I doubt that I will be in Albuquerque this summer, and I have a question now. I am just starting a S&S L for which I plan to do my first complete Renner back action replacement kit. But first, this action produces some numbers which seem to suggest contradiction with earlier implications (regarding key ratio) or at least raise a curious problem. The numbers are as follows: Key Ratio = .460 Shank Ratio = 6.753 Wip Ratio = 1.3923 Strike Motion Ratio = 4.3250 Not impressive to say the least! Yet the Down Weight in the tenor averages 45g, the Up Weight, 26g. Granted these old hammers are worn (the average tenor hammer weighs 6.7g) but how does it make sense that we get such great touch weight measurements with capstans so far off? If I move the capstans one full cm as required to achieve a .50 Key Ratio, they will be completely off the cushions. What now? My new hammers have not even arrived yet, but I should be able to solve ratio problems by studying the old parts. Anyway, I am using the Renner N.Y. dimension parts which duplicate the old (with smaller knuckle). David, have you (or anyone else) been able yet to incorporate the geometry of the back action into your motion ratios? The impact of bad geometry here must be magnified by the less leveraged shank, or is it? Other than in these churches recently discussed with missing bass strings, how often is the piano played with the dampers off? If I jumped the gun on this summer's forum, I'm sure there'll still be plenty of fresh, virgin ground to plow. Thanks. Dennis Johnson St. Olaf College
This PTG archive page provided courtesy of Moy Piano Service, LLC