Aiden CC

Thank you! I'm glad it's starting to come out. The final billet has 128 layers of two alternating steels I had already refined to 6 folds. It seems I always end up with this sort of mokume hada, probably due to how material moves under a press.

Thank you! I do think it’s telling that there are specialists who primarily make habakis. Not much progress on these blades, but I did finish the sanding and start the etching process for the tanto: It still needs a bit more work to get the hamon to pop in more light conditions, but it does come out quite well in the right light.

It will be interesting to see how that one turns out! Did you fold the steel at all, or just consolidate and forge it out? I have made some jewelry out of hearth steel that wasn’t folded at all and it has a look that is quite different, but still nice IMO. I was feeling fairly lazy this afternoon, so I decided to do something I had meant to for a while, since I could mostly just sit around and watch it. I collected this fatwood two years ago, but I stored it in two plastic bags and it still gave off a strong smell. I still have about 2/3 left. A very simple setup, just two cans and the ground. I normally hate briquettes, but the low maintenance, consistent heat worked well here. Too much heat, and the tar will come out faster than it can condense in the can and burn up in the fire. Im surprised how much water was left in the wood, I’ll have to separate it out. This stuff is nice to have around for projects where I want everything to be as “from scratch” as possible.

I had two opposite visions for the KITH this year, so I decided to make both, and let whoever gets my entry decide. The first one started out a bit rough: I believe the first or second puck from the left is what ended up as the edge bar. I re-melted it from some wrought iron round bars. Meanwhile, the other knife needed somewhat more precise treatment. I chose to take a warikomi approach for this knife, the body is from a link of small anchor chain, opened with a chisel for the hearth steel edge. Here’s where the blades stand now, the right is made from MagnaCut. I don’t have as many pictures of it yet, but I have something a bit… different planned for the handle. That’s it for now, thanks for looking!

It’s a bit hard to tell, but it may be a bit high? If the sparks look good everywhere, my guess would be you might need a higher temperature and/or a faster quench. I would try a thinner coupon in water, and maybe shoot for a higher quench temperature than you are used to with modern steel.

This could also be a due to inhomogeneity of the puck, which I have often experienced in my own re-melts. If the puck doesn't settle low enough in the fire, I have found it leads to a well carburized top and under carburized bottom, potentially having to do with the amount of time material charged at different times was able to be a liquid or "slush" in a part of the fire where it could pick up carbon. I would recommend grinding a flat surface and carefully comparing the sparks from different parts around the edge as well as how that whole surface sparks. Every once in a while I still get material that averages out to be 0.4-0.5% C from a high carbon and low carbon layer, which I use for cladding around a higher carbon core for swords, etc. (though looking at metallographic analyses of a number of medieval knives, the edges were often in that range and actually quite soft by modern standards!). I use either water or a fast oil (Parks 50 for me) depending on the blade geometry, though admittedly I always quench swords in water because I don't have a large tank with oil.

Good on you for getting into it! There is definitely a learning curve for this process. Are you cutting the charcoal before using it? It's hard to tell, but it looks like there are some large pieces in the photo. I usually will buy 2-3 bags of charcoal, Royal Oak is my personal favorite, mostly because it isn't very "sparky" while burning and cracks less (maybe it's a bit dryer than other brands"), then I go through and make sure all the pieces are under around 1-1.5" on their largest dimension. Most of the pieces are small enough out of the bag, but I cut the big ones down with a big knife. This helps keep the appropriate spacing between pieces of charcoal and makes sure that the fire "settles" at the right rate as everything burns down. As others have mentioned, air and temperature control are your likely problems here. It's somewhat counterintuitive, but I have found that (to a point) more air = more carbon, at least for this setup. My best guess is that a higher air flow causes the hot-spot to be bigger so the material spends more time in a liquid/near-liquid state picking up carbon. Too high and the heat goes almost all the way to the bottom and you get cast iron. One other important detail which you already noticed is making sure the bottom of the furnace is hot enough. You need to slowly build up the fire from the bottom up. I like to start with a few inches of charcoal and a low air blast and wait until it is all burning, then repeat with a few more additions, gradually increasing the air. If you don't have enough heat low down in the beginning, the puck will settle too high in the furnace where the air blast will oxidize it and turn it into a foam, which looks a lot like what you have. I have found that when this happens you can't really make anything from the melt, not even wrought iron, since if has too much oxide in it to consolidate. Hope this helps!

Looks great! Type M is definitely under-represented in replicas as you mentioned, which is a shame because they often have a quite elegant look. The sword recovered from the ice in Norway with a mismatched type H (?) lower guard and type M upper guard has some of my favorite proportions among swords from this era..

Composition definitely, though not necessarily hardness difference. A combination of iron/steel and high P iron will behave differently than two steels with Mn, the bright one also having Ni as used in modern steels. I’m not as sure about the hardness difference. It’s not uncommon for micro hardness measurements to be made in sword blade sections but I don’t know if I’ve seen one examining pattern welding. The second material after has some carbon in it, sometime an even being a medium carbon steel, and in those instances may be harder than the high P iron. The most common explanation I’ve seen in the literature is that the phosphoric iron provides a “light etching” region, while the steel provides a “dark etching” region. This is true when polished an etched for metallography but only because the high P regions become frosted and appear lighter than the still mirror-like regions which aren’t etched as aggressively. When you do a ferric chloride cosmetic etch, the high P regions become much darker. Here is a bar where I tested this out: You can actually see the contrast reasonable well straight off a 220 grit belt in the second picture. This is a very high P iron though, though later pattern welding did sometimes use iron with quite a bit of phosphorus.

The big blade made it though heat treatment without any cracks, there are a few “folding scars” here and there, but it’s way better than the last blade. You can see a bit of the layering in the scale here. This was a water quench, which was definitely a bit tense. Not shown is a bit more grinding, the blade is down to 810 g. My plan is to not etch this blade, but we’ll see how it goes. Also, debatably whether it’s a sword, but I did the finish grinding, rough sanding and habaki for this sunobi tanto: In my opinion the most difficult parts of mounting a Japanese blade, the habaki and saya fit-up are now finished. This blade is made from 12-fold steel wrapped around a wrought iron core, with a deliberately irregular hamon. Once I carve the channel for the tsuka core I’ll polish the blade. I’ve gotten a glimpse of it at the coarse stages of grinding, but I’m excited to see how it comes out in detail.

I think it comes down to the difference between abrasives of different hardness/shapes and how a loose abrasive acts differently than one bonded to a surface. Softer abrasives have a notably different effect on the hardened and un-hardened parts of the surface. They also break down and constantly expose fresh grit so that they are cutting as opposed to burnishing. In addition, loose abrasives cut differently, and the slurry formed on top of the stones also participates in the process.

Also worth noting is that a polishing with fine, friable, abrasives avoids burnishing and leaves a more "open" surface, which shows features in the steel better. Stefan Mäder had several early medieval blades polished by a professional Japanese sword polisher with interesting results, presented in "Stähle, Steine und Schlangen". It's speculative, but below is an image from that work showing what pattern welding looks like with a very fine polish with natural stones.

Just make sure they aren't complain about grinding, because the pile of half finished blades is what I'm avoiding by doing stuff like this . I blame it on the press. Back when it was all hand forging I would stop when I was too hot and tired to keep going,, now I don't know when to! To peek behind the curtain, this went from puck to blade in four sessions, following a (fairly flexible) overarching plan. I've found that planning goes a long way when working with material like this, not the least to keep the motivation for the final product alive. The first one, I worked one of the melts up to 3 folds and turned some previously refined material into sanmai bars and then a few knife blades, afterwards working the second large melt up to 1 fold. Second, the 3 fold material was cut and stacked, then brought up to final layer count, and I got all the little pieces welded for the core bar. Third was when everything came together; the 1 fold material was cut and stacked, then refined along with the core bar, everything welded together, then forged into a preform. Finally, was a short session with minor adjustments to the preform and beveling. I was shooting for three originally, but had to quit early to make it to other plans on time.

I finally had some time to do real work in the shop, and made some progress bringing that blade to life. I needed more material, so I went though my pile of little scraps and squished all of the highest quality pieces into tiles. A large piece was prepared as a base and the piles were quenched, ground clean, and broken to inspect them. All the best pieces were then stacked and welded. Hearth steel pucks always have uneven composition, and I have found this to be the best way to ensure only the absolute best parts are used. This will be used for the cutting edges. Now, for the billet, everything is 7 folds. The top is that high quality bar, which consolidated well and maintained good carbon content. Below it are two slightly lower carbon bars (though still definitely hardenable). Not shown is the fact that all the surfaces are ground clean. I welded the bar, drew it out, and folded it so the best material would be in the middle. This billet may look massive, and that’s because it is, being about 6 lbs. After a series of heart breaks with this material, I’ve found the cause is usually trying to save a bit of material. After that, lots of drawing! This is certainly the largest piece of hearth steel I have ever worked with. It started out as somewhere around 8-10 lbs of wrought iron, two extra large pucks and a similar quantity of little scraps broken off from maybe 5-10 different melts. I like to weld on wrought iron tangs when possible and thus blade already has enough steel in it if you ask me. I used to do a single sided lap weld, but found this method to be easier and more consistent. Here’s where it stands now. The blade is 31” long, 2.5” at the base, both will come down by a hair. I also revised the profile taper a bit. The design for this blade started with the feel I want it to have when held, and with this length, I think that would be better served by a pointier blade. I didn’t get a chance to weigh the blade, but I think it will need to lose 30-50% of its weight in grinding. Better than the last one that came out of the forge basically at the target weight!

I think the main thing I learned from this is to be extra careful with cleanliness while folding. I forgot to take pictures but I’m working down that material and opted for a cut-and-stack in a few places rather than just folding. I also trimmed off the ragged ends which have been a source of problems in the past. I loved the feel of that blade and have been wanting to try paying more attention to sword dynamics and design and apply points from @peter johnsson’s work. My goal for this blade is one thing that’s agile but still has some authority, so I opted for a narrower blade with a bit less profile taper. The design below still has some kinks to be worked out, I now see that I need to fix the curve at the tip to be more even. I’m also not sure about the guard length, I may bump it up. The real grip will also need to be narrower. I want to get together about 4 lbs of hearth steel to weld around an iron core for this blade. That should hopefully leave extra that I can cut off to use for other projects.