Loose Saya

I have bought a second hand iaito via my instructor. The saya is quite loose on the habaki, the sword will slide out by itself. Also the mouth of the saya has a slight crack which may be the reason why it is so loose.

Is there a way of reinforcing the koiguchi to prevent it from splitting any further? Also how can I make it a tighter fit around the habaki?

Avagadro,
It sounds like you have two problems here, a loose fit between the koiguchi and habaki, and the cracked koiguchi. This is the more difficult to fix. The koiguchi is designed to be replaced (actually the whole saya can be rebuilt). Depending on your woodworking ability, you can buy a replacement from Fred Lohman Co. and remove the cracked one and install the new one. This usually involves several fit checks, shaving, sanding, to match habaki and saya, and relacquering. The repair for a loose fit is simpler. With use, the habaki will slowly wear the koiguchi, this is to be expected (metal is harder than wood). Go to you local hardware store and buy a roll of 1 inch wide, heat activated wood veneer. A roll should cost about $10 and last you and everyone in the dojo for years. The directions usually tell you to use an iron as the heat source, but it won't fit into the small opening of the koiguchi. Cut and fit a piece to match the inside of one side of the koiguchi. I use a motorcycle tire iron, but any piece of metal slightly smaller in width than the koiguchi will do (large flat blade screwdriver). Heat this (use a propane torch or over a gas stove flame, etc.) until it is too hot to touch but not red hot (suggest you experiment with the veneer on an old piece of wood to get the temperature right). With the fit veneer piece in the koiguchi, use the heated tool to on it, pressing to activate the glue. Trim and sand as necessary and do a fit check with your sword. Repeat on the other side of the koiguchi if necessary. This should fix the loose problem.
Good luck.
R. A. Smith

My fix for the loose koiguchi problem is perhaps simpler and definitely cheaper. Buy a 1/4" square hardwood dowel and a bit of Elmers Carpenter glue. Won't cost you more than a few dollars. Helps to have a small wood file handy. Small enough to fit in the koiguchi.

Use a knife to shave of a thin layer of the dowel. Doesn't really have to be an exact match. This should usually be about the same thickness as a toothpick, or sometimes smaller depending on the severity of the problem. It only needs to be maybe a quarter inch to half an inch long. Glue it to either the mune side or the ha side just inside the koiguchi. Never ever to the sides, as that can force the glue which holds the two halves of the saya together to crack more easily. Use a butterknife or something to apply a little pressure for a few minutes so that the glue sets. Clean up any excess glue.

Insert the sword back into the saya. Gently cinch the blade back into the koiguchi. In all liklihood it won't quite fit, but that's ok because the goal is to press the shim into the glue so that the glue will set. Be careful not to push the shim in when you set the habaki in the koiguchi. Wait an hour or so for the glue to setup. Then remove the sword. Clean any glue off the habaki. There shouldn't be any.

Now if the sword didn't fit completely in the koiguchi, you need to file the shim down a hair. Keeping the end of the saya up in the air, carefully file down the shim. Shake out the dust and retry the fit. If it still doesn't fit, repeate until it does. It should fit a little tight at first. It'll loosen up after a bit of use.

As for the cracked saya, that's a tougher problem to fix. One common way to prevent the crack from spreading is to wind a thin strip of ratan around the saya from the koiguchi to below the crack. This is not a method I am comfortable describing in any detail, but it can be done. If you're not VERY comfortable with the idea, find someone else to do it for you who knows what they are doing.

[QUOTE]Originally posted by Charles Mahan:
My fix for the loose koiguchi problem is perhaps simpler and definitely cheaper. Buy a 1/4" square hardwood dowel and a bit of Elmers Carpenter glue. Won't cost you more than a few dollars. Helps to have a small wood file handy. Small enough to fit in the koiguchi.

Use a knife to shave of a thin layer of the dowel. Doesn't really have to be an exact match. This should usually be about the same thickness as a toothpick, or sometimes smaller depending on the severity of the problem. It only needs to be maybe a quarter inch to half an inch long. Glue it to either the mune side or the ha side just inside the koiguchi. Never ever to the sides, as that can force the glue which holds the two halves of the saya together to crack more easily. Use a butterknife or something to apply a little pressure for a few minutes so that the glue sets. Clean up any excess glue.

Insert the sword back into the saya. Gently cinch the blade back into the koiguchi. In all liklihood it won't quite fit, but that's ok because the goal is to press the shim into the glue so that the glue will set. Be careful not to push the shim in when you set the habaki in the koiguchi. Wait an hour or so for the glue to setup. Then remove the sword. Clean any glue off the habaki. There shouldn't be any.

Now if the sword didn't fit completely in the koiguchi, you need to file the shim down a hair. Keeping the end of the saya up in the air, carefully file down the shim. Shake out the dust and retry the fit. If it still doesn't fit, repeate until it does. It should fit a little tight at first. It'll loosen up after a bit of use.

As for the cracked saya, that's a tougher problem to fix. One common way to prevent the crack from spreading is to wind a thin strip of ratan around the saya from the koiguchi to below the crack. This is not a method I am comfortable describing in any detail, but it can be done. If you're not VERY comfortable with the idea, find someone else to do it for you who knows what they are doing.[/QUOTE]

Darn!!!! I LIKE it!!! I think I'll try it on my saya, which is a tad loose. I'd read some time back about a similar fix, but it involved using leather, which obviously can't be filed down to a custom fit. Thanks for sharing!

Heh. I've had a lot of practice refining the process since taking up a shinken a year and a half ago.

The thing to remember is to avoid getting glue on the blade. It takes only a VERY thin layer on the shim to get it to stick. Wipe off the excess before inserting the sword and above all avoid letting saw dust or anything potentially abrasive fall into the saya. Best to work with a slight down angle whenever possible.

I would just use duck tape ^^ j/k

and i hope you didnt pay TOO much for it considering its condition, and i also hope the Sensei warned you of the problem before you bought it. What ever you do i hope it works out for you.