[pianotech] Wandering Capstan Screws

[tnrwim at aol.com]

David

The first question: The round sticker w/cloth against the round capstan. That is the ideal situation. The two round surfaces work very well together, without creating any friction.  

The other question/concern, about the screw moving. I don't understand how a screw could turn in the wood, unless it was loose enough that it could be turned by you fingers. There is nothing on the felt that would be able to turn it. 

You mentioned new carpets and new windows. Have these people been doing lot of renovating in the house? New carpets give off a lot of moisture. New windows mean there is a lot of moisture coming in the house while they are replacing them. Any painting going on near the piano? All of those things will create a lot of swings in humidity and temperature. 

If there is a lot of renovating going on, perhaps you need to ask the customer when all the work will be done. Then, when the house is stable, check the hammer line again.

Wim







 



-----Original Message-----
From: david <david at piano.plus.com>
To: pianotech <pianotech at ptg.org>
Sent: Mon, Dec 5, 2011 11:23 am
Subject: Re: [pianotech] Wandering Capstan Screws


Thanks for those further thoughts, folks.
I made a silly mistake, wasn't thinking (am on a course just now and it's
uite intensive).  The piano action DOES have stickers.
Thinking then about putting action cloth on the ends of the stickers, and
eplacing the screws with capstans:
Might there be a concern about the two curved profiles? Would the
elatively narrow-radius curve of the now action-cloth-clad sticker ends,
ear 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
an't be swelling THAT much, to cause all that lifting. Could the wood of
he keystick be of some particularly "soapy" variety, that shoves the
crew threads around, with cyclical changes in humidity?
With regard to humidity changes, I have wondered for a while if there is
ome cyclical change going on in that room even thought it doeosn't feel
amp.  The answer, I think, is yes.  The room, a study/spare bedroom is
ust across a corridor from the kitchen, and very near the back door. It
s quite possible that there could regularly be brief bursts of
oisture-laden air, which then gets cleared in some way, but in the
eantime has condensed inside the piano.
An additional factor at the moment is recent replacement of the windows,
hich 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
heck out a problem following the window replacement - the half-blow pedal
od had become dislodged) and I suggested leaving the tuning until the new
arpet 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
impled/ridged they are.  If I don't replace the screws with capstans,
hen 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
udden surge of moisture-laden air into the room from the kitchen, it
an't condense in the piano.
Best regards,
David
ww.davidboyce.co.uk

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