But the radii are not the same, are they? And therefore they travel different distances. Balance rail/key interface to tip of capstan is not the same distance as wippen heal/contact interface to wippen center? David Love www.davidlovepianos.com > Ron Nossaman wrote: > > I don't know for sure, but I think so, with the right capstan angle > > and profiles. The contact points would change, sure, but I think > > nearly all, if not all sliding could be eliminated. That's if you > > didn't go above the magic line. If the radius of the capstan and the radius of the curve of the wippen heal are such that the capstan must travel the same distance along the curve of the wippen, as the wippen must travel along the curve of the capstan, there is no sliding friction. The two surfaces roll together synergistically. There is still a certain amount of friction, but not so much as with sliding contact conditions. Whether it be above or below the magic line is irrelevant. Frank Emerson
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