action return noise

[FSSturm@aol.com]

I should have thought a little more before presenting this problem to the
list, and it would have helped if I had been more explicit in what I wrote.
On further thought, it's obvious that three things most likely cause the
noise:
1) hard letoff felt (though it looks ok to visual inspection, and when I
needled one it didn't seem to help).
2)too strong jack return spring
3) too loose jack pinning.
I have also thought that since the jack tail hits the letoff button (almost)
simultaneously with the jack regulation button hitting the spoon, maybe there
is chatter involved. Anyway, this is where I will begin to focus when next I
have time with the piano (probably next summer). (and BTW, I am certain of
the noise source. I eliminated other potential sources one by one, and was
able to reproduce the noise by holding the wippen where the jack tail would
hit the letoff button and tripping the jack. tripping the jack in other
positions didn't make the noise.)

To give a little background, I noticed excess return noise and feel several
years ago on this  piano, and attributed it to hard knuckles, loose shank
pinning, and hard key bushings and keybed felt. About three years ago I
rebuilt the piano and corrected all the above - new shanks, rebushed keys,
new keybed felt, among myriad other things. Maybe I was distracted by other
considerations and didn't pay enough attention, but I didn't notice the
return problems at that time.

Then a couple weeks ago, when I had time to play the piano for a while after
tuning (my way of unwinding, getting in a little practice, and
troubleshooting/ looking for troubles, all at the same time) I noticed the
noise and return "bumpy feel". Of course I was quite distressed, since I feel
responsible for the piano having rebuilt it so recently.

I notice a similar upstroke feel on a few other grand pianos, though not all
that many. It occurs when the finger is slightly retarding the upstroke of
the key, a fairly common occurrence during light or slow playing. It is
bothersome like damper levers bouncing on the backs of keys (too high upstop
setting) or non-checking hammers bubbling (the perennial Steinway struggle
between reliable repetition and pianissimo checking). So I put the problem
before the list in hopes that others might have addressed it already.

I'm beginning to think that this is one of many problems with multiple
contributing factors. There's the sudden release of the jack from behind the
knuckle, together with possible chatter or jerk against the knuckle; the
repetition lever coming in contact with the wippen, and perhaps chattering
against the drop screw; the jack regulating button hitting the spoon; and the
jack tail hitting the letoff button. Maybe some action geometries make these
things happen more simultaneously than others, with the result being quite a
knock felt by the finger about midway through the upstroke.

I suspect this becomes particularly annoying when the "shock absorbers" are
worn: pinning becoming loose, wippen cushion, jack button, and letoff felt
becoming packed and hard, etc. Anyone else have thoughts?

Thanks for the responses. They have helped enormously in getting the old mind
focused better.

Fred Sturm
Albuquerque, NM