Capstan angle

[Phillip Ford]

>I'm not talking about the overlapping holes, you can simply plug the old
>ones.

I don't understand why there would be any overlapping holes.  If the 
capstan is angled back and you want to angle it forward and keep the 
wippen heel contact point the same, the holes would be in a 
completely different place (and obviously at a different angle).

>   Flipping the angle will move the capstan contact point on the key
>well away from the balance rail reducing the mechanical advantage
>considerably (assuming the contact point on the wippen heel remains the
>same.

The key ratio is determined by the distance of the [wippen heel - 
capstan contact point] to the balance point.  It's not dependent on 
where the capstan enters the key.

Phil Ford

>   Likely you would not have room under the heel to maintain the
>same capstan/key contact point and have the top of the capstan centered
>in any way under the wippen, if even contacting it at all.  You could,
>of course, cut off the wippen heel and relocate it, you would then have
>to recalculate the new wippen lever ratio into the equation. 
>
>David Love
>davidlovepianos@comcast.net
>
>-----Original Message-----
>From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On
>Behalf Of Sarah Fox
>Sent: Sunday, April 17, 2005 9:46 PM
>To: Pianotech
>Subject: Re: Capstan angle
>
>Hi David,
>
>>  Flipping the angle the other way is not so easy unless you are going
>to
>>  make new keys.
>
>That's pretty much what I had concluded.  I was content with the SWR
>about
>where it was, and there was no need to reposition the capstan.  Flipping
>the
>capstan angle while preserving the position of the head would result in
>overlapping holes.  Bummer....
>
>>  Unfortunately, the original angle often places the
>>  capstan so as to give the proper key ratio.  Flipping the angle the
>>  other way will likely result in a rather high overall action ratio.
>
>You mean because of the contact point on the capstan being in the middle
>of
>the head, rather than on the far edge???
>
>Ah well...  It's not something I'm burning to do.  ;-)
>
>Peace,
>Sarah
>
>
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