Hello Paul, Regarding the back rail cloth: I recall that the piano is 9' long with tapered length keys. Is the key height measured at the front of the keys uniform from 1 to 88? Is the existing action cloth more or less centered under the back checks and therefore at an angle to the front edge of the keys? I am puzzled that the capstan on key 1 never reaches the ideal line between the key fulcrum point and the wippen center. Since the hammers seem to be worn, if anything, I would expect the capstans to be raised to compensate for the hammer wear, and yet the symptom you describe indicates either that the capstan is too low, or that there aren't enough punchings on the balance rail. If you can, you could also do some detective work and figure out what all was done to the piano since it left the factory. Often, the problems are caused when "repairs" are done. For example, was lead added to the action after it left the factory, or do all the leads look like original equipment? Did someone replace the hammers with ones of wrong hammer bore distance? Regarding the weight problem, normally, a piano will have around 14 grams of friction weight in the bass, and less than 10 g in the treble. The friction is calculated from (DW-UW)/2. This is the force required to overcome the action friction when pressing down on the key. The other number that is way off on this action is the balance weight, which should be around 35-38g. BW=(DW+UW)/2. In theory, you can install light hammers and remove lead, but you do need significant weight in the hammers for a piano that size. I would therefore measure the strike weights of the hammers and see where they fit on David Stanwood's curves. If you aren't familiar with this subject, he has some papers on his web site and some older PTG Journals have them too. In a nutshell, you adjust the hammer weight to match the piano size, the action ratio, and the desired balance weight and inertia of the action. The subject can get more complex if you aren't happy with the action geometry, but I will assume that piano was in acceptable working order at one time, and that you don't need to redesign the action. Anyway, I would check the key height from 1 to 88 first and solve that problem before dealing with the weight. Best regards, Vladan ================================================= Thanks for the reply Vladan. It is nice to share my thoughts with someone else. Regarding the backrail cloth.... There should be a straight line from the bottom of the key at the balance rail pin to the center pin of the wippon where, when the key is depressed half way, the top of the capstan should be. I get that on 88, but not on 1. On 1 the key would have to be more than fully depressed for the capstan to make this line. And it tapers up to 88. If nothing else, shouldn't there be some consistancy? Or, doesn't this matter? Are the capstans in the wrong place? Because of this, I'm wondering if there was some compensation somewhere else (like excessive leading) to make up for this. Regarding the weight.... I assume that the 7 grams you are referring to is an estimate of the amount to move the new parts, correct? And.... Doesn't it make sense to maintain the existing hammer weight and reduce the weight in the key to increase the down weight and corresponding up weight reducing the overall inertia of the action? Paul. __________________________________ Do you Yahoo!? Yahoo! Mail is new and improved - Check it out! http://promotions.yahoo.com/new_mail
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