Capstan angle

[David Love]

No, this was old, pre-experiment.  Clearly incorrect.  

David Love
davidlovepianos@comcast.net 

-----Original Message-----
From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On
Behalf Of Phillip Ford
Sent: Tuesday, April 19, 2005 11:43 AM
To: pianotech@ptg.org
Subject: Re: Capstan angle

>
>I'm not sure why that wouldn't improve the key ratio.  You have a
>straight up capstan with a key ratio of, say .52 (using the Stanwood
>method).  You relocate the capstan keeping the contact point with the
>wippen heel the same but moving the capstan key contact point closer to
>the balance rail by angling the capstan.  The measured key ratio will
>now be less than .52 and the overall SWR will have decreased as will.
>
>I'm not sure I even understand what is meant by
>
>"What they have accomplished is to move the
>contact point between the top of the capstan and the
>wippen heel a little closer to the balance point, so
>that the key ratio has changed."
>
>Do you mean by virtue of the capstan leaning it now contacts the wippen
>heal on the front edge of the top of the capstan?  I would say that is
>probably insignificant.  Much less, anyway, than the repositioning of
>the capstan/key contact point.
>
>
>
>David Love

I'm not sure if this clarification is still needed, but I thought I
would 
follow up anyway.  Yes, I am saying that the leaning of the capstan is 
causing the contact point to be more to the front edge of the capstan
top, 
which is bringing the point of force application on the capstan a little

closer to the balance point of the key.  It seems like it should be 
insignificant, but as your experiment shows, what matters is the point
of 
force application, so this small change is significant enough to affect 
touchweight.

I mentioned this because I have heard a few people say that they have 
decreased touchweight by leaning the capstans back and they seemed to be

assuming it was because of the capstan leaning.  It wasn't.  It was 
because, in the process, the point of force application was moved
somewhat.

Phil Ford 


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