|
Post by mrstabby on Dec 6, 2023 9:34:47 GMT
Are there any? I mean I have seen some examples and they surely exist, but are there any modern production blades?
I am not looking to buy, just interested. I know the Japanese Ken were like this, and many early swords had a hardenable edge and iron core, but I am interested if there are people who produce them nowdays.
|
|
|
Post by bwaze on Dec 6, 2023 10:44:18 GMT
Now it's really much more expensive to make a blade with iron core and steel edges than all steel blade. The only other option would be shallow hardening, but you'd get a blade that can much easier stay bent than the standard thoroughly spring tempered steel we're used to now, so again something buyers wouuldn't really appreciate.
|
|
|
Post by AndiTheBarvarian on Dec 6, 2023 10:50:17 GMT
Afaik jian can have it. Some modern repros have a special tempered center (torch?) which is softer, but not DH with clay.
|
|
|
Post by mrstabby on Dec 6, 2023 10:56:59 GMT
I thought as much, but most of this is also true for the single edged variants.
Though the negatives might be more pronounced on a double edged blade. The edges are harder, but you don't get as much stability as you get with the single edged thick spine. Still interesting that there just don't seem to be many differentially hardened DE blades, though I remember a DH Jian. I do prefer spring tempers myself, I was just wondering.
|
|
|
Post by demonskull on Dec 6, 2023 11:04:29 GMT
Andi is correct. Different hardnesses can be achieved by hardening the entire blade to the desired hardness then by apply heat (generally with a torch to the center), while maintaining the hardness on the edges by using a heat sink of sorts so the increased temperature doesn't reach all the way to the edges, the hardness is drawn off creating a softer core but still keeping those edges at the desired hardness.
|
|
|
Post by AndiTheBarvarian on Dec 6, 2023 15:03:55 GMT
|
|
|
Post by jcmt03 on Dec 6, 2023 15:38:14 GMT
I dont think they do it with their swords, but Arms&Armor slack quench their spear heads to achieve historically hardened edges with a softer core. I'd bet that some of the pattern-weld-loving smiths have done it/would do it.
|
|
|
Post by AndiTheBarvarian on Dec 6, 2023 16:19:06 GMT
Yeah, that's another method. I've just seen it in Forged in Fire, a hamon without clay, just with special quenching. But there on a single edge knife.
|
|
|
Post by crazyjons on Dec 6, 2023 16:26:53 GMT
Ewert Oakeshott mentions it in records of the medieval sword, he talks about heating up a rod of iron and placing it in the Fuller to soften the metal there.
Also Tinker Pierce talks about using a torch to soften the center of a euro sword in his write up in the sword making section stickies.
|
|
|
Post by AndiTheBarvarian on Dec 6, 2023 16:43:50 GMT
A torch or a hot rod is the same principle. The slack quenching is drawing the blade out of the quenching fluid before it's completely cooled. The thinner edges are quenched hard already but the thicker center is still hot enough to temper itself softer.
|
|
|
Post by izzy on Dec 6, 2023 17:41:21 GMT
|
|
|
Post by mrstabby on Dec 6, 2023 18:28:00 GMT
Speaking from 2 examples I have/had Legacy Arms seem indeed to be slightly softer towards the middle, but it does not go deep, where a fuller is ground in, the metal is equally as hard as the edge, never thought this was intentional since it is so slight.
|
|
|
Post by larason2 on Dec 6, 2023 22:47:36 GMT
Some Japanese swords still have a double edged blade for a part of some pieces, and the smiths clay harden those. There's also more than one smith that contribute to the blade smith forums that use clay to differentially harden a sword, say for a viking or migration era sword. It exists, but compared to through hardening in an oven it's more time and labour intensive, and it fails more often. I guess what's the point if you're not going to finish it in a way that brings out the hamon? I think that's why most swords are through hardened. Even the smiths that make DH migration era swords etch them so you can see the pattern and hamon.
|
|
|
Post by cptraph on Dec 7, 2023 1:46:01 GMT
Out of curiosity what exactly are the benefits of having a sword with a core made of iron and edged made of steel?
|
|
|
Post by AndiTheBarvarian on Dec 7, 2023 2:00:44 GMT
The edges would be quenched hard for a better durability for cutting. The iron core can't be quenched hard and would remain soft but tough, bending but also rebendable. That doesn't sound well for us today but in an ancient battle it was better than a broken sword or a sword with very soft edges. Katana follow this principle too.
|
|
|
Post by cptraph on Dec 7, 2023 3:18:24 GMT
The edges would be quenched hard for a better durability for cutting. The iron core can't be quenched hard and would remain soft but tough, bending but also rebendable. That doesn't sound well for us today but in an ancient battle it was better than a broken sword or a sword with very soft edges. Katana follow this principle too. Are there any benefits to the sword being equally hardened?
|
|
|
Post by treeslicer on Dec 7, 2023 3:31:58 GMT
The edges would be quenched hard for a better durability for cutting. The iron core can't be quenched hard and would remain soft but tough, bending but also rebendable. That doesn't sound well for us today but in an ancient battle it was better than a broken sword or a sword with very soft edges. Katana follow this principle too. Are there any benefits to the sword being equally hardened? Why sure! The process is simpler, and the smith can be less skilled, so production is faster, with lower costs. Something like through-hardening to a spring temper can be adequate with a cavalry saber, or a chopping or thrusting sword, but IMHO, it's not what you need with a katana. DH has also proved superior in bolos and kukris.
|
|
|
Post by cptraph on Dec 7, 2023 3:53:52 GMT
Are there any benefits to the sword being equally hardened? Why sure! The process is simpler, and the smith can be less skilled, so production is faster, with lower costs. Something like through-hardening to a spring temper can be adequate with a cavalry saber, or a chopping or thrusting sword, but IMHO, it's not what you need with a katana. DH has also proved superior in bolos and kukris. What about for a double edged sword?
|
|
|
Post by larason2 on Dec 7, 2023 4:12:22 GMT
Old swords used a wrought iron core because that's what they had. Hardening iron (steel) was relatively hard to make, and time consuming, and knowledge of the process was not universally shared, whereas wrought iron was relatively easier and more plentiful. Wrought iron also has the benefit of showing a pattern if you etch or polish it. At least for migration era swords, the appearance of this pattern was important. Among modern smiths, having the wrought iron pattern in the blade body is considered very aesthetically desirable. In practice, wrought doesn't actually bend very often if it has a hardened edge, and as mentioned, it's actually pretty easy to bend it back.
Through hardened blades are not equally hardened. The exterior is hard all around the blade, but the core is still soft, exactly like a differentially hardened blade. As mentioned, this is easier to do, especially if you have one of the modern tempering ovens where the temperature and time are programmable. I suppose the sides are less likely to scratch, but I wouldn't say they are less likely to bend (at least, it can be done!). Nothing wrong with through hardening, but I'd say without a hamon they are a bit less aesthetic.
|
|
|
Post by mrstabby on Dec 7, 2023 6:36:37 GMT
Through hardened blades are not equally hardened. The exterior is hard all around the blade, but the core is still soft, exactly like a differentially hardened blade. As mentioned, this is easier to do, especially if you have one of the modern tempering ovens where the temperature and time are programmable. I suppose the sides are less likely to scratch, but I wouldn't say they are less likely to bend (at least, it can be done!). Nothing wrong with through hardening, but I'd say without a hamon they are a bit less aesthetic. That's not neccessarily true, it depends on steel and heat treat. Deep hardening steels like 5160 will be hard all the way through unless you do some specific things like blowtorching after heating, interrupting the quench like A&A does on spear tips.
|
|