bridge pin layout offset revisited

[Gene Nelson]

Thanks Terry,
Curious what the single hole in the middle of all of your templates is for?
Gene
  ----- Original Message ----- 
  From: Farrell 
  To: Pianotech List 
  Sent: Sunday, September 23, 2007 6:04 PM
  Subject: Re: bridge pin layout offset revisited


  Hi Gene,

  You can also control the string angles across the bridge be varying the distance between the bridge pin rows.

  "Does anyone put new bridge pins exactly on the location mark without an offset - depending only on the pin diameter, pin angle, front to rear pin spacing and wire diameter for the string angle/offset across the bridge?"

  Yes.

  Setting new bridge pin location arrays also will allow you to even-out string spacing. Going to vertical hitches are a plus in that process.

  But original bridge? Not rescaling to allow new speaking lengths?



  Terry Farrell
    ----- Original Message ----- 
    Thinking about bridge pin lay out here and have questions.
    Have a new board with recapped bridges made of laminated maple - planed to bearing hight and ready for new bridge pins to be located.
    It is very tempting to use the old bridge cap for the new pin layout but will not take this approach.
    I have been in shop and class where I was shown how to use clear Plexiglas templates to offset the pin from the pin location/string line to get consistent string angles across the bridges. Researched the archives to get some numbers and a formula to make this work. (Thank you Ron Nossman) I must now put this information into my new bridge.

    I have also read in Wolfenden's book and could find no reference to offsetting the pin from the string line/position in any way that was used in his designs. If this was not done on pianos of his era you would think that the changing string angles would be noticeable on different parts of the bridges? 

    Does everyone use some sort of offsetting formula for locating new bridge pins? Does anyone put new bridge pins exactly on the location mark without an offset - depending only on the pin diameter, pin angle, front to rear pin spacing and wire diameter for the string angle/offset across the bridge?

    Wolfenden also mentions the need to slightly widen the longer strings at the bridge pins so that the longer strings do not touch when vibrating. Is this just a spacing issue and widening is whatever you can get away with or is there some way to figure how to do this? I had always thought that the hitch pin diameter determined the bridge pin spacing but not necessarily in the bass? Widening would seem to alter a calculated offset?

    Thanks for any of your thoughts.

    Gene Nelson
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