String breakage in relation to hammer mass

[Delwin D Fandrich]

>
> <<"The short answer is maybe, but probably not by itself."
> Del">>
>
> Del;
>  The question was "contribute" not 'cause'. In my way of thinking the
> "heavier" hammer will "contribute" in several ways, i.e., a. It will
result
> in more forceful playing to acheive the same volume as with a lighter
hammer.
>  b. It will have a longer force dissipation contact time with the string.
(?)
> among others.
>
>   Although "saturation" certainly figures in the equation at some point I
> would think that the 'significant' differences would not show up until the
> higher end is reached, or is my thinking faulty here?
>
>   It really is interesting how a tounge in cheek remark will foster so
many
> different responses and viewpoints Huh? :-)
> Jim Bryant (FL)

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Jim,

That is why I said "maybe...."  There are precious few absolutes in this
business.

Still, piano action dynamics are such that for a given amount of energy
input to the key there will be a given amount of energy at hammer impact
regardless of the hammer mass.  The lighter hammer will have attained a
higher velocity and the heavier hammer a somewhat lower velocity, but the
actual amount of energy transferred from the finger to the string will
remain essentially the same.

Also, at the ridiculous extremes of key velocity, for every given action
there will be some finite amount of energy transfer possible, again without
regard to hammer mass.  The key will simply bottom against the front rail
punching before the hammer impacts the string.

As may be, I'm not convinced it is the actual amount of energy involved, but
the rate at which that energy is transferred from the hammer to the
string -- along the resulting energy mix set up in the various partials --
that contributes to the string breaking problem.  And that is a function of
the density and shape of the hammer.  Hammer size is not an issue since it
is not a reliable indicator of either hammer density or stiffness.  Hammers
of equal size can vary considerably in mass, density and elasticity.  Nor is
the original pressing technique an indicator -- a hammer can start out quite
nicely elastic and be made both stiff and dense by the addition of
chemicals.

Most massive hammers are, by design, quite dense and physically
unyielding -- and, hence, become every technicians voicing nightmare.  When
these hammers impact the string(s), there is no give to them as the
resulting hard-sounding tone quality attests.  To some extent the initial
harshness also common with these hammers can be lessened by loosening up the
surface of the hammer.  So factories typically "fuzz" the surface somewhat.
This works nicely on the showroom floor and for a few months of normal play,
but it soon wears away.  Then the technician is left with the task of making
the piano sound "like it did when it was new."

In desperation, the technician tries all sorts of things to cope -- needles,
steam, chemicals of various types, mechanical squeezing, whatever the
desperately inventive mind can think of -- to lessen the impact shock of the
hammer against the string(s).  And, who knows, in time the technical
community may well develop sufficient technology to cope successfully with
these things.  But should it all really be necessary?  Surely not.

Very dense hammers are easier -- and cheaper -- to make consistently than
are resilient hammers, but I can discern no other justification for them.
They do help overcome the acoustic characteristics of the excessively stiff
and massive soundboards and light, floppy rims, but these are problems of
the piano builders own making and need to be addressed at the design and
manufacturing stage.

My advice for years has been that if the technician receives a set of these
rock hard hammers, they should be sent back to the supplier.  If they happen
to come pre-attached to a piano, well....

So, until I come across some compelling argument that convinces me
otherwise, I am of the belief that it is the  unyielding and inelastic
nature of the dense hammer, coupled with the shape of the hammer at the
striking point, rather than its actual mass, that are most often the
culprits.  A broad striking shape -- one with a relatively large radius by
design, or one that is actually flat from wear, and regardless of the
elastic nature of the hammer -- is quite hard on the string.  Given both a
broad striking "point" and an inelastic and unyielding foundation, the poor
strings don't have much of a chance.

(Notice, none of the above detracts from the need to keep an action properly
regulated.  Nor does it detract from the players responsibility to play the
instrument properly.  There are some folks who, for the good of music in
general, probably shouldn't be allowed to play anything except worn-out
Grand spinets and the occasional Brambach grand.)

Regards,

Del