Tuesday, October 7, 2014

Sotomaru Kanna — part II

Finally done.

Learnt a lot and feel like a plane maker. Dai maker, pardon me.

So recap from yesterday which I forgot completely already.

Make 3 sides square, mark your lines, make a hole connecting the lines.  As usual, I marked the mouth on the other side and took 2mm off to avoid tear out when coming from the top side. But once the hole was made I realised, oh great genius, that the mouth needs to be curved as the blade and not straight.

I looked at the geometry, and it seemed that the round escapement I had made was actually also useful to define the geometry of the mouth. These japanese guys are really clever, it would have take at least 5 planes to me to realise that.

So, after a few hammers, grinding and more hammering the blade was straight enough to try to fit it, then 2 hours millimetre by millimetre hammering in the blade, paring the bed, hammering the blade, paring the bed, hammering the bed and paring the blade, the blade was deep enough. How much is deep enough? deep enough is more than not yet there. I didn't take pictures of the process mainly because it's really boring and tiresome and you can find it all over the inet. So, blade was deep enough and I turned the dai and the fun begun:

I like the recursiveness of planing a plane. I used my beloved 60 1/2 for this. I had not the slightest idea of what curvature give to the sole. I mean, I know the blade has a given radius, but when you intersect that with a plane an angle different from 90 degrees you get some complex mathematics as they say in my job and I was far too hungry for trying trigonometry tonight. Anyway, as you plane off the bed, keep on looking to the blade (which is just 1mm off from the edge of plane) and try to make the distance between the sole and the blade constant along the width of the blade. That ensures that you have the right curvature. And not really the whole width, you want the sides the be a bit off. 

Anyway, just try it and you will understand.

(Thanks to Jason from mypeculiarnature we have a picture to express what I mean

Look closely at the middle one. Only the central part of the blade is actually cutting, the sides are covered by the lateral recesses so they cannot cut. If you don't do this, your plane will jam on the sides.)

A quick touch on the stones, and the blade looks sexy and ready to use. 

Did I say already that with all the hammering the bed and paring the blade I broke a piece of the side?

And here it is, waxed, on top of the new shooting board and next to the sexy little starrett for scale.

Oh, I forgot to say that I didn't measure anything. I'm training myself on the forgotten art of doing things by feel rather than by numbers. The angle of the bed was taken from another plane with a bevel gauge, the position of the blade is by the look of it and the thickness of the dai just comes from when the blade was deep enough.  All in all, it has a really nice feel this little fellow —for a trashy blade, a piece of fire wood and two nights of work, not bad at all.

EDIT: I got a book today in the mail I forgot I have bought. The Forgotten Arts by John Seymour. I open a page at random and I see the cooper dressing a stave on these large coopering planes. It reads: "The physical process of dressing  a stave to the correct shape is wondrous, because no prior measurement is made. The cooper selects exactly the right number of stave blanks, considering variations in width, and shapes them all to fit one another by eye only." What Seymour doesn't know is that plenty of measurements were made prior to the first shaving. Density, length, humidity... they all are measured by the experience the cooper has, even if no number is ever written down. Our bodies are extremely sensitive machines that can collapse hundreds of variables into one single feeling. But to achieve that, you need a certain intimacy, an intimacy with both the world and your own experience. “He knew, not by theory, but more delicately, in his eyes and fingers...” would Sturt say about the wheel right. To then add in sadness that those intimacies are over. Far from that, I would say, those intimacies are just beginning...


  1. It's a perfect fit! That last photo is particularly good (and it shows an additional, seldom mentioned benefit of Japanese planes: They are the perfect thing to hang on the wall. "Modern art for modern living!).

    Beautiful work.


  2. Thanks Jason!

    And indeed, japanese planes are the only tools that wife would allow in the living room. I hope she one day learns to appreciate the beauty of shavings too.