Well after tackling the careful disassembly of a piano the bookcase part should be easy, huh? It is apart from having to work with curved surfaces if you are accustomed to box construction. Once you get the piano to your work area, finish gutting it. You’ll notice from the pictures that in the process of gutting our donor piano we had some damage (surface splintering) to the interior, which we then filled with water putty and sanded smooth. This is difficult to prevent due to the laminated construction.
Create a stable base out of new lumber or saw up pieces from the top, etc. Next is to stabilize the carcass and add in shelving. The key to working with the curves is to mark your work piece directly from the carcass versus trying to measure. A simple ¼” plywood back completes the bookcase save for finishing. We attached our back to the case and then routed it to size with a bearing-guided router bit, but you could just as easily cut it out with a jigsaw.