More Agraffes and Tech Bulletins on line

[PianoGuru@aol.com]

> the thread size of my agraffe was not available in Helicoils.  The
>agraffee was 1/4" by 36.  He believes that a good epoxy should do >the job.


I do not believe that epoxy would be a good solution.  There is a great deal
of upward pull applied to the agraffe, and the best of epoxies may not be
adequate to the task.  My experience with helicoils has been that they work
OK until the threaded member is later removed.  At that point the helicoil
tends to either come out with the threaded member, or be forced out when it
is re-installed.  It pretty much a one-time fix.

There is a reason that the tiny 36-thread/inch is used.  It is necessary to
allow "overtightening" to the correct alignment of the agraffe.  With a
courser thread, I am afraid that you might have difficulty with aligning the
agraffe to the strings.  A 36 thread/inch agraffe can be overtightened up to
a 1/4 turn to achieve the correct alignment, while a 18 thread/inch agraffe
would break off before yeilding to this amount of overtightening.  The best
alternatives are an oversized agraffe, mantaining the 36 thread/inch but with
a larger diameter, or the special threaded insert described in our Tech.
bulletin.

Many of you on Pianotech have responded to the question raised regarding
Tech. bulletins being made available on line.  We are looking at alternative
to make this possible.

Frank Emerson
Baldwin R & D