Tuesday, August 25, 2009

First Light XXXVII

The 37th installment in the build up of a Japanese garden lantern. Previous posts are archived to the right of the page, so please take a gander at those first if you are new to this blog and are hoping to make any sense of the material to follow(!)

Still working on the lattice. The 'X' center bars were complete at the conclusion of the previous post - now it was time for the surrounding pattern of truncated bars, which when laced together will produce a quadruple diamond pattern. These bars - kumiko - are a little more slender than the main 'X' bars. This is similar to a Japanese pattern often used in shōji and window grilles, called oyako (親子), which means 'parent and children'. Two small bars paired with one larger one - you get the allusion I'm sure.

So, first thing was to do some drawing atop the fixing jig:


The result is the establishment of the lines for the smaller kumiko:


Next I inserted a central 'X' assembly into the fixture:


The reason? Well, one thing I wanted to avoid was cutting the half laps on the parts in such a way that I had an unattractive pattern, or worse, a weak assembly, or worst, something that couldn't be assembled at all. Therefore, just to be sure of what I was doing, I superimposed the parts one above the other so as to be absolutely clear as to which side of each bar the cuts needed to be made on to give the desired result:


Next I trenched out the jig for the smaller kumiko:


After that, I could re-install the central 'X' assembly and rout a half lap on each side of the center, two topside and two under. Here's the 4 assemblies after that stage:


Next step was to mark out along the sides of the main bars at he new laps for the mitered lap housings which accept the smaller kumiko - I've got a Lilliputian Starrett engineer's square perfect for such tasks:


When it comes to squares, there really are only two brands, I have found, worth spending your money on: Starrett, and Mitutoyo.

A little further along in the process, and I have a small factory enterprise underway as I work on putting the half-laps on to the sets of peripheral kumiko, and then cutting and mitering the crosswise lap housings:


A completed assembly of smaller kumiko:


At last all four sub-sets were fitted up:


Next it was time to put the smaller kumiko sub-assemblies back in the fixing jig so I could cut the half laps for the 'X' brace assemblies to be fitted to them. This stage had to be done separately from the other half-lap cuts in the smaller sub-assemblies given the fact that the joining of two un-equal thickness pieces in a housed half-lap means that the smaller piece needs a wider lap and the larger piece needs a deeper housing (or you end up with, uh, fun and games with the mitered abutments - no thanks!):


A while later, I was able to fit up the 'X' bars, one by one - the top bar locks the whole works together:


I wish that was a clearer picture -sorry!

And here's a completed kumiko assembly:


Then there were four:


Getting the assemblies out of the fixing jig requires care and patience as the fit of the individual bars is somewhat snug - take a bunch of bars together and it's really wedged in there let me assure you. It would be all too easy to break a joint trying to lever a bar up out of a trench. No such bad luck occurred however - whew!

Next time, post 38, I'll show how I dealt with by far the trickiest part of making these lantern grilles - the attachment of the kumiko assemblies to the frames. Stay tuned.

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