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Post by Deleted on Jul 13, 2009 18:43:13 GMT
I was thinking about how a tsuka is made. My understanding is that it's two pieces of wood, each with a space for the nakageo to fit in, that are then glue together. The idea being the nakageo just fits down in the the opening created by the two halves. Hopefully I have that part right, if not please enlighten me.
Now I was always under the impression, or maybe it just seemed simpler, that the two halves glue together, with the seem aligned with the edge and mune of the sword. So the seem was on a vertical plane. But then after thinking about that design I realized that puts a weak point, the glued seem, righ where the nakageo is going to be pressing against the tsuka.
It seems to me, now, that as you swing and hit something, there is going to be a lot of pressure from the nakageo, going against the vertical plane (mune and edge) on the inside of the tsuka. So by that maybe it's best to built the tsuka so the seem is on the horizonal plane, along the sides of the nakageo. Ah now I understand, I thought.
But then as I thought the whole process of the sword through I realized you then drill holes through the tsuka on the sides for the mekugi. Hmm that means the holes are going right through the glued seem, which could cause some weakening of that joint. Hmm, but does that outweigh the other orientation of the tsuka?
So, what say you more learned of the katana? What is standard, what is best? What do you do when making a new tsuka core?
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Post by Deleted on Jul 13, 2009 19:14:37 GMT
The vertical split makes carving the channel for the nakageo much easier. Making wide shallow cut outs ( instead of deep narrow ones) allows for a more precise fit. Most wood glue joints are stronger than the surrounding wood. The split tsuka pictures I have seen show cracks at the corners,not at the seams.
I am not a katana/tsuka expert by any means. these answers are from standard woodworking practices and lots of reading. I am sure the experts will have more to say.
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Post by Deleted on Jul 13, 2009 20:34:48 GMT
The seam should actually be more to one side of the halves, and not in the middle. One half is carved deeper than the other. As Pilgrim says, the glue seam is often stronger than the wood.
But the tsuka core is just a part of the construction. A full samekawa wrap further strengthens the tsuka, and the ito pulls the whole thing tighter. The samekawa has the seam down the omote side. The fuchi strengthens the most stressed point, the joint between the tsuka and the blade.
But what is crucial is the perfect fit of all the parts.
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Post by Deleted on Jul 13, 2009 22:00:07 GMT
Ah OK that makes a lot sence. One side is cut a little deeper so the seam is just off center. I see what you mean about the "whole package" making it all stronger. I figured the fuchi held it together at the end there, but didn't even think about a full wrap with ito combined. Yet another good reason to have a full wrap over panels. I'm not sure that particular reason is known or realized among the novice sword enthusist. Ah yes, the glue joint being stronger than the wood. It all comes back to me now, as I hear my highschool woodshop teacher in my head. Thanks guys.
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Post by mrkrinkle on Jul 13, 2009 22:32:31 GMT
Yes, a full same wrap is desirable, (not just for strength, but you can get a nice emperor node) but it is also much more expensive and a lot more difficult to accomplish. The same has to be softened and then it needs to be stretched and the seam needs to be cut evenly, then it needs to be glued on perfectly or you will get little bubbles under it and can have a crackling noise when the katana is handled. I've never attempted a full same wrap due to the price and what seems like a like of work....but I have looked into it and found some articles that gave me this tidbit of info.
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Post by Deleted on Jul 14, 2009 19:07:24 GMT
I went through the entire article found at the top of the sticky thread here about building your own sword from bare blade. Wow, there is a lot to putting a Japanese sword together from a bare blade. I was kind of overwhelmed really, at how much, and time, and some special tools and jigs and the such to do it all right.
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Post by Deleted on Jul 14, 2009 21:21:34 GMT
You'll get far with a fine saw, a good knife, a chisel, some files, some glue, a hammer, a drill and a ruler. It will only take longer. I built my naginata in the kitchen using only hand tools common around the house. The most important tools is a well thought out plan and a gallon of patience.
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Post by Deleted on Jul 15, 2009 21:00:27 GMT
LOL hmm patience, I'm not always known to have that. LOL But aside from that, how do you do your tsuka ito? You have some great work I've seen here, and after reading those articles I was wondering if you use a jig to hold the tsuka while wrapping, or just do it all by hand?
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Post by Deleted on Jul 16, 2009 12:16:37 GMT
I tape a piece of leather to the edge of the kitchen table, and "clamp" it between the table and my stomach. Works great for me.
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Post by Deleted on Jul 16, 2009 16:22:45 GMT
Is the same a finished leather or like rawhide? Does it shrink to fit as it dries? Is a full wrap much stronger than panels?
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Post by Deleted on Jul 16, 2009 18:49:37 GMT
Ah OK I get you. Basically just need to keep it held down in place so you can use both hands working the ito? Makes sense. Grey, my understanding is the same is dried stingray skin. Panels are just that, a section, or strop cut out of a full skin. A panel just goes down one side of the tsuka. A full wrap, is basically using the entire skin of a stingray (or darn near) so the entire tsuka is wrapped with the skin. wb8.itrademarket.com/pdimage/48/796748_3aef_1_sbl.jpg
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Post by Deleted on Jul 18, 2009 19:13:37 GMT
samegawa, when its dry its very hard and somewhat brittle. but after soaking it in water it softens and can be wrapped around the tsuka,I suggest wrapping some cord arround the entire lenght really tight, this will keep it from bubbling. then when it dries its very hard again.
ito-maki, I've actually been doing this myself lately, and its not the difficult. I find the easiest way for me is to hold it in my hands. if its clamped down you'll need to keep unclamping it to turn it over correct?
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Post by Deleted on Jul 21, 2009 2:49:43 GMT
The traditional same skin is basically stingray rawhide. Basically the same thing a dogs bone is made out of, only with stingray skin, so you can see how soaking it and fitting it around the tsuka and then drying will really add some strength.
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Post by Deleted on Jul 24, 2009 17:12:16 GMT
Oh wow, yea I didn't realize it had the consistancy as the dog hides, that's some tough, hard stuff when dried. Was already planning on it, but for sure getting a full wrap for any custom work.
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