How To wanting to make a honsanmai katana looking for good spring steel for the spine?

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Evan Wilson

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Hello I am looking for recommendations on what steel I should use for the spine.

A little about what I have,plan on using and am looking for.
I have some of Don Hansons W2 I plan on using for the edge and I have some bloom steel I made from old wrought and meteorite to use on the sides.
I am wanting to forge a hirazukuri katana or wakizashi because of the geometry I want to reinforce the spine with a good spring steel to minimize any potential sets the blade might want to take.

I am looking for a good shock resistant steel to use on the spine looking for something that does not need to be hardened for good shock resistance.

I have read up on a few steels 5160,9260,EN45,EN42J and S7. any recommendations welcome.

quick edit:the only spring steel I have worked with under the hammer is 5160
 
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Sounds like an ambitious and fun project!
I don't have the experience or the tools to even think of attempting something like be this. No forge press, power hammer or strong, willing and simple friends! :-D
Personally, id go with a hardening steel, not something just strong. You want Steels that are fairly close together metallurgically speaking, so they weld together easily, from what I understand.
 
I would concentrate on the ha and not worry too much about the mune. Use any steel that will take a beating. 1070, 4160, 5160, 9260 would all be fine.
 
A.McPherson said:
Sounds like an ambitious and fun project!
I don't have the experience or the tools to even think of attempting something like be this. No forge press, power hammer or strong, willing and simple friends! :-D
Personally, id go with a hardening steel, not something just strong. You want Steels that are fairly close together metallurgically speaking, so they weld together easily, from what I understand.
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I don't have a power hammer or forge press either the bloom steel will weld to anything as for the other metals they just need to stick together the blade profile on both sides runs flat no central ridge like people are used to seeing and the spine will be clayed and soft anyway so I want to avoid a full through hardened blade

link to examples https://studyingjapaneseswords.com/tag/hira-zukuri/
 
Stacy E. Apelt - Bladesmith said:
I would concentrate on the ha and not worry too much about the mune. Use any steel that will take a beating. 1070, 4160, 5160, 9260 would all be fine.
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what do you mean by focus on the ha? from what I know is the Ha is just the cutting edge and that will be W2 so the blade shape I am going for does not have a central ridge Examples here: (https://studyingjapaneseswords.com/tag/hira-zukuri/ )

by using bloom steel on each of the sides the carbon content once done should be similar to 1060-1080 on the sides of the blade and around .90 - 1% carbon on the edge and will have a grain just like the real things

I am focusing on the mune because of the drawbacks of the blade profile and I want the sword to be as long as I can get it looking alot like an actual katana forged in japan while trying to rival top perfomance cutters made from a solid chunk of modern mono steel without compromise on the hada and the beauty that it has and Don Hansons W2 is known for being able to get some amazing hamon's if you know what your doing
 
So you're going to forge the whole thing out by hand? Man, that's a lot of work! Good on ya!
Best of luck!
 
What I mean is the ha is the part that cuts. The rest just slides along after it. In your hon-san-mai mix the only part that will get any stress is the ha. Do all the forging and HT in respect to the ha. The cladding will be hardened but not as hard and brittle as the ha and the rest will be pearlite and will remain softer and tougher.
The ha-gane is the main hardenable metal. I usually refer to all the metal below the hamon or san-mai line as the "ha". In san-mai the core is all ha-gane, thus all exposed core to the edge is ha. In your hon san-mai the core is half ha-gane. The upper half of the core would be mune-gane. The bloomery steel is the ji-gane.

Note to others:
San-mai is a tree layer construction of three pieces of steel with softer steel on the outside and hardenable high carbon steel as the core. Hon-san-mai is three layers, but the center layer is two pieces. The ha-gane is high carbon hardenable steel and the mune-gane is a low carbon soft steel. The sides are medium carbon and provide toughness to the sword without causing brittleness. This makes the spine and side able to take heavy blows as well as bend more in combat or cutting without breaking the blade.
 
Stacy E. Apelt - Bladesmith said:
What I mean is the ha is the part that cuts. The rest just slides along after it. In your hon-san-mai mix the only part that will get any stress is the ha. Do all the forging and HT in respect to the ha. The cladding will be hardened but not as hard and brittle as the ha and the rest will be pearlite and will remain softer and tougher.
The ha-gane is the main hardenable metal. I usually refer to all the metal below the hamon or san-mai line as the "ha". In san-mai the core is all ha-gane, thus all exposed core to the edge is ha. In your hon san-mai the core is half ha-gane. The upper half of the core would be mune-gane. The bloomery steel is the ji-gane.

Note to others:
San-mai is a tree layer construction of three pieces of steel with softer steel on the outside and hardenable high carbon steel as the core. Hon-san-mai is three layers, but the center layer is two pieces. The ha-gane is high carbon hardenable steel and the mune-gane is a low carbon soft steel. The sides are medium carbon and provide toughness to the sword without causing brittleness. This makes the spine and side able to take heavy blows as well as bend more in combat or cutting without breaking the blade.
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Thank you for clarifying what your saying makes sense thank you for that.
I will take what you have said into consideration and try to find what I think will work best.
 
Hephaestusforgecraft said:
I've been forging on raw chunks of meteorite so this should be a slow walk in the park.
thank you.
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I competed on a popular TV show for bladesmithing a couple years ago and when it came time to make my handle thought I’ll use Loveless bolts which if you aren’t familiar are just a screw and two sleeves that tighten together to fasten the handle along with glue. I had used that exact handle hardware in my shop atleast 1000 times before using them on TV and have done quite a few more complex handle constructions so in my head I thought that step will be a walk in the park. Ended up screwing up the handles and starting over on that step 3 times and then still cross threaded one bolt on the last attempt and had to fill the bolt head with glue and sawdust. It survived and I moved on in the competition but long story short often when we feel something is going to be a walk in the park and simpler than something else we have been doing is when the simplest of tasks will give you more trouble than you could imagine. Good luck on the project and I look forward to hopefully seeing photos when you complete it.
 
Joshua Fisher said:
I competed on a popular TV show for bladesmithing a couple years ago and when it came time to make my handle thought I’ll use Loveless bolts which if you aren’t familiar are just a screw and two sleeves that tighten together to fasten the handle along with glue. I had used that exact handle hardware in my shop atleast 1000 times before using them on TV and have done quite a few more complex handle constructions so in my head I thought that step will be a walk in the park. Ended up screwing up the handles and starting over on that step 3 times and then still cross threaded one bolt on the last attempt and had to fill the bolt head with glue and sawdust. It survived and I moved on in the competition but long story short often when we feel something is going to be a walk in the park and simpler than something else we have been doing is when the simplest of tasks will give you more trouble than you could imagine. Good luck on the project and I look forward to hopefully seeing photos when you complete it.
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yes with all complex projects and at times even simple ones errors and problems occur I am sure I will run into a few some key points being that I dont have a time limit and when problems happen I can afford to think about the best way to fix/correct them while taking a break.

Forging raw chunks of meteorite is no simple task the stuff likes to crumble and existing flaws like to open up on you.
you also need to have a good idea of what the composition is if you are forging dronino ataxite or gebel kamil these have an average of 15% - 20% Ni in them and will not take to welding to it's self to well.
forging meteorite at times is like trying to forge cast iron.
even making canister damascus is difficult to achieve flawless results simply do to all of the issues that meteorite brings.

I moved from 1095 strait to meteorite damascus with very little experience in between.
the first 2 billets of meteorite damascus I made was with help and guidance and I have seance moved onto making my own by hand.

I know the things I need to improve on what I can do and what I cannot I research and ask for guidance often before going into a projects and take steps to mitigate issues before they happen through proper preparation by knowing these things most can plan on how to forge even a complex blade by working around what we know we will likely have issues with.

for example I am going to have to forge this out by hand and personally I want to do it that way however when I start the billet I cant have it thicker than 2" by 1 1/2" and because of wanting to make a honsanmai I will likely take the spring steel and w2 and forge weld them together before adding the bloom steel to the sides helping to leave less room for error when forging the piece.

thank you for the encouragement and I will try to have a preform before winter and see if I cant post an update once some work has been done.

If you ever forge some meteorite I recomend Aletai from china around 5-7% NI around 1% cobalt and the rest is iron it is known to have heavy stone inclusions but forge welds to it's self amazingly I have pounds of the stuff because it can be picked up cheaply and forging the raw chunks is similar to muonionalusta and gibeon the way it forges
 
I'm interested in seeing how this turns out - especially since you are looking at a hira-zukuri design which is more often associated with tanto and wakizashi They are know as great cutters b/c of the bevel angle but the ha doesn't get a lot of support. How thick are you looking to make the spine? You're going to a lot of effort to develop a really durable core, but the ha may end up being the weakest link.

My experience is with monosteels (hopefully going to change in the near future) but one thing that quickly comes to mind is going to be the challenge of quenching a blade of this size with the number of different steels and blade geometry you're using while avoiding making pretzels and worse. Since you are using W2 on the ha and claying the blade are you planning for something like a partial/interrupted water quench or similar?

You've clearly have a lot (infinitely) more experience than me at laminate constructions, but considering the complexity of the project would it be a good idea to prototype things with something tanto sized first to see how things go? The big bonus is that once you finish the katana you get an automatic daisho out of the whole process. :)

Now, I'm coming at this from an iaido background so the swords I've used all have had shinogi and I don't do a lot of tameshigiri/batto. So YMMV, void where prohibited, take everything I say with a large grain of salt, these are the ramblings of an old deluded man, etc.

Good luck and please post updates as you progress!

-bill
 
I have two antique examples one with a 6mm spine at the tip and 9mm at the base of the blade:tanto and a ko wakizashi with 3mm at the tip and 8mm at the base of the blade. I would like to have the spine 3-5mm at the tip and 12-15mm at the base of the blade I don't like how wide examples of this style blade often are and will shoot for a blade being less wide and with an aggressive taper is my goal.

the W2 ha should be plenty tuff as long as I temper the blade to around 52-56 Rockwell aiming for 54 will likely quench in parks 50 oil.
involving water might turn soul crushing if it goes wrong so I will be avoiding water.
oil quench wont make the most of the hamon,I wont be able to afford to mess the quench up.

making a prototype is a solid Idea I might make a long tanto to start this would give me a better idea of what to expect.

Thanks to everyone for the help suggestions and support.
 
I agree that an O-tanto would be a good start to this project.
I think that considering the complexity of the kitae, and doing it by hand, a wakizashi would be wiser than a katana. An O-wakizashi with proper length koshirae will be a lovely sword - 24"/60cm nagasa and 12"/30cm tsuka = 36"/90cm sword.
 
Sori is often negative or straight in an oil quench. With your steel mix I would not expect sori.
I would suggest forging in the sori. I usually leave extra height to the billet to adjust the sori in final grinding in case it isn't sufficient.
 
Stacy E. Apelt - Bladesmith said:
Sori is often negative or straight in an oil quench. With your steel mix I would not expect sori.
I would suggest forging in the sori. I usually leave extra height to the billet to adjust the sori in final grinding in case it isn't sufficient.
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Stuart Davenport Knives said:
Just remember if you plan on quenching in oil, you will get a negative sori (tip bends down, not up).
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thanks to both

Stacy E. Apelt - Bladesmith Stacy E. Apelt - Bladesmith and Stuart Davenport Knives Stuart Davenport Knives​

for mentioning this about the sori will definitely forge a test blade I have gotten sori with w2 in oil. dont know what to expect with this though,expect a forged test tanto in the next month and hopefully a heat treat within two weeks after that.
 
quick update:was told by a friend that I should not mix shallow hardening steel with through hardening steel and was given a piece of 50100 to use in place of 52100 for the spine.
The bloom steel is consolidated and has been folded once needs 3-5 more folds.
the bloom steel was melted with a 50-50 mix of meteorite and wrought iron the meteorite used was Aletai with a general chem. comp. of 90.5 % iron 8.2% nickel and 1.0% cobalt. and small amounts of muonionalusta and campo del cielo both of these two meteorite were small amounts used sub 150 grams.

the bloom was melted in a hearth made from firebrick and some steel wire started with 5lbs of total metal and ended up with 4lbs 3and a half being use able.
left with 1lb and 2.3 oz after consolidation and the first fold.

someone offered me the chance to own a forge press and I took them up on it so will not need to be doing this all by hand much longer.
might finish a tanto by hand but anything after will be using the press for sure.
 
I must have missed something. I thought you were going to use something like 5160 for the spine. In a knife thickness, all the steels we have talked about will through harden.

I don't see any reason to substitute 50100 for 52100 anyway. 50100 and 52100 are both 1+% carbon ... and as said above ... they are through hardening in a knife thickness. They are equivalent to your W2 edge steel in use and HT. Nothing wrong with that, just different than what you started with.

Here is a graph with 1095, 50100, 52100, and W2:

1693217108843.png

Here is the analysis of Don Hanson's W2 (the low Mn is why it gets a great hamon):
C .95
Mn .22
V .19
Cr .15
Si .23
Mo .013
Ni .08
Cu .14
 
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