[pianotech] Force equivalents in different actions

[David Love]

What kind of soundboard and scale are on this piano.  Did you build a new
board and new bridge for this one?  The original Knabes are a bit all over
the place with very high tensions through the tenor region but not so high
tensions in the treble.  I'm not arguing that the heavy hammer is "bad" in
terms of tone.  Only whether it's appropriate in a given situation (touch
weight aside).  A heavier hammer won't necessarily compromise clarity in the
treble in my experience, but it depends on the scale and soundboard
response.  On an old Steinway with original and weaker board this hammer
might not be a good choice depending, of course, on what you're after.

David Love
www.davidlovepianos.com


-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Gene Nelson
Sent: Wednesday, March 24, 2010 3:21 PM
To: pianotech at ptg.org
Subject: Re: [pianotech] Force equivalents in different actions

I have restored an older Knabe - as it was my piano I chose to experiment. 
After stringing I used a few hammers and ended up with Peter Clark's 
Classical West hammers - they are big, dense and cold press - similar to 
Isaac's.
Strike weights are quite heavy - 13.5g at A0 and tapering along a typical 
Stanwood curve for that range.
The action geometry was altered to accommodate and the ratio is quite low 
with 10.3mm dip and 45mm blow. Three and a half leads in the bass and 
tapering to one on the hammer side of the top three. I also like low 
friction so the touchweights are all 52g down and range evenly from 32  to 
38 up from bass to treble. Checking is set at 6.5mm right now - WNG checks 
allow this. It feels and sounds good to me.
After Del's class - spent the day today reducing bearing - especially in the

bass/lo-tenor and did improve the tone slightly.
I have been lectured about the down side of heavy hammers to include much of

what you say about the force that hits the string - slower moving from heavy

and faster moving from light but overall power/force the same - wear and 
tear on bushings etc. I do listen, believe me.
I think that the point about action saturation cannot be excluded as 
certainly everything flexes more with heavy.
The hammer will only accelerate so fast and how would anyone know if you 
were at the saturation point? That would remove anything resembling a linear

relationship and put an upper limit on force applied to the string.
Maybe WNG shanks can help reduce saturation but that is another story.
And the tone is different. I believe felt resilience plays a roll.
I have also been lectured that heavy in the treble is not good - with 7.5g 
sw at G7 I have great power and clarity - go figure. If the hammer string 
contact is calculated on the high side, it is not muting any pleasing 
harmonics anywhere on the piano. Lowest 4 notes excluded.
Ready to get hammered publicly.
Gene