action ratios

[Richard Brekne]

"David C. Stanwood" wrote:

> 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.

Well, this is exactly what I do. I start of with Distance ratio to get an overall
idea of what the action design is, and plug that into the balance formula as an
"assumption". And because I have been useing your FW max table as "givens" as
well, all I have to do is match a SW curve to that ratio which gives me the BW I
want. (Most often have been using 38) As I've said before the disadvantage with
this approach is that you are bound to that one particular set of published FW
values. On the other hand this approach works well, and is a great way of getting
started learning the routines and theory needed to do much of what your
Touchweight Design is all about.


> This requires a standardized measuring system for distances 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....

I measure 5 mm key travel against hammer travel. Easy to insure 5 mm key travel,
not difficult to measure pretty accuratly hammer travel. 5 or  6 samples are
quickly done and it gives me a working value for Ratio.

> 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.
>

It would be indeed. I am convinced that in the end, the weight and distance ratios
should be the same. (or very very close to it) At the end of an installation I run
through DW and UW on all 88 keys to get both Friction and BW figures. This points
me straight in the right direction to solve any problems with individual keys.

The point being that if you know FW, SW, WBW, and R, then BW is the result. Works
great, lasts along time, but binds you to one FW table..... grin...... but then
you cant have everything unless you pay for it eh ?

--
Richard Brekne
RPT, N.P.T.F.
UiB, Bergen, Norway
mailto:rbrekne@broadpark.no
http://home.broadpark.no/~rbrekne/ricmain.html