frame and case design

The basic frame of the pandalon will be constructed of softwood 2x4s, creating a box structure along with a plywood back panel and plywood soundboard.  The plywood panels will form a sandwich, attached to the front and back faces of the 2x4s, except for strategic regions of the soundboard where the 2x4 underneath will be carved away, to allow the soundboard to vibrate freely in those regions.
Wider flat lumber will cover the perimeter outside the 2x4s, forming the sides of the case and adding additional stiffness.  The wrestplank will be formed of two oak planks, glued together to double their thickness.

I was originally planning to use a very simple perimeter outline for the case, a narrow triangle ("shard of glass"), with a straight side on the right, where most pianos and harpsichords have a curved "bentside".  However, given the high length-to-width ratio of my non-foreshortened, 4-octave design, it is desirable to truncate the acute angle at the tail end, which otherwise would extend, dramatically but inconveniently, more than an additional foot beyond the length needed to accommodate the longest string.  And given the desire to have the string endpoints located at a consistent distance from the places where they pass over the bridge (in order to obtain consistent down-bearing force for each string, on the bridge), it is convenient to have a shape to the "bentside" which is more concave than a straight line.  However, I'm still not going with a curved bentside; instead, my "bentside" will be composed of two line segments, allowing better string endpoints while still preserving ease of construction with my limited tools and shop facilities (which is one of my main design priorities; not only for myself, but to make these designs easier for others to build as well, if they should wish to do so).

I was planning to use long bolts and hardware through the 2x4s, basically pinning them all together such that the bolts would support all the tension even in the absence of glue (which would simply serve to firm-up the structure).  But given how strong this new formula of Elmer's wood glue seems to be, I think that as long as I can obtain good glue joints, I don't need to count on additional strength from any metal fittings.  Hence, fittings can be smaller, though still present: I will use long screws to firmly attach the lumber together and hold everything effectively "clamped", while the glue joints dry.