[CAUT] Shank Pitch

[Alan McCoy]

Ric,

I think what Jim is referring to here is a study that Chris and Rick
Baldassin did regarding flange pinning and hammer tone (using a spectrum
analyzer), not flange pinning and shank resonant frequency.

Alan

-- Alan McCoy, RPT
Eastern Washington University
amccoy at mail.ewu.edu
509-359-4627


> From: Richard Brekne <ricb at pianostemmer.no>
> Reply-To: "College and University Technicians <caut at ptg.org>" <caut at ptg.org>
> Date: Mon, 25 Feb 2008 19:37:37 +0100
> To: <caut at ptg.org>, "David C. Stanwood" <stanwood at tiac.net>
> Subject: [CAUT]  Shank Pitch
> 
> Hi Jim.
> 
> Point taken, and I think I understood you from the beginning. I'm
> assuming that the kind of differences in tone that a looser pin will
> make are different then a shank with a soft spot causing an abnormally
> low resonant frequency.  But, since I dont know more specifics about
> what Chris was exactly getting at... I'll have to reserve further
> judgement until I get a chance to try this out myself.
> 
> Sorting by frequency ahead of time is indeed easier then sorting by
> weighing.  And all this has gotten my head a scratch'n again :)... so on
> the set of D shanks I'm about to weigh I will cross check just for the
> sake of interest.  I have a set of weighed shanks ready to install for a
> Bechstein B also... I can check the resonant frequencies of them and
> cross check them as well. Should go fast enough.
> 
> Most certainly tho... if Chris has demonstrated that pinning can effect
> shank resonant frequency... then these are best sorted ahead of time.
> I've heard of the adjustable friction flange... but never tried them...
> so I cant speak as to how they work.  Perhaps Stanwood himself may chirp
> in here.
> 
> Cheers
> RicB
> 
> 
>     Ric,
> 
>     My point was only that pinning irregularities (along with some other
>     factors) can also cause differences in tone. While your teacher's
>     demonstration showed something, how would you know it is shank
>     differences and not something else w/o taking off a shank and
>     thumping it? I'm not trying to "be contrary" as someone else said,
>     it's just that this demonstration of thumping a block of wood, then
>     taking off the shank and showing the shanks are indeed different
>     (bad?) would be a very good trick to know. You answered that below
>     by saying that they replaced the bad shanks. This may be easier than
>     all this weighing/measuring of shanks! (Hence my query) That's why I
>     thought what you said was very important.
> 
>     BTW, Chris won't publish the pinning studies. He said they were not
>     extensive enough, but that they basically showed him that tone is
>     indeed affected by loose/tight pinning. (Something most of us
>     accept, but many do not, and thus don't repin often) I've heard that
>     David Stanwood has some "adjustable flanges" that have some kind of
>     screw adjustment to increase/decrease friction, and that this has a
>     marked affect on tone. I'd sure like to see a study on that! It
>     would disprove Steinway's assertion (In their manual) that "A flange
>     may have zero friction as long as there is no side play..." This is
>     simply bunk, IMO.
> 
>     Regards,
>     Jim Busby
> 
>