Touch weight

madelyn mrykalo madvinmryk@yahoo.com
Thu, 18 Dec 2003 21:56:02 -0800 (PST)


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Hi-

Of course you can have acceptable DW's & UW's and at the same time have a wide range of moments of inertia, some which may be acceptable and some which may not be.  Or the front weights could be too high.  That's why I don't think UW/DW alone tells us enough about how the action "feels".  

 

Here is a formula for moment of inertia (I):

 I= m1r12 + m2r22 + m3r32 + ... + mnrn2   

 

Where m is the mass and r (radius) is the distance that the mass is from the balance hole of the key.  The key itself has some moment of inertia too.

 

So the action in question (Wim’s D) might weigh off acceptably (DW and UW), but also may have a too heavy a front weight, and/or moment of inertia.

 

Stanwood has come up with a good standard of front weights.  Moment of inertia standards are a little more ambiguous at this point. More importantly is that the moments be reasonably smooth from key to key.

 

Brian is right.

 
Brian Lawson <lawsonic@bdmail.co.za> wrote:
Hi, I think he is referring to the English language with use of a virgule and
not a division sign

3 : a mark / used typically to denote "or" (as in and/or), "and or" (as in
straggler/deserter), or "per" (as in feet/second) -- called also slash, solidus,
virgule

Brian



----- Original Message -----
From: "Richard Brekne" 
To: "College and University Technicians" 
Sent: Thursday, December 18, 2003 3:29 PM
Subject: Re: Touch weight




madelyn mrykalo wrote:

> HI-More telling than downweight/upweight is moment of inertia/front
> weight (which are two different things). UW/DW will not, in and of
> itself, tell much of anything about the action's feel.
>

I think you want to explain this a bit further for us. How exactly are
you ariving at the moment of inertia (for the key) and what does
dividing that by FW tell us exactly ?

Cheers
RicB



Vince Mrykalo
University of Utah

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