Fun with Ko-Ko-Gen and other Facts of Wood


Starting off from where I left you on my last post, staring at the end grain of some old douglas fir decking. In many respects, perhaps not remarkable lumber, but I love the warm glow and even grain, it is something as to character that I look for in other species of timber to favour. This material will be planed down to 1/4″ and given tongue and groove edges with my plow plane.


Stable material like this behaves during sawing! I also have a much better understanding of how much set the saw needs for me to re-saw and leave a nice surface like this.


I recently bought Chris Hall’s “The Art of Japanese Carpentry Drawing, Volume II: Fundamentals of Kokogen”, which I have found to be totally worth the outlay of cash for a bit of scarce knowledge in the English language.  Now I get the whole unit triangle thing, and kept on having these dumb moments where I felt like I was in high school geometry again (although I loved geometry!). Now when reading “The Complete Japanese Joinery” I see something like, use reverse chogen slope, and it seems pretty straight forward, sort of. There’s theory, and then there’s putting it to practice.


Both the edge cut and the face cut of a hopper (splay sided box) can be determined directly with different segments of the unit triangle for the overall rise/run. Unfortunately I still had a bit to learn about what value is used on which side of the sashigane, and marked out the wrong angle for the miter cut on the board edge.


But the layout looks so promising! Meh. Now it just looks wrong. Still some challenge left in executing these diagonal grain cuts with a hand saw.


I didn’t have time to try again, off to lunch with mother and my niece Lilly. This is what I look like close up to a four year old, haha. Childs eye view?


She was by today as well picking up a special delivery. Anyone know what this tool is for?


Slicing some different kinds of domestic truffles! I’ve never tried any of these before, the smell was very rich in an off sort of way.


The grain of this beam is what I think of as rich in an off sort of way. As in, off enough to break the window from swelling and bowing in the middle during a freak 1000 year rain event we had not too long ago. Beautiful patina for some old redwood 6×6 that’s taken fifty years of weather and sun.


Up next, daiku study group day. And what mysteries of joinery might this shachi-sen hold under key?

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