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Post by Deleted on Oct 31, 2008 14:14:51 GMT
That i have a bo-hied through hardened katana and one day while cutting with it, it suddenly snaps into two right in the middle. Not wanting to throw a good piece of high carbon steel, i was thinking of re-forging it into into a katana or wakizashi where the two pieces are forge-welded (<The right word?)?. What i've learned is that you'll have to anneal it so that it'll lose it's temper making it easier to work with. What i'm wondering is, can it be done?
Will the bo-hi make leak in oxygen to oxidate the steel when it is being re-forged (Which is a bad thing right?)?
Or will the already forged katana be to hard to work with?
Thanks
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Post by Deleted on Oct 31, 2008 17:50:17 GMT
I would say it's not possible to do it and have any sort of quality result. Could it be forge welded? Sure. But I don't believe you could make anything useful as an outcome. There is a reason why broken swords aren't 'repaired' by combining the two pieces (that I know of, of course). Normally you take the piece that still has a point and cut a tang into it. Even the original tang end wouldn't be as useful...as even through hardened blades have a somewhat differential hardness rating from spine to edge. You could grind a point on it (carefully so as not to ruin the existing heat treat) but it wouldn't be as serviceable as the original.
Anyhow, this is my opinion based on my limited experience =). Please wait for other opinions as well, I certainly don't know everything, or even 1/100th of everything lol.
Cris
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Post by brotherbanzai on Nov 1, 2008 0:26:53 GMT
My opinion is that it would be an unreasonable amount of effort to put into it for what you could get out of it. Just make it into a pair of short blades and buy a new katana.
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Post by Deleted on Nov 2, 2008 8:11:35 GMT
Thanks for the reply guys. Guess i won't be re-forging and will be shortening... Much easier. Just a few questions, what do i use to shorten my blade and should i go with Option 1 Or option 2 Thanks
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Post by Deleted on Nov 2, 2008 8:22:08 GMT
As it's through-hardened it probably won't matter too much... but a broke-back katana has its own appeal!
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Post by randomnobody on Nov 2, 2008 8:22:33 GMT
From what I seem to recall reading or hearing somewhere, option two is generally seen as the preferred method. At least, in differentially hardened blades, the idea being that the tip will still be the same hard, sharp metal as the rest of the blade, versus the softer stuff of the spine...however, in the case of through-hardened blades...the difference in hardness is seldom so substantial. Though were it me...I'd still go with 2. It just looks better to me, for one thing. Ah, beaten. Yes, that way. Another benefit to this method is, should you feel so inclined, you could forge in a new kissaki from this cut (in a through-hardened sword, that is; again the hardened edge is a different matter), but it does just fine as-is.
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Post by Deleted on Nov 2, 2008 8:56:56 GMT
Option two is the proper method for a differentially hardened blade, as has been said.
However, since yours is through hardened, my advice would be to cut the blade off with a cut off wheel as in option 1, then grind it into a curve, using the original kissaki as a template. Keep the steel bathed in water as you cut and use short bursts of pressure, cooling in between rather than a long drawn out cut. In this manner you'll end up with a 'ko-katana' of sorts. When you're done with the grinder (you'll have to regrind in new bevels for the kissaki), you can use files and then sand paper to repolish the blade. UNDER NO CIRCUMSTANCES allow ANY color to enter the blade from grinding or cutting. If you do so, your existing temper at that point is basically trash, and you'll need to grind back to where there is no color in order to maintain hardened metal at the tip.
It I were to somehow snap a through hardened katana, this would be my choice of which way to go.
Hope that helps!
Cris
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Post by Deleted on Nov 2, 2008 11:01:22 GMT
Wow, a ko-katana!! Never thought of that. Always thought i'll end up with a wakizashi. Thanks canderson!! Maybe i'll go with option 2 because as randomnobody said, i'll be able to form a REAL kissaki if i were to feel inclined. Thanks for the tip random!!
Will an angle grinder work for the job? Or will have to use something with a little umph?
An extra question; I heard that you'll be able to differentially harden a through hardened blade right? Just confirming.
Thanks
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Post by Deleted on Nov 2, 2008 21:48:52 GMT
Wow, a ko-katana!! Never thought of that. Always thought i'll end up with a wakizashi. Thanks canderson!! Maybe i'll go with option 2 because as randomnobody said, i'll be able to form a REAL kissaki if i were to feel inclined. Thanks for the tip random!! Will an angle grinder work for the job? Or will have to use something with a little umph? An extra question; I heard that you'll be able to differentially harden a through hardened blade right? Just confirming. Thanks The advice I gave you will give you a 'real' kissaki, if you grind it, then file it that way. And yes, an angle grinder has PLENTY of juice to give you the results you need. Remember, short bursts, lots of water. Your real work will be in filing previously hardened metal. Don't take too much off with the grinder...finish with the files, and you'll be fine. Practice with the files on a piece of wood first that you cut into the shape of the trimmed up broken blade...it really does help you get an idea of what you'll need to do. My advice would be to grind the profile of the kissaki down first (the outside shape of the blade looking down flat), then determine where you want your geometry change from blade to kissaki. Mask this off and confine your work to that area. The ground profile should have left you a nice flat surface to draw your edge centerline on. From there it's just a matter of lightly taking off material at an angle from the edge to the spine. Get it mostly flat with the grinder, then finish with files. And remember, if a real kissaki were that easy to pull off, all of the chinese knock off's would have them...it's a complex area and it's much more simple to just carry the current edge bevel through to the point, then counter polish. It won't look bad, and putting all the work of a real kissaki onto a snapped blade seems a bit of a waste to me. To be honest I wouldn't recommend ever 'reforging' or 'rehardening' anything on that sword, particularly if you don't have any experience smithing in the first place. There's a lot of stresses and such involved and you'd probably just ruin the blade totally. On top of that, you already have sori built in...differentially harden it without some experience in how to control it, and it's going to go nuts. The other thing is, you may have a steel that's not really good for differentially hardening in the first place, and since that steel which was through hardened (normally tougher than differentially hardened) in the first place snapped/broke...it's not really what I'd call a candidate for differentially hardening anyhow. The last reason I wouldn't recommend it, is forging does remove material from steel, in the form of scale. There is also some small amount of carbon loss (particularly on a thin edge section). Both of those factors will require regrinding the entire blade if you try to reforge then reharden a finished blade. Not a simple prospect, to say the least, and without experience in forming bevels and maintaining your lines, your chances of totally ruining it just went up tenfold. All around, just not worth it =). Which is why I suggested simply reforming the kissaki and going with that. Good luck, and make sure to take pictures of your work so we can see too! =) Cris
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Post by Deleted on Nov 4, 2008 3:01:50 GMT
That i have a bo-hied through hardened katana and one day while cutting with it, it suddenly snaps into two right in the middle. Not wanting to throw a good piece of high carbon steel, i was thinking of re-forging it into into a katana or wakizashi where the two pieces are forge-welded (<The right word?)?. What i've learned is that you'll have to anneal it so that it'll lose it's temper making it easier to work with. What i'm wondering is, can it be done? Will the bo-hi make leak in oxygen to oxidate the steel when it is being re-forged (Which is a bad thing right?)? Or will the already forged katana be to hard to work with? Thanks I am having trouble understanding your questions, is english your second language? The Bo Hi will make regrinding a new tip into the broken end of the long part troublesome if you want it to curve like a regular katana, but will not be a problem if you curve it down. I would just grind the tip down, and make the broken tip into a knife by grinding a tang onto it, if yo do not have a grinder then you will have to go at it with a file, in which case good luck, the steel is probably soft enough to get by with a file. No need to normalize/anneal, in which case you would have to reharden it. IMO the blade is not worth reforging into anything.
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Post by Deleted on Nov 4, 2008 3:04:13 GMT
That i have a bo-hied through hardened katana and one day while cutting with it, it suddenly snaps into two right in the middle. Not wanting to throw a good piece of high carbon steel, i was thinking of re-forging it into into a katana or wakizashi where the two pieces are forge-welded (<The right word?)?. What i've learned is that you'll have to anneal it so that it'll lose it's temper making it easier to work with. What i'm wondering is, can it be done? Will the bo-hi make leak in oxygen to oxidate the steel when it is being re-forged (Which is a bad thing right?)? Or will the already forged katana be to hard to work with? Thanks I am having trouble understanding your questions, is english your second language? The Bo Hi will make regrinding a new tip into the broken end of the long part troublesome if you want it to curve like a regular katana, but will not be a problem if you curve it down. I would just grind the tip down, and make the broken tip into a knife by grinding a tang onto it, if yo do not have a grinder then you will have to go at it with a file, in which case good luck, the steel is probably soft enough to get by with a file. No need to normalize/anneal, in which case you would have to reharden it. IMO the blade is not worth reforging into anything. Ok lol, I'm an idiot. I TOTALLY forgot the bohi =). Cris
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Post by Deleted on Nov 4, 2008 6:45:36 GMT
I am having trouble understanding your questions, is english your second language? Well, kinda... I mostly speak chinese in school but english at home. But still... Anyway, I just want to take 10" off my katana because it's all bent, chipped and s***... I've already thought off making the cut off section into a knife even before i posted this thread... Just wondering how to do it so that i don't mess up and end up regretting. But i've been wondering how to grind a kissaki with a bo-hi engraved blade if i go with option 1...
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Post by randomnobody on Nov 4, 2008 6:57:48 GMT
Simple: Don't go with option 1. Option 2 really is the better. At least, I would personally prefer it. Not as though that means anything...
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Post by Deleted on Nov 4, 2008 7:48:31 GMT
I am having trouble understanding your questions, is english your second language? Well, kinda... I mostly speak chinese in school but english at home. But still... Anyway, I just want to take 10" off my katana because it's all bent, chipped and s***... I've already thought off making the cut off section into a knife even before i posted this thread... Just wondering how to do it so that i don't mess up and end up regretting. But i've been wondering how to grind a kissaki with a bo-hi engraved blade if i go with option 1... You can still do it, it'll just look a bit odd with the way the bohi extends to the yakote. Not as odd as a backwards tip imo...but odd. Remember, the tip geometry narrows to the point at the yakote (look at your remaining piece). Once you get past the thickness of the material of the bohi webbing, it will be gone. Cris
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Post by Deleted on Nov 4, 2008 23:13:30 GMT
No worries, I was just curious. Cut the 10 inches off going slow with a cutting wheel on a angle grinder, or spend alot of time doing so with a hack saw. Option 2 is your best bet, option 1 is possible but it would take quite a good bit of skill.
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