Loose flange on let up? - NOT

[Mike Erickson]

I have changed my original subject from: "Key let up - knocky noise"
                              to: "Loose flange on let up? - NOT"
Sorry List, A BETTER description of the noise I heard is  "a loose
flange type of sound" rather than "knock" and my first tendancy was to
check the flange screws. It is a wood-to-wood or wood-to-hard glue or
wood-to-metal "click" or "tick" or "tap" type of sound.  And I am now
sorry that I used "knock" in my first posting, because "knock" would
describe a deeper tone than what I am hearing. 

Thanks to Fred T. , Ed F. , Glenn, Ralph M., Anne B. ,Roger J. , Jon P.,
Vince, Bob A., Eric L.  Les S., John E, Howard R.  for their many
ideas... some ideas I will check out.
Other ideas I have ruled out.

  >>>>>  Question # 1, clarified:
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 loose flange type
of a sound. After finding the flanges tight, my second guess was a loose
hammer head, but those were also tight. I perceived the noise at a low
level throughout the action, which is
acceptable or at least bearable, but I perceived the noise at  a notable
loudness on several notes, randomly, mostly in the midrange of the
piano.

The noise is present with the action out of the piano, ruling out sharps
hitting the fallboard.  The noise is present with the key isolated ( key
held down immobile- while letting hammer drop down to rep lever), ruling
out key bushings, key leads, and key to stop rail.  The random,
non-consecutive appearance of the noise would rule out glides or loose
rails.
I thought, maybe the shank was hitting "tapping" the top of rep lever
height adjustment screw , but when I held a piece of bushing cloth
inbetween - still no improvement.  The "shank cushion?" is plenty soft. 
I squeezed the knuckle with my pliars to test hardness, and concluded
that it was about the same hardness as the adjacent non-clicky
knuckle... next time, maybe I'll switch hammer assemblies to see if
noise switches also.  I don't remember testing the tightness of the
knuckle core in the shank ... I should have.  Could a loose telflon
bushing cause a loud "woody tappy" noise like that?  If so, how would I
test each bushing to know which needed repair?  I will check the
regulation buttons at the next tuning.  The noise occurs without the
jack moving away from it's rest position, ruling out the jack hitting
the opposite side of the window.
I will check out many of the suggested colliding parts that you have all
mentioned.

Thanks,
Mike Erickson, Tucson
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