rear string lengths

[David Love]

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Re: rear string lengthsSo what would be your typical string deflection =
angle in the treble and tenor sections, and how much would you back it =
off in a short, tuned, backscale as one would find in an S&S?

David Love




  ----- Original Message -----=20
  From: Delwin D Fandrich=20
  To: Pianotech=20
  Sent: December 05, 2002 9:47 PM
  Subject: Re: rear string lengths



    ----- Original Message -----=20
    From: David Love=20
    To: Pianotech=20
    Sent: December 05, 2002 4:59 PM
    Subject: Re: rear string lengths


    We don't have the luxury of that much backscale length on the =
standard S&M, I mean S&S where zero bearing is the usual target.   I =
assume that is one of yours. =20
  It's a M&H BB.

    I am curious about the bearing in the treble section as it relates =
to backscale length.  Minimizing the bearing in the bass is something I =
am aware of for the reasons you mention.  But what about in the treble.  =
Would you consider modifying the bearing there depending on backscale =
length?=20
  Depends on what you mean by "modify." And what you mean by "bearing." =
I go by string deflection angles and adjust distance bearing to give me =
the string deflection angle I'm after. No, I don't vary that much at =
all. Unless I'm working on one of the S&S pianos with that ridiculously =
short tuned duplex backscale they used for a while. Then I back off =
some.

    And back to the question posted earlier and addressed to some degree =
by Ron O., what is the ideal backscale length for each section?  How =
much must the backscale length deviate from the ideal length before you =
would consider modifying the bearing (if you would)?
  Well, I can tell you what I like to see back there, but as to whether =
or not it is ideal I can't really say. I'm not yet convinced there is an =
ideal. Probably more like an ideal range. Or, perhaps, an ideal for each =
type of scale -- long, short, high-tension, low-tension, etc. -- =
modified by the characteristics of the soundboard.=20

  Generally I like to see (starting from the top of a typical 4-section =
scale) from 50 to 100 mm in the top section; from 75 to 150 mm in the =
next section down; from 150 to 200 mm in the tenor section; and whatever =
you can get in the bass. This depends a lot on what you want out of the =
bass and on how long the piano is. I'd be happy with 100 mm in a 150 cm =
grand but not in a 275 cm piano.=20

    And something else I've always wondered about, why, on many pianos, =
do hitch pins in the treble and tenor of many pianos not follow the =
curve of the bridge, but seem to go in a zig zag sort of pattern?=20
  A safety device to avoid setting up a stress line in the quite brittle =
gray iron casting.

  Del


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