Plate Bushings - was Re: Bushing vs. bigger pin?

[David Ilvedson]

Yamaha doesn't fit their pinblocks to the plate flange and they tend to be
very stable creatures.  When there is a problem it usually is because the
pinblock is not tight against the plate above it.  I have let the tension
down on a few un-controllable pianos and tightened the plate screws into the
pinblock and I had a different piano when I was done, as far as tuning
stability.

David I.

-----Original Message-----
From: owner-pianotech@ptg.org [mailto:owner-pianotech@ptg.org]On Behalf
Of Richard Brekne
Sent: Tuesday, May 30, 2000 12:52 PM
To: pianotech@ptg.org
Subject: Re: Plate Bushings - was Re: Bushing vs. bigger pin?


Nothing really so mythtical about this really, we have obviously two myths.
I will name them...er.. lets see... ah.. "The myth of the moving pinblock"
and "The myth of the crushed pin bushing"

Neither of these claims has any real supportive evidence, and both seem to
have holes in the supportive reasoning, especially I might say the second
of these two.

The claim is that the first myth cannot possibly be true because if the
pinblock moved due to the fulcrum effect placed on the pins by the
bushings.. then the bushings would surely crush. While its easy to picture
this happening it simply doesnt take into account that the amount of
pinblock movement necessary for a significant impact on tuning stability is
no where near the amount necessary for the bushings to crush.

It amazes me how (depending on what one argues about) some movement
tolerances concerning pin movement in relationship to tuning stability can
be so unbelievably small, and then in the next moment those same tolerances
can be the size of a football field in comparison.

Mythed by a mile ???  Strrriikeee One!

grin..





JIMRPT@AOL.COM wrote:
>
> In a message dated 5/29/2000 4:42:59 PM, you wrote:
>
> <<"Not my bag really.. but I just love it when I see myths attack by
counter
> myths...grin.">>
>
> Richard;
>  Your so-called "counter myth" mythed by a mile.  So, if you would so
kindly,
> point out a "myth" in my response?
> Jim Bryant (FL)

--
Richard Brekne
I.C.P.T.G.  N.P.T.F.
Associate, PTG
Bergen, Norway