[pianotech] Action ration measuring

[David Love]

OK, I got everything from the description except the hammer out so that
changes that number to 135 from 127.  That raises the ratio to 5.58.  I
remeasured the displacement as carefully as possible and got pretty much 6
(36/6).  Going to the tip of the hammer pushes it up to 5.87 but you have to
wonder about the meaning of having to tweak each number and what that means.


 

	
Ea

Ra

	Ratio

		

Key

240

128

	0.53

		

Wippen

63

83

	1.32

	Action Ratio


Shank

17

135

	7.94

	5.58

 

 

David Love

www.davidlovepianos.com

 

 

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Ron Nossaman
Sent: Saturday, September 22, 2012 8:57 AM
To: pianotech at ptg.org
Subject: Re: [pianotech] Action ration measuring

 

On 9/22/2012 10:30 AM, David Love wrote:

> Using your method (if I understood it correctly) I get the following 

> on my action model.

 

As unclear as my description was, I put the attached jpeg together. That
might change things.

 

 

>The measurement of dip to hammer travel yields 37/6 or

> 6.16.  Interestingly, your method of measuring the levers yields a lower

> AR than my method (measuring the key to the end and the wippen to the

> jack center pin) yet moving the dip measurement 20 mm in from the end of

> the key will, of course, produce a higher action ratio than mine

> measuring at the end of the key.

 

Wip out and hammer out is different too. Hammer out, for instance, is 

about half way between center pin to molding center, and center pin to 

strike point.

 

 

>Perhaps these things are action

> specific, though it's hard to imagine why.

 

I don't see how they could be either. Check the drawing against my poor 

description of measurement points, and see what you get. ???

 

Ron N

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