Friday, February 26, 2016

Fastening the Bottom

I finally got the four planks comprising the bottom fastened together today.  I say "finally" because I can well imagine in the old days someone building one of these boats in a week, which is how long we've been here.  But there has been lots of talking to visitors, a long interview with three reporters the other day, and just time spent sharpening up my tools and getting the lay of the land.

I lay out a center point where each edge-nail will go.

Making the pilot hole with the chisel first I make a cut one side of the line...

...then a cut on the other side...

...then wedge out a little square of wood.

This leaves a rectangular hole the same cross-section as the nail.  Then I pound the chisel in, rocking it back and forth a bit, and cut a hole a bit shallower than the nail.

Pilot holes down the edge of a plank.


A view of a pilot hole, with a nail mortise below it for the adjacent plank.

Today's papers had stories about me.

Given how long the interviews lasted I am surprised by how short the articles are, but the free advertising should be good for business, as Earle Brockway always said.

The local boatbuilder dropped off some waterproof glue for me.  Its a two-part deal with a small bottle of liquid accelerant.


I had to carefully prop one edge of the outer planks to hold their slight bevel while I nail.  

The last step is pounding the edge with a hammer, called kigoroshi.  You can see one compresses just the center of the edge, leaving the corners untouched.  The idea is when the planks are fastened the unsupported corners will collapse a bit and later when the wood fibers in the center spring back it makes for a super tight fit.

Glue spread on the plank edge.  In the old days boatbuilders used raw lacquer, and in this area raw lacquer thickened with wheat flour (today an 85-year old man told me that).  Then everything is edge-nailed together.

I cut plugs for the nail mortises, using my original pattern to lay them out.

I trim them so they don't quite fit, which means I have to hammer them home, ensuring a tight fit.  My teachers did not use patterns for this work; they could chisel mortises that were all identical working by eye, and they could cut plugs using just a large chisel.  I have nowhere near that level of experience and never will.

I cut the plugs using a circular saw...

Then split them to get two plugs.

With a plane, saw, and chisel I fit them all.

Because the grain of the plugs runs at right angles to the planking if the plugs are fit tight they won't come out, but I am gluing them regardless.  Its actually not a waterproof glue but it should keep them stuck in there.  You have to drive them in carefully, putting pressure on the end and hammering down at an angle to keep the heel of the plug tight to the mortise.


My Tokyo teacher used to trim them off with an adze so I will too.  The hardest part is making sure that feather edge of the plug (to the left) is down tight to the base of the mortise.  Otherwise when you plane it (tomorrow) it doesn't look clean.

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