Bridge design

[Farrell]

Just for the yahoo of it, I took another peek at my Bechstein and there is absolutely NO dogleg at either the first or second break (down from C88). At the first break, there is absolutely NO deviation in the bridge pinning pattern trying to keep the scaling smooth (all pins are placed the same distance away from the bridge cap edges). At the second dogleg, the pins on the treble side are like the first break, but on the bass side of the break, there is a very small deviation (maybe a millimeter or so) to compensate for smoother scaling.

Interesting.

Terry Farrell
  
----- Original Message ----- 
From: "Overs Pianos" <sec@overspianos.com.au>
To: "Pianotech" <pianotech@ptg.org>
Sent: Friday, March 28, 2003 3:02 AM
Subject: Re: Bridge design


> >Del wrote:
> >>  This theory also explains why
> >>  so many builders were reluctant to put a dog-leg into the bridge at
> >>  plate/scale breaks to maintain good scaling. They were not just being cheap
> >>  or negligent.
> >
> >Ahhhhhhhh. I have a 5' 10" 1900 Bechstein awaiting rebuilding and 
> >the long bridge has absolutely NO HINT of a dogleg at any of the 
> >breaks. The curve is perfectly consistent. I had noticed that a long 
> >time ago and felt surprised that a manufacturer like Bechstein would 
> >be so cheap as to not go the distance of putting on a proper dogleg. 
> >Now I know that being cheap is not likely the answer. Thanks.
> >
> >Terry Farrell
> 
> That just depends what their design priorities were since, when 
> there's no dog leg, the tension percentage adjacent to the plate 
> struts will be a complete disaster (I have the 6' scale in my 
> collection so I know this to be the case). The top break can be laid 
> out with good scaling and virtually no dog-leg by using the width of 
> the bridge top, running the bridge pin field to the back on treble 
> side of the strut and vice versa on the bass side. But the second 
> break down will definitely be a scaling problem unless a dog-leg is 
> incorporated. Although this will involve quite a deal of extra work 
> when shaping up a bridge, it definitely does yield tuning stability 
> benefits if the scale is not compromised across the struts.
> 
SNIP
> 
> Ron O.
> -- 
> 
>         OVERS PIANOS
> Grand piano manufacturers
> ________________________
> 
> Web:   http://www.overspianos.com.au
> Email: mailto:ron@overspianos.com.au
> ________________________