On Tue, 08 May 2001, "David Love" <davidlovepianos@hotmail.com> wrote:
>Attached as an excel spreadsheet is some data on a Steinert 6' grand
>that has some problems.
>The hammers and shanks were recently replaced (not by me) and the
>customer is not happy with the way it plays. The action feels very
>heavy. I would appreciate any input on solving the problem. The
>customer likes the tone so I am reluctant to alter the strike weight
>except perhaps at the upper end of the piano. The key ratio is high
>and I am considering moving the capstan. The piano currently has a
>17mm knuckle and moving to 18mm is another possibility. Any
>thoughts?
It doesn't matter whether you adjust the leverage by moving the
capstans or the knuckles, the re-hung action will require a deeper
dip and possibly a a shorter blow. I'd go figure the capstans, be
cause a mm error in the cap line will be magnified far less than one
in the knuckle mounting
>Is there a rule of thumb about moving the capstan and the resultant
>change in downweight: i.e., 1 mm toward balance rail equals a
>reduction in DW of x?
Why not be more direct in your route, and just figure out what
balance weight you want to get from a capstan move, and move the
capstan until to arrive at the target BW? The rule of thumb you're
looking for would actually be a local leverage ratio. DW of course is
an overall measurement, so it would necessarily include variables
outside this local situation (ie., the key leverage). BW has the
advantage over DW measurements in that friction has been stripped out
and you're considering solely weight.
Bill Ballard RPT
NH Chapter, P.T.G.
"I go, two plus like, three is pretty much totally five. Whatever"
...........The new math
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