Dear Paul, I too have encountered this problem of the hammer back shoulders bumping on the tops of the backchecks. Usually this is the result of a low string height. When the string height is low, the backchecks need to be lower as well. To determine correct backcheck height, slowly play sample hammers through escapement and drop, but not through aftertouch. At that point the hammer tail should be a couple of millimeters above the top of the backcheck. For me this problem is usually most apparent in the lower end of the middle register, say from note #21 on up a bit. If you find that the backchecks are indeed too high, you may be able to tap the backchecks down on the fluted wire; otherwise you may be faced with pulling them from the key and reinstalling, perhaps with a new set. Regarding the jack jamming into the felt in the window of the repetition, this is usually caused by a spread problem, assuming that the regulation is correct. My understanding is that the Steinway & Sons specification for spread has changed slightly since they converted to the "improved" goemetry. So it would appear that you will need to determine the knuckle set of the shanks and flanges used before you can determine the correct spread for that design. Personally, I prefer a blow distance of 1 3/4" to 1 7/8" for a Steinway B. Widening the blow would reduce the jack travel, but would exascerbate the backcheck problem. Removing some of the butt felt in the window could result in the jack clicking against the tip of the hammershank flange upon a hard blow. Practically, however, unless the jamming of the jack is inhibiting key travel I would not be overly concerned about it (the key travel should be stopped by the front rail punching, not the jack). A easy solution may ultimately be to widen the blow as long as this leaves you with sufficient aftertouch. This may be one of those situations where you need to keep aftertouch to a minimum in order to make the action work without a major redesign. Regards, Charles Charles Ball, RPT School of Music University of Texas at Austin ckball@mail.utexas.edu
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