Rock Maple Hammer Cores

[Delwin D Fandrich]

> -----Original Message-----
> From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org]On
> Behalf Of John Hartman
> Sent: February 19, 2004 7:20 AM
> To: Pianotech
> Subject: Re: Rock Maple Hammer Cores
>
>
> Delwin D Fandrich wrote:
>
> > I've been hearing about the tonal characteristics of the
> various species of
> > wood used for hammer moldings for something over four decades now. And,
> > still, I remain unconvinced.
> >
>
> Del,
>
> Some good points made in your post. It's true that, overall, the molding
> wood is not as great a factor effecting the weight of the hammers as the
> density of the felt. But in the high treble the wood is an important
> factor. To get the hammers it this area to be as light as some of the
> originals from pre WW2 you need as light a molding as possible. While I
>   agree that the wood species does not bear directly on piano tone heavy
> hammers can have negative effects both tonally and mechanically.
>
> BTW even the lightest felt used today is at least 20% more dense than
> the felt on hammers from the past.
>
> John Hartman RPT


Well, I had thought that was the point of my post -- that overall hammer
mass and density is the factor in question, not the specific gravity of the
wood used in the molding. That (the specific gravity) happens to fall within
a relatively narrow range for all of the woods deemed strong enough to use
for hammer moldings. Regardless of the species used this is going to be
somewhere around 0.50 and 0.65. Considering the amount of wood used in the
individual hammer molding this is not a significant factor. More to the
point is that those on the lighter side also tend to lack the strength of
those on the heavier side and therefore must be made somewhat thicker to
compensate, thereby negating any advantage they may possess by having a
slightly lower specific gravity.

Unfortunately, many, if not most, hammer makers are using hammer felt that
is far too dense for good piano tone -- a soapbox I've been on for several
decades now. During the press cycle the inherent stiffness of this felt puts
a rather higher stress on the hammer molding and forcing the use of thicker
(and heavier) cross-sections which drives the overall mass of the finished
hammer up even further.

As well, many of the maple moldings I have seen look exactly like the
moldings being made of woods lacking the strength of maple. Rather than
taking advantage of the superior strength of maple and trimming them down
accordingly they simply use the same size and type of molding regardless of
the wood species. Let's not place the responsibility for the overall mass of
these maple moldings -- or the completed hammer, for that -- on the poor
maple tree but on the hammer maker who, either through ignorance or
laziness, fails to take advantage of the strength of the wood at hand.

I've encountered too many excellent hammers on old pianos using maple
moldings appropriately to accept all this "modern" hoopla over the perceived
tone qualities of one wood species over another at face value. Rather than
fussing about the species of wood used in the hammer molding we should be
pressing the hammer makers to give us hammers of lower density and greater
resilience, shaped properly and using moldings of appropriate shape and
cross-section.

Del