[pianotech] Measuring Action Ratios

[David Love]

I'm sure he has, and he's not the only one.  This topic came up not too long
ago and several methods were outlined by various people.  If you have keys
made by various key makers around the country you will discover that the
methods they use can yield quite different numbers which makes communication
along these lines difficult at best.  An action from one key maker I know
targets something around 4.8 as his standard but that same action produced
by another keymaker would be considered 5.6.   Those differences are all
owing to how they measure the individual levers.   One of those two must be
wrong, it seems to me, or at least have some other meaning.

 

The discussion that came up previously was which method of measuring most
closely mirrors the SWR method that comes about from an analysis by weight.
I'm sure DS could chime in on that, if he wanted to.  Finding a system in
which weight and distance methods yield the same numbers under ordinary
conditions seems like something important.  So far, I find the system that I
use (not the hammer travel/key travel number but the individual lever
measurements, to be the most consistent in that respect, though it's not
perfect.    

 

David Love

www.davidlovepianos.com

 

From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Dale Erwin
Sent: Wednesday, January 16, 2013 6:35 PM
To: pianotech at ptg.org
Subject: Re: [pianotech] Measuring Action Ratios

 

Perhaps David Stanwood could weigh in on this. No doubt he's experienced
this in his massive studies of such things.

Dale Erwin R.P.T.
Erwin's Piano Restoration Inc.

 



 
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