Stephane mused: >Indeed, I find it very difficult to achieve very even backchecking >too. I bend the backcheck wires with my fingers with the action on >a bench or on my knees until I am satisfied, but then, when putting >the action back into the piano, nothing is that even anymore (why ? >due to minute change of shape of the action when bedded in it's real >bed ? or due to differences in rebounding force of the hammers >against the strings ? who knows ? I promise that my blows are quite >even, because I practice a lot for that.). Check position depends on the relative position of the hammer and backcheck (obviously) and these can vary according to: (a) hammer is checked while the keytail, and consequently check, are still moving upward, (b) vibration in the key tail, and consequently check position, (c) momentum of the hammer, a function of blow, strike point, and string parameters, or (d) impact time, also a function of stirngs etc. Any, or all, of these factors may be different for a benchtop experiment vs rebounding off the real strings. What are you using to rebound the hammers on the bench? Of course the other suggestion above, viz. distortion of keyframe and consequently variation in prior-set position of the backchecks as the keyboard is bedded vs on the benchtop. As well the dynamics of an action on the bench are different from the in-piano keyboard. Stephen -- Stephen Birkett Fortepianos Authentic Reproductions of 18th and 19th Century Pianos 464 Winchester Drive Waterloo, Ontario Canada N2T 1K5 tel: 519-885-2228 mailto: sbirkett[at]real.uwaterloo.ca http://real.uwaterloo.ca/~sbirkett
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