OK, you have check all those things so pick the worst offender and let's do some evaluation. First, check the pinning of the hammer shank. Eight swings is the outside limit on this pin. If you get ten or more swings the spring will need to be weaker to prevent rebound upon release. Spring tension is a major source of repetition failure. Six to eight swings is the envelope. The wippen post pinning is also critical. Without the spring it should not move when swung but should move with a light finger touch. There should be perceptible resistance by finger pressure, otherwise, the spring tension will be too weak for good repetition. Check the touch weight. Measure the up weight and the down weight. The average of the two must not be less than 34 grams and should be 38 to 40 grams. Much high then 40 gets into the too heavy range for any other than a professional. 42 to 48 can cause tendentious in anyone. Determining if the capstan is in the proper location is more complex. You must have the up weight, down weight, hammer weight, wippen weight, key weight and exact key ratio. Subjected to Stanwood's formula will give you a strike ratio which determines if the capstan is properly located. In the Hamburg factory the action is assembled completely before being fitted into the piano. In New York they fit the keys to the case, set the stack to best tone at top and a mark at the bottom and then determine capstan location. This procedure does not allow for the capstan location to be consistent from piano to piano, unfortunately. BIG difference. We are past the time when friction is considered to be an enemy and now realize that it is critical to proper action functioning and needs to be controlled more precisely than previously thought. To go any further we need numbers. Have a great weekend. Newton
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