Mason bearing quandry

[Erwinspiano at aol.com]

HI JD
  Oh I love this stuff.  I'd love to see these  pianos. From your description 
it sound as if they have crowned ribs.  Any  cracks...ridges etc? This is how 
we learn important things.  Pianos that  have held up in climates such as 
yours without benefit of modern climate  control.  You know...what do I know?
  The radii you describe are new board values. Fantastic.  report back on the 
end result sometime.
  Also so the angular deflections are of the utmost  interest.
  Dale
  

At 10:59  am -0400 9/5/07, Erwinspiano at aol.com wrote:

>   On another  note concerning the wooden gauges. I recently had a 
>1966 BB Mason  & Hamilin.....  With no compression ridges or cracks &  
>only exposed to the beautiful CA climate for 40 yrs & with a  church 
>building around it to buffer any humidity effects, this pianos  belly 
>is  pristine...

Hello Dale,

I read your message  on returning from some experimentation and 
measuring of my current main  project.  This is a piano that has lived 
in the glorious English  climate for 140 years, for the last 12 of 
which it has been on its side  unstrung in a breeze-block garage or a 
barn with no sort of climate or  temperature control winter and 
summer.  I have two of these and the  one in question is to receive an 
experimental soundboard, despite the fact  that the original board is 
perfect in every way.

I did some rough  measurements of the crown of this board this 
afternoon at each of the 12  ribs and discover that the average 
curvature has a radius of 45 feet and  ranges from 60 feet at the 
central ribs to 20 feet at the outsides.   The underside of the ribs 
are perfectly straight, since it was established  English practice to 
plane the ribs straight after the crown had been  produced.

So far as I can tell there has been no deterioration of the  condition 
of this board (or that of the piano's twin) in 140 years of  neglect 
of anything to do with climate.

I shall soon be taking  measurements from the twin, which is unstrung 
and still has the frame in  to see what the angular deflections are. 
I rarely bother to measure these  before I unstring a piano since they 
would normally tell me nothing very  useful.

As to your M & H, I think I'd leave it as it is, as I think  you will, 
unless you think awesome is not good enough!  :-)

JD







************************************** See what's free at http://www.aol.com.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: https://www.moypiano.com/ptg/pianotech.php/attachments/20070509/e611bce3/attachment.html