---- david at piano.plus.com wrote: > it doesn’t take long for > the cloth surface of the wippen underside to wear to a different shape, > such that in time convex capstan bears on convex wippen. Exactly. And that is another reason why the comparison to involute gears is weak. The involute curve, as applied to gears does not reduce friction. In fact, it increases friction. To counter this in involute gear design, they use harder materials and improve provision for lubrication. You can't get much softer than felt, which makes our application a weak candidate for the involute concept. Frank Emerson
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