Pinning and Tone

[Alan McCoy]

Hi,

Very engaging thread. Question tho. We can measure friction easy enough by
either a gram gauge or a swing test, or both. Though this measures "gross"
friction and doesn't address unevenness within a flange's bushings.

We can create a firm bushing, we hope, by several methods - using high
quality felt, burnishing, sizing, "zapping" lightly or somehow heating the
pin to iron the felt. But how does one test for firmness in any
quantitative, definitive way?

Alan

> -----Original Message-----
> From: caut-bounces@ptg.org [mailto:caut-bounces@ptg.org]On Behalf Of
> fssturm@unm.edu
> Sent: Tuesday, October 14, 2003 6:09 PM
> To: College and University Technicians
> Subject: Re: Pinning and Tone
>
>
> Quoting Ed Sutton <ed440@mindspring.com>:
>
> > Jim-
> snip
> > 1- A few years back David Stanwood was using hammer flanges with
> > adjustable
> > friction to control touchweight. The flange had two tiny set screws
> > above the
> > center pin which could be adjusted to change the friction.  This
> > would allow for a
> > number of experiments without even removing the flange from the
> > rail.
> >
> snip
>
>    I'll just suggest here that use of the Stanwood flange might
> not quite be the
> same as re-pinning. In re-pinning, there is also a question of
> firmness in the
> interface between pin, felt and wood - where one is affecting the
> dimension of
> the felt (and largely by compression more than by removal of
> material, if one is
> doing what should normally be done) - more or less evenly around
> the whole
> circumference of the pin. I _think_ there might well be a
> difference. The set
> screws (I remember only one set screw, but could be mistaken)
> operate from
> only one direction (each). They could well increase friction, but allow
> "sloppiness" in other directions.
>    Friction per se would most likely affect only the dwell time
> of the hammer on
> the string. Firmness in isolation would have its greatest effect
> on the wobble (or
> lack of same) of the shank during the stroke and rebound, and
> hence on what
> the hammer is doing while in contact. I am picturing those high
> speed films,
> showing all kinds of vibration and flopping around of shank and hammer.
>    As several have mentioned already, this is the sort of thing
> that is next to
> impossible to test with reliable experiments. Maybe we're best to
> rely on what
> our experience has at least seemed to demonstrate, together with
> our mental
> picture of why (though often the two are hard to reconcile).
> Regards,
> Fred Sturm
> University of New Mexico
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