Saturday, March 28, 2015

Gateway (79)

Post 79 in an ongoing series describing the design and construction of a kabukimon, a type of Japanese gate. This is a project for the Museum of Fine Arts in Boston. Post 1 in this series can be found here if you'd like to start at the beginning. Each post links to the next at the bottom of the page. Recent installments also to be found in the 'Blog archive' index to the right of the page.

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Another longish day, with some solid progress to show.

With the side door fitted, I turned my attention to fabricating the receiver piece which incorporates the door striker plate. I didn't prepare any drawings in this case. This is what I came up with 'winging it':


The uphill side, which would be hit by the rain, has a quarter-circle curve, and the lower terminates in a sort of drip edge (right).

Here's the funky little mortise for the striker plate and it's built-in receptacle:



 The receptacle (not sure that is the technically correct term for the part) fitted:


And then the striker plate:


Positioned on the wall post for a look-see:


The receiver is attached to the wall post by two GRK timber screws - the heads of these screws are recessed in a counter bore, and these in turn are capped by umeki:


Another view:


Just for comparison, here is the new part with the original - which was simply glued to the post:


Some of the parts on the original gate were oddly chunky, the receiver being a case in point. It's additional height beyond the door thickness simply provided more wood for the door catch to grind off.

I made sure the chamfer on the post stops and turns right where the receiver piece connects:


And ditto on the other end:


That completes work on the door and related framing - - except for the yatoi sen, which are the means by which much of the framing on this project connects. These are a type of floating tenon, some on this project come with a block hammer head end, and some come with a dovetailed hammerhead end. Depends how the connection goes together.

I made the stock out of Burmese teak off cuts, and once the pieces were made, I had to fit them to their respective parts, assemble the parts, and then mark out the points where the wedging keys, or shachi-sen, will be fitted. The trenches for the shachi sen have already been cut on the relevant timbers.

There are seven of these floating yatoi sen on the gate, and it seemed efficient to make them all at the same time even though they varied in certain details.

Here's the header for the paneled left side of the gate, beginning its slide down 'the pole':


'The pole' is a literal translation for the type of joint here, which is a rod tenon, or sao tsugi, sao meaning 'rod' or 'pole'.

The connection is reinforced against lateral and twisting loads by two stub tenons, and the central large tenon traps the yatoi sen in place:


The header fully down, with a square to check:


Then I mark out the mortises for the shachi sen, disassemble the parts, and cut the trenches on the key.

Here's one with the block hammerhead form, inserting from the rear of the flanking post:


All the way in, down so that it is recessed from the surface - this, to guard against any shrinkage in the post bottoming out the yatoi sen, which would push the flanking post off of the main post:


On the other side, the yatoi sen emerges:


It is a pretty darn strong connection, and super discrete. As mentioned many posts back, in attempting to match the aesthetic of the original gate, which employed many threaded rods, I have employed this form of all wood joinery. It'll last longer and no one will notice the change.

The same routine then commences with the fitting:



My wife popped by the shop at the time I was fitting the yatoi sen, and although I wasn't in what you might call an especially photogenic state, appearance-wise (a rare moment for me, let me assure you), she offered to shoot a little video. Seemed like it would be a good way of showing a little assembly work - gives you an idea of how the parts fit together:



That's all for this round. However Sunday is a brand new day and there is a list of tasks ahead....

Thanks for visiting the Carpentry Way. Comments always welcome. On to post 80

10 comments:

  1. Chris,
    Thanks.
    Thanks for the standard you are striving for.
    And thanks for taking the time and making the effort to share.
    Very Best Regards,
    Mike

    ReplyDelete
    Replies
    1. Mike,

      appreciate the comment and your sentiments.

      ~C

      Delete
  2. Every time i see a video of you test-assembling such perfect fit joinery, i keep wondering how much sweat you spent to disassemble it without hurting both you and the wood...and which moment gives you more thrill... :D

    ReplyDelete
    Replies
    1. Marecelo,

      thanks for the comment! Yes, I have to be careful in disassembly as sometimes the wood can flake or split at tight spot. It's good to have clamps on hand to hold certain surfaces down when pulling things apart.

      ~C

      Delete
  3. Hi Chris

    Would the striking piece have been mounted using floating double dovetail keys (like in post 73) on very old gates?

    The chamfering looks fantastic. I am pretty sure that I would have rushed the job and ended up having a chamfer all the way along the edge.

    Happy Easter
    Jonas

    ReplyDelete
    Replies
    1. Jonas,

      is it Easter already?

      On very old gates, there wouldn't have been a lock like this, so I'm not sure exactly what they would have done. While double-dovetail keys are a possible connection, if you pushed very hard on the door, the connection would be prone to opening a bit. As such keys are loaded, the side grain in both the key and the surrounding material gets compressed, and when the force lets off, the connection would be loose. They are not that strong a connection, and it is best to use them in sets and pairs if possible - on a receiver piece like the one I made, it would only be possible to fit a couple of small keys in. The use of timber screws seemed the most practical solution to a strong connection that could be demounted later on if it got damaged. On an old gate, such connections would commonly have also been made with iron spikes.

      ~C

      Delete
    2. Hi Chris.

      Thanks for the explanation. I can relate to the idea of being able to remove the piece if it should ever be damaged.

      In Denmark the Easter holiday started Friday, but I can't remember if it technically is Easter yet, or if it actually first start this next Friday.

      A totally different question:
      Have you ever visited Kanazawa Castle in Japan? My younger brother took me there once (he lives in Japan). Of all the buildings, carpentry and joinery I saw on that entire trip, this made the biggest impression on me.
      There was an "exploded" joint where you could see the individual pieces that connected the 2nd tier floor to the main posts. Absolutely stunning.
      If you have the chance, I can highly recommend to go see it.
      Brgds
      Jonas

      Delete
    3. Jonas,

      no I haven't checked out Kanazawa-jō, except in pictures. i have visited Ōsaka Castle, and that was pretty cool.

      ~C

      Delete
  4. I like the hammerhead assemblies, great solution!

    You set an incredible quality standard!

    ReplyDelete
    Replies
    1. Brian,
      thanks, glad you like it. Sometimes a little improvisation is needed huh?

      ~C

      Delete

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