Touchweight Metrology Question

[Roger Jolly]

Hi David,
          I think I would agree with you. My thoughts is that the stack is
mis located, or the rail needs re locating. But I would like to see the
friction more even, and have the dip measurement with .010- .015" after
touch, before making some kind of judgement.  I would bet this action works
with 9mm or less dip.
Dip spec is 10mm.
I have found that dip gives all kinds of clues, along with the status of
the magic line. I have fixed far too many troublesome actions, just working
with these two parameters.
Yamaha over the years have been remarkably accurate with the sizing of
their components. The way they install key leads, and capstans, is also
consistent, and almost fool proof.
Rail installation is the most common variable that I have found.
The key pins on this vintage are brass, and are prone to tarnish, hence my
concern about cleaning up friction issues first.
At this point I would like a little more imformation.
Regards roger


At 10:57 PM 5/16/02 -0700, you wrote:
>Bill:
>
>I'm not sure I would agree with your assessment of putting 18mm shanks on
>this piano.  The SWR for the naturals is already 5.5 on average (some are
>even lower if the measurements are correct).  If he puts on an 18 mm shank
>it will lower the ratio to under 5.  That's too low and will create some
>regulation problems.   The BW's are erratic because the KR is different
>between the sharps and the naturals (.50 and .48 respectively).  This has
>created a different ratio between the sharps and naturals and has resulted
>in erratic balance weights even with a relatively smooth SW pattern.
>
>David Love
>
Roger Jolly
Balwin Yamaha Piano Centres.
Saskatoon/Regina.
Canada.