[pianotech] Wandering Capstan Screws

[david at piano.plus.com]

Thanks for those further thoughts, folks.

I made a silly mistake, wasn't thinking (am on a course just now and it's
quite intensive).  The piano action DOES have stickers.

Thinking then about putting action cloth on the ends of the stickers, and
replacing the screws with capstans:

Might there be a concern about the two curved profiles? Would the
relatively narrow-radius curve of the now action-cloth-clad sticker ends,
bear OK, and be stable enough, against the radius of the capstan surface?

I am still kinda feeling that the blue felt on top of the capstan screws
can't be swelling THAT much, to cause all that lifting. Could the wood of
the keystick be of some particularly "soapy" variety, that shoves the
screw threads around, with cyclical changes in humidity?

With regard to humidity changes, I have wondered for a while if there is
some cyclical change going on in that room even thought it doeosn't feel
damp.  The answer, I think, is yes.  The room, a study/spare bedroom is
just across a corridor from the kitchen, and very near the back door. It
is quite possible that there could regularly be brief bursts of
moisture-laden air, which then gets cleared in some way, but in the
meantime has condensed inside the piano.

An additional factor at the moment is recent replacement of the windows,
which meant the room was cold and damp for a day or two.

But its still an intriguing question as to whether the screws move.

I will be returning soon to tune the piano (my recent visit was just to
check out a problem following the window replacement - the half-blow pedal
rod had become dislodged) and I suggested leaving the tuning until the new
carpet was laid and the piano placed where it's to go in the room.

I will check out the undersides of the blue felt and see how
dimpled/ridged they are.  If I don't replace the screws with capstans,
then I will mark them and the keystick, and see if there is any movemment.

It occurs to me also to suggest a Dampp Chaser, so that if there is a
sudden surge of moisture-laden air into the room from the kitchen, it
can't condense in the piano.

Best regards,

David
www.davidboyce.co.uk