Key let up - knocky noise

[Baldwin Yamaha Piano Centre]

Mike Erickson wrote:
> 
> Although there are plenty of piano tooners of lower caliber than I, I
> am still ashamed to admit, after a full year of training, fourteen years
> of piano servicing, and sitting through more Grand Regulation Seminar
> classes than I can remember, -> that I still have "grand action phobia".
> Coming out of those classes does help me to face my fears, and I usually
> understand one more small tidbit after each class,    But like
> tuning..., it takes experience on hundreds of different pianos until you
> realize the potentials and limits that "tuning" can bring to each make,
> model, age, and condition of piano.     "Is it me? the voicing ? poorly
> designed instrument?"  Now, after thousands of tunings I am confident I
> have a good sense about what can or cannot be improved in the tuning,
> and somewhat with voicing and upright regulation. I don't, however, have
> such a great sense when it comes to grand actions.  It's mostly a hate
> relationship at this point. I would hate to sell a job to a customer,
> struggle for days on the action, ask for help, only to find that it is a
> hopeless cause or that my efforts have made things worse. That is why
> when there is
> big-big trouble in a grand action, I usually refer the job to local
> technicians who have immersed themselves in grand action servicing
> and/or rebuilding. Maybe I'll quit tiptoeing and really fall into it
> someday.  Until then, thanks for listening and I will humbly ask my
> stupid symptomatic questions about the mysteries I encounter.
>    Question # 1, encountered 10/7/97, 35% realive humidity, a 1965
> Steinway L, teflon bushed.
> When the key is let go, on the up stroke, there is a woody knocky sound.
> I perceive the sound at a dull level throughout the action, which is
> acceptable or at least bearable, but I percieved the knock at  an
> obnoxious volume on several notes, mostly in the midrange of the piano.
> Hoping I could help this by some flange tightening, I found all flanges
> to be tight. Hammer heads - tight. Although balance rail bushings seem
> overeased, when the key was held securely, the same "knock" was heard
> when dropping the hammer down onto the rep lever.
> I thought, maybe the shank was hitting "tapping" the top of rep lever
> height adjustment screw head, but when I held a piece of bushing cloth
> inbetween - still no improvement.  The "shank cushion?" is plenty soft.
>   After 48 minutes of trying to isolate the cause, I gave up. I smiled
> at the customer, told her I was "exploring" (although didn't tell her
> why or what for, since she hadn't complained of anything) and, of
> course, charged her no extra for my venture.
>   I only service 6 other Steinways, so I'm not sure if this woody knock
> noise is native to telfon Steinways or all grands.
> I don't remember the other times I have encountered this and cannot make
> the connection. Any ideas?  Any help appreciated !
> 
> Mike Erickson,  Tucson, AZ    mwike@flash.net
Greetings Mike,
                  You have probably answered your own question. Rebush
the offending keys, If the piano in question has no hard wood shoes,
chances are the keys are also chucking,( back and fore motion,) if you
steam out the old bushings it usually swells the balance rail hole
enough to tighten the key. The teflon bushings can create some strange
noises,so double check them.
Hope this helps.
Roger Jolly.