Soundboards: Thickness and Area

[Erwinspiano@aol.com]

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In a message dated 10/17/2003 8:15:19 PM Pacific Daylight Time, 
Crashvalve@aol.com writes:
In a message dated 10/17/03 10:51:55 PM, Erwinspiano@aol.com writes:




If you took out the old boards in 5 Steinways of any give model you'd find 
some way thicker or thinner than the others but with a general range or 
parameter. I've measured a 70's CD S&S B with a soundboard max. thickness of .310 in 
the middle as S&S & other are generally thinned around the edges for 
flexibility (diaphramized as S&S says)  That would be considered thin for a B. On the 
other hand I've seem them as thick as .375 ish. The thin one sounded totally 
awesome & I was surprised it wasn't a "thin" sounding piano. In my work I'd be 
using Sitka panels &  opt for something about .340 to.360. For smaller models 
thinner is fine, .300 to .325ish. By the way You own an A I'm told & I've found 
it common for them to be .350 ish. Ds & Mason BBs can be as thick as .400. Not 
sure this more than incidental trivia but you asked.

  Regards--Dale Erwin

 Dale,
have you ever tried to measure board thickness on a board in place ? I expect 
it could be easily and very accurately done with a depth mike whose spindle 
is cut down a LOT, but this requires drilling a hole in the board.
Regards,
Glenn Coleman 
       Glenn ,Yes I have & you are correct. First it's possible to take 
measurements around the bolt holes with a wire caliper. 2nd small holes drilled 
behind the bridge or around the edges & later filled with a toothpick is kosher, 
but why would you wish to do this? 
   I've done this only once & that was to diaphramize a very thick board in a 
Yamaha C-7. I also refinished the board afterwards so no big deal. The board 
was .400 thick in the middle and tonally a bit stingy. Thinning it helped to 
reveal a more lively tone i.e. better sustain.
  Regards-Dale

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