Capstan angle

[David Love]

Flipping the angle the other way is not so easy unless you are going to
make new keys.  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.  Ron
Overs knuckle to center pin distance is, if I recall correctly, 20 mm.  

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 6:37 PM
To: Pianotech
Subject: Re: Capstan angle

Hi Vladan,

> I have never understood the reason for the capstan
> angle on older Steinways.  If anything, it seems to me
> that the angle is in the wrong direction.

My thoughts as well.  My Wissner has Steinway's patented backwards
capstan
angle duplicated faithfully.  If I ever change capstan position, you can
bet
I'll flip the angle the other way.

I don't think the backwards angle really hurts anything, at least with
regard to friction.  That's more a matter of magic line stuff.  However,
adjustments to the capstan height would result in alteration of the
radius
from the centerpin hole to the capstan/wippen contact point, as well as
the
radius from the contact point to the wippen flange center.  Since these
changes would be in an opposite direction, they would change the overall
SWR
for the key -- increasing it as the capstan height is increased.  IMO,
that's the biggest weakness of this weird capstan angle.

> Can anyone give me the patent number for that Steinway
> patent?  Maybe I can find an explanation there.

If you find it, please let me know WHAT they were thinking!  (I have my
suspicions about what they were smoking...  ;-)

Peace,
Sarah


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