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Thread: Post-setup: 15th+ fret buzz

  1. #1

    Default Post-setup: 15th+ fret buzz

    I got my mandolin set up nearly perfectly. I sanded the bridge bottom to perfectly contact the top plate, based on the intonation positioning that I figured out through testing, repositioning, testing, etc... String heights from above the first fret are 0.013" and 0.010" for the GD and AE strings, respectively. The string height at the 12th fret is around 0.060" but varies a thousandth or so between the smaller and larger strings. To compliment the 12" radius on my fretboard I applied a 12" radius to the nut and the bridge saddle. Note that the saddle is at its lowest setting on the adjustable bridge.

    After I got it all tuned up I started plucking the individual frets. Everything was fine until around the 15th fret, where I started getting the dreaded string buzz, primarily on the G and the E strings. As I went to higher frets it continued, and the D and A strings started in as well. All of the earlier frets sounded fine. From examining with the naked eye it does appear the strings are making contact with additional frets nearer the bridge. (I did level the frets before all of this and also checked the neck to make sure there was no bowing, which there was not. The fretboard is completely flat/straight.)

    To me, the logical solution is to slightly raise the saddle with the adjustment wheels on the bridge so that those frets nearer the bridge are not interfering. My only concern is that I believe the 0.060" string heights at the 12th fret are already bordering on too high? So lifting the saddle would further exacerbate that problem.

    Am I worrying about nothing? Should I just go ahead and raise the saddle on the bridge?

  2. #2
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    Default Re: Post-setup: 15th+ fret buzz

    First, raise the bridge and see how far up you have to go before the problem goes away.

    Ideally, a mandolin should play if the distance between the 12th fret and the bottom of the string is .060". That is assuming that you are not picking the strings too hard. But another .010" is not the end of the world.

    If you have to raise the bridge very much, check the following things:

    1. Check for loose or poorly seated frets. Check this more than twice.
    2. Get out a short straight edge and make sure that there are not any frets that are too high. If there are any high spots, the offending fret[s] should be levelled individually.
    3. Double check the integrity of the glue joint between the fingerboard and body.

    Go to frets.com for info on how to locate a high fret.

    If all of these things check out ok, run a Sharpie across the tops of the frets in the offending area and kiss them lightly with your dressing tool. See frets.com about this also. Then, re-crown and polish them.

    If this doesn't take care of it, I would recommend that you find a friendly repairman and have him look it over. He may be able to see something that you have missed. He may find a loose fret that you cannot see, or detect a rise or bump in the fingerboard or frets that you are missing. No matter how well you go by the book, a second set of eyes is sometimes necessary to diagnose problems.

    A common problem that I had until I got my sea legs was that I had fret ends that were loose, but I hadn't learned how to see them. And when I tried to level by dressing down, it didn't fix the problem because the loose frets kept springing back up.

    On most fret jobs, I cross-polish with a fine sharpening stone after I have levelled the frets and before I crown them. I feel that this is especially important on radiused fingerboards.

    Good luck.

  3. #3
    Registered User Charles E.'s Avatar
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    Default Re: Post-setup: 15th+ fret buzz

    Sorry, deleted post.
    Charley

    A bunch of stuff with four strings

  4. #4
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    Default Re: Post-setup: 15th+ fret buzz

    I'm sure someone will correct me if I'm wrong, but I'm not sure the radius of the saddle should be the same as the fretboard radius. I've made guitars and I learnt from somewhere that it should be slightly larger, in my case the guitar was 16" radius and I made the saddle at around 20", and it works for me. The fact that you say the G and E strings buzzed initially makes me wonder whether the saddle makes them lower than they would be with a wider radius, if that makes any sense. Just a thought.

  5. #5
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    Default Re: Post-setup: 15th+ fret buzz

    Since you set your string height by measuring the G and E strings that should be correct and you shouldn't have string buzz. You may have to adjust the D and A if the radius is off, but the G and E should be fine. I would look for another problem.
    THE WORLD IS A BETTER PLACE JUST FOR YOUR SMILE!

  6. #6
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    Default Re: Post-setup: 15th+ fret buzz

    I'll bet a nickel that one or more of the last few frets is loose or high, or that there is a rise in the fretboard over the body, or a combination of all of these.
    Look it over again very carefully. You might want to push down on the fret ends with your thumb nail and see if any of them are moving.

  7. #7
    Registered User sblock's Avatar
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    Default Re: Post-setup: 15th+ fret buzz

    Above the 15th fret, the fingerboard on an A5 or F5 model is supported by the fretboard extension (a separate, glued-in piece) and not by the neck itself. One many budget models, and also some others, the neck joint is not especially strong, causing the neck to rise up very slightly over time. This produces a slight bend in the fingerboard, over the point where the fretboard extension joins to the neck. The result is that frets above 15 get progressively "higher," and they interfere with good action. You can check for fingerboard flatness, particularly in the region around the neck/extension joint, using a good straightedge. You can also do this by eye (although less well), by sighting along the fretboard from the bridge side. If you see a change in the plane of the frets, then that's your answer. A lot of budget mandolins have problems in the highest frets fore this reason.

    P.S. If you never play up there, you can just leave it alone!

  8. #8
    Luthier Tom Haywood's Avatar
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    Default Re: Post-setup: 15th+ fret buzz

    What method did you use to install the frets? Did you bend each one before installing it?
    Last edited by Tom Haywood; Jul-01-2020 at 8:18pm.

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