The Steinway Bell Bolt/ How tight

[Delwin D Fandrich]

If you are trying to use the bell/bolt arrangement to alter string bearing
in some way, you're on your own. I have no advice. For the system to work as
a mass-coupler, however, finger tight plus one turn is adequate.

One caveat, however: Steinway has often furnished a square, rather crudely
made nut for this purpose. It can bind and give a false impression of
'tight.' If you insist on using the original nut you might consider putting
a washer in there to give the nut a smoother fit and a more consistent feel
against the bell as it is tightened.

Del

----- Original Message -----
From: "Bill Ballard" <yardbird@pop.vermontel.net>
To: "Pianotech" <pianotech@ptg.org>
Sent: September 17, 2002 8:47 AM
Subject: Re: The Steinway Bell Bolt/ How tight


> At 2:16 PM +0200 9/17/02, Richard Brekne wrote:
> >>PIANO2NR@aol.com wrote:
> >>
> >>Does anyone know how tight the bolt that goes through the bell is
> >>supposed to be?  Finger tight plus 1 full turn?
> >
> >That is nearly exactly the word I got from the head of S&S Hamburgs
> >technical support section just a couple weeks ago.
> >
> >But then he also mentioned that a bit tighter was ok too as long as
> >it increased sustain. I would be real carefull about tightening this
> >myself without having some way of knowing just how much the plate
> >was being stressed.
>
>
> I remember bringing up the subject in June of 98. Rick Davenport's
> story about Heiner Seinwald (?), the Fazioli tech, working a miracle
> on a piano in Rick's shop (not a Fazioli). Don Mannino's contribution
> to this thread was, "I would be hesitant to do what Heiner does
> without knowing what he knows".
>
> Knowing how much the plate is stressed requires knowing where it lies
> flat before the bolt begins to deform it. In a plate with a tension
> load, that's not reliably readable.
>
> I remember Jim Coleman remarking that such a maneuver was not likely
> to remedy slim or negative downbearing because the board would squash
> to return the downbearing pressure to the pre-maneuver level.
>
> But that bolt can definitely stiffen up the plate web, which is what
> I gather Heiner was sensing with his finger tips.
>
> Bill Ballard RPT
> NH Chapter, P.T.G.
>
> "I gotta go ta woik...."
>      ...........Ian Shoales, Duck's Breath Mystery Theater
> +++++++++++++++++++++
> _______________________________________________
> pianotech list info: https://www.moypiano.com/resources/#archives