Dear Avery: All kinds of trouble can be experienced if the action is not at the correct height. A basic premise is that the hammer flange center pin must be at the height that allows the hammer shank to be level when the hammer contacts the string. Of course, the hammer boring length must also be correct for this model in order for the first premise to be realized. In most factory setups, the bracket feet are shimmed up to accomplish this basic setting. If one shimmed up only the hammer rail (which is unthinkable) the action spread would be changed. Sure, you could then shim up the action wippen rail too, but why not just do the bracket shims? If one can assume that the action worked properly originally, then there is normally no big problem in getting back to that original position. HOWEVER, to play it safe, first shim the brackets so that the hammer position is right (shanks level when hammer touches string). Next, adjust action rail forward or backward to center over the existing cap- stans (this may change the action spread, but you probably don't know what that measurement was originally anyway). Next check the sample touch weight of keys in all sections. Write down the gram weights. Next, check the hammer blow-keydip relationships. When the wippen rail is too close to the front (ie the action spread is too short) the touch will be heavy and the needed keydip will be less to accommodate a standard hammer blow distance. And, vice-versa, when the wippen rail is too far back (ie the spread is too wide) the touch will be lighter, but will require more keydip to accomplish let-off and drop. Write down the sample gram weights. The worst-worst case scenario might require moving the capstan line, but I would normally be suspicious of that requirement. At any rate, if you feel you need to make any monumental changes, do it for 1 note sample in each section before you change all 88 notes. Caution! Heavy hammers could fake you out into doing all kinds of weird things here. Make sure your hammer tails are properly narrowed before making any touch weight judgments Jim Coleman, Sr. On Mon, 16 Sep 1996, Avery Todd wrote: > List, > I finally received the action brackets for the Marshall & Wendell grand > but find that the the new ones are 1/8" lower than the old. To duplicate > the action height, is it correct to shim under the hammer flange rail then > bed the bracket feet to the key frame? > Advice one more time would be appreciated. Hopefully, this is my last > post about this piano. Except to say, maybe, that it turned out great. :-) > > Avery > > _____________________________________ > Avery Todd, RPT > Moores School of Music > University of Houston > Houston, TX 77204-4893 > 713-743-3226 > atodd@uh.edu > _____________________________________ > > >
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