Ready to fit the arms to the rear posts. I had rough cut the rear arms but I had to fine tune the cut somewhat with the angles and widths to get a tight fit into the rear post notches. No problem as the front is not glued up!
With the rear fitted, I glued the top of the arms to the front stubs.
Next, after re-establishing my lines, I used a bandsaw and handsaw to trim the front of the arm. I decided to shape the tight curves of the front first.
Because the legs are parallelograms, some angles are not 90 degrees!
I shaped the front curves using rasps and files. I then bandsawed the rest of the arm followed by rasps, files and spokeshaves. Here is the arm finally shaped, with the various shaping tools that I used.
Arms make a difference to the look of the chair! I will round over the edges later. Before glueing / screwing the arms in place I need to figure out how to do the ebony splines. I may want to cut the spline grooves before glue-up. Not sure at this point.
One can probably make router templates and jigs. I may try to do so in the future if I make more than one of these chairs. However, shaping by hand is not that difficult. The Nicholson 49 pattern maker's rasp is a terrific rasp. It really hogs off material fast and makes short work of bandsawn surfaces. A fine file will then smooth out the rasp surface. After that, sanding is no problem. I've got an assortment of rasps and files. I left North Bennet Street School with a big appreciation for the power of the rasp and file. I also use the Lie-Nielsen spokeshaves. 2 larger sizes (one flat and one curved) as well as a small size with an even tighter curve.
One could also use a drum sander. I do not have one. A decent machine will be a few bucks. I will keep an eye out for a used one. But space will be an issue.
Here is an important tip. A router will cut exactly to one's template. However, when shaping by hand one uses the template to trace the outline of the curve with a pencil. Then one cuts/shapes to the pencil line. However, pencil lines can be heavy. Lets say one shapes "close" to a pencil line. Well, this can mean an extra 1/32 thickness. If you add both sides then one may have thickened the piece by almost 1/16. Now, if one was not close in making the original template and left it heavy by, say 1/32 to 1/16 as well, then one may end up with a piece almost 1/8" thicker than the drawing calls for! This extra width may have a big impact (for better or worse) on the piece. I know - from direct experience. One really needs to shape so the pencil line is almost all gone - barely detectable. If you go too far, use the template and re-draw the line and slightly adjust the shape, shifting the template a bit so it fits the piece. That pencil line is the key. (If you are REALLY good, then you can shape without pencil lines. Then you are an artist at that point!)
Oh yes, for measuring and marking curves, these are necessary. I have 3 of them. I frequently use 2 of them and sometimes require all 3 for compound angle measurements. I like the Starrett's as they lock in place very well. Some cheapos do not lock in place well and the angles can get out of whack.
