[CAUT] Gravalla Tension regulator

[David Ilvedson]

I don't suppose you have any pictures of what was done to fit a Mason/Hamlin tensioner in the steinway?   It's amazing what techs will try on a piano...

David Ilvedson, RPT
Pacifica, CA  94044

----- Original message ----------------------------------------
From: "Scott E. Thile" <scott.thile at murraystate.edu>
To: "College and University Technicians" <caut at ptg.org>
Received: 9/25/2007 8:34:01 AM
Subject: Re: [CAUT] Gravalla Tension regulator


>Interesting article, Ron. I stand corrected in terms of the direction of the
>forces at play... 

>It would be interesting to know what would happen in your model if the board
>were glued into the jig like it would be in the piano. I suspect capturing
>the board by gluing it down (after it's crowned) could still contribute to
>resisting forces by preventing the ends from moving as freely (regardless of
>the direction). 

>Even if stiffness of the rim assembly does not contribute to retention of
>the crown and/or downbearing, it does effect tone production. My experience
>is the effects are dramatic, especially in projection, and especially in the
>"killer octave".  My point is that regardless of the effects of maintaining
>crown, stiffness in the rim assembly seems to be is an important factor.

>Back to the original question. I like the wood stiffener as well as the
>other method's Steinway uses to achieve stiffness in the assembly. That
>stiffener would appear to be an attempt to address the killer octave, and I
>think it works. I recently rebuilt a D with a new board, and I replaced that
>little stiffener, as well as lots of other work to rim and braces, which had
>been significantly compromised in order to include an M&H tensioner at one
>point. It's hard to know if any of that contributes to the success of this
>piano or it's just benefiting from the new healthy board.

>Steinway's methods of stiffening the assembly seem to work really well, and
>they seem to hold up at least as well over time as other methods. I would
>not want to eliminate one of them in order to install another....

>In pianos, Scott
>Murray State, Murray, KY

>> -----Original Message-----
>> From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On 
>> Behalf Of Ron Nossaman
>> Sent: Monday, September 24, 2007 10:26 PM
>> To: College and University Technicians
>> Subject: Re: [CAUT] Gravalla Tension regulator
>> 
>> 
>> 
>> > The piece that is in there is intended to stiffen the belly 
>> rail, and 
>> > it works. My understanding is that it is under tension as 
>> opposed to 
>> > compression. It's pulled end to end as it holds the bell rail from 
>> > pushing out under the down bearing on the board. If you 
>> picture that 
>> > it's easier to understand it's size than if your thinking 
>> compression 
>> > like the beams.
>> 
>> The belly rail won't push out from downbearing load. If 
>> anything, it'll pull in. Soundboard crown isn't an arch. See 
>> April 2006 Journal, "Rib crown as an End-Buttressed Arch".
>> 
>> Ron N