Wooden training knives

[TheFatBaron]

So, this'll be a little different than most of the projects here. I do martial arts (aikido and a couple Japanese sword arts) in my free time, and have a small business (and I use that term very loosely) making wooden training weapons in a couple different style.

 

A friend of mine I train with bought an ipe bokken (long sword), and snapped it roughly in half on its first strong hit.

 

 

There's really no way to repair major damage like this, so he asked me to make some tanto (knives).

 

 

After cutting out the damaged sections, I was left with enough for three tanto. One is solid ipe. The other two I used some scrap eucalyptus (which is too fragile for impact weapons) to fill out the shape - one joined with a full-lap joint, the other with a half-lap dovetail. While they're not used for wood-to-wood impact, they do get abused in other ways, so I didn't want to chance gluing up an end-grain joint.

 

 

 

Here are the final products:

 

 

 

 

[TheFatBaron]

Oh - so, I realize that this is a little more "worklog" than many, but I'm curious what you guys think about the wood combination, and if you had any thoughts regarding alternative joints for endgrain like this.

[duckkisser]

that joint had to have been interesting to get just right.  how did you go about making that type of dovetail joint.

[TheFatBaron]

Duck -

 

I found a link (from somewhere in this forum, actually) to an page with tons of photos of joints, and saw it there. From there, I did a bunch of image searches on Google, and a bunch of sketches to make sure I got the general principles. The pictures above were actually a test cut that was done purely by hand. Cutting the ipe was pretty easy - it's essentially cutting a half-lap joint, then cutting the end into a dovetail.

 

For the final cut, I re-used the same piece of ipe (I just made sure the cuts were actually flat and square). I took a new piece of eucalpytus, made sure it was square and oversized, and the cut the first part (essentially the half-lap part) on a tablesaw to get it dead flat and square. After making sure I had plenty of eucalyptus to work with (remember, the ipe was already at it's "final" dimensions, I transferred the tail (I think that's the tail) shape to the eucalyptus, and carefully cut it out.

 

For me, I think the trick is to always leave yourself room to work. I left the half-lap portion a little long, just to be safe. I cut the receiver for the dovetail too tight at first. And then I left myself plenty of eucalyptus to cut away in the final shaping. Since I do the final shaping with chisels, spokeshaves and files (and occasionally an orbital sander), as long as the joint was tight, it didn't need to be perfect in any other dimension. You can see some spots where that didn't quite work and I had to use epoxy and sawdust to fill some gaps.

[woodieboy]

That's a very clean work! Nicely done.