Thursday, July 23, 2009

First Light XVIII

This lantern project thread, now running to 18 parts and on-going, details the build up of a Japanese type of freestanding garden lantern, commonly seen in Shrine precincts. My palatial workshop for these proceedings is my apartment kitchen, and a sawhorse serves as my workbench as I tackle the work primarily with saw, chisel, and hand-plane. Previous postings in this thread can be found archived in the sidebar to the right of the page.

The ridgepole was the next item up for work. Actually, there are two ridgepoles, this is the lower and principal structural ridgepole. The other will be more like a cap and tie-down than a support. After the usual round of sawing the piece from a blank, then squaring, jointing and dimensioning with the hand plane, I had the piece ready for joinery processing. The first matter at hand was to put in the mortises for the stub posts, or tsuka, along with their respective mortises for their pegs:

Besides the mortises for the tsuka, I also put in square through mortises that will be used for fixing the upper and lower ridgepoles together:

Next it was time to process the backing cut on the ridge, a bevel taken both sides so as to form a flat surface for the upper roofing boards to lay against. Here I've begun shaping the backing cut using a 54mm plane:

When the planing was done, the ridgepole had truly taken shape:

Then it came time to make the tsuka, which I cut in chain fashion from a single stick of wood. Hopefully the knifed layout lines will be adequately visible in this photo:

Out came the router, and here we are partway through the cut out:

I use the router to deck the tenon cheek surfaces, then use a chisel and paring block to trim the tenon shoulders clean. If I had many more pieces to do, I would have set it up differently, using the router to process the cuts against the end grain, which would have obviated the step of paring with the chisel. For just two pieces there's no point in bothering with the set up for that.

Here are the completed tsuka, in all their cute little splendor:

Time to put the ridge on to see how it looks:

Another view:

You can see to the right a slight gap where the long side keta laps the short keta, which is caused by the ceiling panel being slightly over-dimension and hanging up in the rebate on the short keta. That problem will be attended to when I take the upper frame apart again.

Time for a little Japanese terminology: the word for ridgepole is muna-gi , written in kanji as: 棟木. The second character, '木' read ki/gi, is tree, and derives from a pictograph of a tree. A nice easy character that is commonly seen and pretty easy to remember I think. The first character in that compound is of more interest this point. '棟' is an amalgam of tree, '木' compressed to the left side, and '東' on the right, which is read variously as azuma or higashi. This element comes from a pictograph of a sack bound on two ends with a stick running through it:

This element has come to have the meaning of east, given the direction of the rising sun, and the figurative idea of piercing, the suns rays piercing the earth. This element, a character in it's own right, also refers to Eastern Japan as distinct from Western Japan.

Now, when the character for east, '東', is put together with tree/wood, '木', to make, '棟', the meaning of eastern tree is not in fact the result, as one might assume. Instead, the core idea from the pictograph above, that of the stick piercing or running through the sack is taken; thus '棟' refers to the wood which runs though from one end of the building to another, the ridgepole in other words.

Another carpentry-related Japanese word which uses the character '棟' is tōryō, 棟梁、literally ridgepole beam, a reference to the head carpenter. Like the ridgepole, the head carpenter is the one who ties all the parts of the entire project together and is critical to the soundness of result, hence the analogy.

Next time, post 19 in this series, I'll be working on the other parts of the roof, or maybe on the lattice screens, so please stay tuned to find out what unfolds.

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