Saturday, May 8, 2010

Screen Play (15)

Here it is: the 15th post in this build thread, with previous episodes archived to the right of the page.

Yesterday's posting showed the initial steps in cutting the joints found at the ends of the frame's lower tie. These joints both attach to the feet with cogged laps, and receive haunched through tenons from the frame legs. Here's a picture to refresh, as it were, the part which I am working upon:


Bear in mind that the above is a concept sketch from a few months back and I have since made several minor revisions here and there as full-scale drawing work was completed.

Here we are at the completion of the mortising for the through tenon:


As you can see, the hole does not go clean through completely, as the bottom of the piece has another 1/2" or so of material to be removed right across (that the side with the lap joint) - there's no point cleaning up the last bit of the mortise.

With the tenon done, I next processed the tenon haunches, and here I am cleaning up the corners with a chisel:


The completed haunched mortise:


Now, about that 1/2" lap of material to be removed, the one I just mentioned above:


And then the shoulders were cleaned up with a chisel:


Another view:


That was that, the joints are complete - yet, to soothe my paranoia, I placed the cross-tie atop the feet to confirm that the locations of the mortises were still in the right place:


Yep, looking okay:


With the joinery part done, the next-to-last step was the chamfering of the arrises:


That upper surface chamfer is not 45˚.

Another view, though I'm not sure if it's all that clarifying:


Final step on these pieces will be the finish planing, which I leave for the time-being.

Next up will be the latticework, or kōshi (格子). Here's some of the stock ready to go:


All for today - thanks for dropping by and stay tuned for more posts in this thread. Next: post 16

3 comments:

  1. Chris,
    The "not 45 degree" chamfer. Is it what was referred to at Eastwind as saruboo? Or the angles formed by a right triangle with sides measuring 3-4-5.
    Michael Morningstar

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  2. Hi Michael,

    yes, you're right, I did use the 'sarubō'(猿頬) profile. The word sarubō, by the way, means "monkey cheek". There are a few different ways to produce that profile, but the chamfer is around 60˚/30˚ on the stick. It's a common profile for decorative ceiling support rods, or sao-buchi (竿縁).

    Now, a 3-4-5 triangle profile is termed 'sashigo'. This comes from the reading of the characters 3-4-5 (三 四 五), which would ordinarily be 'san-shi-go', however this is shortened to 'sa-shi-go' in carpenter parlance. The sashigo profile is similar to sarubō, however the angle is 3/4, or [TAN 0.75], or 36.87˚/53.13˚.

    Thanks for asking and observing that comment in my blog!

    ~Chris

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  3. A brief follow-up on my previous comment: here's a link on JAANUS mentioning the 'monkey-cheek' profile:

    http://www.aisf.or.jp/~jaanus/deta/s/sarubootenjou.htm

    Cheers,

    Chris

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