Richard has made a correct distinction between "maximum energy transfer" and "most efficient energy transfer", a distinction which I carelessly muddled in my post. As far as action makers specs go, all I can say is that this is the procedure as taught in the Hamburg Steinway factory. As I stated there are dozens of contingencies that can make this regulation impossible or subject to compromise. As with so many aspects of piano work, the utilization of this element requires experience and common sense. I invite anyone interested, to experiment with changing the jack/shank contact angle, and to notice the coincident change in the touch, particularly in the critical first millimeter of key movement. I think the value of a perpendicular contact will be manifest in most well designed actions. Jerry >In my neighborhood Newton's laws of acceleration are in force, >as long as there is contact of the jack with the hammer (knuckle) >during any phase of its movement. Maximum energy transfer can occur >at any point, depending on the downward velocity of the key. The most >efficient energy transfer (not necessairly maximum) should occur as >you suggest at 90 degrees of the jack to the hammer shank. > Whether this perpendicular relationship should occur at the moment >of movement or say half way through the movement is a matter of >secret considerations by action makers. If that is the case, then >they should supply the angle of the jack to the hammer shank when >the action is at their specs. Now who does that? >Richard The Home Boy Moody
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