>I need to tread this water carefully because I am aware that I am no expert on this subject. But most responses to this question have included suggestions regarding changes to key leading or action geometry. I would suggest that if DW was a "pretty even 52 grams" and then "two weeks later, the weight was back over 60 grams" the solution will be found in regulating friction. The source of such DW changes necessarily excludes issues of key leading and/or action geometry - unless, of course, these factors are changing over the course of two weeks. > >Terry Farrell After you measure the UpWt with your 60g DownWt you'll probably find that Friction Weight is high. (DownWt-UpWt)/2 gives the Friction Weight and indicates the total friction at the front of the key from all the parts that move against each other. Normal average Friction Weight of around 12 grams is normal in a well functioning action. Key Bushing friction is often the problem with newer pianos and is often overlooked. Try isolating and identifying the contribution from the key bushings as follows: Remove the stack and set it aside. Place a weight on the back of key sufficient to hold the key down on the back rail. A key leveling lead works nicely or jiffy leads on the back side of the key. (The amount of weight is not important so long as the key sits down on the back rail.) Measure Up and Down Weight of just the keystick calculate Friction Weight. Keystick friction weight may be rated as follows: Low = 1 - 3 grams, Medium = 3 - 6 grams, high = above 6 grams. Always lubricate the key bushing cloth with dry teflon. This reduces the coefficient of friction between the pin and the felt and saves wear and tear on the bushing cloth. David Stanwood
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