[CAUT] caut Digest, Vol 1092, Issue 50

[Michael Wathen]

Jim,

One common reason for string breakage is that the speaking length of the string is not correct.  If that is the case then increasing or changing the diameter will have no effect. I don't offhand know the calculation but I do remember that it is independent of the diameter of the string. I remember that a few years ago we, on the list, people predicted the pitch at which different size diameters of strings would break for note C8.  If I remember correctly we verified this result. It made no difference what the string diameter was they all broke around the same pitch.

  Let me suggest that you restring the section or sections and modify the bridge with Wapin.  Very easy to do if you're restringing anyway.  

I'm not sure about this and perhaps Eric or Lawrence could respond.  There are a number of practice room pianos at CCM that have Wapin on them.  I have a hunch that Wapin will also reduce string breakage.  The practice room pianos have had Wapin on them for over ten years now.  I wonder if the string breakage is less on these pianos.

Michael Wathen

  -----Original Message-----
  From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org]On Behalf Of pianomanwo at aol.com
  Sent: Sunday, November 26, 2006 8:51 AM
  To: caut at ptg.org
  Subject: Re: [CAUT] caut Digest, Vol 1092, Issue 50


  Hi Bill

  I am replying to the problem of strings breaking on the Kawai KG2 e,c,d,ect. Changing the strings will not eliminate the problem, but it will slow up at first. what seems to have worked for me is when I restrung the piano I went down 1/2 size on the wire and gage them slightly heavy letoff and have lost only 4 strings in 10
  years This piano is in a heavy used classroom.

  Walter Oventrop RPT SLPS 

   
  -----Original Message-----
  From: caut-request at ptg.org
  To: caut at ptg.org
  Sent: Fri, 24 Nov 2006 1:00 PM
  Subject: caut Digest, Vol 1092, Issue 50


Send caut mailing list submissions to
    caut at ptg.org


To subscribe or unsubscribe via the World Wide Web, visit
    https://www.moypiano.com/resources/#archives
or, via email, send a message with subject or body 'help' to
    caut-request at ptg.org


You can reach the person managing the list at
    caut-owner at ptg.org


When replying, please edit your Subject line so it is more specific
than "Re: Contents of caut digest..."
Today's Topics:


   1. Re: breaking strings, Kawai KG-2A (1997) (Jim Busby)
Attached Message
        From: jim_busby at byu.edu 
        To: caut at ptg.org 
        Subject: Re: [CAUT] breaking strings, Kawai KG-2A (1997) 
        Date: Fri, 24 Nov 2006 12:20 PM 

  Hi,

  I haven’t measured it but the angle looks “normal” (within range), but I will check it along with the other things you mentioned. Good list.

  We keep the hammers shaped and voiced regularly so I don’t believe it is that. Since it is mostly the Kawais that break more I’m suspicious of “scaling anomalies” and such, but since having several “CAUT witnesses” of the string fatigue diagnosis my bet is it’s probably that. 

  Thanks again,
  Jim Busby BYU


------------------------------------------------------------------------------

  From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of Geoffrey Pollard
  Sent: Thursday, November 23, 2006 4:23 AM
  To: College and University Technicians
  Subject: Re: [CAUT] breaking strings, Kawai KG-2A (1997)

  Hello Jim,

  I would try to get a good handle on front duplex to capo string angles as part of information gathering during rescaling. It is not unknown for this angle to be excessive in Kawai piano trebles at times. If the angles are OK (11 - 20 degrees - perhaps using Ron N's device shown in his 9/11/06 post on this list) - then wire fatigue, hard hammers, flat hammers, scaling anomalies, capo profile, string cushion friction (in no particular order) are some likely culprits in my view.

  Regards,
  Geoffrey Pollard


  -----Original Message-----
  From: caut-bounces at ptg.org on behalf of Jim Busby
  Sent: Tue 11/21/2006 12:20 PM
  To: College and University Technicians
  Subject: [CAUT] breaking strings, Kawai KG-2A (1997)

  List,



  We have four KG-2As that now break strings regularly (weekly) in octaves
  5-7. The bass is also becoming "thumpy". Granted, they are very heavily
  used (Up to 17 hours a day), but we try to keep them voiced and
  regulated so I don't believe maintenance is the issue; I think the
  strings are simply fatigued. (I can break strings myself with 20 - 30
  good solid blows.) I tried decreasing the blow to give a bit less power
  hoping that it would diminish the breakage, and that helps somewhat, but
  I don't like to sabotage piano performance just so I can work less...
  BTW, the strings break mainly at the v-bar.



  I will be restringing these pianos next month (I've HAD IT with them...)
  so does anyone have any advice concerning the scaling, etc.? I will be
  dressing the V-bar and doing all the usual prepping. This is a high
  tension scale and I'd love to redesign it but don't want to put that
  kind of time and money into these...



  Any helps out there???



  Thanks.



  Jim Busby BYU







_______________________________________________
caut list info: https://www.moypiano.com/resources/#archives

------------------------------------------------------------------------------
  Check out the new AOL. Most comprehensive set of free safety and security tools, free access to millions of high-quality videos from across the web, free AOL Mail and more.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: https://www.moypiano.com/ptg/caut.php/attachments/20061126/ea52f6a9/attachment.html