Horn troubles...or not?

[Delwin D Fandrich]

MHoffman11@aol.com wrote:

> Greetings listees,
>
> I thought I looked at it closely.  I swear the bolt was touching the horn
> before I dropped the tension for restringing.  Now there is a gap of about
> 3/16.  I searched in vain for a wedge that I'm sure wasn't there in the first
> place!  This is an Adam Schaaf grand (made 1919).  Tuning stability was good
> before tension was dropped.
>
> Anyway, that gap is bothering me.  I'd feel a whole lot better if there had
> been a wedge that had fallen out.
>
> I can turn out the bolt to meet the horn, but should I?  Visions of cracked
> plate abound in brain.  On the other hand, does the plate flex THAT much?
> Would turning that bolt out CAUSE the plate to break under tension?

--------------------------------------------------------

Mike,

The question is, what is the bolt anchored to in the belly rail?  If it just
dead-ends into the belly rail without much support behind it there easily could
be enough wood movement to account for a 4 to 5 mm gap once string tension is
removed from the plate.  It is also possible that it wasn't adjusted correctly at
the factory.  In any case, you can be quite sure that it was the intention of the
designer that the bolt and horn meet prior to the application of string tension.

To comment on a couple of other comments that have been made on this topic to
date:

    --  Ron:  Yes, plates do flex.  Quite a good deal, in fact.  But it is
unlikely that the designer intended to build in any "pre-flex" prior to
stringing.  Horns of this type are intended to reduce plate flex to a practical
minimum.  (They are also intended to save iron.  Plates using this design can
generally be made quite a bit lighter and still end up with good overall
structural stability.)

    --  Mike:  I have also encountered one Steinway B without a wedge.  In this
case, however, the horn and the collector were so close without tension that
there really wasn't room for a wedge.  On rebuilding, if the gap between the two
was more than about 1 mm, I would strongly recommend making and installing a new
wedge..

    --  Good question, Ron.  What were you doing bouncing on these plates?
Diving board break?  Or what?

Regards,

Del