Overly tight tsuka

Emil · June 3

Since purchasing this katana in Tokyo, it has now experienced all four seasons here in Scandinavia.

Even from the start, the tsuka has always been overly tight. While it's slightly more manageable in the dry winter months, the fit is still too tight year-round, and it worsens noticeably in the humid summer. The mekugi it came with is aggressively tapered, which hints that it was a long time ago the mekugi ana aligned well. The shirasaya tsuka surprisingly fits perfectly all year round.

The blade is a Showa-era military piece that was used for tameshigiri in Japan, which is why it’s mounted in uchigatana-style koshirae. Unfortunately, sending it back to Japan for professional adjustment isn’t an option.

Would it be too risky to attempt a careful adjustment myself?

At this point the tsuka risks getting damaged from just mounting it in Koshirae, potentially worsening the cracks in the tsuka.

kissakai · June 3

If you search for this topic there are numerous ways of removing a tsuka

Then get someone to split the tsuka and a refit

Emil · June 3

Just now, kissakai said:

If you search for this topic there are numerous ways of removing a tsuka

Then get someone to split the tsuba and a refit

I was thinking along the lines of using a small file and adjusting it without disassembling it.

It turns into a international project if I need to have the handle rewrapped.

Brian · June 3

I assume it is just the tsuka, not the saya that is tight?
Personally, I think this is a fairly easy job for someone who is handy. Long thin files, working very slowly and removing very little at a time. No sandpaper, just files. Careful examinations should tell you if you need to remove a bit front to back, or if the sides are the problem. Just a few light strokes may find a high spot that is the main problem. But don't do this if you are not used to working with your hands and files.

Robert S · June 3

5 minutes ago, Brian said:

I assume it is just the tsuka, not the saya that is tight?
Personally, I think this is a fairly easy job for someone who is handy. Long thin files, working very slowly and removing very little at a time. No sandpaper, just files. Careful examinations should tell you if you need to remove a bit front to back, or if the sides are the problem. Just a few light strokes may find a high spot that is the main problem. But don't do this if you are not used to working with your hands and files.

Agreed. And additionally if the tang isn't already marking the inside of the tsuka where it binds, you could usefully put a little graphite (soft pencil lead) on the tang before you insert it, which will rub off on the tsuka where it binds, allowing you to see the high spots

Emil · June 3

Yes, it's only the Koshirae tsuka, the saya fits well

Thank you! This is really valuable advice @Brian @Robert S

ROKUJURO · June 3

Emil,

the Japanese SAYASHI do not use files for that purpose but specifically shaped rasps which work faster. These are available at NAMIKAWA HEIBEI if I remember correctly. I think I bought mine there.
They come in different length for SAYA work as well.

When you work on your TSUKA, be careful not to remove too much wood! You want a good tight fit in case you use your sword for TAMESHIGIRI!

Emil · June 4

Perfect, thanks! @ROKUJURO

Brian · June 4

11 hours ago, ROKUJURO said:

Emil,

the Japanese SAYASHI do not use files for that purpose but specifically shaped rasps which work faster.

Exactly why I suggested files. Rasps remove too much material fast. Since I expect he only needs to relieve a fraction of a mm, files will prevent him removing too much material and take it much slower. Plus mid sized needle files are cheap and easy to use, and come in many shapes.