Bridge Crown

[Farrell]

Thank you for all your comments Del. I appreciate them big time. While I feel very comfortable accepting info like '45 lbs. pressure produces optimal rib-to-soundboard glue joints' and other stuff, I just can't picture this one. Ron N. says the same as you. I have no doubt you are right.......buuuut. Well, I guess you know what I have to do!

I'm gonna cut this short because I'm gonna tune some pie-annas this week, and I'm gonna get some good sleep, and I'm gonna buy me some wood, and then I'm a gonna build me a soundboard.........soon. (I guess I need to build a press, do some experimenting, and tear apart an old piano first!)

Night, night!

Terry Farrell
  
----- Original Message ----- 
From: "Delwin D Fandrich" <pianobuilders@olynet.com>
To: <pianotech@ptg.org>
Sent: Monday, February 18, 2002 1:27 AM
Subject: Re: Bridge Crown


> 
> ----- Original Message -----
> From: "Farrell" <mfarrel2@tampabay.rr.com>
> To: <pianotech@ptg.org>
> Sent: February 17, 2002 7:06 AM
> Subject: Bridge Crown
> 
> 
> > When building a new bridge, my understanding is that you will want to put
> a concave curve along the long axis of the bridge bottom (or maybe you will
> even want to modify an old bridge that does not seem to have the proper
> bottom curve). But how much curve? I strongly suspect no approach to this
> will be perfect, but we presumably should have some target in mind. Do we
> clamp the soundboard into the piano (or install it), let it equilibrate with
> the shop environment (letting it achieve its normal crown), and then attempt
> to put the same crown as the soundboard has inversely on the bottom of the
> bridge? Or do we want to guess at how much the board will compress under
> string load and target that curve/crown? Or do we want to approach it in
> some other manner? Or just put a 60-foot radius on the bridge bottom and get
> some sleep?
> >
> 
> 
> Save yourself some anxiety and catch up on that sleep. Leave it flat.
> 
> Del
>