After reading a number of articles and books during the past few years about the plywood sandwich and L girder principles, I am thinking of bringing the two ideas together. Plywood sandwich for the end sections for stability and strength, L girder for sides which should reduce twisting and allow me to construct curved baseboards (hopefully). The centre beam is at the moment only a single piece of plywood. Not sure that this would need to be a full sandwich like the end pieces?
Locating and fixing the boards together is still open to discussion but I would like to make use of pattern makers dowels at each end of the end sections for accuracy. Possibly an old method of Coach Bolts for drawing the boards together tightly and securely in the centre of the end sections. Coach Bolts will be internal to the baseboards, I would like to keep the sides free of as many fixtures and fittings as possible.
I am also thinking about constructing the end pieces with the outer face deeper than the internal face. This should allow two boards to be fixed together and the profiles cut as one. Just thought, the L Girder sides could be constructed differently as well. Another sketch is needed.