Floating Serpentine Shelf #2: Torsion Box Design

In my final design, each individual shelf and vertical side is a narrow torsion box (1 3/4” thick) with a skeleton made of 3/4” thick plywood spines and ribs and skins of 5mm (roughly 3/16”) thick plywood. The back panel is constructed similarly, with wider structural parts.

My plan was to attach each individual shelf to the back panel with a pair of 3/4” dowels and multiple #14 wood screws and to attach each side to its surrounding shelves with 3/8” dowels and wood glue.

I’m no engineer, but I thought and hoped that this structure would decrease weight and increase rigidity enough to make the overall shelf strong and stable. My estimate weight was 87 lbs (which turned out to be a bit low—the final weight was closer to 100 lbs).

-- Ron Stewart