At 9:45 AM -0700 6/7/03, Delwin D Fandrich wrote: >This is the part that intrigues me. The ability to set very close >letoff and the ability to control the action at pianissimo levels. At 7:46 AM -0700 6/8/03, Delwin D Fandrich wrote: >So, when I hear some say some grand action design can be regulated >with let-off right up to within 1 mm of the string line I at least >want to give the thing some thought. And one of those thought is, "I >wonder how this thing would work with a nice graphite-filled ABS or >Nylon jack?" Are you perhaps thinking of the final turnstile the hammer has to go through to make it to the string, the friction barrier of escapement? At the initial turnstile (DW, or in a non-friction world, BW), nothing happens until you put the correct number of coins in the slot. At escapement, with the hammer's momentum, at least you get a consolation prize for being a dollar short: a "Viennese escapement". As in the Prell-mechanik, the rep lifts the hammer until the jack tender hits the LO button, and because the driving force at the key is less than the escapement friction, everything stops dead in its tracks. Except for the hammershank, which if the LO is close enough, has enough momentum to go the remaining distance. On its way back down from the string, it is checked not by the rep spring pressure in drop, rather by sitting itself back down on the jack which has not moved from its pre-LO position, because escapement never occurred. The most obvious part of the consolation prize is the hiccup we all know and love, when the hammer bounces (albeit, slowly) off the jack and grazes the string again. I've always believed that one of the least easy of factors determining the threshold sound (ie, minimal LO) to control is escapement friction. It's partly a function of jack alignment, jack/rep spring strength, knuckle shape and leather friction, hammershank ratio and SW. It's nice to inventory these factors, but I have often been in the situation of unable to alter escapement friction nearly as much as I'd like. Escapement friction is a turnstile. You can reduce the hiccuping by fattening the LO. But the size of this friction determines the quietist sound one can get out of a piano. So Del, would the lubricity of the jack top make a big difference here? Bill Ballard RPT NH Chapter, P.T.G. "Can you check out this middle C?. It "whangs' - (or twangs?) Thanks so much, Ginger" ...........Service Request +++++++++++++++++++++
This PTG archive page provided courtesy of Moy Piano Service, LLC