Extreme jumpiness

[paulrevenkojones at aol.com]

 Tom:

If you read Jim Ellis' articles on the physics of tuning pins, you'll be able to picture the possible issues which might be contributing to this. It sounds as if you are putting a great deal of unresolved twist in the pins in only a portion of the length of the pin because of any of the reasons you list below--cracks, uneven drilling/reaming, contamination, poor choice of pin size, all or in combination. It sounds, from your description, as if you are coming close to tearing the pins in half. I've done it, and it isn't pretty. Question the man who restrung it and find out the conditions and materials he used. There may be a clue there.

Paul


 


 

-----Original Message-----
From: Tom Sivak <tvaktvak at sbcglobal.net>
To: pianotech <pianotech at ptg.org>
Sent: Wed, 17 Oct 2007 7:33 pm
Subject: Extreme jumpiness










List
  
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Have had the displeasure of tuning an old upright which has been restrung with new oversized pins.? I was called in to tune it by the man who restrung it; he asked me to CA the pinblock because the strings kept slipping flat.
  
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So I went, CA in hand, and found that about 20 pins had fallen, some were a 4th under pitch!
  
I got out my tuning lever and pulled the offenders up to pitch and was shocked to find how tight the pins were.? On some of the pins, I literally had to use ALL MY STRENGTH to make the pin move at all.? (And I'm 6 feet tall and 210 pounds.)? Then it would jump a whole step, and I'd try to coax it back, but it would jump back down, too low, and...you know the routine.
  
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The reason I'm writing is to gain some insight into this situation, hopefully.? How can a pin be sooo tight that I have to extend my lever, watch it bend as I
 apply pressure, hoping that my lever won't break, just trying to get the pin to move...and yet not be able to hold?

Now, I've been there three times in the last two months.? The first time, I did not apply any CA to the pinblock.? My God, they were so tight, yet jumpy to the max.? Because it took so much strength to get the pin to move, it was difficult to make any small movements.?? I thought, with my superior tuning lever technique, I would be able to get the pins to hold.? HA!? 
  
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Next time I applied CA to all the pins that had slipped.? After it dried, they were tighter than ever, even harder to get them to move.? One month later, about half of them had slipped again.? I re-applied the CA and was there last week.? Only about 6 of them had slipped, but it still boggles my mind.
  
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Understand that it is just as difficult to get the pins to go flat.?
 I mean, as you try and turn the pin, and it jumps to the sharp side on you, and then you try to push it back down, and it jumps to the flat side, and you toggle back and forth...it's just as hard to get the pin to move south as it is north.
  
?Tuning pins too big?? Cracks in pinblock? (O
  
Any thoughts?? pen faced pin block, showing no cracks...)?? Should I use WD-40 instead of CA?? (Just a joke...just a joke...)

Tom Sivak
  
Chicago



 


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