[pianotech] Wandering Capstan Screws

[david at piano.plus.com]

Excellent thoughts, thanks, Wim.

I have been tuning this piano since 1988 and the phenomenon has existed
the whole time.

I replaced the capstan screws with thicker ones years ago thinking that
this might solve the problem but it did not.  Like you, I find it hard to
think that the screws could turn in the wood; they are tight.

Thanks for the commenbt about sticker curve against capstan curve.

Best regards,

David.
www.davidboyce.co.uk

>
> 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
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> -----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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