post pitch-raise creep?

[Joe And Penny Goss]

Hi,
I would tend to agree with the 40% overpull only in the way you are using it  (tuning only one center string) and then unisons, then the  bass, but only on younger pianos and with a limit of 30 cents under pitch. to help avoid string breakage.
I find that measuring A2 and taking half that value on my SAT lll,  gives me a bass only a few cents off. Then remeasure at the tenor break and at B4, first treble, and C6.
The result usually is a piano that sings again, with just a little touch up on a pitch raise of up to 30 cents,
Some times it is the bass that needs raised to the tenor, and other times the tenor needs adjusting either up or down. Then another fine tuning and string seating in one month when the owner gets their next pay check <g>.
Some times one gets lucky up to 50 cents but usually it is a two pass deal over 30 cents.
Oh yes, C7 to the top I tune so that the right string ( first tuned ) middle string (second tuned ) are just a tad sharp of what the red lights show is the target.
Then the left is tuned to the stopped lights. By the time the left string is pounded in the other strings have fallen, and if I am lucky, match the last tuned string.
"Different Strokes" <G>
Joe Goss RPT
Mother Goose Tools
imatunr at srvinet.com
www.mothergoosetools.com
  ----- Original Message ----- 
  From: David Nereson 
  To: Pianotech List 
  Sent: Sunday, July 09, 2006 5:56 AM
  Subject: RE: post pitch-raise creep?



    -----Original Message-----
    From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org]On Behalf Of Farrell
    Sent: Friday, July 07, 2006 6:04 AM
    To: Pianotech List
    Subject: Re: post pitch-raise creep?


    Doesn't sound right. When doing the PR, are you using an ETD?  

    Only to measure the amount it's flat and to tune the initial A4 sharp by 40% of the amount it was flat.  

     Unisons as you go?  

    No.  All the middle strings, then all the unisons, then the bass, which sometimes needs very little raising.  I can do it fastest that way.    

     41% is very large percentage for overpull. Most ETDs recommend between 20% and 35%, depending on the area of the scale. 

    And I say that's usually not enough.  If it's 20 cents flat, half of that (50%) is 10 cents, and a third of that (33%) is about 7 cents.  So I pull A4 halfway in between those numbers, or about 8 1/2 cents sharp, which is roughly 40% of the amount it was flat.  (I notice in other posts, some tuners use up to 37% in some areas of the piano.)  Then I do the pitch raise, all the octaves, then all the unisons.  Almost every time, A4 ends up right on 440, and the rest of the rough tuning is very close.   So I go ahead and do the tuning (fine tuning).  It's after I'm done with the fine tuning, when I go back to check for anything that has slipped, that I find the middle of the piano and the low tenor has crept sharp by a beat or even two.  

    Immediately after the PR, do you check the middle section for pitch?  

    Yes, and it's almost always right on 440, so I proceed with the fine tuning.  It's after the fine tuning that I find it has crept sharp in the middle.  The low tenor is also quite sharp, so now I leave that area a bit flat during the pitch raise.  And during the tuning (fine tuning), the SAT always seems to "tune" the bass too flat, even if the bass didn't need a pitch raise.  

     If it is at or near target, there is no reason for it to creek up.  

    One wouldn't think so.  

     How large a pitch gain are you talking about?  

    Anywhere from just a few beats flat to a half-step flat.

     I've never noticed such a phenomena.

    That's "phenomenon."  Phenomena is plural.  (Just for your own info.)
    --David Nereson, RPT

    Terry Farrell
          
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