An interesting problem has just come to light, and I would welcome any advice.
The restoration of one of my large Lachenal MacCann duets necessitates replacing the entire outer moulding which holds the ends and fixes them to the action board. I decided to do this, as the existing woodwork, and indeed metal ends, are very clearly not original, and are very crudely made, and spoil the overall appearance quite a lot. I copied the moulding from another instrument, complex ebony/teak with lots of shaping and rebating. No problems though, until I began to make the former on which to glue it up into a frame, and found that the bellows are quite badly non-symmetrical. That is to say, each end is not a perfect hexagon, but has possibly moved out of kilter during its life, or probably during its poor repair. The bellows seem quite rigid though, are in fine condition and function very well.
My inclination is running in the direction of building the ends to fit the bellows whatever their shape, rather than trying to straighten them up with the possible consequence of breaking glue lines and causing damage to the leather-work. What do the experts think? Any advice/musings welcome.