Fw: Twisting New Bass Strings

[Farrell]

I don't think Jim monitors the Pianotech List. I sent this email to him also. If we are looking for his direct input, I think we need to send our posts to both the Pianotech List and to Jim Arledge. Jim, if you are comfortable reponding to the Pianotech List, that would certainly be appreciated - or if that requires subscribing and you do not wish to, if it is okay with Jim, would the person that Jim replys to please forward his response to the Pianotech List group? This seems to be an interesting thread to many.

Terry Farrell
  ----- Original Message ----- 
  From: PAULREVENKOJONES 
  To: Pianotech List 
  Sent: Saturday, August 04, 2007 11:45 AM
  Subject: Re: Fw: Twisting New Bass Strings




  Terry and James:

  Thanks much for the response. I still have some questions.

  In a message dated 08/04/07 09:20:38 Central Daylight Time, mfarrel2 at tampabay.rr.com writes:
    Dear Terry,

    Thanks for the e-mail. Let me put in my two cents. 
    First , let me say that false beating is our enemy.
    You probably would not put a twist in plain wire. Right?
  Probably not, but twisting doesn't cause false beats, it merely shortens the length of what is being twisted and requires higher tension for any desired frequency.
    However there is a reason you should put a twist in most bass strings. Here is my simple explanation of why.
    The old fashion, tried and true traditional synchronized lathe winding technique yields one minor anomaly.
    After the string is made it will unwind or backlash a little when removed from the machine. This is due to the torsional forces imparted during the winding process.
    The reason string winders have traditionally recommended to put a twist in the wire on installation is simply to off set this built-in backlash. It should take less twists (maybe only 1/2) in the big wires and more twists (maybe 1 1/2) in the small ones. The exact amount will be known by your string maker.

    Well, my approach was to build a new type of string winding machine that among other things calculate this backlash and turn one side of the lathe at a slightly different rate as to offset the backlash. The length and diameters being  variables. The proof that the derived formula  works is that when the string comes off my machine there is no backlash. So why twist?
  So, if one end is turning slightly slower, there is a built-up twist in the core when the string is done? And after being released from the lathe, that twist is now being held by the crimped ends of the winding at the swage? So the core wire is internally torqued (torsioned) and on installation without a twist will act like a string that has had a twist put on it when being strung? So in essence, the swage is being made to act as a torsion clamp for the twisted core? Is this a fair restatement of what you're describing?

  During stringing, when turning the core wire onto a tuning pin, generally the core is being twisted in the opposite direction of the winding (check this out by installing a bass string, then while still slack remove it from the hitch pin--it will "untwist" slightly, maybe a half-turn, in the direction of the winding). This would argue for me that under any circumstances a twist in the direction of the winding at the hitch pin on installation is advisable to offset the untwist and compensate for lack of internal torsion in the core to clamp the winding at the swages. 

  Am I totally off-base here?

  Paul 
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