action return noise

Keith A. McGavern kam544@ionet.net
Thu, 05 Dec 1996 00:03:38 -0600 (CST)


>I service a Mason & Hamlin CC (ser #1601, but I am quite sure it was made i=
n
>the 60's) that has a bad case of action return noise: a clattering sound wh=
en
>the key is released. I finally traced it down to the jack tails slapping
>against the letoff buttons. In a way, the noise is less troublesome than th=
e
>feel through the key to the finger...
>
>...Many thanks,
>Fred Sturm, Albuquerque

What you have described does not add up in my mind, Fred.

You say, "...the jack tails slapping against the letoff buttons.", and
"...a clattering sound when the key is released."  By "jack tails" do you
mean the toe of the jack lever which is in contact with the letoff button
during escapement.  If the toe of the jack were the culprit, would not the
clattering sound occur when the keys are being depressed?

Or maybe you are referring to the longer part of the jack lever slapping
against the regulating button, not the let-off button, when it returns to
its home position?  If this is the case, some more things to check:
hardened regulating button cushions  and/or loose jack center pins, along
with the possibility of hardened knuckles mentioned earlier?

Keith A. McGavern
kam544@ionet.net
Registered Piano Technician
Oklahoma Chapter 731
Piano Technicians Guild
Oklahoma Baptist University
Shawnee, Oklahoma, USA






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