nut compensation - 25.5" scale

Discussion in 'PTC - PRS Tech Center' started by David L. Smith, Feb 3, 2017.

  1. David L. Smith

    David L. Smith New Member

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    Customer brought in a 25.5" scale guitar which was previously butchered by someone trying to install a locking nut. I must rebuild the nut end of fretboard and re-route a new nut slot. What is the distance used by PRS on 25.5" scale length guitars for the nut compensation? Need distance between 1st fret and nut at low & high E strings. Tremonti Baritone hybrid tunes as C# .
     
  2. bluefade

    bluefade New Member

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    For that info, I would go to PRS directly.
     
  3. David L. Smith

    David L. Smith New Member

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    I already tried that. PRS asserts that said measurement is "proprietary" and will not divulge it. That means that I must now rely on finding another luthier who has actually taken that particular measurement, with the appropriate level of accuracy and precision.
    It is not "forbidden knowledge", it is just something that will require an extra level of independent, empirical investigation and measurement to obtain. PRS is not inclined to readily share that information.

    Luthiers are more inclined to share information and tips that they have discovered.
     
  4. charliefrench

    charliefrench New Member

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    Maybe there is a formula that will help you determine the measurement that you need?
     
  5. David L. Smith

    David L. Smith New Member

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    Still need these measurements. Can anyone help?
     
  6. David L. Smith

    David L. Smith New Member

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    Still need these measurements. Can anyone help?
    Can anyone discern this specification by actually measuring a John Mayer Silver Sky model, or a SE Mark Holcomb model, or a Mark Tremonti Baritone Ltd. Edition model in their shop?
     
  7. jxe

    jxe babe en der wood

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    given the fret placement, can’t you do this with pure math?
     
  8. David L. Smith

    David L. Smith New Member

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    So...you can't provide the requested measurement either.
    Don't want to be curt, but, I'm not looking for arm-chair theorists.
    I am seeking someone who can actually use a set of digital calipers on an actual guitar.
     
  9. jxe

    jxe babe en der wood

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    you sound pretty smart, i’m sure you’ll think of a perfect brute-force solution to this complex and difficult problem. best of luck.

     
  10. David L. Smith

    David L. Smith New Member

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    Did not intend for my reply to sound as rude as it came out.
    I appreciate the math and physics that go into the calculations, and have a healthy respect for those who engage in that.
    It's just that is not what I am looking for. I want to replicate the old set-up (with its own shortcomings and imperfections) as closely as possible.
    What I have experienced so far is that most PRS owners are very specific as to how they want work done on their PRS. Good or bad, they want their instrument repaired so that it is nearly indistinguishable from how it came from the factory.
     
  11. Rider1260

    Rider1260 New Member

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    David - I know someone with a Silver Sky and I have calipers.
    I will try and get your measurement this weekend.
    PM me with all the measurements you need.
     
    Boogie and Collywobbles like this.
  12. David L. Smith

    David L. Smith New Member

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    I am looking for the distance, measured from the face (end of fingerboard) of the nut to the center of the 1st fret. To put things into perspective, the usual standard distance (derived from most fret positioning calculations) puts that nut to 1st fret distance around 1.4312 inches. As a cross check, the center of 2nd fret should be about 2.782 inches from the face of the nut, and 3rd fret at 4.057 inches from face of nut. Not sure if the amount of compensation is the same distance (parallel to fret) on each side (low E & high E), or if there could be slightly more compensation on the low string side.

    Thanks for the offer to help.
     
  13. Collywobbles

    Collywobbles New Member

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    Forrest White (Leo Fender’s factory manager / general manager 1954 - onward) has a chapter in the back of his autobiography on fret placement and describes the system he developed for use at Fender that was more accurate than the system initially used by Leo for the first Broadcasters /Telecasters made before he arrived.

    He lists a fret placement multiplier guide on page 222 for determining the fret placement on any fretted musical instrument as a distance from the nut.

    I’ve just listed the first 12.


    The table is as below:

    #1 0.05613
    #2 0.10910
    #3 0.15910
    #4 0.20630
    #5 0.25085
    #6 0.29289
    #7 0.33258
    #8 0.37004
    #9 0.40540
    #10 0.43877
    #11 0.47027
    #12 0.50000

    The example given in the book is for calculating fret position from the nut for a 24 inch scale length

    #1 24” x 0.05613 = 1.347”
    #2 24” x 0.10910 = 2.618”

    Etc, etc, etc

    #12 24” x 0.5 = 12 inches

    So it should be pretty easy to work backwards from that to calculate your nut position from the first fret if you know the scale length.

    From Fender The Inside Story by Forrst White, Miller Freeman Books, 1994
     
    #13 Collywobbles, Nov 7, 2018
    Last edited: Nov 7, 2018
  14. Collywobbles

    Collywobbles New Member

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    Forrest's book is a really interesting read if you're interested in the origins of Fender guitars (and hence the Silver Sky). George Fullerton and Bill Carson's autobiographies are also interesting and provide an counter view as Forrest and George (and Bill, who sided with George) didn't always see eye to eye. Richard Smith's Fender - the sound heard 'round the world is also excellent as are A. R. Duchossoir's books on the Telecaster and Stratocaster (ditto his two books on Gibson Electrics).

    [​IMG]
     
    #14 Collywobbles, Nov 7, 2018
    Last edited: Nov 7, 2018
    bodia likes this.

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