on needling old upright hammers

[Dave Nereson]

----- Original Message ----- 
From: <Alpha88x@aol.com>
To: <pianotech@ptg.org>
Sent: Tuesday, July 20, 2004 8:20 PM
Subject: on needling old upright hammers

>            Two more questions:
>            1. On these 100 +, - year old upright hammers (or for that
matter
> any old old hammers), is it possible that one could needle them to sound
> really much better and less shrill, do a good job, satisfy the customer,
and then 6
> months later get a call that the wool is falling to dust off the hammers?
>
>             I really do have an over-active imagination, yet I do only
have a
> whopping 1 yr. plus experience, and as a rookie, I just have these
thoughts.
> Some of these hammers when you file them, especially the old ones, their
> filings turn to DUST on the workbench. It's scary...and

    When you first start filing a hammer (several strokes in the same spot,
in the same direction, trying to get a layer started), yes, the filings are
sorta like "dust", but fiber dust, not dirt dust.  But once the layer is
started, and you follow it around the shoulder up toward the crown, it
should be coming off more in shreds that are connected together (which they
are -- that's what the felting process does when they make the hammers).  If
the filing is producing dust as though you were sanding balsa wood or
styrofoam (not bead styrofoam, but the foam type like you stick flower
arrangements in), then the felt is past its useful life -- dead, no more
connected fibers or tension or resiliency.  But needling won't cause that;
it's a combination of climate changes and age, I believe.

>            2. Would needling deeper than 3/16" to lets say, 1/2" on the
> shoulders, give any benefit?

    Possibly, if you can get needles to go in that far, but I would think
only on the most dense hammers.  I don't know if I've ever gotten a
1/2"-inch long needle to sink all the way into a hammer -- maybe with just a
single needle and hammers that are already extremely soft.  I find (here in
dry Colorado) most old hammers to be already quite soft around the
shoulders, and only the crown is packed down or worn flat.  Many old pianos
have grooves so deep in the hammers that the felt is surrounding the strings
and muffling the tone.  After filing hammers, the tone is usually brightened
up to just about right.  Sometimes it comes out too bright, and I'll have to
voice them back down a bit, maybe in the 11:30 and 12:30 areas.  But "sugar
coating" is just a shallow (1/16" or so) needling around the crown, which is
done last, like fine-tuning.
    Now and then I run into a set that is leathery on the outside, as though
the felt is covered with a thin layer of leather.  I don't know what causes
this.  The needles don't want to poke through the outside surface, but if
you prick into the side of the hammer, it goes in no problem.  Still not
sure what to do with these.  If they're really harsh and bright, I'll use
the ViseGrips technique.

 <<Does going deeper into the hammer release more sound?>>

    I'm not an expert voicer, but I'm sure it depends on hammer density and
tension.  With dense hammers, even a single needle will go in only so deep.
Then I think it's more the number of stabs that has an effect rather than
how deep.  What you do to old hammers is not the same as you'd do to new
Renners or Asian hammers.

>        No, I have never tried steaming hammers. I'd be concerned on
hammers
> this old that they would "unravel" "unwrap" from their cores.

    >
> Julia Gottchall,
> Reading, PA
>

        Nah!  You'd have to hold each hammer into a concentrated jet of
steam for probably a half minute or more.  With steam voicing, you're just
"dipping" the crown of the hammer into the steam for about a second, or if
you use the damp cloth / hot iron method, you only apply the iron to the
hammer for 2 - 3 seconds.
        Now, again, I'm in dry Colorado.  Maybe hammers that have spent most
of their lives in humid climates behave differently, but even the few I know
for a fact came from Hawaii or Florida were not drastically different.
        --David Nereson, RPT