Hi Dean Most places I've run into make a clear distinction between grand aftertouch and vertical jack escapement. Grand aftertouch is a different thing, tho to be sure it also involves the jack escaping from under the knuckle to a similar degree. That said there are some clear and significant differences which I am sure you already know when it comes down to it. Vertical pianos have nothing that is correspondent to drop in a grand. Nor do that have that little rise afterwards the Japanese like to refer to as Hataraki when the key is further depressed past drop. Indeed the whole grand aftertouch is quite a bit more then simple escapement of the jack from under the knuckle. Vertical pianos simply have escapement and catch. In some cases one can regulate a vertical so that the sensation of aftertouch seems a bit similar to the grands.. but most often you don't really get all that close. There is no built in <<bump>> at letoff/drop. It has to be simulated by letoff/catch and that relies a bit on a few related factors like the friction interface between the jack top and the leather of the knuckle, the effective weight of the hammer falling back onto the catch, return spring strength, and the like. Even the critical element of jack escapement itself is a bit different in the grand. If you dont escape at 1 + mm then you end up experiencing some degree of blocking. Bobbling alone due to lack of jack escapement in the grand is fairly rare IMB. Cheers RicB Ric, I don't think I've ever remembered hearing that jack escapement on a vertical is not aftertouch. I'm curious as to why? Seems like in both cases we are talking about jack movement after clearing the knuckle. Dean
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