" . . . I think that I have absorbed the principles of coinciding arcs, key ratio, and so on, that underlie the grand piano. . ." The geometry of good uprights are no less critical than in a grand. Coinciding arcs apply equally. Look in your supply house catalogs for a book explaining upright geometry. No higher math required than being able to count to ten on you fingers. (About all I can do.) It is a good book and will explain tolerances and how to compensate for stickers and dowel capstans. My library is in storage. Newton
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