Now the (main) frame is ready, it's time to construct the rearfork. This part consists of two rear stays. Each of them will be constructed of two layers of birch plywood (5,5 mm - for strenght) plus one layer of whitewood (18 mm - the 'fill'). Again, the whitewood will be perforated to save weight.
These are epoxied together. Between the frame and the rear stays, two additional layers of whitewood (each 18 mm) are added to gain the correct inner width of the rear fork. As the bike lacks suspension, I'd like to be able to mount wide tires. Later on, I'll experience if this is necessary.
Next step will be attaching the rear fork to the (main) frame.
Keep on cycling!