agraffes on bridge?

[Delwin D Fandrich]

----- Original Message -----
From: <JIMRPT@AOL.COM>
To: <pianotech@ptg.org>
Sent: Thursday, September 23, 1999 1:55 PM
Subject: Re: agraffes on bridge?


>
> In a message dated 9/22/1999 11:27:37 PM, musicmasters@worldnet.att.net
> writes:
>
> <<  However, if the bridge agraffs have
> upbearing, how does this comport with the treble section, which has
> traditional bridge pinning?    Isn't it really strange to combine
upbearing
> and downbearing
> on a bridge? >>
>
> <<"Doesn't the upper "traditional" treble have downbearing?">>
>
> Brian H.;
>  Del or Ron N. would be more qualified to answer this question than I
> but......
> Yes in most cases of agraffed Sohmers the upper treble has 'normal'
> downbearing, probably supported to some extent by the 'upbearing' on the
rest
> of the scale as well as crown built into the treble section of the board
??
> The bass section of these thingees also has "normal" bridges.

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

I've not studied the characteristics of piano soundboards using up bearing.
I am aware that several have been made, but they are now quite old and
probably beyond their musical best.

I have given some thought to "agraffe bridges," however.  There are no
inherent technical reasons why some system of this type would not work as
well as, or better than, the bridge pin system currently in common use.  The
bridge system must do two things:
    1)    It must efficiently terminate the speaking length of the string.
    2)    It must efficiently transfer the vibrating energy from the string
to the soundboard.
Any mechanism that accomplishes these two tasks can be used.

There are some issues that must be considered with any string termination
system.  Among them are:
    1)    Cost.  The conventional bridge pin system has been used so long
that most high production companies now have automated systems for drilling,
notching, pin insertion, etc.  The actual cost in these pianos is quite low.
For pianos like the Steinway, tradition is probably motivation enough to
continue using the bridge pin system.  It does take a bit of training to
prepare a human to do this task.  Once trained, however, the cost of doing
the job by hand is still not all that high.
    2)    Downbearing.  The system must provide for string loading of the
soundboard.  This can be accomplished by any string termination system.  The
soundboard does not care how it gets loaded, just that it is.
    3)    Service.  The system must be trouble free and long-lived.  Here
the bridge pin system does not fare so well.  It is very problematic.  But
some other systems don't do much better.  The agraffe systems have a problem
with bridge roll.  Unless they alternate the string deflection, in which
case they tend to split bridges.
    4)    Stringing.  The system must provide for easy stringing.  Both at
the factory and in the field.  It is not likely that any new system will be
any easier to string than the good old bridge pin system.  Agraffes have a
problem with the center string through the trichord section.  The sides can
be slotted for easy insertion of the two outside strings, but this doesn't
work for the center string.  Stringing is generally more difficult with all
of the different systems I have seen.
    5)    Acceptance.  The technical community is slow to accept any new
innovation in the piano.  Even ideas like the vertical hitch pin still face
an undercurrent of opposition even though it is clearly a superior system.

There are probably some other important considerations I've not thought of
here.  From time to time I work on this little problem.  I have come up
with -- and discarded -- probably a half-dozen designs that would work
better than the current bridge pin system.  But they all have failed one or
more of the above tests.

Del