Wednesday, December 24, 2014

Gateway (XIX)

Post 19 in a series describing the design and construction of a kabukimon (a type of Japanese gate). Previous installments located by way of the blog archive to the right of the page.

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My days of late are evenly split between re-sawing stock...


...and working on the rot repair splices for the kiosk:


I had imagined at the outset that splicing in new post lowers would take around three days, however I had forgotten how much more time-consuming these can be as compared to regular splicing with fresh stock.

For one thing, access to the existing posts is always slightly awkward:


Here I've rough cut the largest chunks out of the splices:


Notice the detached chunk on the left side? It contains the housing the previous carpenter had cut for the crossbeam. This joint doesn't make much sense to house so deeply as the beam does not bear any load, it simply keeps the posts apart a set distance and that's about it. I'll be detailing the connection differently.

Both existing posts are significantly out of square, by around 1/8" or so. This makes layout and cutting of the scarf joints a wee bit more involved. Plus, on the backside of the posts there are complications, like this groove milled in there for carrying electrical:


A closer view shows that we have both a groove and the stress relief kerf to deal with:


The kerf was originally patched with a sliver of wood, but the posts must have been a bit green as they shrank further, deformed, and the filler strip is now semi-attached at best. 

The other post has only the kerf and semi-attached filler strip to contend with:


After rough cutting the splices a bit more, I decided it would be prudent to repair the internal surfaces a bit with some patches. It will make for a better mechanical connection in the splice itself.

After shaping some patch pieces, out came the epoxy and (all) the bar clamps:


I like to put lots of clamps on, but am careful not to draw them up too tight so as to potentially starve the juncture of glue. A maxim from jūjutsu is that to pin someone skillfully is to 'pin lightly', and I take this forward into woodwork as 'clamp lightly'.

A closer look at one side:


And the other:


While letting that dry for 24 hours, I turned my attention to more stock prep. I had originally obtained two kabuki, the main cross beams. Kabuki literally means 'crown wood'. The entire structure is named after this aspect in fact. At that point in time when i ordered the timbers for this project I was undecided as to exactly how the joinery between the kabuki and the main posts would be arranged, so I decided to get a spare kabuki in case it was required due to drying or milling losses, and in case my joinery choice necessitated having large extra sections available.

After drying the material for 6 months in dehumidification, one of the kabuki had bowed a good 1/2" over its length, and through subsequent milling of the stock to S4S, I ended up with one kabuki just at dimension and the bowed one ended up of course being under dimension. The under-dimensioned stick was destined therefore to never become a main crossbeam for this gate, however it was of adequate dimension to serve as the source for the crown beam's nose pieces. Yes, the joinery arrangement had been settled upon, partly in reflection of the outcome from drying and milling. I'm glad I had the spare stick as it allowed me to make the optimum choice in regards to the joinery.

I dragged the undersize kabuki out so I could get at it, and as a first step laid out and ripped some strips from the beam, strips which will serve to patch the stress relief kerfs in other timbers:


More ripping allowed those two filler pieces to detach from the beam, and one did so with an entertaining noise and movement- a bit of stress had been released:


These filler pieces, despite the bowing, will still be perfectly useable for their intended task.

Then the beam was marked out for cross-cutting, the marks were double-checked and a few dust clouds later, there were three pieces where there once was one:


The two nose pieces were able to fit through my SCM planer, though they were quite heavy and required careful handling:


These things are a bit heavier than I wish to physically carry, at least when we are talking repeatedly carrying, so I 'walk' them around on their end grain to get them back for another pass through the machine.


After a dozen passes, two nose pieces for the kabuki now milled to dimension, plus a smidgeon:


Back to the kiosk post splicing work. After the glue had set, I milled the surfaces flat:


 The other one:


I next cut the 'T'-shaped stub tenons on the ends of the existing posts, and trimmed the abutment on the stepped portion of the splice where the wedge will be fitted (not illustrated).

A bit more trimming of the broad cheeks of the scarf allowed me to reach the point where I could check how those abutments were shaping up with the repair post pieces:


Obviously, the repair post is a good couple of feet long at this point. Be funny to overlook that detail and return the kiosk to site so that it was 10' tall all of a sudden.... I think they'd definitely notice that!

The splice seemed to be coming together okay:


Another view:


A while later I had the other repair post getting introduced to its new partner:


That splice also looks like it should come together decently - the remainder of the fitting will involve trimming the stub tenoned ends of both pieces, along with their receiving grooves:


My weapon of choice for a fair amount of the slice and dice action is this 54mm timber slick by Takashiba:


This is one of the first Japanese chisels I acquired while living in Japan. Takashiba chisels are quite good, but I couldn't tell you what kind of steel he uses.

The ura:


I set the splice work aside again and returned to timber prep. This time, the task was a simple one: cut the kabuki to length:


Cross-cutting is a simple and easy task, yet not one entered into blithely, especially in this case. There are no options for replacement should the beam suffer any miscutting, especially given all the effort so far to control checking, to dry it slowly and carefully over many months, and having gone to the trouble of taking it down to Long Island for S4S milling. You can see in the above picture that I was just barely able to squeeze the required dimension out of the timber, and the portion I am lopping off is conveniently removing the one portion of the beam which is a hair under size. That worked out well, and I will say that the above outcome is directly the result of personally attending to the milling process, knowing where I could leave off bringing an entire surface down clean, balanced off against the required dimension.

So, I scrutinized my drawings, stared hard at the number for the length, laid out to that number on the stick, plus a few inches. Then scrutinized the drawing again, asked myself some questions about the basic logic of the number in reference to other parts of the structure, and, feeling doubly-sure about the measurement, re-checked my marks. I stared hard at the tape....

Then, inhale, stare hard at the line, and cut:


And cut:


Separation anxiety now resolved:


Might want to look at cleaning the camera lens, huh?

I have a good slab of a tree here:


Well, getting there, bit by bit. Thanks for visiting, and all the best for the holidays!! On to post 20.

4 comments:

  1. Replies
    1. Paul,

      this is exactly how the addiction starts...

      Delete
  2. It all looks very heavy. When are you going to get that Barth lifting table?

    ReplyDelete
    Replies
    1. Hi Tico,

      well, when I have a spare $6000 kicking around. Those lifting tables are more expensive than I thought.

      In the meantime, I like to use leverage, johnson bar, pallet jack, rollers...

      ~C

      Delete

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