Wednesday, January 13, 2010

Battari Shōgi 13

Lucky number 13 in the post train. I'm approaching the conclusion of this build thread on a type of folding produce stand that attaches to the front of traditional Kyōto-area merchant's houses, or machi-ya. Previous posts in this thread are to be found in the 'Blog Archive' to the right of the page.

The next step in the joinery work, pretty much the last step for that matter, is the connection between the legs and the stretcher. I was going to do a simple housing for the joint, but then changed my mind and opted for shouldering the joint on the broad faces. This allows me to chamfer the arrises of the stretcher without any gaps showing at the joint interface, or recourse to cheesy interupted chamfers that show a portion of end grain.

First step was to rough out the cheeks of the tenon, which I accomplished with my router. The tenon is 0.25" slimmer than the stretcher. Then I used a marking gauge to define the twin tenons with haunch:


Out comes the ailing 240mm ryoba, though the rip side of the tool is in good shape, and a new episode of Sawing for Teens:


Getting closer:


Then a little final trimming with a 10mm chisel:


Time to offer it up to the leg to see how it fits:


It was tight, but no trouble to fit:


A look from the other side:


A better perspective perhaps, if I take a step back with the camera:


You might notice that the leg is now curvilinear. It became this shape not for stylistic reasons, but because I wanted to have the leg assembly fold up to be flush with the underside of the bench. Most of the Japanese examples I have looked at don't seem to bother about this, but I thought it would look a little cleaner if the legs tucked in out of sight when the bench is in the 'up' position, and at the same time have the stretcher laying flat against the underside of the cross-pieces. Also, given the heavy weight of the Wenge, I was looking for places to slim the piece down where I could and shave some ounces here and there. The original legs were 5cm x 12cm in section, and even in pine that is way too stout for the purpose of carrying a couple of people. The new legs in Wenge are 1.75" thick and 3.5" wide.

To get the legs flush I needed to offset the stretcher, or nuki, forward from the centerline by 0.4375" (7/16"). In order to conceal the off-centered position of the stretcher, I brought the leg edges forwards and around the offset stretcher centerline in a serpentine manner. The result is that the stretcher is centered on the body of the leg.

I did find another example of a battari-shōgi with curved legs:


Unlike the legs in the above example, which curve out at the feet, mine tuck in at the bottom, that is, they are shaped somewhat in the reverse of the above. In the above example, it doesn't look like the stretcher lays flat against the cross-pieces, but that could just be the camera angle.

One more trial assembly was in order to check how the leg assembly worked with the hinges, etc.:


At this point, the tenons on the stretcher are left long by about 0.125", and thus interfere with the leg swinging all the way in:


Once the pieces are assembled for good, and the wedges driven in, the twin tenons will be trimmed flush with the exterior face of the leg, and the leg assembly can tuck right in.

I put the bench onto the floor, standing on its four support points, for the first time. Here's the side view:


Another small task to deal with was trimming the frame so as to allow it to clear the support ledge on the bolster when the bench is swung up into the upright position. I accomplished this trim cut with my router, swung around on the axis of the hinge pin (using a temporary dummy pin for the purpose):


Here's a check to confirm the operation of the leg:


Looks good:


Well, that's 98% of the way there with this project. All that remains is some more finish planing and scraping, and then the oiling and the piece will be ready for assembly. Stay tuned for more, and thanks for dropping by the Carpentry Way on your journey today. Go to post 14.

3 comments:

  1. Hi Chris,

    I'm curious how you made the cross grain cut between the tenons on the stretcher. That isn't the waste piece -intact- on the floor in the "getting closer" shot, is it?
    The methods I can think of (coping or bow saw, etc.) must be a pain in wenge, and wouldn't leave a nice clean cut as seen in the pics...

    -Matt

    ReplyDelete
  2. Hi Matt,

    haven't you heard of Porta-Lazr®, the handyman home laser system?

    Just kidding! That piece on the floor isn't the waste piece from the tenon cut-out, it's just a little off-cut scrap I was using as a support underneath the tenon while I cut it out. I first drilled the corners out and then used a router freehand to sever the piece of waste from the stock. Then I set up a paring block, with that little support piece underneath, and chopped the end grain clean across. Make sense?

    Still, that laser, or perhaps an industrial water jet cutter would sure be handy at times... :^)

    ~Chris

    ReplyDelete
  3. Looks great Chris. I still don't think the people at the museum really know what they are getting here. But it should last them well into the next three centuries.

    ReplyDelete

All comments are moderated:

Anonymous comments will be deleted

Spam will be deleted

Comments containing links unrelated to blog content will be deleted