New action-parts problem

[Mark Dierauf]

>>Here is what happens: On fast repetition, the hammer gets stuck in the
>>backcheck before the jack re-sets.

  I have seen this problem a couple of times, particularly after reshaping
hammers, IOW, shortening the bore length. One theory that I heard was that for a
time, S&S was setting the top actions relative to the keybed, instead of
relative to the string plane. Joe Bic told me to check the height of the whip
center pin, but I can't remember the specs he quoted to me - you should call the
factory and get the straight dope from them.

>> Could slight change in hammer bore + - 3/16 affect this.

  The last one I worked on with this malady developed the problem after the
second hammer filing, and I was only able to 'fix' it temporarily by setting the
blow to over 2", and increasing the key dip proportionately. Needless to say,
repetition suffered. With the blow set to factory specs, the shanks were 1/2" or
more above the rest cushions and the jacks met the knuckle cores at an increased
angle (>180 degrees). I later replaced shanks, flanges, whips, and hammers and
now the piano regulates normaly.
  One other thing - you didn't say if the whips were replaced. I have had
extremely poor luck mixing old and new parts on Steinways, even relatively new
ones  - there are a bunch of different configurations out there. Now I pretty
much insist to my customers that it's all or nothing. besides, the Renner (and
the *new* NY parts) are so nice!

                  Mark Dierauf
                  Concord, NH

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