Filing over-needled hammers

[Kent Swafford]

Kent Swafford wrote:

>I have a bit of a situation with a B in the studio of a concert pianist.  
>The studio is a "voicing-intensive" situation and the hammers have been 
>over-needled with glover's needles.
>
>(FWIW, I don't use glover's needles and strongly recommend against them, 
>based on the damage I have seen done with them.  They slice hammer felt 
>open.)
>
>A large number of these hammers are split open on the surfaces of the 
>crown on either side of the striking area.  Smooth shaping while filing 
>is impossible due to the fact that the wool that is pushed into the 
>crevices during filing strokes is not removed, and builds up as ridges.
>
>The piano does not sound all that bad yet, but my thoughts on this could 
>change if I get a phone message to the contrary in the next few days.
>
>Obviously, the hammers will have to be replaced shortly, but I need to 
>keep this piano functionioning during the months that it will take to 
>schedule new hammers.
>
>I have considered soaking the hammers with an extremely dilute juice, 
>hoping that the fibers would hang together enough afterwords to 
>facilitate good shaping.
>
>Any thoughts?
>
>Kent Swafford
>University of Missouri-Kansas City, Conservatory of Music

Well, I didn't really want to juice these hammers.  They are Ronsons and 
one assumes that if they have been over-needled, this means, since 
Ronsons start out relatively soft, that they have already been 
over-juiced at some point.

Newton suggested using a power tool to shape these things.  I use the 
Foredom tool with the band-sander attachment, which appears to have been 
just what was needed, thank you.  I have now accomplished the original 
objective which was to decrease and make uniform the strike point on the 
hammers across the scale.  The band-sander smoothed these hammers so well 
that I am even wondering if I will be able to go back to a paddle next 
filing.

The problem remains of how to fit a hammer to the strings when much of 
the strike point is a hole, but the bottom line is that for the moment, 
the voicing has been improved enough that voicing is not the highest 
priority service item for this instrument.  This is a teflon-era piano 
which has had the shank & flanges, wippens, and damper underlevers 
replaced.  A nagging slow-repetition problem (that I assume is 
geometry-related) remains in this action that I am embarassed to say I 
have not been able to get a handle on.  Next call.

Kent Swafford