Buttressed Arch. Question for Ron N.

[David Love]

>From a design novices perspective, ribbing the panel at a 60' radius through
the panel and 6% emc seems inadequate to form enough crown especially in the
upper end of the piano.  

David Love
davidlovepianos at comcast.net 

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Fenton Murray
Sent: Saturday, April 15, 2006 11:39 AM
To: Pianotech List
Subject: Re: Buttressed Arch. Question for Ron N.

How are you
crowning boards, incidentally?
Ron,
I'm doing my first solo flight on an upright. Ribs at 60'. Go bar press.
Getting ready to rib the panel at emc about 6. RH in my area typically in
the 60's all year.
----- Original Message ----- 
From: "Ron Nossaman" <rnossaman at cox.net>
To: "Pianotech List" <pianotech at ptg.org>
Sent: Saturday, April 15, 2006 8:03 AM
Subject: Re: Buttressed Arch. Question for Ron N.


>
> > Yes, better, thank you. As one guy building soundboards, I'm not sure
how to
> > use this info. but it helps me to understand the system.
>
> That's what the information is for - understanding what is,
> and more important in this case, what is not. How are you
> crowning boards, incidentally?
>
>
> >IS there a force
> > pushing the rim out,
>
> No, there is not. There is some rotational force on the belly
> rail from string downbearing because it's cantilevered, but it
> has no affect on crown.
>
>
>
> >and is there any advantage to trying to make that rim
> > immoveable,
>
> Absolutely. I routinely add bracing to the straight side, and
> particularly to the belly rail (mass too, here). It doesn't do
> the slightest thing for crown, but it raises the impedance of
> the rim and belly rail so it absorbs less of the soundboard's
> energy, improving tone and sustain.
>
>
> >and is there a consequence to it moving with respect to the
> > soundboard?
>
> Yes, it absorbs energy that should ideally stay in the soundboard.
> Ron N
>
>