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Can I repair my saya?


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Looking for tips and advice please:

My han-dachi saya has become enlarged in its throat area, so much so, that the sword will fall out if not handled with great care. This is obviously not a good condition for me to be in.

So I am asking if a home repair is possible? and if so what materials and adhesives are needed! Looking at the saya in hand, it seems as if a piece of packing is missing, as opposed to the mune having sawed away at the mouth.

I feel quite confident, that with the right guidance, I could tackle this task and would love to give it a go, unless advised otherwise.

Denis

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Bear in mind I know nothing about doing this, but my first instinct would maybe be to try very thin strips of balsa wood inside the mount of the saya. Only enough to hold the habaki. Soft enough to mold itself to the habaki I think, and can be bought in very thin strips.

Obvious course of action is to split the saya to do any repair, but that isn't going to be practical if you intend to do this yourself.

 

Brian

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Hi, keep in mind as you consider taking on this task that this piece is one of keys to the sword not only being 'locked' in so that if properly done it doesn't simply slide out, but it is also a key piece (in combination with the habaki) to ensure the sword is properly spaced and suspended inside the saya when fully seated. In other words, it's something you want to be quite careful when making.

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Denis -

If you insert a shim on the sides of the koiguchi the saya is more likely to split. The best way to go is to insert your shims at the ha and mune (top and bottom). Very very thin leather works or if you can get it paper thin slices of cedar the Japanese call kyogi. The danger lies in the glue used. Make sure you use nothing with any petroleum or other chemical base. Simple white glue works fine but must be thoroughly dry before you return the sword to the saya. If you make your own rice-glue use it sparingly and remember to completely dry it, before returning the sword to the saya.

 

I have done this many times for swords used in our dojo, it is quite easy to do and harmless if you follow the advice above,

-t

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....My han-dachi saya has become enlarged in its throat area.....So I am asking if a home repair is possible?....

Yes, we can!

 

The secret is not only to find thin strips of wood but to rework the glued-in pieces with a rasp and make sure the KOIGUCHI has a tight fit to the HABAKI without causing pressure. As has been said this is a standard service for SAYA in use, and SAYASHI prepare fine pieces of soft wood for that repair. Also, the Japanese have a number of fine woodworking tools for this purpose, e.g. a long SAYA rasp can be obtained from NAMIKAWA HEIBEI, but your local tool dealer might have something less expensive. A coarse file will do, but never use sandpaper!

 

In many cases, old SAYA may also suffer from a broken horn KOIGUCHI, which might get dry and brittle with age. It can be replaced but this will demand some fine work and use of URUSHI.

 

I wish you good success!

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Evening all,

 

I asked the self same question some time back on The Japanese Sword Forum.

 

Brian, if you would not object, here is an explanation with illustrations from Kensen san, who is a skilled traditional craftsman.

 

http://www.thejapanesesword.com/forum/v ... f=37&t=162

 

Cheers

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Gentlemen, most comprehesive range of answers, it is quite late here, so I want to appraise all you have said, and respond with some points already in my mind. Together we will win.

 

Till later thanks

 

Denis.

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Thanks Brian. My only reservation with balsa (I had considered it) is, I thought it was too soft, and would need more attention in the future. Splitting the saya if that was the only way, I agree with you is a no no for me at home.

Franco. Your point in the forming of the koiguchi, and its function to support the habaki and then the blade, is an instruction I will be mindful of. Thanks.

Thomas. I think the thin veneer of some wood is the way to go, more control over the build thickness. Your tips on glue choice, I had not considered, but make serious sense. Cheers.

Sebastien. They say a picture is worth a thousand words, thanks for the diagrams.

Jean. I was having thoughts on the trimming of the repair material; I was avoiding sandpaper, as I was concerned about grit parting from the paper inside the saya. A rasp of course will rough the surface with little cutting effect.

Thomas. Hi! I hear what you are saying, the thumb on the tsuba is always advised, even when the sword is ‘tight” But my real worry is that a moments inattention, by myself or a third party, could cause the blade to exit the saya, the serious consequences of that I will leave to you to imagine.

Malcolm. Your post confirms the way to go, build up the mune area, avoid side packing (split danger). Nice one.

Guys, I will do some laying out of the task tomorrow, and be back to nit pick the way ahead, Your response has been real. Very gratefull.

Denis

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As you look at the mouth of the saya, I am sure you will have noticed, that the mune ‘floor’ in the saya has almost gone. A build up of this area, will most certainly be needed.

I propose not to build a ‘flat’ floor, but to use two strips, and form angles that will conform to the mune, and then to the habaki.

Also mindful of the advice, that undo side pressure here, will transmit to the koiguchi, I do have strength here due to the han-dachi metal band, but still caution is advised.

After sourcing all the materials, I will proceed with habaki detached and in hand. This I am thinking will allow me to align the habaki, square to the koiguchi. The smaller adjustments, with blade and tsuka, being done in the final fit.

Thank you all for the help I asked for, and please! Any points or omissions in my thinking, please advise me.

Denis.

 

“We shall be unable to turn natural advantage to account, unless we make use of local guides” Sun Tzu.

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......A rasp of course will rough the surface with little cutting effect.....

Denis,

my experience is just the contrary, especially when you use a quality rasp (Japanese tools are usually among the best available). A good new rasp will easily remove a lot of material with little effort, depending on the size of the teeth and their number! Of course this is only the first step in the work, and the surface has to be smoothened afterwards with other tools. Rasps are made in a wide variety from very coarse to quite fine.

 

The mentioned NAMIKAWA rasp is quite slim and very long, it's working part has the cross-section and shape of a blade, and it is made to adapt a used SAYA to another blade with a slightly different SORI and thickness.

 

A KOIGUCHI needs only very fine tuning when you start with thin wood strips. A few sharp knives (small KOGATANA for woodworking) and a good file might do the job then.

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Jean

My unfamiliarity with the rasp mentioned, led to me making a wrong call, thanks for the brief. Now having fitted the habaki into the saya, a new story appears.

Come back to me on this:

Using a gap gauge it is evident that the koiguchi, has no contact with the sides of the habaki, to me that is where the maximum contact is needed? Isnt that what the cat scratching is for? The contact between the mune area, and the koiguchi is not present, until the habaki can enter to a point, beyond which the seppa would allow, a small insert is needed here.

I need to; fine tune as you say! Just add fine wood strips either side of the koiguchi, to conform to the profile of the sides of the habaki. Just reclaiming these areas will I feel not give rise to splitting pressure??

The habaki will not be fitted flush with the koiguchi, but will stand proud with a sight gap between the koiguchi and first seppa when tsuka is assembled. From this point, I hope a gentle pressure with the palm on the kashira will set the blade secure.

Denis

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It is exactly as you say: you are striving for an airtight fit, so glueing in pieces of wood and fine-tuning the contact zone between HABAKI and wooden inserts with tools is the work to be done. You will want also to respect the angles of the wedge-shaped HABAKI.

 

NEKO GAKKI are indeed made to improve the secure fit of the blade in the renovated SAYA.

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Good morning Denis,

 

Just a thought.

 

Looking at your photograph of the habaki inserted seems very tight at the mune.

 

Which suggests perhaps that the habaki may not have been the original habaki.

 

There seems to be no apparent gap in the koiguchi sufficient to balance the loss of timber at the base (Mune), note the thickness at the top (Ha).

 

Is it the angle of the photograph?

 

Cheers

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Ok Jean. I am good to go.

I am lucky to be an ex aero modeller, and I have a good friend who still is. He has a supply of good wood veneers; it when wet will conform to any shape, then when dry, retains that shape, you can see where I am going here, it’s worth playing with. My thinking is: that conforming the veneer to the habaki then shape the koiguchi to accept the insert would be the easier job. Cheers.

 

Hi Malcolm

It’s a yes to your observation! When I first started to examine the saya as a problem, it looked to me as though the koiguchi had broken up and fallen out. As per my first photo, its not pretty. But there is actually a seat for the mune.

When I thought of fitting the habaki alone, the uneven proportions were very visible. I like you suspected a ‘miss-fit’ of parts here. Comparing to other saya’s I have, and that point becomes very apparent.

To address this, the habaki should be let into the ha area a little more, this will allow inserts into the mune area and “lift” the habaki. I don’t have any choice on this course of action, as the koiguchi is fitted with a metal reinforce band, the mune will ride on this, unless great care is taken in blade return.

Denis.

 

Ps. During all the above regular, trials with the habaki and blade into the saya need to be done.

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  • 1 year later...

Ok job done.

 

Not deciding on a koiguchi total rebuild, I decided that the grip on the sword by the habaki was all that was needed.

So at the top two runners as fenders from the metal, and one at the bottom to straighten the habaki into the saya.

All set with rice glue, (making sure its total dry) and now a tight fit with room to spare without touching septa.

Ok not an invisible repair, but no damage done, and can be repeated at a later date if needed, but a safe sword.

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