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Post by Deleted on Oct 5, 2010 3:58:01 GMT
My Ronin Pro model 2 has an incredibly loose saya, to the point where the blade is literally sliding out of it with no resistance. Infact, the saya is actually cheaper than stainless steel wallhanger swords I've seen. Its a beautiful saya, absolutely, but it just doesn't fit my sword properly.
I've tried shimming with wood veneer, but it only seems to be a temporary fix. I need two pieces of wood veneer for the sword to fit properly, and it degrades over the course of a few weeks. Are there more permanent solutions to fixing my saya? Maybe I should contact Ronin Katana and possibly get a new one?
Any advice would be welcomed, this is the best sword I've ever seen or used, but this saya is bugging me to death.
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Post by Hyoujinsama on Oct 5, 2010 4:02:01 GMT
Shimming the koiguchi is the only real fix for that, and it may always be a temporary fix, especially if one is doing nukiuchi without supervised training (which may not be the case, here. Just stating).
Something I used to do was use those little wooden stirring sticks you get at places that have little cups of coffee, like some gift stores or small banks. Glue them in on the ha and mune sides and file them down to fit.
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Post by Deleted on Oct 5, 2010 4:05:10 GMT
My saya actually doesn't have a koiguchi, its bare wood at the top. Maybe I received a defective saya?
Edit: Unless my definition of koiguchi is wrong, thats a metal piece at the mouth of the saya?
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Post by Hyoujinsama on Oct 5, 2010 4:10:53 GMT
Koiguchi is just the opening of the saya. There are horn and metal parts by the same name, but it's just the mouth. Do you have any pictures of the opening?
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Post by Deleted on Oct 5, 2010 4:12:12 GMT
I'll take one right now, edit with pictures incoming. Edit: Flash makes everything look dirty.
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Post by Hyoujinsama on Oct 5, 2010 4:35:10 GMT
That's a nice, thick horn koiguchi. Looks pretty good as far as I can tell.
All I could really suggest from what I'm seeing here is adding more in the way of shims. Perhaps add some to the two facets on the mune side to keep too much from building up on the ha side.
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Post by Deleted on Oct 5, 2010 4:37:35 GMT
I'll give it a try. Thanks for the help, I really appreciate it.
+1 karma.
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Post by Lobster Hunter on Oct 7, 2010 8:35:54 GMT
Yup, building up the ha and mune side with strips of thin wood about the length of your habaki and wood glue worked pretty good for me. I don't know if this was the best method but I did it this way:
First test the fit by sheathing your sword with the shim in place without glue. If it's way too tight, file down the strip a bit and try again. If you use sandpaper, be sure to wipe off the piece thoroughly as sand particles in your saya can scratch your blade.
When you start to get a good, firm fit, affix the shim with a good amount of wood glue, wipe off the excess gunk and hold it in place for a few minutes with a chopstick or something to give it a chance to bond a bit.
Either sheath your sword carefully so the habaki can put some pressure on the glued shim or gently stuff some rolled up paper or something in to the mouth of the saya to provide that pressure.
Let it dry overnight or for at least 5 hours. Why 5 hours? I don't know. 5 is a good number.
Test the fit. If it's too tight, carefully file down the shim a little at a time and keep checking the fit. I actually used a thin strip of sandpaper glued to a chopstick for this part and tried to make sure the hard particles didn't end up in the saya. I guess a skinny file would've been better so don't be like me, use a steel file if you can.
It's not unusual to have a small millimeter or more gap between the koiguchi and seppa when a sword is "fully" sheathed. I would think that it's better to have a fit that is slightly too tight at this point rather than slightly too loose, since over time, the fit will loosen a bit with use.
When you're filing down the glued shim, work with the opening oriented down so the sawdust and crud will fall out, not in to the saya. Wipe clean with a piece of cloth wrapped over a chopstick or something.
Be sure to not shim the interior SIDES of the saya since it was constructed as 2 halves glued together and too much pressure could split it. That horn koiguchi looks pretty sturdy but it's best not to take chances.
Good luck.
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Post by Deleted on Oct 19, 2010 17:09:00 GMT
Hi Yuyuko,
It looks like you added the shim to the top of the saya, the edged side. This is not advisable because the blade will be making contact with the shim very often (especially in the case of improper drawing. But hey, it happen to everyone), and it will not only be worn down more quickly, but will also dull the blade. You should shim the wider side instead.
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Post by Deleted on Oct 20, 2010 18:58:30 GMT
Shimming it on the ha and mune won't do much for keeping it in the saya. A katana relies on the friction between the *sides* of the habaki and the wood to stay in place, so you'll need to shim the sides with thin wooden shims. Do it properly and you won't split the seam. Doing it right means that there is just enough firm friction as you slide it home. Too much pressure is when you have to push hard to get it in.
Right now, I'd guess that you have too much clearance - or not enough contact - between the saya and the sides of the habaki. You could always remove the tsuka, seppa and tsuba from the sword, then slide the sword into the saya to see how well the habaki fits (or doesn't) in the saya. That will then give you a good idea of the thickness of shim to cut for either side.
Do not, on any account, use sandpaper to adjust the shim to the correct thickness - grit in the saya is exactly what you don't need. Use a small rasp instead. While you're at it, I'd take out that shim on the ha side altogether. It isn't going to do anything except wear away whilst dragging on your cutting edge and dulling it.
What sort of wood? Honoki, if you can get an offcut (no point in buying a whole blank), alder or beech. Shave off a couple of suitable pieces with a chisel.
It may be the flash, but the wood looks oily. If it is, that will also be reducing friction. Furthermore, the oil will need getting out of the wood before you glue a shim, otherwise the glue won't take. Which is going to mean using something like a xylene-based thinner to dissolve it out. This will no doubt require great care cos I've no idea what the lacquer is, and you want to avoid marking it, making it tacky or dissolving it.
Kevin
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Post by Dan Davis on Oct 20, 2010 22:21:51 GMT
This is bad advice. Do not do this.
All katana taper from shinogi to ha and all habaki do the same. Shims placed in the koiguchi at the mune will lift the habaki up and press the habaki surfaces corresponding to ha-ji more firmly into the koiguchi. It will do this WITHOUT affecting the lateral blade alignment within the saya.
Shims should only be placed at the ha-machi side of the koiguchi if chipping or scraping has caused material to be removed from that area. Pressure on this area will generally not help as a typical habaki is straight-sided along the surfaces corresponding to shinogi-ji.
In looking at the opening of your saya I note that the edges of the wooden core that correspond to where the habaki seats at mune are worn, rounded and scalloped out. A poorly fitted habaki is the most common reason for this type of wear, and shimming the ha-machi side of things has likely only accelerated the process.
I recommend looking closely at your habaki to see if it has a squared off front edge at mune, and to make sure it fits flush with the mune-machi. A few seconds with a file and sandpaper may solve this problem permanently, and a couple of shims on the mune side of the koiguchi should then restore a nice tight fit.
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Post by Hyoujinsama on Oct 21, 2010 0:08:26 GMT
This. +1 for a good post, Dan.
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Post by Deleted on Oct 22, 2010 12:27:06 GMT
I think we’re at cross purposes here. I’m not talking about sticking in coffee stirrer type shims. What I'm talking about is, if there is too much play between the long sides of the habaki and the koiguchi or if the contour of the koiguchi is incorrect, properly relining the longer sides of the koiguchi, to the full depth of the habaki, and to exactly the correct contour required by the habaki for a good fit along its length. Though by now mune will need some attention. Now you can shim at mune and it should, if the koiguchi is cut properly (see Figure 1) shove the habaki firmly into the taper towards ha. However, the contours of the koiguchi on its long sides may not complement that of the habaki – the manufacturer only needs to have cut them at slightly the wrong angle to cause a problem. This won't necessarily be visible to the eye unless you check the fit with the habaki. If the sides of the habaki and the koiguchi diverge then you can shim the mune for all your worth; in the worst case, the long sides of the habaki will never contact the sides of the koiguchi except down by ha (see Figure 2), and most of the friction will between the ha side of the habaki and the saya. It is a simple matter of geometry. I’m not even going to go into the relationship between the surface of the habaki (and I've included some pics of Japanese habaki so that visualising things is easier) and the contour of the koiguchi as you go down the throat of the saya, but suffice to say you can get problems there as well. You have to think in 3D. Anyway, if you have a situation as in Figure 2 you will, by shimming at mune, briefly increase the degree of friction. However, every time you draw and replace the sword, you get accelerated wear in the region of ha until the sword is loose again. So you shim again and the process starts all over again until the saya becomes unsafe. You wind up effectively filing away at the ha side of the saya. I’ve seen this happen. You’re actually getting it in reverse with this saya. He’s shimmed at the ha, forcing the mune of the habaki into the saya, causing increased wear and the observed ‘scalloped’ look at mune. OK, he’s forcing it out of the taper, but if the geometry of the taper is incorrect you’ll get the same effect by shimming at mune. Now shimming at mune may or may not work with this saya. We don’t know. We don’t know how well the habaki is fitting in the koiguchi. We don’t, as yet know, if the problem is a badly cut koiguchi or a problem with the habaki. We don’t know because none of us have the sword in hand. It may be that shimming at mune could be completely inappropriate because it doesn’t take account of the cause of the problems. Again, we don’t know. But relying on shimming at mune would be a bad choice if the koiguchi contour isn’t correct and remains uncorrected. So first you need to look at the fit to see if there is a problem there. Because if there is and all that happens is that the saya gets shimmed at mune, the OP will be coming back in a few months saying “I've been shimming at mune, as you advised, and now I've got a hole in the side of my saya.” My guess is that the koiguchi hasn’t been contoured to the habaki properly. Just cos it's new doesn't mean it's cut right. I’ve seen that with some mass produced saya and the OP’s remarks suggests that care wasn’t taken in the production of this saya. Sometimes the contour may get overcut in manufacture. Sometimes the angle is just slightly wrong. Maybe a machine wasn’t adjusted correctly and maybe quality control missed one. In any case it is being done to a price, not a quality – it is not being done by a craftsman who will take every care to make sure that it is exactly right. Now if my guess is correct, then the koiguchi will need relining, as I suggested. OK, I called the inserts shims – that’s what they basically are and that’s what I think of them as. Mind you, you do need some skill to reline the koiguchi properly – maybe cabinetmaker level – and the trick is to make the repair near invisible. Fortunately my grandfather was a cabinetmaker and taught me a few things. The above isn’t a hypothesis. I’ve seen damned good craftsmen reline the koiguchi of antique saya precisely because the contour was screwed by wear. Well the alternative, a new saya, is a bit of an expense if the saya is an antique in otherwise good condition and removing the play will fix it. Again, 30 years ago I had exactly the same problem with the saya of my then katana as the OP. I relined the koiguchi as described and that solved the problem permanently. So permanently that several years and a fair bit of iai later it was still fixed when I decided that a new saya was in order. By that time (about 25 years ago) I was making saya for the swords I was making for martial artists – this at a time (before the internet) when ‘production katana’ meant ‘Spanish made 440 stainless blade, plastic saya and plastic tsuka with bad rayon tsukamaki’ and nothing else. Carving lots of saya by hand – and making mistakes - gives you an insight into how they work. Based on that, I don’t like inserting wood at mune unless there’s a damned good reason for it, such as lost wood, and only after I’ve gone over the whole relationship of habaki to koiguchi to make sure that there are no other problems. By the time I'm done, it will fit perfectly. Now if folks don't want to take any notice, that's fine. No skin off my nose; there’s plenty of happy collectors and martial artists out there. I'll let my work and my company’s work, do the talking, cos right now I’m a bit busy fixing two rather abused shingunto saya, which has included splitting and cleaning the liners. Kevin
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Post by Lobster Hunter on Oct 23, 2010 12:48:16 GMT
Kevin,
I think the reason why shimming the mune or ha is generally recommended as a quick and easy fix is because it's a safer bet for most people. There's less of a chance of compromising the integrity of the saya. The problem is that many lower end production sayas might not have properly reinforced koiguchis and a bad shimming job on the sides by someone with less experience could be bad news. However, your point certainly seems sensible in that if done just right, shimming the sides so that the habaki makes good contact on all sides of the koiguchi should result in a more secure and long lasting fit.
Thanks for sharing your experience with us.
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Post by Hyoujinsama on Oct 24, 2010 0:14:31 GMT
Kevin, I think the problem was with this part right here:
From almost every sayashi, martial artist and habakishi, I have been told (and found from my experience) that the friction is most important on the ha and mune. Even looking at the nihonto that have passed through my hands, the most pressure is on the ha and mune.
Also, from John Tirado and Sayashi.com:
"Certainly, the production of the saya is a bi-lateral process except that the ura of the saya does not get the recess for the ha as noted earlier on the omote. When complete the fit should be just touching at the sides with the majority of the hold at the ha and mune. Care must be exercised so as not to scratch the polished areas of the habaki. On niju habaki, when properly made, the a set of rails created by the outer jacket are fitted so as to create channels of hold at the ha and mune."
That said, I think it the best way to put it is: A close fit on all sides is important, but the hold/friction fit of the habaki and koiguchi junction should be on the ha and mune sides of the habaki, not just to preserve the seams of the saya, but also to preserve the broad (sometimes decorated and polished) faces of the habaki.
Also Kevin, by the way.
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Post by Dan Davis on Oct 26, 2010 12:46:40 GMT
Kevin, Sorry for the slow reply, I am in and out a lot lately and have not had time.
I did not say that you were wrong, I said it was bad advice. I said this for the two reasons already covered by Lobster Hunter and Hyoujinsama, and because it does not really apply in this situation.
If you look at the photo provided by the OP you can clearly see where the throat of the saya has been pressure-burnished by the habaki and it is easy to see that the burnishing is pretty even; indicating a relatively close fit to the habaki. You can also observe that the throat has an even thickness all around the inside of the koiguchi except at mune, where it is gouged out, primarily at the peak in the center of the habaki.
We are all pretty much in agreement that the shim at ha was a bad idea and should be removed; in fact if you look at both my original post and your replay again you will see that we say almost the exact same things on the subject.
Finally, let me say welcome to the forum and can I recommend you join the "Manufacturers and Vendors" group; I have been doing this for 37 years myself and 25 years of experience is quite a lot.
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