[CAUT] Shank Pitch

[Ken Zahringer]

I have just been watching this thread, too.  The whole subject is new to me
and fascinating.  I have, like Norman, done a fair amount of reed organ
work.  This last bit gave me a thought.

Is it possible that thinning the sides of the shank would decrease mass and
thus raise the pitch, but have little effect on stiffness, since the bending
stress on a shank is mainly in the vertical plane, but maybe thinning the
top or bottom would decrease stiffness and lower the pitch?  I haven't tried
this.

Regards,
Ken Z.


On 2/22/08 9:25 AM, "Ron Nossaman" <rnossaman at cox.net> wrote:

> 
>> Chris & all
>>  
>> I do know that to lower the pitch on a reed organ reed you scrape
>> material from the bass end of the reed making the mass of the end of the
>> tongue heavier in relation to the overall reed and the pitch goes down.
>> I have never tried it on a hammer shank but I can see where the same
>> principle would apply.
>>  
>> Norman Cantrell
> 
> Hi Norman,
> In the organ reed, scraping the tip of the reed removes mass,
> raising pitch. Scraping the base end of the reed decreases
> stiffness, lowering pitch.
> 
> Resonant frequency in anything is determined by a combination
> of stiffness and mass. In the case of hammer shanks, it would
> appear from the reported results that the loss of mass
> realized in thinning has a greater affect on "doink" pitch
> than the loss of stiffness.
> 
> I don't tune shanks, so I wasn't aware of this. I would have
> expected the shank pitch to drop. Interesting.
> Ron N

-- 
Ken Zahringer, RPT
University of Missouri
School of Music