Making Shear Steel and a Small Seax

[Matthew Paul]

Not too long ago I did some playing with making blister steel and shear steel. I dont claim to be an expert at this and I know that there are many people out there who have much more experiance with this aspect of blade making. I also know that there are a lot of people out there who have not had the chance to do much experimenting with this sort of thing. So, I will share what I have learned so far, and if anyone would like to add to it, that would be great.

When carbon is added to wrought iron through carburization it becomes blister steel. It is called this because the carburization causes small blister type formations on the surface of the steel. Carbon is added to the steel through the use of charcoal in a mostly sealed container. I say mostly because I left a vent hole to vent any moisture that was held in the charcoal, so that I did not have a pipe bomb sitting in my forge.

I did a test run. I welded up a small container to house the wrought iron and charcoal powder. The iron was set in the center of this metal "crucible" and crushed charcoal was packed in around it. Then the container was welded shut. The container was brought up to heat in the forge and left to soak for 45 minutes. After this the "crucible" was left to cool and the container was cut open. I did a spark test to determine if any carbon hand been added to the iron to create steel, and if so, roughly how much.
 

This is a photo of the container in the forge coming up to heat:

This first photograph shows the spark patten of the wrought iron as I found it in a friends barn. Notice that it is a dull spark with no starburts. You will see the star bursts that I am talking about in the images following this one.
 

This photograph shows the spark pattern of the 1095 steel that I use to forge my knives. I use as an example of carbon content. 1095 contains .95% carbon. Notice how the sparks burst off into other sparks.
 

This photo shows the spark pattern of the carburized iron, which is now steel. Notice a similar spark pattern to the 1095. It appears as if there is more carbon on the surface metal than the 1095. This material started off as the wrought iron in the first photograph. It is from the exact same bar shown in that photo.
 

The "Starbursts" in the spark patterns show the carbon content of the metal. Less = less carbon. More star bursts equates to more carbon.

So, I heated it, quenched it, and hit it with a hammer. And it broke like a file... That's good news! However, the grain structure is very large, So I will have to see how much I can shrink that down. I'm not sure how fine it can become as this started out as wrought. But we will find out soon.
 

The "grain structure" appears to be very large at this point. I did not normalize before I quenched and broke the piece and I did not do a quench and break after I normalized it. I should have. Would anyone know if this large grain is due to the fact that this was/is wrought iron or simply from the extended heat exposture, or more likely -- both.

I think I did a good job for not really knowing all that much of what I was doing on this run at it besides my own experiances and the little that I read on the internet and saw on Rich Hale's youtube vidoe.

I forge welded the two halves togeather and hammered it into this little 3" bladed "Seax" so that I could test the steel.
 

As forged.


Cleaned up.


 

So here is the finished test product. I did not go crazy with the handle or etching as Im more worried about how this will work out. Just a little hickory off an old sledge handle. There is a small inclusion on the left side of the blade just above the cutting edge, tword the rear. I wouldent sell something like this but I wanted to do some testing. It has proven tpo be a non issue this far.



 

I wound up using it for several weeks, beating on it and it has held up well. No different than a 10xx steel, except for a little more frequent sharpening.


Since this has held up well,  I  rehandled it in elk antler that my grandfather shot while hunting at my uncles ranch in Idaho. I split some leather down with this blade, and put it togeather. Well, here are the results. I love it.
 

Thank you for having a look. Any additions or comments would be appreciated.

From what I have seen, Next time I would like to use some more charcoal and/or give it a longer cook to get some more carbon into it. I'll have to weight the charcoal and steel, and also use some thinner stock next time. The iron was 1/4" thick, and I think that I could get more carbon per volume of iron if it had a much thinner cross section. But, we will see.

[ThomasPowers]

Ric is the expert on this; if you want more information on the historical methods "Steelmaking before Bessemer, vol 1 Blister Steel" is a good place to start as for the process "The Cementation of Iron and Steel" has exhaustive details---you don't need to use charcoal---you can use diamonds

 

As for the grain growth; the traditional method for refining it was heavy forging and being careful not to soak the piece at high temps afterwards.  I don't know if normalization will work to refine wrought iron grain as it generally does not have the modern alloying that helps this out.

 

For my experiments I took a thin walled pipe and crimped the ends and tossed it in the gasser when I was working on other things.

 

I like your finished blade and think it would have been quite OK to sell it to a person interested in historical re-enactment.  I do not think the turks head adds to the second handle though---just something to trap crud while using the blade!

[Matthew Paul]

Thank you Thomas. I'll have to pick up that book when I get a few dollars to spend.

That's a  good idea of letting it soak while forging other things, save some gas.

And Thank you for the compliments on the blade. I'm not normally a fan of wraps or knots on knives but I decided to go with it on this one. It's sealed up with some CS glue but I could always remove it later on.

[Timothy Miller]

Very cool, thanks for sharing.

[ThomasPowers]

Carve the design into the antler!   You can usually ILL even pretty esoteric books through your local library for a trivial sum letting you figure out if you really want to spring for a copy of your own.  (for example look at the prices on things like "the celtic sword, radomir pleiner; or "The Knight and the Blast Furnace", Alan Williams)

 

the flat cut masonry nails make quick bone and antler carving chisels

[Loneforge]

Cool walk through, thanks! 

[Wayne]

I saw somewhere that they had been making blister steel at colonial Williamsburg - ironpacked into a metal box with charcoal and other carbon then putting it in the middle of a clamp when they fired a stack of bricks

Wayne

[ThomasPowers]

In England they tended to use large stone boxes and 1" sq rods packed into them kept at a dull red for up to a week---helps explain why steel was so much more costly that wrought iron!

 

(I first found out about "Steelmaking Before Bessemer" when I was assistant to Ric at a Quad-State demo on multiple ways of making steel---I ordered the book(s) as soon as I got home---still had my coat on!---and got the only used copy listed for America back then.)

[Rich Hale]

Thank you for crediting me for helping you through my u tube video.....If you would please post a link I would like to see it as I have not made one,,,,,,  :blink:

[Matthew Paul]

Thank you for crediting me for helping you through my u tube video.....If you would please post a link I would like to see it as I have not made one,,,,,,  :blink:

Man do I need to get some proper rest.....  Ric Furrer. :D

[ThomasPowers]

Just picked up a book on the painter Bruegel and saw a knife in one of his pictures that was a really good match for yours when it had a wood handle.

 

"Classics of the World's Great Art: The Complete Paintings of Bruegel" copyright 1967 Standard book number: 8109-5502-4

 

The peasants' wedding.  The book has a closeup that shows the knife well on the main table under the elbow of a fellow handing bows of something around.

[Timothy Miller]

Just picked up a book on the painter Bruegel and saw a knife in one of his pictures that was a really good match for yours when it had a wood handle.

 

"Classics of the World's Great Art: The Complete Paintings of Bruegel" copyright 1967 Standard book number: 8109-5502-4

 

The peasants' wedding.  The book has a closeup that shows the knife well on the main table under the elbow of a fellow handing bows of something around

They are eating porridge or at least that's what they told us in art history class.