Steinway D key levelling (Hamburg model)

[Michael Spalding]

Cy,

If you look at the action from the side, you'll see that the backcheck is
nearly centered over the backrail felt.  So putting the weight behind the
backcheck  causes the backrail felt to act like a pivot, actually
un-weighting the balance rail.   Putting the weight in front of the balance
rail causes  positive weighting of the balance rail, which is closest to
the "real-world".    With 90 grams of weight, placed 3/4" either side of
the pivot point, the difference in weighting at the balance rail 8" away
would be 17 grams.   The other way of looking at it is, since the top
action rests on the capstain, the leveling weights should be placed as
close as possible to the capstain, which would be the front side of the
backsheck.  Not to mention that there is often no room for the weights
behind the backchecks, due to  interference with belly rail or
damper/sostenuto stuff.

hope this helps

Mike 


> [Original Message]
> From: Cy Shuster <741662027@charter.net>
> To: Pianotech <pianotech@ptg.org>
> Date: 10/19/2003 11:37:50 AM
> Subject: Re: Steinway D key levelling (Hamburg model)
>
>Snip>
> The issue of "how much back weight" is interesting.  It's similar to the
> question of how much weight to use when measuring key dip.  Can there
really
> be that much more force if the weight is hung behind the backcheck rather
> than in front of it?  Surely it's proportional to the distance of the
weight
> to the balance rail -- 10 or 20%?  A steel rule doesn't sound like much
> weight.  Hmm -- I guess the correct answer would be "just as much weight
as
> the action applies at rest"...
>
> --Cy Shuster--
> Rochester, MN