string seating - was bridge caps

[Ron Nossaman]

>> During the wet cycle, 
>
>This sounds great.. could even be exactly whats happening. Or it could be just
>a compounding factor.

Could be, but I did run an experiment that showed me the bridge surface
does move up and down the pins with MC changes in the bridge. How about
doing us one to measure the up force necessary to push a string under, say
the usual arbitrarily chosen 160lbs tension about 0.010" up a pair of
bridge pins against 1° downbearing, 10° pin stagger angle, and 20°
inclination angle. If it's over 1470psi, we'll have a winner. If not, we'll
be back where we started.  




>Heres the other point that makes me scratch my head....xxx the question
this fact raises is
>why doesnt the string conform to the somewhat rounded profile of the bridge ?

Depends on the overall downbearing angle, doesn't it? As the board sinks
and bearing approaches zero, what happens?  



>> If the pin is even a little loose at the bridge surface, it will
>> flagpole and produce false beats.
>
>I'll buy this... but this seems like a different issue ?? I dont seat strings
>on the bridge to solve any false beating myself.

I don't either, but a whole lot of techs out there do so regularly, which
is why I wrote the original post in the first place.



>> Seating the string will knock it down on
>> the bridge, creating a slight negative front bearing angle between the
>> speaking length and the length of string that wasn't touching the bridge
>> prior to seating.
>
>Do we know this or is this speculation ? 

Speculation, at this point, based on what I think I know about physics and
mechanics. I said at the beginning of the post that this was my idea of how
all this worked.   



>Can you demonstrate this to be true,
>and why then the same string under the same conditions "bend" nicely over the
>bridge if you simply remove the bridge pins ?

Does it, or is this just speculation? 


> I would think that you would have
>to have a point on the bridge near the edges that was below the level of the
>front temination point, or the bearing point behind the bridge in order to
>create what you describe above.

Exactly the point.



>I wonder also if you could explain what you mean by
>"behind the  (-20°) vertical.

The bridge surface is the horizontal termination, the pin is the vertical,
only it's not vertical. Any way I could possibly have said this would have
been challenged by somebody, so I went for literal.


Ron N