Bridge pin spacing

[Conrad Hoffsommer]

At 05:09 8/13/2006, you wrote:
>At 4:15 am -0500 13/8/06, Conrad Hoffsommer wrote:
>
>>Looks like a Baldwin SF10.  If it is, you'll also finds that the 
>>string sizes drop back across that break. (The size on the treble 
>>side is larger than the size on the bass side.)  Both bridge pin 
>>spacing and string sizes are scaling solutions to having a bridge 
>>which doesn't deflect from a straight line when going under a strut. (methinks)
>
>Supposing that the curve of the bridge is continuous under the bar 
>as you say, which seems likely, then I would guess that at the point 
>in the middle of the picture where the front pins are moved back 
>there is an increase in wire gauge.


BTW, seeing the Accujust hitchpins confirms the Baldwin ID...

Anyway...  Yup. Just found my notes on this computer...  2 of 16.5 
and 2 of 16 ga. on bass side, then 2 of 16.5, 10 of 16 on treble side.

 >The picture does not show what happens to the bass side of bar, and 
I've never seen a Baldwin, but almost certainly the front pins are 
again moved forward and the wire gauge remains the same on the notes 
each side of the bar.

As I recall,  the spacing between the front and back bridge pins on 
the bass side of the strut is also narrow for about 4 unisons.


>If you consider a "standard" piano with the usual dogleg in the 
>bridge under the bar, each time you increase the wire gauge going 
>down the scale the tension drops, to rise gradually towards the next 
>gauge change.  By increasing the speaking length as the wire gauge 
>is increased, as happens here, the tension is increased to a value 
>closer to the tension on the upper note strung with the finer wire.
>
>The increasing of the speaking length at the point shown in the 
>picture is a preparation for the second tension adjustment that must 
>take place as the bar is crossed.
>
>JD

Unfortunately, I have my notes re:scale lengths at school, so I can't 
throw them at you, right now, to confirm or deny.



Conrad Hoffsommer
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