kneading hammers

[David Boyce]

Rupert, you mention that Howe talks about kneading hammers.  I've just 
trawled through the chapter on Voicing, but can't find the reference to 
kneading.  What page is it on?  I have the "Revised Third Edition"  - is 
yours a very old copy, perhaps an earlier edition?

The topic of using pliers to gently squeeze the sides of hammer felts to 
soften them has been mentioned here before, some years ago.  I tried it once 
on the 1920s Challen grand belonging to friends of mine, with great success. 
There are plenty of those small Challen grands around in the UK.  They are 
very solidly built, but just not all that great, and they all sound similar. 
The hammers on my friends' piano were very hard, and the tone horribly 
bright and tinny.  Having read the reference on here to the use of pliers, I 
gingerly tried one hammer and was pleased with the result. Proceeding 
carefully, I did the lot, and got a most pleasing result in very little 
time.

If the jaws of the pliers are dirty or oily they will of course mark the 
felt, so perhaps thin cloth could be stuck to the jaws of the pliers, or 
placed between them and the hammer, just to keep the hammer clean.

I would stress that I used this method on an older piano of no particular 
quality, with very hard hammers.  I would proceed very carefully indeed on a 
newish high-quality piano where you only want to make very subtle tonal 
adjustments.

Best wishes,

David.


Please could someone give some advice on exactly how
to go about kneading hammers as suggested by Alfred
Howe in his book on Scientific Piano Tuning and
Servicing (1947)?

He mentions gas pliers, and kneading in alternate
directions. Others on this group have in the past
explained how they have used vice-grips.

I would like to know exactly where to apply the
pressure, and how much pressure to apply.  Should the
felt thickness be reduced by 1/2 or some other
fraction?

Can the felt be permanently damaged?  Is it inherently
more harmful than needling?

Thanks for any tips.

Rupert