Bass bridge bearing

[Roger Jolly]

>On another subject, I've read or heard that the total downward pressure
>on the soundboard is about 1500 lbs., and that the approximate downward
>pressure of one string on the bridge is about 7 lbs.    1500/240 strings
>= 6.25 lbs. per string and  7 lbs. x 240 strings = 1680 lbs. total. , so
>these two figures are in the same ballpark.   That means a 42-string
>bass bridge would have about 300 lbs. pressing down on it.  Can that be
>right?  Many bass bridges are cantilevered out  --  no matter how good
>the glue joint, and even with screws into the apron from the back of the
>soundboard, it seems that two 150-lb. people standing on the
>cantilevered bass bridge would break it right off!

Hi Dave, 
               In many pianos the bass string tension is almost double the
plain wire tension, with a corresponding increase in down bearing pressure.
 However, the strings are wider spaced, compared to say the treble, also 1
and 2 string unisons,this helps distribute the load over a wider area.
Greater stiffness and mass per unit length of the taller bass bridge, helps
with supporting the load, as does the positioning and height of the ribs .
An over simplification of a complex subject, that will lead into the old
Impedance, Reactance, debate.  
I'm sure Ron and Del will contribute.
Just some thing to muse over.
Regards Roger
Roger Jolly
Saskatoon, Canada.
306-665-0213
Fax 652-0505