[pianotech] Hammer Flange Friction

[Don Mannino]

Paul,

 

3 reasons off the top of my head:

1. The hammer head control tends to be better, less fishtailing.  In
uprights the jack contact point is very close to the hammer butt center, and
stress on the center is high.  The motion of the hammer mass is also in a
different direction compared to the jack's force.  So a more firmly
controlled center tends to improve the tone.

2. Hammer springs can be strong in many upright pianos, and they return the
hammer too fast in many cases.  This can reduce the repetition rate by
getting in the way of good jack return. If the jack spring is strong and
hammer return is a little slowed, then the jack can reset without the wippen
having to drop all the way to rest.

3. Setting the hammer friction at 6 - 8 grams can induce enough damping
factor to reduce hammer bounce, which also improves the consistency of
repetition.

 

Do these fit in OK with your ideas?

 

Don Mannino (from London, ON)

 

From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of PAULREVENKOJONES at aol.com
Sent: Friday, June 04, 2010 1:25 PM
To: pianotech at ptg.org
Subject: Re: [pianotech] Hammer Flange Friction

 

 

 

In a message dated 6/4/2010 8:28:38 A.M. Central Daylight Time,
donmannino at ca.rr.com writes:

but most vertical actions perform better with the hammers a little on the
snug side.  

Don:

 

Can you please expand on this a bit. i have some ideas of why you think this
is so, but I would like to hear your take first. 

 

Paul

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