Wednesday, June 17, 2009

First Light III

When I last left off, I had commenced the cut out for the support arms, hijiki. After the needed pieces were sawn, I used a 70mm kanna to clean them up, following the pattern of taking one face out of wind, squaring up an adjacent face, then the other, then the last face. After that, using my digital caliper to check and re-check, I dimensioned the pieces down to size, leaving them just a hair fat at @ 0.005" oversize on the sides, and about 1/64th+(0.015") on the vertical dimension. That leaves me enough room for a final light pass with the plane on the sides at final assembly, and enough extra on top to adjust for any inconsistencies in fit with all the parts coming together at one place.

Then I used a trim router to cut the housing seats, and followed that by paring the cog abutment walls with a chisel and guide block:


Once the first piece was cut out, I tested the fit:


I followed by cutting the cog lap housings in the crosswise piece, and then set about cutting out the half lap with mitered abutments, or mengoshi (面腰) in Japanese:


The half lap cut nearly complete:


I then pared the abutments to 45˚, with a small paring block I made up with a scrap of Mahogany:


In retrospect, I think the next time I will make these mitered abutments a little less pronounced for depth - probably at .125" or .1875" they would be about perfect.

A bit more paring:


The completed lower face of the first hijiki, this one having 0.25" deep cog housings unlike the second piece which h 0.25" deep housings


You know, maybe it's subconscious on my part, but this part is starting to look awfully reminiscent of a Shimano bicycle derailleur:


Hah! -now that my 'secret' is out of the bag, I can move on, perhaps living out a quiet retirement in the countryside (just kidding of course! :^))

The completed half lap on the first piece:


Then a trial fit of the two pieces at the top of the post, which also allowed me to do a little scribing. As the top piece of the first 'X' bottomed out, I marked the meeting point with the front of the cog housing on the post face, a process repeated on all four faces:


Back to a little freehand work with the sweet-runnin' Festool 1hp. router, OF1010:


After the router work to deck the housings, I completed their walls with some chisel paring work. Here's the completed second piece lower face - it looks like it could have a starring role as a set piece for a Battlestar Galactica model:


Note the second piece has the 0.5" square through mortises now roughed out. I used a hand drill and then a chisel to do the mortises. Here's how the two lower hijiki look, on the bottom face, when they are lapped together:


Another trial fit:


Down, down down:


Success!:


The initial fit was acceptable, though I need to do a little more flattening of the top face, which had been left a bit over dimension anyhow:


Next post in this thread, I'll show how the second 'X' is fitted up to the first. I might want to return to my other thread on 'fun in triangle land' (kō-ko-gen hō) before too long however.

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