hammer brushing

[Tom Cole]

John M. Formsma wrote:
> 
> ...Anyway, used the brass brush, and also tried a small steel bristle brush. Do
> you know if steel is acceptable to use on hammers, or should one stick with
> the brass? I know brass is softer than steel, and will remove less. However,
> on this piano, the hammers were quite grooved, and the steel took a bunch of
> that out, whereas the brass did not do as much removal.

John,

I've used varying types of brushes and mostly use one with steel
bristles. It's more aggressive but also can be used with a lighter touch
to fluff up the outer layer of the strike point.

Another type of brush is called a file card; it has very short bristles
and can remove some material like a sandpaper paddle if you want. I
don't have much experience with this approach but it has worked well for
others.

Regarding steel or brass, I don't think it makes much difference. More
important is how you use the brush.

I have mixed feelings about hammer brushing. I've substituted for
another tuner at churches where he tunes regularly and have noticed how
the hammers suffer from the biannual treatment. The brushing does not
eliminate the grooves nor improve the shape. The technique used, I'm
sure, enters into it: a straight-across-the-strike-point approach,
scrubbing back and forth, which appears to be causing the felt to part
at the strike point.

I use the traditional technique of stroking toward the strike point, as
if it were a sandpaper paddle, to get rid of the crustiness in the
string cuts and, at least, try to improve the curvature of the crown. It
makes a big difference on a piano that needs to be voiced and, if they
like the result, it's easy to sell them on a proper voicing job. If they
don't like the result, the brightness/harshness will return soon enough.

Tom

-- 
Thomas A. Cole, RPT
Santa Cruz, CA
mailto:tcole@cruzio.com