Help needed with Epi Les Paul action adjustment

Discussion in 'Epiphone Les Pauls' started by Manyxe, Nov 23, 2017.

  1. Manyxe

    Manyxe Junior Member

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    Hi, n00b with a problem here!

    I have an Epi Les Paul Traditional Pro on which I installed a Bigsby B7 with a Vibramate, going from a 10-46 string set to an 11-56 with no ill effects, played great, no need for additional set-up or adjustments.

    A few days back I took off the strings completely to treat the fretboard with a little lemon oil, and left the guitar for a couple of days. Now, when I tried to string it up with a set of 9-42 strings, the bridge is waaay too low, the strings won't stay in their saddles at all. If I heighten it to match the string height, the action is way too high.

    So, here's my question: what do I need to get the action back to a reasonable height? I'm guessing adjust the truss rod, but in which direction?

    Thank you in advance!
     
  2. WaywerdSon

    WaywerdSon Senior Member

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    Are you planning to stick with the 9s? You will need to adjust the truss rod. The lighter strings are allowing the neck to be more convex because they dont pull as hard. You will need to tighten it, one of the luthier types can give you a bit more detail
     
  3. T00DEEPBLUE

    T00DEEPBLUE Senior Member

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    The lower tension of the 9-42's compared to the 11-56's that were on it is causing the the neck to go into a backbow, which in turn is lowering the action to the point of causing the strings to buzz out. That's to be expected.

    The bridge string height doesn't change with different string gauges, the neck relief does. Adjusting the bridge height to compensate for the change in neck relief means that not only is the neck relief still set wrong, the bridge height is now set wrong too. All you'd be doing is further compounding the problem.

    Read this guide:

    https://www.ultimate-guitar.com/lessons/the_guide_to/truss_rod_tips.html

    You need to mess around with what degree of neck relief works for you. I personally like 0.3-0.4mm at the 7th fret, which is 8-12 thou.
     
  4. Dolebludger

    Dolebludger Premium Member

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    It seems to me that the truss rod would have to be loosened to get rid of back bow (aka convex neck relief). Hopefully the truss rod is dual action, which will force the back bow out immediately. If it is single action, it might take the 9s a bit of time to pull out a back bow.
     
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  5. charlie chitlins

    charlie chitlins Senior Member

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    Easiest to put the heavier strings back on, let it alone for a few days, then try the 9s.
    Check neck relief though.
    Fret a string at the 1st fret and the fret where the neck joins the body.
    Check if the string clears the fret midway between.
    I once dropped my 69 Tele and it got a back bow...the TR didn't break or anything...I put the neck between 2 stacks of books and put another stack in the middle.
    Not very elegant, but that was about 10 years ago and it's been fine since.
    What's the explanation?
    Who cares?!
    It worked.
    Don't do anything, though until you're sure it's a relief issue.
     
  6. Dolebludger

    Dolebludger Premium Member

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    There really is an explanation here. With a single action truss rod, when reducing the sting pull, some pressure is often required to eliminate back bow.
     
  7. Charlize

    Charlize Member

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    This is not to help the neck problem, but if you had a 56 low E, and now a 42, you may need a new nut.
     
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  8. Dolebludger

    Dolebludger Premium Member

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    Charlize,

    Yours is a great suggestion! A year ago I bought a used Carvin that the former owner (idiot) had put 56s on but fortunately (for me) had not filed the nut for strings that large (I use 42s). Because the 56s were so big, tight , and high I couldn't play anything on it the way it came. Conversely, if the former owner had filed the nut for the heavy strings, my 42s would have been fretting out all over the place and a new nut would have been needed.
     

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