Action Ratio and Dip and Blow and Etc.

[David Love]

I prefer a shorter blow and less dip.  10 mm dip is my target.  10.25 on a
concert grand.  Otherwise, it looks good.  5 g friction is slightly high for
the shank.  Three grams would be my preference.   Different manufacturers
have different specs and performance on the flange pinning.  

 

David Love
davidlovepianos at comcast.net
www.davidlovepianos.com 

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Farrell
Sent: Sunday, July 08, 2007 12:10 PM
To: Pianotech List
Subject: Re: Action Ratio and Dip and Blow and Etc.

 

As suggested, I fully regulated my sample note #40 and regulated friction.
Friction in key is <2g, wip flange is 2-3g, shank flange is 5g (it was next
to zero).

 

Here's how things shake out:

 

DW - 50g

UW - 25g

F - 12.5g

BW - 37.5g

R - 5.7

SW - 9.0 (medium to medium-low)

FW - 19.35 (65% or FW max 30g)

KR - 0.52

Knuckle - 17mm

Action Spread - 114.5mm

 

Blow - 47mm or 1-7/8"

Dip - 10.65mm or 0.42"

Letoff - 1.65mm or 1/16"

Aftertouch - 0.85mm or 0.030"

 

I know my letoff is set real close. I could also lessen blow to 1-3/4 which
would give me a dip of 9.94mm or 0.39"

 

Below is pic of leading on #40 (natural in center with 12g lead sitting on
top at rear of key cover)

 



 

 

Below is action at rest

 



 

 

Below is action at full keystroke (w/ moderate pressure on key - the heavier
end of my Spurlock gram weight set)

 



 

 

Full keystroke again, but here you can see knuckle clearing the knuckle, and
just kissing the fuzzy exterior of the jack cushion.

 



 

 

I'm thinking I got this puppy licked. Am I missing anything? Anyone see
something that is out of whack? Can I assume that if I can do 87 more notes
like this one that I'll have one slick-playing action? Anything else that
would/could improve it?

 

My next post will contain many thank-you's. I'm afraid if I attempted to try
to do justice to that need here, this post would get bumped for being too
large!

 

Jude - you were right about the rep lever pinning - I removed the spring
from it and it was blowing in the wind - zero friction. I repinned it for
5g.

 

And Jon - you mentioned that the capstan/heel magic line is out the window.
Actually, the reason I put that heel extension on there was to get the
contact on the magic line - it was way above it originally. You could just
watch the original capstan slide along the heel. Now, the contact is right
on the magic line at half blow and they move together is perfect unison - no
sliding.

 

Now, the rep-lever/knuckle contact of way out the window - lots of sliding
there. Oh well. Thank goodness for Spurlock Teflon powder.

 

Terry Farrell

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