Lighter or Heavier ?

[David Love]

This is a multi-part message in MIME format.

---------------------- multipart/alternative attachment
Actually I forgot to include my concluding point which is that the =
placement of the capstan shouldn't be made on key ratio alone.  There is =
another factor to consider: convergence.  Though some compromise on =
convergence will not get you into too much trouble, a major compromise =
might and if it is necessary  in order to bring the action ratio low =
enough (it's not usually a problem the other way) then you are probably =
better off using an assist spring to correct the problem. =20

I say this in response to D.E.'s comments on moving the capstan such a =
distance on the Baldwin.  I ran into a similar problem on an older =
Baldwin D not so long ago.  I found that it was not really possible to =
move the capstan as much as was needed in order to get the ratio I =
wanted (even using an 18 mm knuckle) and not create some problems with =
regulation as a function of the compromise in convergence--not to =
mention slicing off wippen heels and the like.  In this case the only =
reasonable remedy was to move the capstan a small amount and use an =
assist spring wippen for the difference.   In this case I used the =
assist spring for about 10 grams of BW, which is my target limit.  I am =
aware that others are willing to go much higher than that, but I find =
that it creates problems with how the action feels.   Anyway, though I =
am not a strong advocate of assist springs, in this case I thought it =
was the best solution.

David Love
  ----- Original Message -----=20
  From: David Love=20
  To: pianotech@ptg.org=20
  Sent: July 14, 2002 9:49 PM
  Subject: Re: Lighter or Heavier ?


  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





---------------------- multipart/alternative attachment
An HTML attachment was scrubbed...
URL: https://www.moypiano.com/ptg/pianotech.php/attachments/d9/8a/5b/a2/attachment.htm

---------------------- multipart/alternative attachment--