Integral attachment, the joining of parts through their form rather than additional connectors or adhesives, is a common technique in many industry sectors. Following a renaissance of integral joints for timber frame structures, recent research investigates techniques for the attachment of timber plate structures. This paper introduces double through tenon joints, which allow for the rapid, precise and fully integral assembly of doubly-curved folded surface structures with two interconnected layers of cross-laminated engineered wood panels. The shape of the plates and the assembly sequence allow for an attachment without additional connectors or adhesives. The fabrication and assembly constraint based design is achieved through algorithms, which automatically generate the geometry of the parts and the G-Code for the fabrication. We present the fabrication and assembly of prototypes fabricated with 3D CNC milling and laser cutting systems, comparing and discussing the advantages and disadvantages of the individual techniques.