action ratios

[David C. Stanwood]

Dear Richard,

"Cleared up once and for all" would be great!  The obvious thing to do is
to take parallel measurements.  Every time you measure SWratio measure the
Distance ratio.  This requires a standardized measuring system for distance
ratios that gives repeatable results.  The results would be interesting to
be sure and it would take a lot of measuring and correlation of the data....  

In a way we are checking the distance ratio by checking aftertouch with a
given dip compared to a given blow distance.  It would be nice to have an
accurate bench tool to check distance ratio as a rebuilding procedure.

David Stanwood


At 06:46 PM 11/2/02 +0100, you wrote:
>This has been up several times and is the source of a lot of head
scratching me
>thinks
>
>The point is that given a simple lever such as a key, the key ratio is
exactly
>the same for weight, distance, speed or whatever else comes into the
picture. It
>you have a 0.5 key ratio, the 10 mm key movement at the front will be 5 mm
>capstan movement. 10 grams downwards pressure at the front will balance 5
grams
>at the capstan,  speed at the capstan will be half  the speed of the front of
>the key.
>
>Now its difficult  to imagine that coupling several levers should make any
real
>difference to this picture. FW and DW together are exactly that which
balances
>the rest of the action. Removing Friction from the picture then its FW and
BW. I
>have never been able to see that the Balance Equation should result in any
>different ratio then any other way of measureing total action ratio. That
there
>are apparent differences I have always chalked up to inperfections in how we
>measure. And I have always felt that the weight method of measureing is
the most
>accurate of the most common methods we use. Besides... its faster and
easier as
>well.
>
>If there is any real difference in overall action ratio and  SW ratio, I have
>yet to see anyone even come close to explaining what it is. I would think it
>would be of value to get this whole matter cleared up once and for all.
>
>RicB