The first part to building this boat is joining and fastening the six planks that make up the bottom. The material is hinoki, quite a bit more dense than sugi (cedar). The side planks of the boat and most of the rest of it will be cedar. I am fastening the boat traditionally with edge-nails.
Though we milled this material with big machines the edges don't fit. Normally this would mean fitting with a handsaw (something I have described elsewhere in my writings) but hinoki is too dense and frankly the process would be too time-consuming.
In Tohoku two years ago my teacher surprised me by running a circular saw through the seams to fit them. I'd never even thought of this, as all of my teachers had done this only with handsaws. It was definitely the answer here given time and the material. It took 3-4 passes to get each seam tight. Its not as easy as it may sound.
My next innovation was one I have been thinking about for several years: a router jig to cut the trapezoidal mortises for the edge-nails. So I decided, given that the bottom alone needed 60 mortises and the side planks 15 each, that it was worth my time to take an hour and make a jig and borrow the shop's big router and straight bit.
It did a great job and all I had to do with square off the bottom. I clamped a straight edge along the mortises and used it to guide the chisel.
The finished mortise.
In another innovation rather than chiseling the hole directly I first drilled two pilot holes the width the nails. These would make the material easier to cut and also guide the chisel. Drilling pilot holes is something I started to do working with college students. as it really aids them in using the chisel.
I also chiseled from the inside out, the opposite of what I have been taught. In a lot of ways it was cleaner and more accurate to do it this way. Here I set the point of the chisel in one hole and lay it tight to the bottom of the mortise...
...and then drive the chisel through the planking.
Again the chisel followed the pilot holes every time. This really takes the guess work out of this process.
Here half the bottom is clamped and getting glued and edge-nailed.
Knowing that all my mortises were exactly the same, I asked if the main shop could mass produce plugs for me. Nakagawa san, the senior employee, was given the job and he set up production.
He made a jig that he screwed to the sliding table of the saw.
The bottom put together. The curved line on the left is actually the final curve of the sides of the boat.
A final note on innovation: all of my teachers in Japan demanded that I do everything the way they did it. Except for one teacher, none accepted any sort of suggestion or innovation from me. My bright ideas were absolutely not welcome. And yet toward the end of my time with my teachers most of them made a point of telling me that I had to innovate. Some even said I had to go beyond them before I could consider myself a craftsman. This seemed so odd: the slavish obedience followed by the exhortation to innovate.
On my bicycle ride around the coast last week I found exactly one wooden boat. It is surprisingly short, only about fifteen feet.
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