I've always thought that this neck shaping belt sander Charles Fox dreamed up is pretty cool. He uses graphite cloth on the posts rather than idle pulleys. I played one of the instruments with this type neck, I do have to say the heel was a little weirdly shaped. Better pictures can be found here: http://www.frets.com/FretsPages/Feature ... fox01.html
Upon further examination --- looks to me like those clamps are holding the graphite cloth in place. I imagine it gets changed often when the machine is used daily.
Yeah it does look like cloth when I blow it up. I suppose the 'secret' of the setup is the jig that holds the neck - a different jig for each kind of profile.
Yeah looks like the geometry is set by the holding fixture location and angle. The platen is symetrical so the holding fixture must get flipped end to end to do each edge.