# Communities > Bladesmiths, Blacksmiths, Artisans and Professionals > Japanese-Style Sword Makers Cafe >  Tsuka wood core question

## Dwight Pilkilton

Or more like a discussion, I have an Iaito that I have owned since the middle 80s and was looking at the wood core for insights (I plan on doing my first Tsuka soon !!) and I noticed that the core was carved much differently than what I have seen in the past. Instead of the wooden core being cut at 12:00 and 6:00 and the Nakago being carved out on both sides...this one was split at 9:00 and 3:00 with the Nakago opening on the top and bottom. This looks like it would be stronger as you have solid wood on top and bottom of the Nakago...but it would make it difficult to carve out the opening and make the Mekugi pin questionable ??

I dunno , you folks chime in!

Thanks and a sleepy Dwight tonight

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## Guido Schiller

I, too, have seen that on Iaitô. It might be stronger (?), but they only can do it this way because Iaitô are kind of assembly line made and the Tsuka don't have to be hand-carved to fit each Nakago individually. The Nakago of each series has the same dimensions, and Tsuka are pre-carved by machines, in which case routing a V-channel and a straight channel respectively into the two halves is probably the easiest approach.

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## Will Graves

merely the most efficient way to machine-rout a tsuka core. I've seen a couple of these. That construction would be so difficult as to be silly to attempt by hand.

But there's good news about that. The construction in question is NOT stronger than it is by the traditional method, particularly if you use Elmer's white or wood glue  to join the halves. Butt joints using those adhesives will produce a stronger area than plain wood. 

That is to say, most species of wood will tend to fail anywhere BUT at the glue joint. And the surface area of a tsuka's halves glued at "12:00 and 6:00" is much greater than that at 9and 3.

Good luck with your project!

-Will

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