Action Geometry - Help

[Avery Todd]

Ron,
   You are probably right about the keybed/bench thing. It's just that I've
never had this problem before with other actions and with the action spread
difference between bass and treble, it sort of threw me for a loop. I
wasn't trying for any kind of accuracy yet, just trying to make sure
everything would "work".
   I think my next step should probably be to take it back to the piano and
set the key height, level and dip, before I start moving the rail (even
though I
can always put it back).
   I like your idea about how you try to "duplicate the keybed"
environment. I'll definitely try that the next time I have to do any kind
of bench regulating.
   Thanks again.

Avery

>
>When you say you duplicated key height on #1 and #88, what do you mean
>exactly?  >How did you do this?  Have you considered that you should try
>to duplicate the >keybed environment on the workbench in order to get
>accurate readings in letoff >and drop?
>
>The method I use involves measuring the height of sample keys in the piano
>>(with cheekblocks screwed into place), then duplicating those heights on
>the >bench using balance rail punchings under the front edge of the
>keyframe.  >Again, the end pins (the ones that go into the cheekblocks)
>are secured to the >bench just as they are in the piano.  If there is any
>knocking at the glide >studs, I put punchings under them as well.
>
>Once you are sure you have "duplicated the keybed" on the bench, you
>should >find setting letoff and drop (rough settings, anyhow) to be much
>easier to do.
>
>I suspect that the jacks are "bottoming out" because the part of the bench
>>under the highest end of the keyframe is slightly lower than what you'd
>find in >the piano.  Also could be that there's a slight rise in the bench
>under the >balance rail at that end.
>
>Bottom line: Make sure you're duplicating the *keybed*, not just the key
>>height.  They're dependent upon one another!

_____________________________________
Avery Todd, RPT
Moores School of Music
University of Houston
Houston, TX 77204-4893
713-743-3226
atodd@uh.edu
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