You don't actually knap bone. Knapping flint, stone, and glass works because of the geometric construction of these materials. Percussion and pressure knapping shape conchoidal fracturing materials through a process of lithic reduction. You are essentially removing a geometric portion (flake) of the material by knocking or pushing it off by applying stress at the proper angle. Bone is not a conchoidal fracturing material. It is worked by primitive or modern means which essentially employ cutting and abrasive means to shape and sharpen the bone. Primitive means utilize stones and rocks for cutting and abrading. Modern means utilize saws and manual or power abrasive wheels, belts, files, and bits.
Brian