Practical Concert Work

[Richard Brekne]

Cy Shuster wrote:

> I'm referring to discussions last year where it was argued that it was
> impossible for wood as a material to support an arch, because of
> cellular-level crushing ("compression set").  I believe the counter to 
> this
> demonstration was to show how little pressure was required to push down on
> the arch and collapse it.  Therefore the wood alone wouldn't be strong
> enough to support string downbearing (for example, the soundboard 
> compressed
> by the rim, without any ribs).
>
And of course none of this took into consideration the cm by cm 
resistance put up by the ribs to any increase in downwards pressure on 
the panel.

We ended up admiting that the actual degree of archlike behaviour was 
probably less important because of the cable like function of the rib 
interface with the panel more then it had to do with the fact that the 
ends of the panel would crush too easily.

Which struck me personally as odd.... given the drawings I provided last 
year that displayed the panel / ribs as being much like a cable holding 
the panel crowned.  Again it seemed to me at the time that this analogy 
was fine as long as it was used to justify an arguement against the arch 
line of thinking... but as soon as the same analogy was applied with 
equal consequence in the direction of  what is being compressed and what 
is being tensioned... then it was no longer vailid.... without any real 
explanation as to why given.


> I don't mean to resurrect the prior argument, but just as in any 
> profession,
> it's difficult for a student like me to try to figure out what "best
> practices" are.


You sure got that right.... the minute you try and ask for some 
clarification  for some of these apparent disparagies... you  find 
yourself immediatly in somebodies doghouse... grin... in this place of 
learning as it were.

But strangely enough... we do get on dont we ??

Cheers Cy

RicB

> --Cy--
>