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The Chair – Shaping the Arms and Back (Part 1)
When I first planned to build The Chair there were two areas that I found daunting and, frankly, I doubted whether I could pull it off. The first was the triangular fingers that joined the arms and the back. The second was the shaping of the arms and the back. The fingers are about as good as they will be, and they are ready for gluing. It is now time to shape the arms and back.
Below is the chair showing the arms and the back …
The roughly shaped back with completed fingers, along with the arms, which are marked out from a template.
Above, the template for the back.
Marked out ready to saw away the waste.
Above and Below: The profile is transferred from one side to the other …
Above: Marked out.
Bandsawed close to the marks.
This is the angle required at the rear of the back. A template is made to check progress. For reference, the angle is the same all the way around. The rear is flat with the exception of the upper and lower edges.
I first attempted to shape the rear with a drawknife. This curly/fiddle back Jarrah is so hard that the razor sharp drawknife could not do more than take shallow cuts. I tried a variety of spokeshaves – all struggled with the interlocked and reversing grain.
In the end I sawed kerfs and along the lower triangle, and used a chisel.
Chopping out as much of the waste as possible.
This Shinto Saw Rasp is fantastic. Coarse one side and fine on the other. It is essentially a bunch of saw blades riveted together. This was not quite as coarse as a 10 grain Auriou, but it is easier to keep flat, which is helpful working the rear of the back.
The arms were marked ….
… and most of the waste was removed either with a bandsaw or a coping saw.
The arms and back were clamped together for a first look.
From the rear.
The parts are dissembled again … shaping of the back continued …
A series of graduated templates were used to rasp the depth of the curve.
Final shaping was completed with the Shinto and Auriou rasp.
The arms were next …
First the upper side was rasped down to the template lines. At this stage this is still parallel with the underside.
Before any angles can be shaped in, the outline is tidied up, again with rasps.
The arms have compound curves. These are calculated by dropping a depth from a straight edge at predetermined distances.
Up to this point my plan had been to shape the entire arm before glue up. To do this I was going to mark the position for the (leg) tenons, which would make it possible to complete the lower side …
However, I realised that there was a flaw in this plan.
The chair back was clamped in a vise and the chair base inverted on top to mark the position of the tenons. I realised then that this method would end up with inaccurate placements if the parts moved from this exact positioning.
There was no other choice – the arms and back had to be glued together, and the final shaping completed with one fixed section, which is essentially as the factory had done.
Glue choice was Titebond Liquid Hide Glue. I had tested a fresh bottle a few days ago, and it created a very strong join. I like that it is reversible, easy to clean up, and does not affect the finish.
Regards from Perth