King Tut's dagger--a blade of meteroritic iron

[A. G. Maisey]

Please accept my apologies Timo.

I was wrong.

My comments were based upon what I have seen made from meteoritic material by modern knifemakers, I wasn't even thinking of use in ancient times, I do know that it was used, but have not studied its use in ancient times.

Still, based upon my own experience in working with meteoritic material, which is not inconsiderable, I do find it very difficult to believe it can successfully cold forged --- but I suppose it does depend upon the meteorite.

Just a thought Timo:- are we talking about cold forging, or cold work?

I've just a done quick scan of the material you have supplied links to, and although I have picked up "cold work", I have not yet seen "cold forge". Cold forging means that you work the material at a black heat, in other words you bring it to a red heat, let the material lose its heat until it is black, then you work it with a hammer until it is cold. This technique is sometimes used to pack the edge of a blade.

"Cold work" means bringing the material to the shape required by cutting or grinding.

[David]

Originally Posted by A. G. Maisey

I've just a done quick scan of the material you have supplied links to, and although I have picked up "cold work", I have not yet seen "cold forge". Cold forging means that you work the material at a black heat, in other words you bring it to a red heat, let the material lose its heat until it is black, then you work it with a hammer until it is cold. This technique is sometimes used to pack the edge of a blade.

"Cold work" means bringing the material to the shape required by cutting or grinding.

At the bottom of the page in the summary on Timo's second link the term they use is not "cold work", but "cold hammering".
"...the examples make it clear that i) iron meteorites may be forged at red heat to nails, horseshoes, hinges, swords, crowbars ploughshares, etc. to maximize weighs of a few kilograms ii) iron meteorites may be cold hammered to arrowheads, knives and other small objects with a maximum weight of a few tens of grams iii) massive iron meteorites have served as anvils for generations. Many of these have survived to our day and may be studied in various museums iv) iron meteorites do corrode in the terrestrial envirionment at the same rate as wrought iron..."
The body of the text around figure 10 on this last link talks repeatedly about the work being shaped by "cold hammering". I don't know if this is the same as "cold forging", but it doesn't sound like simple stock removal to me.

[Roland_M]

Originally Posted by David

I don't know if this is the same as "cold forging", but it doesn't sound like simple stock removal to me.

I'm sure it is not the same. Cold hammering means imho (!) the improving of the cutting edge of a finished bronze sword to increase the cutting performance. This work will be done either without or just a tiny bit of deformation.

It is absolutely impossible to forge cold iron. One can hammering the steel until it is hot, but one cannot forge steel at room temperature! Otherwise one would destroy the crystalline structure of the steel or iron.

One can cut a blade like structure from a meteroid, grinding and cold hammering the edge a little bit. But this have nothing to do with forging!

[David]

Originally Posted by Roland_M

It is absolutely impossible to forge cold iron. One can hammering the steel until it is hot, but one cannot forge steel at room temperature! Otherwise one would destroy the crystalline structure of the steel or iron.

I don't know enough to enter into a debate over this, but keep in ming that we are talking about iron, not steel here.

[Nick Wardigo]

When I first read about Tut's dagger, I was reminded of an old academic paper that I purchased at the Smithsonian Institute maybe 20 years ago: "Two Early Chinese Bronze Weapons with Meteoric Iron Blades"; Gettens, Clarke, and Chase; 1971. I have it in front of me; it still has the 99-cent price tag from when I discovered it in the Smithsonian's gift shop's discount bin. Not exactly a best-seller.

After a cursory search, I see it's available online:

https://www.asia.si.edu/research/dow...%20Weapons.pdf

The paper is very technical in places, but the upshot is that the Freer Gallery of the Smithsonian owns two weapons, a "broad axe" and a "dagger axe", both dating from circa 1000 BCE and incorporating both bronze and meteoric iron in their construction.

I realize Tut predates these weapons by about four centuries, but I find it interesting that two ancient cultures in different parts of the world, understood the importance of meteoric iron and learned how to incorporate it into their current technology.

[Timo Nieminen]

Originally Posted by Roland_M

It is absolutely impossible to forge cold iron. One can hammering the steel until it is hot, but one cannot forge steel at room temperature! Otherwise one would destroy the crystalline structure of the steel or iron.

Put the iron on an anvil, and hit it with a hammer. If it is distorted past the plastic limit, you've changed its shape, and you can forge it. You have to hit it harder than if hot-forging, but it can be done.

I've done it; other people have done it. It is absolutely possible. A simple example: https://www.youtube.com/watch?v=N66-n3FJ5Vw

Originally Posted by Roland_M

Otherwise one would destroy the crystalline structure of the steel or iron.

It isn't a single crystal; it's made up of many, hopefully very small, crystals. This kind of polycrystalline structure can be distorted, so it isn't an impossible problem. (This distortion of the crystal structure is how we can distinguish cold-forged objects from hot-forged objects.)

It does lead to work-hardening, which (if you don't stop and anneal the piece) will limit how much you can work it, especially how thin you can make it.

These two points (needs more force to deform, work-hardening) plus not being able to weld as part of the process are why, for general purpose forging, you hot-forge. But hot-forging generally being better doesn't mean that cold-forging is impossible. If you lack fuel, it might be the only option. If you can start with stock that doesn't need to be worked much to reach its final shape, then it can be a good option even today (forming steel cold in a metal press, panel beating, cold-peening rivets and sword tangs are examples of this).

I haven't tried cold-forging with annealing, so can't comment on effect from experience. In principle, it should work.

Cold-forging, with intermediate annealing, is the natural way that a redsmith/coppersmith who knows nothing of iron will try to forge iron, since it's the way that copper and copper alloys are forged.

[Timo Nieminen]

Originally Posted by A. G. Maisey

Still, based upon my own experience in working with meteoritic material, which is not inconsiderable, I do find it very difficult to believe it can successfully cold forged --- but I suppose it does depend upon the meteorite.

For it to work, the meteorite needs the right range of chemical composition, and not too many defects/inclusions (which means corrosion can be a problem). Plenty of meteorites that will shatter if you try to hot-forge them, too.

Similar problems with cold-forging telluric iron. There are huge pieces of telluric iron in Greenland that weren't used for forging (useful as anvils, though), since high carbon content (they're basically cast iron in composition) makes the iron impossible to work (at least cold).

Originally Posted by A. G. Maisey

Just a thought Timo:- are we talking about cold forging, or cold work?

I've just a done quick scan of the material you have supplied links to, and although I have picked up "cold work", I have not yet seen "cold forge". Cold forging means that you work the material at a black heat, in other words you bring it to a red heat, let the material lose its heat until it is black, then you work it with a hammer until it is cold. This technique is sometimes used to pack the edge of a blade.

Buchwald uses "forge" to mean hot-forging, "cold-work" to include cold-forging, and "cold hammering" to mean cold-forging.

The Greenland iron is worked at room temperature, without being heated. In the modern experiments reported by Buchwald and Mosdal (pg 18), the temperature never exceeded 50C (the piece being heated by the working). Room temperature, anvil and hammer.

Especially for small pieces of meteorite (and telluric iron), the forging was often a simple flattening to as thin a piece as feasible, with the cutting edge then sharpened by grinding. The telluric iron blades were usually still very small after flattening, and would be mounted along a support to produce a saw-like knife.