tapping strings

[Ron Torrella]

> -----Original Message-----
> From: owner-caut@ptg.org [mailto:owner-caut@ptg.org]On Behalf Of Roger
> Jolly
> Sent: Friday, April 05, 2002 8:33 AM
> To: caut@ptg.org
> Subject: Re: tapping strings
>
>  and the pin doesn't climb
> >out of it's hole"
> >
> >
> Hi Ron,
>         Do you have any proof of that statement?  Hydrolic action
> in soils,
> causes fence and telegraph post to creep out of the ground.( very well
> documented)
> With humidity swings in maple, why would the same effect not exist?  High
> humidity exerts pressure on the bottom and sides of the pin, and
> the top is
> free to move.  Once you swing back to a low humidity condition, it's
> possible for the pin to move, dependent on friction. but it can only move
> up, and to the side that is being forced by the side bearing.

Another fly in the ointment......when wood expands in high humidity, don't
holes get bigger? Clicking noises in teflon bushings are usually heard in
the dead of summer. Still, if there's enough of a rise in the board/bridge,
the increased looseness would likely be countered, right? (Maybe this
explains Ron N.'s instistence that pins do not climb out of their holes?) By
the time the board/bridge start sinking (and shrinking), the humidity level
has dropped and the hole, presumedly, would have shrunk, becoming tighter.

With this in mind, isn't it more likely that exaggeratedly low humidity
levels are the cause of loose bridge pins? That seems like an obvious thing,
but I'd think the extra shrinkage would be the cause of crushed wood in the
bridgepin holes -- the result of *low* humidity instead of the typical
result of high humidity.