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String Pitch Range (Wiggly Tuning Pins)

  • 1.  String Pitch Range (Wiggly Tuning Pins)

    Posted 11 days ago
    Sorry for the strange sounding subject title - best I could do. Yesterday I tuned a newer (maybe 10 - 20 years old) Wurlitzer (Samick) fetal grand and a 1979 Yamaha C7. When tuning the Wurly and trying to get any given string in a stable position at the target pitch, if I wanted to move the tuning pin a tiny incremental amount of turn, the pitch would go up or down a good 20 cents on every pin. With the Yamy, I could move the pin tiny incremental amounts (I'm talking less than one cent) easily with the pitch only swinging two or three cents often. Tuning pins on both pianos were in a nice-for-tuning torque range. The Wurly wasn't terribly difficult to tune (it wasn't difficult like some S&S uprights - although I know my description of tuning it sounds like an S&S - but it was different), but it sure felt strange and sounded strange as I tuned it because of the pitch swinging wildly all over the place on each string. I mean this Wurly was crazy! The Yamy tuned like a dream - total control with super-minimal pitch swinging.

    And FWIW, the Wurly had a typical distribution of false beats above A4, while the Yamy had maybe two slight false beats (okay, I'm exaggerating - maybe there were three slight false beats) - so darn clean - what a pleasure to tune that treble!

    My question is why the difference? Both pianos had strings that rendered quite well - pitch moved easily and smoothly up and down. It was just the huge difference between how much pitch change occurred with a small incremental turning of the tuning pin. What's up there?

    Without being the one who tuned them, I would guess that the Wurlitzer had super small diameter tuning pins - but no, they were 2/0 (or so). The torques were similar. I didn't measure, but I think that the string coils on both pianos were proper (just a few millimeters off the plate). Could the Wurly have pins made of some sort of rubberized steel (lol)? What gives?

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    Terry Farrell
    Farrell Piano Service, Inc.
    Brandon, Florida
    terry@farrellpiano.com
    813-684-3505
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  • 2.  RE: String Pitch Range (Wiggly Tuning Pins)

    Member
    Posted 11 days ago
    The difference is in the amount of friction at the bearing points, and length of NSL (which will be different in 3 pins of the unison). If the Wurly had only minimal string deflection under the capo bar, minimal felt bearings and compression, and only a single counterbearing bar of  probably brass, those parameters creates a minor bearing friction on string rendering during tuning. SL pitch moves a bit too easily with minimal flex at the pin, especially if termination angles are low. As well, if the length of the Wurly front segments were relatively short, not as short as an upright, but not as long as many in many grands, there would be less elasticity in the string NSL. Less elasticity means it takes less flex of the pin to cause the string to move over the friction bearings.  Two strings with identical friction conditions, but different NSL lengths, will render over the friction point differently.  In the S&S upright, the combination of less elasticity in the NSL, because of the short upright NSL's,  and low capo termination angles under the pressure bar, is what creates their patented, impossible to tune with stability tuning condition. String movement , and thus SL change in an S&S upright is aggressive while tuning.

    I would suspect from your description, where you said that the Wurly wasn't as bad as an S&S upright, that the NSL's were longer (being a grand) than the S&S's short upright NSL, but the termination angle was low, and there was little if any felt bearing. Rendering was a bit too easy, but still manageable.

    The C7, and most Yamahas, before they get too old, have slightly sticky friction points, which render well. Slightly sticky but not too sticky, is a helpful tuning condition. The slightly sticky friction,  would be caused by a combination of termination angle over the capo, the Yammy hardened capo, width of counter bearing felt, degree of compression of counter bearing felt. The length of the NSL then, relative to those friction conditions, would determine how easy it was to tune, with strings rendering well enough to know where you have set the NSL tension, relative to SL pitch, but not giving you misleading readings of what the installed tensions were, because the bearings were too sticky.

    By manipulating all the various conditions of the NSL, relative to plate's webbing imposed NSL lengths, I have been able to create really compliant, easy to tune instruments the last couple of years. That combined with tuner friendly torques, creates pianos where I just tune the damn thing, rather than discuss with it, at length, whether it is trying to scam me or not when tuning. Also, as I worked on analyzing the parameters of the NSL setup in rebuilding, my tuning stability just got better and better. It became clearer and clearer, both while tuning and while setting up a rebuild's NSL, how each of the parameters can be read, while tuning, so there are way less surprises after I remove the lever from the pin.

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    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
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  • 3.  RE: String Pitch Range (Wiggly Tuning Pins)

    Member
    Posted 11 days ago
    Could also be soft steel on the Wurly pins, which is a parameter, hard to know on that one. I don't have to pay any attention to that parameter on my rebuilds. I'd be curious to see the front segment of the Wurly.

    ------------------------------
    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
    ------------------------------



  • 4.  RE: String Pitch Range (Wiggly Tuning Pins)

    Posted 11 days ago
    Darn, I shudda took pictures......  :-(

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    Terry Farrell
    Farrell Piano Service, Inc.
    Brandon, Florida
    terry@farrellpiano.com
    813-684-3505
    ------------------------------



  • 5.  RE: String Pitch Range (Wiggly Tuning Pins)

    Registered Piano Technician
    Posted 10 days ago
    I know you would have said if this was an issue, still I have to ask, how often had the Wurlitzer been tuned before you got there?

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    Cindy Strehlow, RPT
    Urbana, IL
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  • 6.  RE: String Pitch Range (Wiggly Tuning Pins)

    Posted 10 days ago
    Hi Lucinda - as I recall, I had to do a rather large pitch raise - I think 100 cents or so. So unless someone is tuning pianos flat, I think this was one of those many pianos that get tuned one time when new and then not tuned for decades.....   :-(

    And I will be going back to this piano to tune it in a couple weeks - all I did the other day was raise the pitch. I'll take some pictures also.

    ------------------------------
    Terry Farrell
    Farrell Piano Service, Inc.
    Brandon, Florida
    terry@farrellpiano.com
    813-684-3505
    ------------------------------



  • 7.  RE: String Pitch Range (Wiggly Tuning Pins)

    Posted 10 days ago
    Some pianos flag pole easily. Whether it's a lousy wood for the plate bushings and/or a shorter pin, those qualities might be the difference.
    Jim Coleman said as you pull on an upright, the pin wants to climb in the hole taking the the pitch sharp.
    The shorter pin still has the same distance from the tip to the plate but the ratio changes quick if you shorten the pin.
    Bob Davis was practicing a technique that he kept the pitch from climbing higher than the target pitch by flag-poling the pin as he rotates. He started on grands and was trying this on uprights. It actually works incredibly well but sure takes some energy.

    My thinking is,, if you start the pull and pitch goes wild sharp,, you had to have pulled the speaking length to a higher tension.
    If you didn't rotate the pin,, then you flag-poled it.
    Try Bob's technique,, counter the flag pole by flexing the pin. On a grand, push down on your hammer as you rotate and watch the ETD. Keep it dead on pitch as you rotate.
    Sitting facing the piano for a fetal grand,, I sometimes use a jerk method until it's close enough to smooth-pull the fine tune.

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    Keith Roberts
    owner
    Hathaway Pines CA
    209-770-4312
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