Fw: Fw: Larudee's mystery - Was: Ditch the tuning pin bushings

[Erwinpiano]

----- Original Message -----
From: "David Skolnik" <skolnik@attglobal.net>
To: <pianotech@ptg.org>
Sent: Thursday, May 17, 2001 12:13 AM
Subject: Re: Fw:

  David wrote
> I am imagining that if one  were able to control the amount and
consistency
> of torque in a repinned block, using even 4/0's or 5/0's, a good fitting
> tuning tip, and acceptable range of friction across front bearing points,
> you would have little trouble doing a good fine tuning.
> David Skolnik
>
> David , Your  above paragraph says more to me than any previous tech-no
facts presented so far. In all practicality,l if the pins render and refrain
from touching the plate ,stable ,precise tuning is possible but if the
torque goes up, on any size pin, the tuner will have more trouble getting it
in tune and getting it to stay there.

     Dale Erwin
>
>
> At 10:47 PM 05/16/2001 -0500, you wrote:
>
> > >
> > > I can think of two good reasons.  Presumably we want tuning pins to be
as
> > > narrow in diameter as possible because a) the amount of leverage
(torque)
> > > exerted by the string tension increases with each increase in diameter
> > > (radius) and b) the amount of string moved per unit of rotational
movement
> > > also increases accordingly.
> >
> >
> >
> >Yo Dale,
> >Wouldn't the torque from string tension relative to the area of pin in
contact
> >with the block be pretty much the same regardless of pin diameter? With
the
> >moment arm of the string torque being the radius of pin diameter, and the
> >block
> >contact surface area varying with the circumference (pi*D), doesn't this
> >proportion scale? Remember that I'm missing the standard math receptors
in my
> >alleged brain, and am prone to orders of magnitude estimation errors in
these
> >things. The string movement per degree of pin rotation is shore-nuff
smaller
> >with a smaller diameter pin. So with the string tension "holding power"
being
> >more or less equivalent, and the "effect per movement" increment being
smaller
> >with smaller diameter pins, I'd have to agree that smaller is better - to
a
> >degree. With bushings, I'd say 1/0 were quite possibly a better choice
than
> >2/0. Without bushings, I would still consider 2/0 a better choice for the
> >flagpoling thing, unless blessed with an open face block.
> >
> >My take, whatever.
> >
> >
> >Ron N
>
>