Lighter or Heavier ?

[David Love]

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It's hard to say whether there is really an incorrect key ratio.  The =
key ratio is only incorrect in so far as it contributes to an overall =
ratio which is too high or too low.  To simplify, it's really how it =
combines with the knuckle radius that's important.  Whereas a .52 KR =
might not work with a 15.5 mm knuckle radius, it will work fine with a =
17 mm one, generally.  Similarly, a .55 KR, as you sometimes find in =
older Mason Hamlins or Baldwins, will require an 18 mm knuckle to get =
the overall ratio in the 5.5 - 5.9 area where (I think) it belongs.  =
There are, of course, other considerations in choosing this combination =
of levers.  The smaller the knuckle radius the greater will be the =
friction because of the increased weight bearing on the knuckle.  So if =
you are opting for a heavier hammer, you are better off going with a =
longer knuckle radius.  Very light hammers, as are found in older =
Steinways, do just fine with shorter knuckle dimensions without too =
great an increase in friction.  Just a few thoughts.

David  Love=20
  ----- Original Message -----=20
  From: Tom Servinsky=20
  To: pianotech@ptg.org=20
  Sent: July 13, 2002 5:23 AM
  Subject: RE: Lighter or Heavier ?


  I there was a "theme" to this year's convention IMHO, it was =
diagnosing key ratios. Between Stanwood's all-day class and Richard =
Davenport's "What if", incorrect key ratios have to be dealt with during =
our rebuilding procedures, or our problems will continue.
  The common plan of attack for a number of years has always been to add =
lead when the key weight is too extreme (high). Even though we get the =
DW down ... something always hinted that we were treating the symptoms =
and not the disease.
  Incorrect key ratio creates a vicious cycle that affects everything. =
We have to learn to understand and correct these problems and make them =
a normal part of the rebuilding procedure.
  Tom Servinksy,RPT=20

   : owner-pianotech@ptg.org [mailto:owner-pianotech@ptg.org]On Behalf =
Of Erwinspiano@AOL.COM
  Sent: Friday, July 12, 2002 10:26 PM
  To: pianotech@ptg.org
  Subject: Re: Lighter or Heavier ?


    In a message dated 7/12/2002 4:20:20 PM Pacific Daylight Time, =
Richard.Brekne@grieg.uib.no writes:



      Subj:Re: Lighter or Heavier ?=20
      Date:7/12/2002 4:20:20 PM Pacific Daylight Time
      From:Richard.Brekne@grieg.uib.no
      Reply-to:pianotech@ptg.org
      To:pianotech@ptg.org
      Sent from the Internet=20

              Hey Ric


           I followed this only briefly. Bussssy week. Oh my goodness! =
Any way There is an experience I've had a few times with some actions =
where the key ratios and action ratios were really good. Without getting =
into many measurements just let me say that the effect was that even =
though static down weights approached 60 down on my Symphony Stwy D =
(1940) and the upweights were a nice snappy 28-30. No one has ever =
complained about the touch as being heavy.=20
       John O' Connor played it a time or two as well as others. and =
never a complaint about the touch being heavy.  Seems to handle rapid =
passage work effortlessly. It has some lead closer to the balance rail =
as it's a accelerated action.     =20
         I've also learned  from installing new key sets with corrected =
key ratios that less lead is used and similar results are attained. I =
believe  some lead is required  to give the piansit some semblance of  a =
"the normal feel" related to inertia and that some inertia IMO is =
desirable in a piano action. Physics says were going to have some like =
it or not but is better managed with efficient leverages.  When some of =
these systems are right it's like a supercharged V-8.
      My point is that the down weight upweight discussion takes on an =
entirely different parameters when things are set up right as opposed to =
the funky key and action geometry we deal with day in and out. Bottom =
line is that some action.key systems static weights may seem high ( 60 =
over 30 ) but the dynamic effect when the keys are in motion tells an =
entirely different and pleasant story.
      Does that make sense to any one but me?
         >>>>Dale Erwin>>>>>>>



      Thanks again Ed and Dave... and St=E9phane for your interest

      Seems like we have two ideas about how inertia levels affect
      the touch of the piano. On the one hand we've said several
      times the the higher the inertia the slower the action
      repetition... and this has been equated loosely with terms
      like sluggishness and then from this perspective, heaviness.
      Then on the other hand a bit more lead is said to perhaps
      lead to a lighter "feel" due to the help inertia lends ones
      the key is in motion.

      Interesting and to some degree conflicting lines of
      thinking. All and all it leads one to think that Stanwood
      ideas are fine.... a great refinement in relation to simple
      DW/UW measurements.. but perhaps should be refined further
      to somehow put a number on inertia .... inertia zones
      perhaps.

      I agree tho in the answers you two kindly voluntered that
      DW/UW has a direct relationship to "touch" or "feel", yet
      that these are also affected by other relationships.=20

      Thanks again... would have liked to heard from others...
      but. :)

      Cheers
      RicB





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