Shin Gunto Tsuka repair - In 101 easy steps

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I recently acquired a nice gunto with a damaged tsuka - to the extent that the sword would not lock up in the saya.  So I decided to repair it.  The fittings on the sword are high quality and they are all original (and matching numbered).   There are 4 seppa on each side of the tsuba; another sign of quality fittings IMHO.  I will post pics of the fittings at some point; for now - lets concentrate on the tsuka.

Here it is removed from the sword and the ito moved out of the way to expose the damage.  Basically a chunk of the wood and rayskin on the outside (omote) is gone so there is nothing for the latch (chuso) to lever against for locking up.   The inside (ura) of the tsuka is in fairly good condition.

outside side  inside ura side 



After I examined another tsuka I thought that the best approach would be to restore the missing wood. I made a repair piece whose profile matched the missing wood.
    
I also added two small pieces of wood - on the front to prop up the chuso spring and another to reinforce the back for where the hole for the the mekugi (peg) will be drilled later.  These were glued on.  The replacement wood was fitted as closely as possible to match the missing wood...

I first glued the repair wood in place and drilled/reamed the hole for the peg.  I also glued a strip of fabric to the end of the tsuka to take up loose of the fit of the fuchi.  One thing I learned is that fine adjustments are necessary to restore the functionality of the lock (chuso).  You have to observe how the parts interact (or should interact) and adjust as necessary.

Here is the tsuka with the repairs




At every step I would test fit the parts and also try to see if the chuso would latch properly into the saya.

Here was something that I had to figure out.   This is the fuchi (end cap for the tsuka) that has the chuso installed.  I wondered if the spring rests in the square "hole" or if it sits against the blade.  It needs to lever against something afterall.   I decided that the way it worked is that the spring rests inside the hole and uses it to lever against.   I took a long time trying to decide if this was correct or not.  (I also had to bend the spring back to its proper shape as it was bent way too much to compensate for the damage...that took a long time to correct....



I tested the fit and found that the chuso would not lock up   so I made a number of small adjustments.  First I noticed that the part that locks into the saya was bent; I very very carefully straightened it out (this took a number of tries - using a vice and tapping it with a small hammer (the metal bends very easily).    After testing again, it still would not lock although it was closer...

I then noticed that there was a gap between the wood and the fuchi right where the chuso spring rests.

See that little gap- I had to fill this in!   With what??   So I decided to fill the gap with cryo (super glue) reinforced with baking soda powder.
After filing it down to shape... (pic not in focus)





Here are pics showing the parts assembled for test fit.

The pic below show the chuso (latch) sitting above the rayskin; 


it must be below the level of the rayskin like below.  I determined that only the rayskin holds the latch in place - you would think there would be wood or something else to hold it down... It took a lot of fiddling with the fit of all the parts to get the latch to have enough tension to lock when its below the level of the rayskin (I'm putting slight pressure on it below)   Now, the parts align and the latch seems to work!




On to the repair of the missing same (rayskin)

TO BE CONTINUED

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Here is part 2.

 

So I got myself some rayskin on ebay from China - its OK - about what I expected.  The nodules of the repair piece are smaller because its from a younger ray so there will be differences between the repair and the original.  So be it.  So what I did first was to create an outline of the repair piece that I planned on

integrating with the existing.

 

After tracing out the pattern I trial fit the piece

 

And I cut a piece to match the "inlay" and discovered that what I needed to do was to cut out

the pattern while keeping extra rayskin to create strength to the repair area.  Rayskin is tough

stuff and provides a lot of strength for the thickness of the material.

 

 

My best friend - the dremel - made this possible - but really tests your patience and skill

 

I then test fit - modified - test fit - modified about 500 times and got this result (I colored the

rayskin with acrylic paint after 100 color match tests).  One major discovery I made was that if

I scortched the skin with a torch lighter it colored the skin with a nice brown tone approximating

the original.  Its like rapid oxidizing, I guess.

 

 

 

Ok, so its looking OK but still very much an obvious repair.   So then I got an idea - what if I use

my dremel skill to inlay tiny pieces around the border to blend in the repair.  We are not talking about

micro level repairs... so after about 4-5 hours of cutting, shaping and inlaying (secured with thin

superglue) here is the result.

 

 

Not too bad...  now, on to the ito repair....