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

[larudee@pacbell.net]

Yo Ron,

Wouldn't torque from string tension be strictly a matter of the distance of the
string from the axis of the pin (radius) and the amount of tension?  It's basically
the same thing as torque from a tuning wrench (sic!) on a smaller scale.  The same
force results in more torque when applied to a wrench with a longer handle than
with a shorter one.  Similarly, the string doesn't have as much leverage on a
smaller pin.  The part that counts is the radius at the point of string contact.
The radius at any other point on the pin does not affect torque, only the forces
that might counteract torque, like friction.

Paul

Ron Nossaman 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