I designed a modular book shelf with two types that can be stacked together. In the first cut-sheet, I forgot to incorporate the cutting radius of the drill bit and realized that I have to put in fillets with 1/8″ radius. For each modules, 11 layers of profile components are held by 8 structure components that hold them together with press-fit connection. Profile components are divided into 4 parts in order to conserve the sheet material.
Joints for the assembly of profile components are puzzle-like that they fit together. Joints in between two different components fit also in the same way but cross each other perpendicularly. Dog-bone fillets are made inside to incorporate the size of 1/4″ diameter drill bit and 1/8″ radius fillets are placed at the entrance of the socket to make the assembly easier.