Friday, May 14, 2010

Screen Play (17)

Before I get to today's update on the tsuitate, I thought I'd mention that I've been making good progress on Volume III of The Art of Japanese Carpentry Drawing, which is devoted to splicing joints. So far I've drawn about a dozen joints, and I'm just getting started. This volume will cover the most useful and important Japanese scarfs and splices, of use to joiners, timber framers, and furniture makers. The joints will be dealt with in a kihon/henka fashion. Kihon (基本) are the standard forms/methods of a thing, and henka (変化) are the variations. Thus on the kanawa-tsugi joint for example, I have one kihon and 6 henka (so far!). I'm trying to plug away at it, drawing a new joint or variation every day, and intend to have the essay available for sale by the late Summer or early Fall. It will probably be 75~100 pages. Yes, just on splicing joints. The price will likely be in the ballpark of the Volume I and II set currently for sale, and I have also decided that I will discount the price 25% for those readers who have completed the study material and exam from the first offering.

I'll be following up that with Volume IV, which will be devoted to splayed post work, and I expect that could easily run 125~150 pages. I intend it to be the most complete treatment of that compound joinery issue ever published in any language. Some of it I have already written, however I plan to greatly expand upon my previous work.

Beside that drawing work, I've been getting ready for an upcoming presentation of Japanese carpentry and wooden architecture for the Japan Society of Boston. That takes place on June 13th. I've also received an invitation to show work at the Fine Furniture Show in Rhode Island, happening on October 22nd or thereabouts. That will be the first show I've ever gone to as an exhibitor and have quite a few plans for that percolating away. It's exciting! This current project may end up in that show unless I sell it before then.

Anyway, here we are at the 17th installment of the Japanese freestanding screen build-up. Previous postings are archived to the right of the page.

I've made good progress with the kōshi, subject of the previous couple of posts, and today I decided to finish off the haunched tenon joint that connects the frame uprights with the sill, or lower tie piece, and the two feet. The first task was to knife the shoulders, for which I clamped a large square, or kane-jaku, to the leg, along the plumb reference line, and then sliced along the pencil line:

Then I kerfed the sides of the tenon with my circular saw:

Here we are after both tenons are roughed out:

Then I routed the surfaces clean, leaving this as the result:

Target thickness for these tenons is 1.25":

Next I set up the kanejaku again, this time with a paring block at the end so I could trim the shoulders down to the knifed kerfs:

Out comes the tsubaki abura (Camellia oil) and a chisel:

A reasonable start is made:

Since two of the sides of the stick are already template routed and are curvilinear, I can't readily pare in reference to those faces without getting into another jig build, so I freehand trim to the marks with a chisel, and then shave the area with my shoulder plane:

Every once in a while I check with a straight piece of metal to see how flat the surface of the tenon shoulder is - here you can see a slight gap at the top of the meeting between ruler and wood:

A couple of shavings later, the surface is decked flat:

I very slightly hollow the portion of the shoulder near the root of the tenon:

I do this because the grain of the sill is such that at a dry time of year it could cup outward ever so slightly, and this slight hollowing of the tenon shoulder should keep the fit at the edge of the leg tight throughout the moisture cycle.

Next I chamfer the arrises of the tenon haunch:

Looking nearly done, but there's another step yet:

These tenons are about 1" longer than they need to be, so it was time to trim them to the line:

This is the cut surface I get with a general purpose replaceable blade carpentry saw:

I followed up by paring the end grain clean. This tenon is not really exposed to view, as you would have to lay the entire screen on its side and peer at the under-surface of the foot to see it, but I like to be thorough:

End grain paring done, and arrises trimmed:

And here are the two haunched tenons, now complete except for the peg mortises, which I will mark later by direct transfer:

The pegs themselves will be slightly draw-bored, and will be made of Bubinga. The tenons protrude out the bottom of the feet by a couple of millimeters.

Thanks for dropping by today, your comments are most welcome. --> go to post 18


  1. Great progress Chris. It's exciting to read the news about volume III of Japanese Carpentry Drawing and the Fine Furnishings Show. Keep us posted.

  2. Hah!
    I just learned something. I'm always pushing my luck when using routers to trim the bottoms of housings, and long tenon cheeks. Even with PW offset bases I often find myself extending out too far past the reference.
    Last week in fact, I botched a cogged half lap doing this. Leaving material midspan for support is brilliant, and probably basic woodworking 101.
    Thanks for that Chris. Any chance you'll write a volume on hip rafter layout? I once made a model but skimped on the kayaoi and used the three piece dovetailed keta crossover. Once I finish my house, this is something I plan on delving back into.

  3. Dale,

    thanks again, and will do.


    I'm glad that you noticed that 'hint'. I don't think it is 'woodworking 101' necessarily. It helps to have a router with full base plate (Festool is not a good choice in that regard, so an add-on acrylic base plate is necessary).

    And as far as a volume on hip rafter layout, well, of course that will be coming along. Don't worry about that. The other compound joinery stuff I'm writing is partly intended as preparation for that, though there are several points of connection with splayed post work to hip rafter work. It's all interesting to me. Probably volume 5 or 6 will start in on regular hip rafter layout, with subsequent volumes planned for irregular, curvilinear, and polygonal hip work. Along with all that, there will be further volumes on joinery and other aspects of carpentry drawing.

    Jeez, a lot of work ahead...

    BTW Michael, I have a new and different form of 3-way keta joint that I'm in favor of using these days, a version which I believe you won't have seen before.


  4. Michael,

    this is top secret - NSA top level clearance is required :^)

    I'll be building a small hip-roofed structure in the next few months and I'll be using it in that. I'll send you pictures.



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