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Post by Deleted on May 24, 2009 7:52:35 GMT
Greetings, everyone. I didn't know really where to put this thread, but because there isn't a maintenance/mending forum, i'll put it here....
What is the best way to know of to un-bend a sword? While re-assembling my musha (which was so tight fit it took me over an hour to disassemble) i had to knock the nakago in with more than a 100 hammer strokes, and i'm not kidding. After hammering it in, i noticed the sword was bent a bit in the way i hammered, so i had to flip it, and do another 100 strokes or so on the tsuka to the other side to return it to it's original state. During the process of annihilating my wrists, i thought- "There has GOT to be a better way to do this". So, what would be your way of choice to un-bend your katana? (katanas only), give your way of choice for a bend on the blade, and your way of choice for a bend where the bend point is near the tsuba or right beneath it.
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Post by Deleted on May 24, 2009 17:09:59 GMT
Man thats rough, Im sorry to hear that you bent your blade and i dont think you could properly repair the bend without first annealing the blade to relieve the loaded stress that is now locked into he grain structure at the bend. youve reached what is called the metals "fatigue point'' and like i said you would have to anneal the blade by heating it up to the point where the hard martinsite crystals essentialy DEform (around 1050 dregrees) then by letting the metal cool slowly your back to wrought steel, at this point you heat he blade up to a deep red glow and true the blade back up but of course after this you would have to either re clay, heat and quench your sword or reharden (TH) then temper down to have "like new" blade, but my guess is if you had to beat you sword 200 times with a hammer to put it back together then mabey its simply time for a new blade, and if you like beating swords with hammers so much.. mabey an LP forge I hope this provided you with a least some closure on where your blade stands and im sorry i wasnt able to be of any real help, but i bet if you wanted just a totaly gnarly and rawdog approch you might stand to use a propane toarch and try to just localy heat the affect area to a red glow and then try to true it up on something that gives a little, like a sawed off stump instead of and anvil because you may have a tendancy to bow the blade just hitting it in one area of the blade on an anvil if you dont have two people working on it as soon as it comes out of the forge or in this case from under the blow torch, but if you try this method please heed that you can get some seriosley wacky results just heating up one spot in the steel so, if you do try the blow torch thing remember to be passing the flame back and forth up and down the blade while stopping and focusing on the bent spot this will help the blade heat up more uniformly and help prevent warping from the blade being drasticly differnt temps in spots, any way, this can be a dangerous job so if you give it a shot remeber to be in a well ventilated area since you would be running a torch, some dark sunglasses may help if your overly sensitive to bright light, and by god if your going to beat on that thing BE CAREFULL metal that hot can sear your flesh right off and your would smell your own body burning before you felt any pain cause metal at this temp would just cook your nerves. and one more word to the wise,wear at least somewhat thickish and protective clothing cause you want those little bits of hot ass metal flying off your sword to burn holes in your clothes instead of your skin, www.m4040.com/Knifemaking/Steel2.htm good luck - kevin
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Post by Deleted on May 24, 2009 17:14:01 GMT
i said that marinsite was de forming at aroun1050 what i meant to say what in order to DEform the crystal structure in the steel you need to slowly cool from this temp- sorry bout that guys
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Post by Deleted on May 24, 2009 17:18:51 GMT
The thing is that it IS a new blade. and by "hammer" i mean the little brass hammers that come with the sword cleaning kits. It wasn't a hard bend, something like 3-5 degrees, but it just bugged my eye. 200 times was the total, it was something like a 100 to create the bend, 100 to fix it. The sword now flexes as it should, without bending. About forging.... I'd love to try, but there are no forges around here, at all. I don't have anyone to learn from.
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Post by Deleted on May 24, 2009 21:37:20 GMT
oh shoot 3-5 degrees. did you coax it back into shape while it was in the tsuka? what exactly created he bend again as in how where you holding your sword,
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Post by Deleted on May 24, 2009 21:58:32 GMT
i don't know exactly what created it, after re-assembled it i noticed it was bent, so i coaxed it back into shape while it was in the tsuka. Tomorrow or the day after i'm going to put myself through the hell of disassembling this thing again, to mend it better and fix any mishaps.
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Post by chrisosborne on May 24, 2009 22:04:20 GMT
Not a serious problem really as most of these production swords are not perfectly straight to start with and this may have been the case with yours. You probably didn't notice it until you had reassembled your sword. I can't quite imagine how you might have gone about "hammering in" your nakago, but you most certainly could not have bent the blade with a mekugi-nuki. Anyways, it's easily fixable. Just place a towel over the edge of a hard surface and place the blade(carefully) in your hands with the bent area in between them and flex the blade over the edge. Check the blade after each time until it's straight. For such a small bend a vise would also be OK to use and probably the safest for you. Put the nakago inside the vise just below the bend and gently pull a bit above the bent area. For any serious bend this would not be advisable, as it's certainly not the proper way to straighten a sword, but should work fine for a minor adjustment.
If you're not comfortable with your abilities in regard to doing something like this, and chances are if you had to ask then you probably aren't, then it might be best to send it to someone who is. I would be happy to fix the bend for you for a very small fee plus shipping.
Chris
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Post by Deleted on May 24, 2009 23:10:54 GMT
I'm not from the u.s, so shipping it both ways is out of the question... I thought of using a vise, but i decided to open this thread to see if there's any method that'll spare me from disassembling it again- Dynasty forge swords tend to be TOO tight fit, it took tremendous amounte of concentration and power to pull stuff apart carefully. Same with the nakago, it's so tight in that it takes tons of strokes with a mekugi nuki to take it out.
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Post by chrisosborne on May 24, 2009 23:57:00 GMT
With a bend right at the tsuba/habaki you really need to remove the tsuka again unfortunately. This time use a small block of wood and a larger hammer, it will be much easier. Wrap and tape the blade in paper towels to protect it and then place the block of wood on the tsuba directly against the side of the blade. Tap the tsuka off this way.
You might also want to try this first. Place your hand around the tsuka and firmly up against the back of the tsuba and wrap your other hand around this hand in the same fasion. Now tighten your hands with a forward movement. Done correctly this will create an even pressure all around the tsuba and will usually remove even the most stubborn tsuka. Your hand is not so much moving forward as it is tightening around the tsuka and expanding forward only slightly, so it is a very safe way to remove a tight tsuka, although some tsuba can bite into your knuckles pretty good.
It's also really best to duck tape the edge of the blade when doing any kind of work like this that involves exerting pressure. Fold a long strip of duck tape over the edge leaving a bit of overlap away from the edge. You don't want the tape directly touching the edge as it will not work best that way. Better safe than sorry, one slip is all it takes.
When you get the tsuka off, try one of the first two method I suggested. I think the vise would probably work easiest and be the safest for you.
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Post by Deleted on May 25, 2009 2:54:14 GMT
Here's one thing that may work for you situation. This tool illustrated below is meant for bends in the blade section so I'm not sure if it will or not for your case. But first you will have to totally disassemble your sword in your case. This tool is a God sent for straightening bends and twists in the blade so who knows, if you can see the bend I'm sure you can fix it. Try making the following and see if it will work for you. I make them out of 2x4 lumber and it works just great. I can't take credit for coming up with this design I just know that it works and works well. Hope that will help you, I am sure it will be easier than hitting it with a hammer to straighten your blade.
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Post by Deleted on May 25, 2009 9:33:18 GMT
^ I made a very simple version of this, no holding handles and no refining, just taking 2 2X4's and making slots with a dremel. WORKED LIKE A CHARM. I'm going to make an improved version, the planks will be connected with 2 LONG bolts, and nuts on each side, so that screwing the nuts in and out would set the angle in a very precise manner. This can be a real lifesaver, i think everyone who owns more than 1 sword should have something like this. Thanks wizzbang, i was looking for this diagram.
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