Tuning pin size?

[Farrell]

OK, I'm gonna stick my neck out here among the hysterical experts!

> Since the string is tangent to
> the pin, if you rotate the pin 0.005" in the block to affect a given pitch
> change, that 0.005" could be on the surface of a 1/0, 6/0, or whatever,
and
> the movement and wear would be equivalent - not similar. The 1/0 would
have
> to rotate a greater number of degrees than the 6/0, to move the same
> amount, but the ratio of pin surface movement in the block to string taken
> up would be equivalent with any pin size - as would be the block wear if
> the block's PSI friction load on the pin surface was the same in all
cases.

The block wear would be the same "if the block's PSI friction load on the
pin surface was the same in all cases." But presumably one would be
comparing two pins with equal torque. Equal pin torque with different size
pins would result in the "block's PSI friction load on the pin surface" and
the PSI friction load on the block surface to be less on the block with the
large pins (same total friction value spread out over an infinitesimally
larger surface contact area). Less PSI friction load on block with larger
pins would result in a longer lasting block - if pin turning were what wore
out blocks - which it isn't.

OK, so where did that get us?

I think I am going to cut out the plate webbing of every piano I put a block
in so that I have an open-faced block and then I will use 1/0 pins.

----- Original Message -----
From: "Ron Nossaman" <RNossaman@KSCABLE.com>
To: <pianotech@ptg.org>
Sent: Friday, May 18, 2001 5:52 PM
Subject: Re: Re: Re: Tuning pin size?


> >If "equivalent means essentially the same OK..if however "equivalent"
means
> >the same then..... Nope don't work. :-)
> > 2/0 pin circumference is .88548 and 4/0 is .91374.. a difference of
> >.03816....not much difference but there it is................in order to
make
> >the same pitch change using a 2/0 pin as made with a 4/0 pin the 2/0 pin
will
> >have to move 1.0319 farther than the 4/0.
> >(check my math, and reasoning, though!:-)
> > I agree that wear from tuning plays very little part in pinblock
failure.
> >Jim Bryant (FL)
>
> No, that's not my point. I'm not talking about how many degrees the pin
> must be moved to change the string pitch XXX frequency. I'm talking about
> how far the surface of the pin must move relative to the surface of the
> block. That's what determines wear isn't it? Since the string is tangent
to
> the pin, if you rotate the pin 0.005" in the block to affect a given pitch
> change, that 0.005" could be on the surface of a 1/0, 6/0, or whatever,
and
> the movement and wear would be equivalent - not similar. The 1/0 would
have
> to rotate a greater number of degrees than the 6/0, to move the same
> amount, but the ratio of pin surface movement in the block to string taken
> up would be equivalent with any pin size - as would be the block wear if
> the block's PSI friction load on the pin surface was the same in all
cases.
>
> Whew. This is hard to explain for such a simple idea. If I could wave my
> arms around and draw pictures, it would be easier.
>
> Ron N