Hearth Steel Swords WIP

[Aiden CC]

I’ve wanted to make a full length sword from home made steel for some time now, I started the research for proportions last fall. I had a bunch of new material and decided to go with early medieval instead of Japanese since I have a blade in that style to work on already. 
 

This was an experimental melt with about twice the initial charge. It consolidated well and sped up the process. I may increase my charge size from 1000 g to 1500-2000 g. This piece was folded 6 times and used as the “jacket” of the sword. 
 

Here’s the starting billet. The weight was ~3.5 lbs. It has a wrought iron core, 6 fold hearth steel for the flats, and 10 fold hearth steel edges. 
 

Rather that try and do a wrap, I opted for a fish mouth weld. From what I can tell, it went pretty well. 
 

I’m glad I worked up to this with progressively longer blades. The learning curve would have been even steeper! This blade is 27.5” which is right at the bottom of the normal range from what I can tell. I was shooting for 2.5” longer, but I guess my material estimate was a little lean. It’s possible I should have forged in a bit more distal and profile taper too. I welded on a wrought iron tang to save as much steel as possible. 
 

Also shown are the edge and spin bar for a “Sax 4”. I haven’t gotten around to translating the typology, but the blade seems like a step halfway between the  Nordic long knives and single edged swords. The example I plan to make has a sax blade (wedge section all the way to the spine, 65 cm blade) and a grip almost like a sword (upper and lower guard with a sax-ish “wing nut” rivet block). I figured it would be a good way to practice with a slightly shorter blade and much simpler geometry but basically the same grip components. 
 

How does the profile look? I still need to kick the tang a bit off to one side to establish the long and short edges, but I wanted to do that very intentionally referencing some originals. What might be a good weight for a blade this length? I was thinking maybe around 600-800 g, but it’s tricky to know from originals since most still have the (heavy) fittings still attached. I plan to grind a relatively shallow fuller, but I’ll see what the blade weighs in at as-forged. 

[Alan Longmire]

You know I'm gonna pin this one...  

 

The profile looks good.  I'm not sure what you mean by long and short edges, though?  Might want to do another hour or two of forging on the bevels to get the little wobbles out, but I get tired and skip that step myself so I can't say you have to do it... 

 

I think the weight sounds about right, too.  Closer to the 600g for an Anglo-Saxon sword, closer to the 800g for a Norwegian one in my very limited experience.

[Aiden CC]

Thanks @Alan Longmire for the advice and for the pin! I did a bit more straightening, but I may start some grinding and look at measurements of originals to see if it’s good enough or needs more fixing. Current weight is 1070 g, we’ll see how it goes with grinding. I’m shooting for a more Norwegian style, though the blade is right on the short end of the range.

 

The long/short edge might be more of a longsword thing, but it refers to the edge that is usually forward and the other that is usually back. There are some interesting arguments from wear patterns and general ergonomics that these swords were usually held in the same way when used despite being mostly symmetrical. Often, the upper and lower guards line up, but the tang is off-center in the upper guard. Both of these swords in the Danish National Museum show it a bit, the top one more:

 

[Joshua States]

How cool is this? I keep meaning to get back to the three big blades I have collecting dust in the shop, but things keep getting in the way. At least this way I can watch someone else do it!

[Alan Longmire]

11 hours ago, Aiden CC said:

refers to the edge that is usually forward and the other that is usually back.

 

Ah, gotcha.  Yes, despite being symmetrical they were held with one edge forward.  Thanks for clarifying!

[Jerrod Miller]

In the HEMA community there is a bit of theorizing about the long/short (aka front/back, true/false, etc.).  One common thought is that the long/short descriptor comes from single edge blades (e.g. messers) that had a sharpened clip.  So one litterally had a long edge on the front (or true) side and a short edge on the back (false) side.  

[Aiden CC]

Thanks for the info Jerrod, the term had never quite made sense to me. 
 

I forged out the single edged sword, but the edge bar cracked 1/3 of the way to the tip, so that one will become smaller knives:

Here it is while things were still going well 

 

I decided to do a bit of fuller grinding just to inspect the steel and get ahead of any issues. One side is better than the other, but I think they should both clean up alright. The weight is down to 897 g after profiling and rouging the fuller, but there is still quite a bit of grinding left so it may end up a little lean. The blade is also short for this style, but that might be good given it’s my first real sword. 

[Aiden CC]

I got the rough grind in and it’s pretty much ready to heat treat! I would tidy it up a bit, but I didn’t want to grind any more off before the quench. The weight is down to 710 g, I think this sword is gonna be quite light!
 

The lines between the bevels and fullers could be a bit straighter, but I hope to finalize that after heat treat when I can grind it all the way down. 
 

To replace the transitional sax/sword with the crack in the edge, I forged out another piece of anchor chain and took a piece of hearth steel up to 8 folds and drew it out into edge bar size. 

[Aiden CC]

A quick update before a few weeks where I won’t have much time for these:

 

A repeat of the sax 4, the billet is wrought iron and hearth steel. Interestingly, looking though metallographic analysis of a number of old single edged Nordic swords and long knives, almost all I found didn’t actually have any steel in them.  
 

A lot of steel to manage, but easier for sure than the a two-edged blade. I gave it a little nose dive because I think there will be some curvature picked up in the quench. 

[Charles dP]

Nice work there Aiden.

 

On 3/12/2023 at 7:36 PM, Aiden CC said:

almost all I found didn’t actually have any steel in them.

That is very interesting. I had thought the process of smelting would always carbonise the iron to steel. Clearly I am missing something. Do you know why those are iron?

Edited March 15 by Charles dP

[Aiden CC]

5 hours ago, Charles dP said:

Nice work there Aiden.

 

That is very interesting. I had thought the process of smelting would always carbonise the iron to steel. Clearly I am missing something. Do you know why those are iron?

Thank you! As for the single edged swords, if I had to guess I would say part of what is going on may be that if all you have is iron, a single edged sword may perform better. For the same bevel angle, a single edge sword will be thicker and thus stronger. The geometry of double edged swords requires that they be thinner for the same cutting edge geometry which means they need a stronger material to reach the same bending strength as a single edged sword. The investigation linked below is one of the sources I looked at, if I recall, they examined three single edged swords, two of which were all iron and one of which had some traces of steel. The authors make comments earlier on about X-ray images from other work of single edged long knives not showing evidence of pattern welding or welded on edges. There is still a lot I haven't read, so this is likely not the whole picture!

 

It could also have to do with the single edged swords primarily being a result of (lower quality) local production, while many of the double edged blades (especially the nicer ones) were made elsewhere. Steel does not always gain carbon when it is smelted. Whether or not it does depends on the atmosphere, temperature, etc. of the furnace. It is possible to produce steel directly from ore, but IIRC there is also evidence of small furnaces which could have been used for re-melting iron to carburize it. Some early swords were found that had a medium carbon core with low carbon edges welded on. One potential explanation is that it allows you to sharpen the edge by peining as you would with a scythe. 

 

https://www.researchgate.net/publication/357211244_Viking_Age_Swords_from_Telemark_Norway_An_Integrated_Technical_and_Archaeological_Investigation

[Charles dP]

Thanks for the insights Aiden and thanks for the link. I’ll have to make some time to read that.

[Aiden CC]

6 hours ago, Charles dP said:

Thanks for the insights Aiden and thanks for the link. I’ll have to make some time to read that.

I've been reading archeo-metallurgy when I get burnt out on automotive sheet steel papers and there are a fair number out there. There isn't any metallographic analysis, but if you are interested in Nordic finds, Jørgensen's work has a great number of examples with tracings and measurements:

 

https://www.academia.edu/40119369/32_Waffen_und_Gräber_1999_Weapon_chronology_in_Southern_Scandinavia_in_Late_Iron_Age_Merovingian_Period_Vendel_Period_Anne_Nørgård_Jørgensen_417p_

[Alan Longmire]

If you have a good library you can also get via Interlibrary Loan a copy of Tylecote and Gilmour, 1986: Metallography of early ferrous edged tools and weapons of Britain. Lots of the swords and spears, even some pattern welded ones, are just iron or high-P iron.  There's even one pattern-welded one in which the smith used high carbon for the core bars and plain iron for the edge.  We don't know if that was a mistake, or a deliberate attempt to get a strong core that wouldn't bend with easily-fixed edges... 

[Charles dP]

Thank you both. I will definitely check those out

[Aiden CC]

Made it through heat treatment! This material likes a fast quench and I didn’t want to buy 10 gallons of oil, so I used water with a touch of dish soap. Tempering was done using the forge. by watching the oxide colors. 

[Aiden CC]

A pivot may be required here unfortunately. It looks like there was a pocket running down one of the welds in the cladding material. This is the worst of the spots, but little problems pop up here and there the whole way. The bade weld was in the center of the width and closer than one surface than the other, which unfortunately meant that everything looked fine until finish grinding. 
 

I’m debating whether I want to recycle this blade or bend it into a sculpture, I may take a moment to think on that. 
 

I do have more steel though!

A few of these pucks have destinations already, but I imagine that one or two may end up as edge bars for that sword core you can see haphazardly on the floor under my anvil stand. 

[Doug Lester]

Bummer!

 

Doug

[Alan Longmire]

Squared! 

[Aiden CC]

Having slept on it, my current plan is to grind down through the problems and then weld a pattern welded veneer to each side to get back some bulk. It will likely have to be a lenticular blade as the edge steel is too thin to have a good looking fuller (i.e. only over the pattern welding). I think I need a break from this particular blade though!

I played around with the blade I bit and I think the heat treat went well though! It’s very springy. I think I’ll shoot for a later medieval blade with a diamond cross section to get practice forging and grinding hearth steel blades that long without the complication of a wide fuller. 

 

[Carlos Lara]

Sorry that happened, but could you or Alan explain to a newby like me what's going on? I get that the weld didn't go well, but how do you know it goes down deep? What is a "pivot"? Thanks!

[Aiden CC]

In retrospect, my main mistake was forging too thin to try and get a long blade out of not enough steel. That meant that it went into the quench thin which meant some more material lost to correcting some distortion of the edges. It also meant that by the time I found this, the blade was already under the target thickness so I couldn’t just grind through it. 
 

Here a “pivot” just means a change of direction, either cutting the blade into scraps to use in other projects or finding a way to make it into a different type of sword. 

[Carlos Lara]

I see, thanks! When you're using your own steel, it isn't that easy to just get more! I'd encourage you to keep trying though, and reforge it with more material and try to get it to be like you wanted it. There's something to be said about a creative goal.

[Alan Longmire]

Personally, I like the idea of patterned veneers.  You do see that on some originals, after all!  But I wouldn't blame you if you just slid that one under the bench for a year or two, that was a LOT of work to get to that point.

[Doug Lester]

Remember, a mistake that you didn't learn anything from is a mistake wasted.

 

Doug