filing hammers

[Les Smith]

Greetings, All!

Although I have a couple of moto-tools in my shop, I rarely use them for
filing hammers. While it's true that such a tool can be easily used on a
set of grand hammers, you'll find that with a set of upright hammers, the
action brackets and frequently the dampers themselves make it difficult
to square the tool with the surface of the hammer. This is especially true
with badly worn hammers in compact actions utilizing type "A" boring where
the tenor hammers are set at an angle opposite to that of the bass hammers.
Further, if the high treble hammers are badly worn and little felt is left
at the crown, there's always a chance that you'll take off too much felt
and expose the wood molding underneath. While I am sure that there are
some Moto-tool virtuoso's out there, they appear to be few and far between.
Set after set of grossly mis-shapen hammers that we've all seen in the
field, suggest that in the hands of many techs a Moto-tool can be considered
a deadly weapon and that what's getting killed is the tone-quality of the
piano's involved. The purpose of filing hammers is to restore both the
striking surface AND the correct strike point to the hammer, both of which
are critical to the production of good tone-quality. Because of this, given
a choice of speed or accuracy, I'll personally take accuracy every time.
Which is why, even if you're using a Moto-tool, it's probably a good idea
to go over the hammers again by hand once you've finished. If you're using
fresh, sharp paper, hand filing goes very quickly, while still giving you
maximum control of the strike surface and the strike point. Then, too,
the basic idea is to re-shape the hammer while removing as little felt as
possibe. Use of a Moto-Tool seems to invite excess in this respect. In his
excellent book "Regulating Grand Piano Touch and Tone" the late Danny Boone
devotes several pages and some excellent photographs to the subject of
hammer filing, as does Franz Rudolf Dietz (Steinway, Hamburg) in his short
book entitled "Grand Voicing". Both are worth reading. Neither mentions the
use of a Moto-Tool. Obviously the above remarks would apply equally to new
hammers as they do to old. Equally obvious is the fact that these remarks
only reflect the opinion of one, old-fashioned, over-the-hill tech--namely
me!

Peace

Les Smith
lessmith@buffnet.net