we get some more useful testing done as a result of it.

BD

[admin]

I would like to see the same test against mail alone, if the arrow point bent I would think it was totally useless for the test. An arrow point is something easily hardenable while mail and breastplates not. The case of hard bodkin point against soft mail would make a difference.

That was the point of the test, IIRC the arrows went through the mail alone fairly easily. With the textile on top the mail was undamaged.

Just to clarify, but the diameter of most of the pointy end of a 13thC bodkin is less than the diameter of most 13thC mail rings. So the bodkin will pass cleanly through mail for roughly the first inch and only then will need to burst that one link to allow the rest of the head and shaft to pass through. Asian mail often used much smaller rings, but it was butted rather than riveted and therefore work in quite a different way.
So when you talk about shooting a long bodkin at mail you are really talking about shooting it at one rivetted ring and some padding. The success or failure of the arrow depends principally on those two things - the individual integrity of that one ring and the nature of the padding underneath. Given that a lot of late-medieval European mail consisted of alternate riveted and solid rings - therefore the result of the arrow strike would vary quite a lot, depending on whether the arrow hit a riveted or solid ring.
Again, there are a lot of variables to talk in anything but wide generalities.

[admin]

I take it as a HUGE PERSONAL COMPLIMENT that you are reading my crossbow thread.

BD, everyone I communicate with should take it as a huge personal compliment.

[bigdummy]

I figured you would say that hahaha

[admin]

Here is your summary: In the 14th Century, this is true. At that time only Milan and Brescia were consistently making steel armor. By the 15th Century this practice had spread to southern Germany, and by the second half of the 15th Century both in Italy and Germany tempered steel was the norm.

See that sort of glosses over the period I find most interesting. I'm broadly most interested in c.1360-1430, so what we're seeing is that during that period most armour through most of Europe was iron or low-carbon steel, un-heat treated. And perhaps there was an increase in the amount of heat treated carbon steel armour coming out of areas of Italy and Germany the later in that period you go. More or less.
But as I said earlier, it is very difficult to judge, because:
1) The test sample is very limited in quantity, especially for the earlier stuff.
2) The test sample is probably biased, because most of what survives is Italian and German, and usually high status stuff (that's why it has survived...).

[bigdummy]

I agree with the first part, not enough of the 14th Century stuff survived, but I don't think the second is true, a lot of "ordinary" armor has survived in town and castle armories from the 15th and 16th Centuries and later, you've been to the Hotel Des Invalides in Paris I'm sure, and probably to several of those small museums in Switzerland and Germany, you know what I mean. What Allen Williams tested is a little more in the fancy high-end range, but he also tested a lot of ordinary soldiers armor, and a lot of that, particularly the German stuff, was of high quality.


What little expertise I have though is mostly on the 15th Century, I don't know that much about the 14th. My overall understanding is that armor tended to remain as good as it needed to be; in the 14th Century firearms were fairly rare on the open battlefield and not that powerful for the most part, so iron relatively thin armor was perfectly suitible-It gave good protection against all the weapons they faced. By the later 14th steel was becomming necessary both due to increasingly powerful firearms and crossbows, longbows and recurves, all of which seem to have been getting stronger and stronger, as welll as the increasing ubiquity of specialized armor piercing hand weapons like flanged maces, war-hammers and halberds.

I'll have to go back and look at this part in Williams but I know the Italian centers were making steel armor pretty early and Milan in particular was the "go to" place to buy armor from throughout Europe at that time, much as today it's the "go to place" for purses or shoes. How widely distributed those Gucci or Prada purses are depends a lot on the local economy and income distribution, which varied widely throughout Europe. But citizens of Milan could certainly afford it. So could citizens of Krakow, Danzig, Prague, Wroclaw, and several other towns I've studied.

BD

[leonardo daneluz]

It took me all the night but finally made some samples and put them together with the information necessary to explain, more or less, why I choose these samples.
May be it´s clear, most possible not.
I did it mostly for people who knows little or nothing about steel and it contains some generalizations and creepy graphics.


The purpose of this experiment is related to the following question:
Does this picture represent reality?



This question possibly should not be answered by a simple yes or not. But , since the author of these famous illuminations is universally considered as somebody who was familiar with military life of the XIII century (certainly more familiar than we are), the question is taken seriously by most scholars.
Sadly in the majority of cases the answers can be put into one of two groups: those who take the obvious authority of the painter literally, as in this example from a well know HEMA association:

“The clear effect of even single-hand sword blows against steel helmets. In the center a sword splits the top of a helm from behind. On the right two swords hack into the sides of helmets while a spiked mace delivers a crushing blow. Notice also the portions of each sword (their center-of percussion) that does most of the striking is invariably the last third to second-half of blade.”

And those who argue the complete opposite, often including experiments like this one:

http://www.youtube.com/watch?v=-h0e0NSwYNg

But may be the case is not that simple, nor as easily probed.
So I want to explore this problem even when I am completely sure an impossible one. However its implications may be useful in understanding how this kind of armour was made and what was considered desirable in their design.

First- Reading art

When we see an action movie today most of the actions portrayed are false.
Depending on the film they range to the little exaggerated to the grossly unrealistic. But even in the latter case some realistic aspects are preserved. A bullet could shown piercing more or less things than an actual bullet of that caliber would but it does not explode, for example, it does not changes its direction in the middle of the air, it does not makes a green flame of fire when leaving the mouth of the gun. The same mechanism is used in art of all times: to adjust the nut more than usual, but not to the point it doesn´t fasten anymore.
So, the question we should do may be is more “how much of this picture is real? To which point?”

Second- If it is possible …It would be that way?

One method to start this analysis is to discard what is blatantly impossible. If we can probe that , not matter the force required, a helmet cannot be cut as portrayed we could conclude that the artist imagined that kind of damage.
That should be the case if a helmet does not get cut but collapses with plastic deformation into the head, for example. In that case we could think that the artist never actually saw neither case: not a helmet being cut, not a helmet being hit by such a powerful blow. (this conclusion is debatable since the artist could want to show an extremely sharp blade which can cut into a helmet instead of just denting it, but we are not here working for absolute answers, just posible ones).

Third- The actors.

Here we have a long series of mensurable variables and not so mensurable ones.
In hitting a person wearing a helmet and cutting that helmet we must have the following:
1- A sword edge which will take the hit and cut without crumbling before.
2- A sword body, which would resist the effort and provide enough kinetic energy
3- A person wielding the sword, exerting enough force to put the sword in the required movement. (There should be taken into consideration the relative speed between agent and subject)
4- A helmet able to be cut
5- A head with a mail coif into that helmet not providing enough support to the helmet to avoid the cut
6- A body below the head not absorbing enough energy to avoid the cut.
In this experiment I take for granted 1 and 2. I´ll discuss the reasons later.
3, 5 and 6 are exclude to focus in testing the possibility that, given enough force, a helmet can effectively show a failure pattern similar to that portrayed in the Maciejowski bible.


Fourth Defining a goal.

So we have to find if the helmet can be cut.

A helmet like this one is a piece of an unknown thickness of an unknown iron alloy, with an unknown macrostructure (lamination, inclusions, lack of uniformity in alloying elements) and unknown microstructure (heat treatment, cold working, composition , etc.

There is, of course, the related archaeological record. Sadly for this time frame (ad 1200-1300) is pretty scarce. We don´t really have a lot of this helmets nor were them studied to such extent to have a clear idea how they were made, with which material, which hardening treatment received, if any. And the few analysis show very varying figures.

But we do have hints:
1- We can assume that the helmet isn´t thicker than 2mm nor thinner than 0,5mm
2- The iron alloys of the time seem to range from nearly no carbon content to rarely more than 0,8%.
3- Iron alloys of the time have more phosphorous and sulphur than today.
4- Anisotropies were widespread.
5- Heat treatment, deliberated or not, could be anything.
6- They surely knew cold working techniques.

Our goal will be to probe if any of the possible combinations of the above data can produce the kind of failure shown in the imagen. Which is similar to this


This helmet was subjected to a traditional test. It is an antique and the pattern of the cut shows a remarkable similarity with the one shown in our picture. Since the authenticity of this test has been contested (even when similar test have been performed in a Yoshihara´s blade in front of a crowd) we´ll try to replicate this pattern.

Fifth: The theory
To understand in which circunstances this pattern of failure occurs we should know how steel behaves.
To our question the stress/strain graphic is what shows the forces involved.
Every deformation implies a stress applied. If we vary the composition of the steel the stress to obtain the same deformation varies to.
At first we´ll show just the behaviour into the elastic limit, id est the range of efforts which flex the steel and still it recovers its initial form when the force stops.






Beyond the E amount of deformation the steel bends and remains bent. We can see that the higher the carbon content, the higher the force needed to reach the same deformation. So the higher the carbon content the more difficult to damage permanently the helmet.
As a curiosity I have included the behaviour of pattern welded steel. The elastic limit of patter welded steel can be everywhere since it depends a lot of the position and quality of the welds but before reaching its elastic limit it needs an even higher force to be deformed. This curious characteristic of pattern welded steel has been noted by knifemakers and by the Japanese while researching to find a suitable military sword in the 30`s.
But what happens once we go beyond the elastic limit?
It depends a lot of the heat treatment


Unhardened steel yields, if the stress persists it starts to deform permanently but at higher and higher forces. Beyond certain point it starts to yield at lower and lower forces and breaks.
That means that the stronger condition of unhardened steel is that where it was deformed to such extent that it doesn´t add any additional strength with more deformation.
But (and it is a big “but”) If we left our work hardened steel just in that point any deformation would find less and less strength in the piece, leading to its fracture. So the key for work hardening is a balance between the place where it gained some strength but still is able to oppose resistance to future deformations.
This point is hard to guess, to say the least.
So we find old tools, arms and armour with clear cracks of overworking.
In the case of heat treated steel the elastic limit reaches a much higher point but if it is left too hard it will break with little or not deformation. The higher the tempering temperature the bigger deformation it will allow.
If the temperature in the tempering is high enough the steel will behave as an untreated piece. (stricto sensu= a subcritic annealing)


Sixth The samples

What does it all mean?
That we have such different behaviour in heat treated and untreated steel that we must to make samples for both cases.
And that the same is the case for carbon content.
But the most evident fact is that we don´t have period materials with different carbon content to start. So we must constantly keep in mind in which sense the material we are going to use is different from the ancient one.

The first is the great care we, as a civilization, take to not let impurities make our steel more fragile.
Phosphorous is major problem, it builds hardness while cold worked. Since many things we build are cold worked this is a major problem. Because a cold worked steel is harder but at the same time more brittle.
We do use steels specifically designed to be hardened by cold working, most commonly to make the skin of our cars. But sadly I didn´t have any in my workshop at the moment.
What I did have was SAE 1010 and SAE 1070 which are steels with very low carbon and high carbon respectively.
So I prepared five samples. I used SAE 1010 and SAE 1070.


P1- SAE 1010 “untreated” (annealed)
P2 – SAE 1070 “untreated” (annealed)
P3- SAE 1010 work hardened
P4. SAE 1070 work hardened
P5 SAE 1070 hardened and tempered. (heat treated)

The steel was 2mm thick in origin but reduced at 1,5 mm by work hardening and then to 1mm by grinding.
In the case of the probes not to be word hardened they were thinned to 1mm just by grinding.
The following picture shows the sample made out of SAE 1010 a with a side work hardened. A cut was made on either side. The unhardened one was bent back and forth ten times without fracture. The other one resisted just two folds and broke, but needed more force.


The same was made with a 1070 sample


Beside the fact that work hardening this steel took a much higher toll in my chronic epicondylitis this time the unhardened side took two folds without breaking but just a 90 degrees bend to fracture on the hardened side.
Two more samples were made with annealed steel and a fifth went to the oven to be heat treated.


Seventh- Punishing things

My first move was fixing the sample this way, because I was very confident in the degree of hardness the worked samples reached.


And the blade to be used was a Oakeshott XIIIb Alexandria pattern following the dimensions given by Clive Thomas in an old Park Lane catalog.

The blade is just a 5 % shorter and where mr Thomas measured 1,5mm I left something like 2 mm just because I wasn´t brave enough.
But I didn´t finished the hilt yet so I improvised a handle with leather and tape. The final blade obviously could hit as strong as a blade with a pommel but it wasn´t the point to reach a realistic force, just a realistic pattern of damage made by a realistic edge. The edge is constructed just like it seems to be in the detailed available pictures of the three or four extant specimens of this kind of blades.


My bad at the fixing solution, the samples collapsed easily and needed to be fixed into other ways







At this point it was evident that the samples didn´t take enough hardening. The 1070 sample showed just a little crumbling which can be seen just below the number “7” of “1070”.

Unfolding both samples something appeared:


The 1010 showed that no cut could yield the steel. Only one seems deep enough to show the beginning of a fracture, just in the middle.

But unfolding the 1070 sample was a different history:



Several points had collapsed. It´s important to stress that no complete cut was achieved, just few crumbled zones below the cut. The cut just stretched the steel to the point it couldn´t take no more. This was exactly what I was expecting but in a more extended form.

At this moment it was evident that I under worked the steel, or the steel wasn´t cold hardenable enough or simply 1mm was too much. Which would imply that the cutting of a helmet was impossible to probe without knowing exactly how much more brittle ancient work hardened steel was.

So I decided to give it another try and reworked half of both samples to give them a new series of hits.
This is what I obtained:


This time they kept their shape more and some places which seemed undamaged in the 1070 sample showed a complete cut, so they were very near to be complete since the start.




If the work hardened samples were soft enough to be completely collapsed before being cut it was evident that their annealed version would collapse easily. So I put a hammer under them.
Then I missed a cut and hit the hammer which got cut along with a good nick in the vice. Luckily no damage on the edge.





Something was left yet. The sample hardened and tempered BD asked.



Quenched and tempered at 210 C. But something didn´t went as in the book. Possibly my SAE 1070 isn´t SAE 1070 after all. Because at 210C it should be more resilient. The f*cking thing exploded in sharp pieces.



Having a feeling that tempered steel was too much to risk in that blade I used a saber blade I made some time ago.
It was late by this time but I made a mistake so I tried to fix it by making another 1070 sample from the beginning
Tempered this time at 260 C which should be enough to present some plastic deformation. And I hit it really hard.


Too much for the poor blade and again the sample was too hard. But this time crumbled in the place hit, so it broke not by the deformation on the whole piece alone, but also in the zone actually hit by the blade. Which make me think that samples tempered at higher temperatures would continue following more and more this pattern of less damage in the whole piece and more along the hit itself.
That´s something left to do: intermediate heat treatments. Incomplete hardening, tempering at higher temperatures, etc.



But what happened exactly?
I think that this happened:



conclusions:


The two heat treated samples are in the left, the other ones in the right. We need samples in the middle but it´s predictable that they will have their fracture points well beyond human arm possibilities ( you can see the hypotetical fracture limits over the “strongest blows” line).
Another interesting conclusion is that 1070 annealed seemed to be stronger that 1010 work hardened. So there is a possibility that work hardened SAE 1010 is completely useless to replicate nothing.
Only SAE 1070 work hardened showed a fracture point between the reach of my blows and a lot of stiffness into its elastic range compared to the other three.
To make a great end of this not so serious experiment I did what everybody did: Smash a SAE 1010 helmet to probe nothing conclusively.


But it seems to me that making helmets with soft modern iron would result in either too poor performers or too heavy ones if we try to compensate with greater thickness. Modern mild steel and even modern high carbon steel will deform in a more historic probable way (id est the way shown in the M. bible or in the kabutowari tests) , even requiring much much higher efforts.

[leonardo daneluz]

Well, with some sleep, may be I can clarify my conclusions:

1- There is no reason to think the helmet can properly be "cut" in the sense a tatami math would be cut (at least thickness is really low (as it seems to be the case in the japanese helmet of the picture)
2- But it is possible that the helmet crumbles below the edge of the sword, given a very similar effect but recognizagle by a minutely jagged scar. This is due to the steel in the helmet surpassing its ultimate yielding point
3- The failure can be achieved if that ultimate yielding point is already near into the structure of the steel, which can occur in several situations: a- high phosphorous content, b- extensive work hardening, c- poor heat treating. Or a combination of those factor. All of them usually present in the archaelogical record.
4- If the helmet inquestion has zones with much more than 1mm of thickness its destruction would depend on an extremely weaker material, which would be a less possible situation
5- Completely untreated iron (or steel with very low carbon) would tend to deform but not be damaged in the cut region, reacting as hit by a percusive weapon.
6- Most evidence shows that this kind of experiments would be conducted with metalurgical substitutes which break retaining the general shape of the piece and not those where the piece collapses with plastic deformation. This imply: high or medium carbon steel, work hardened or heat treated or, obviously, steels with a similar composition made for the occasion.
7- Properly heat treated (hardened + tempered) modern steel in thickness of excess of 1mm has an ultimate yielding point well beyond human arm possibilites. It is very possible that, no matter how badly refined was ancient hardenable steel , if more or less properly heat treated, cutting it or damaging it would be nearly impossible.

[bigdummy]

Leonardo, this is absolutely f*cking brilliant. I'm really sorry your saber broke. I wonder if we could use a cheap machete for a test like this? Your sword appears to be really formidable!

This is really good work though, you put me to shame, it's one thing to talk, doing an experiment like this is really cool. Thanks for going through all the effort.



I will go through Alan Williams recorded thicknesses of helmets, I think most are more than 1mm, certainly the 16th C is, but he doesn't get that much into anything as far back as the 13th Century. I'm sure if you go back far enough ... early Medieval, Viking Age, Migration era, Roman era, Bronze Age... you will find some helmets that are 1mm or less. Also Bronze and Brass and other copper alloy helmets, which I'm not sure if they would perform better or worse. I'd guess maybe more denting less cutting? What do you think Leonardo?




I also thought of another thing in favor of the "you could cut through a helmet" argument, the so called "Spangenhelm" type helmets which were made from multiple pieces of iron welded or riveted together. It seems much more plausible to me that rivets could break or a helmet could fail on a weld than a solid piece simply split. In fact I think it was assumed that this is why such helmets were abandoned in favor of helmets made of a single dished piece of iron or steel. But you still see the ones made from several pieces all the way up into the 16th Century in some places, notably in the Baltic which is where the Polish bible in question was made.

The Estonians, Lithuanians, Letts and so on were especially archaic in a lot of their armor design. SOmeone even posted here recently some "leather" vambraces were found in Estonia. These turned out to be iron bars with a leather cover. But sometimes helmets were made this way as well, just an iron frame with organic bits in between. Something else to consider.



Anyway just wanted to thank you for going through this effort Leonardo, I learned a bit about steel from reading your experiment. I hope you do more of this and share it with us.

BD