Down-Bearing for Old Board

[Farrell]

"My advice is od not apply more bearing than is needed to....."

Again, exactly where/how do you measure your downbearing. I have been taught
to measure the gap between the plate ridge in front of the hitch pins and
the string when the string is just touching all the way across the top of
the bridge. Thanks

Terry Farrell
Piano Tuning & Service
Tampa, Florida
mfarrel2@tampabay.rr.com

----- Original Message -----
From: "Erwinpiano" <Erwinpiano@email.msn.com>
To: <pianotech@ptg.org>
Sent: Thursday, February 01, 2001 10:19 AM
Subject: Re: Down-Bearing for Old Board


> Terry
>     I,m sure there are many differing veiws on the subject you raised but
> the answer will probably contain similar threads.  A very fine 4 part
sereis
> of articles printed in the P. T. J. around august ,sept.of 1995 By John
> Hartman has been an enormous help in applying downbearing principles to me
> and others. I beleive the series was called downbearing and the affects on
> tone.  This article includes some guidelines for setting up old boards as
> well.
>        My advice is od not apply more bearing than is needed to compress
the
> board to a flattened  position after it is strung and up to pitch.  The
fact
> that you're in florida means that the moisture content in your board is
> probably high or could be . I think saftey dictates dampchasers be run
with
> humistat for for many  days before making the final determination on how
> much crown was actually acheived(have never had much luck reintroducing
> crown through shimming and I've tried).
>      How much crown is there really ? This should be meas. after drying to
> 45% r.h. to get a real figure.  If a newfully crowned   board exhibits
1/4"
> to 3/8" in the unstrtung condition at 45% how does that compare to what
your
> seeing?  Usually what is typically described to me by others as" alot  of
> bearing" is a board in fairly flattened or flat condition.   I.E. it has
two
> m.m. of crown.  Then you can see thats not much but if thats all you have
> then by all means try to use it to your advantage but do not put more than
> two or three m.m. bearing on the board or something safe.  Remember
> compressing the board changes this light weight structures impedance
(which
> is a good thing) and makes it a more effeicent sound producing device.
> (moving more air / sound waves)
>  Just food for thought and hope it helps
> Dale Erwin
>
>