Making the Downward Arches
The function of the tools I use and how they work are explained here. Specific tools used are noted in bold.
Like the main arch, the two downward arches taper in thickness from the middle to the ends. Originally I thought I’d bend the arches, with the middles bowing outward. It turns out that given the width of the table there isn’t enough room to allow for this. The arches will still have a bit of bow to them, as they taper.
The arches are constructed by laminating together three pieces of baltic birch plywood. This type of plywood has more numerous and densers plies than typical plywood, and results in a very dense structure. The middle piece of plywood is tapered using a power planner, which is like an inverted handheld version of the jointer. The tapers are smoothed with a handplane and sanding. Like the main arch, glue is rolled on and the packet of plies is pressed in the vacuum press.
After the glue dries the arches are cut on the bandsaw. The convex curve is smoothed on the edge sander. The concave curve is smoothed by hand using a compass plane. The compass plan has a flexible sole which can be bent in an unlimited number of radiuses. After this initial smoothing, the final truing of the curves is done with the two arches clamped together. This ensures a consistent and even shape within and between the arches. The curves are tuned using the compass plane, a rasp, and hand and power sanding.