No Power Yamaha revisited

[Roger Jolly]

Hi Ed,
             You raise a very good point, this has been swimming in the 
back of my mind.  Perhaps that is why Yamaha uses that heavy metal beam to 
mount the pedal lyre.   I wonder what the pressure would be at the balance 
rail pin location, on a forte blow. But I would bet is several hundred 
pounds per square inch.   Loads in the keybed and trap work bearing points 
are very large, since they are concentrated in very small areas.
Yamaha also has a quite flat glide bolt, ostensibly to spread the load better.

Regards Roger



At 09:48 AM 5/26/2003 -0400, you wrote:
>Bill writes:
> >I agree that a good healthy blow will put the frame under pressure,
> >but if the BR doesn't have anywhere to go (because the glides are
> >contacting the bed),
>
>   I have been wondering when somebody is going to mention the entrainment of
>the keybed?  Once the glides are in contact, the action cannot move, UNLESS
>the keybed is not absolutely rigid.  But we know the keybed isn't.  This is
>easily seen by depressing the pedals under a very lightly bedded set of 
>glides and
>observing them to lose contact with the keybed.
>    So,  the extra power and tone being ascribed to heavier loading on the
>glide buttons may possibly be a function of preload on the keybed?  And the
>observed differences between makes of pianos may be more due to the 
>differences
>between keybed strength than the flexibility of the balance rails??
>Wondering,
>Ed Foote RPT
>www.uk-piano.org/edfoote/
>www.uk-piano.org/edfoote/well_tempered_piano.html
>  <A HREF="http://artists.mp3s.com/artists/399/six_degrees_of_tonality.html">
>MP3.com: Six Degrees of Tonality</A>
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