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Acoustic truss rod rattle

Discussion in 'Other Guitars, other instruments' started by screefer, Mar 6, 2021.

  1. screefer

    screefer Tele-Holic Silver Supporter

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    This is an ACTG1 Eastman 23.5" scale acoustic with an advertised dual action truss rod.
    I had lately noticed a buzz and initially thought it was the wires of a JJB pick up I had installed. Upon gently shaking the guitar and holding the neck to my ear, I noticed a quite audible rattle. The neck is straight and where I want it. I tried to adjust the rod and it definitely loosens and tightens but the neck stays the same. Could the the truss rod have come undone? I did adjust it slightly (looser) when I changed strings to a lighter set of 11s from 12s.
    After these attempts, the rattle is still there, when shook, but the playing buzz has diminished. This buzz is most noticeable on the open B string.
    Bummer:(?

    IMG_1095.JPG
     
    Flip G likes this.
  2. Boreas

    Boreas Friend of Leo's Silver Supporter

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    Under warranty?

    It doesn't sound like it is functioning at all. It could be stripped, or even broken. It was possibly routed incorrectly, but in that case, the bar should still function. If you can't manage to get any tension/compression on it, it may need to be replaced. BIG bummer if not covered under warranty.
     
  3. posttoastie

    posttoastie Tele-Afflicted

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    May be stupid comment but if the truss rod works then..........
    Make sure the tuners and the washers on tuner are not loose. I bought a Gibson L P that had that issue and the truss was loosened like owner was tying to sort it out.. The previous owner could not find the rattle. 2 minute fix to tighten a tuner and then adjust the truss rod to work correctly.
     
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  4. darkwaters

    darkwaters Friend of Leo's

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    These kinds of things drive me bonkers. My Dot was making a weird sound on certain notes. Futzed with the truss rod. Removed the pickups and screwed them back in. Tightened every screw I could find. Played with the bridge and saddles. Sacrificed to the dark gods. Nothing.

    In sheer desperation I jammed a finger inside the sound hole and felt around. I could feel a chip of wood projecting out of the volume pot hole. Worked on it until I broke it loose, shook it out of the guitar and disposed of it. Problem solved!

    You never know...
     
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  5. screefer

    screefer Tele-Holic Silver Supporter

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    I have emailed Eastman but, of course, everything bad happens on weekends.
    When I tightened a little firmer that before I did noticed a slight back bow. Then when I loosen it to finger tight it comes back straight under tension.
    It definitely is threaded onto the head end. The rattle does not change. I listened real careful to the tuners and it is definitely coming from the neck.

    I know nothing about dual rods. Could one of them be broken loose?

    After all this futzing, the buzz has gone when playing but not the rattle when shaken.
    I'll leave it overnight and wait another day for Eastman's reply.
    Thanks all!
     
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  6. screefer

    screefer Tele-Holic Silver Supporter

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    I just found a 2007 post from Premier Guitar saying to pop out a fretboard dot and then drill a 7/32" hole into the rod cavity.

    https://www.premierguitar.com/articles/case-of-the-noisy-truss-rod-1

    Melt some wax. Insert soldering iron into cavity to warm the rod. Pour melted wax into hole and the warm rod will wick the wax along the cavity.
    Install new dot...Jake the bear.
    Sound reasonable?
     
  7. Freeman Keller

    Freeman Keller Poster Extraordinaire

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    If it has a true double acting truss rod it will be something like this

    IMG_6622.JPG

    This is an LMII rod, most are similar. It has two threaded blocks, one on each end, welded to a flat bar (which is against the straight edge). One block is reverse threaded, like a turnbuckle, the lower rod is threaded on each end, one reverse. The allen wrench pocket is welded to the threaded rod, it is on the right in the picture.

    When the rod is adjusted to its neutral position the flat bar is straight as shown in the picture. At this position the adjuster turns very freely for a little bit either direction, then it starts tightening. When turned CW the blocks are pulled towards each other, the bar is bent down on the ends and up in the center. This would be applying a force to the fretboard in the center and the head and heel to counter relief from the string tension. This rod has one full turn CW

    IMG_6623.JPG

    Lots of bending force, eh? That is why we make truss rod adjustments in very small increments - 1/8 turn can have a lot of effect.

    Here is the rod turned one half turn CCW from neutral. It would be applying force to give the neck more relief. That is a supposed advantage of double acting rods however I have never seen a case where someone had to add relief.

    IMG_6624.JPG

    So, what is wrong with yours. If it is working correctly it will have a neutral point where the neck is relatively flat and you can easily turn the adjuster maybe 1/8 turn each direction. Then it starts getting tighter as it is pushing up or down on the underside of the fretboard - it will get progressively harder to turn until something gives - fretboard pops off, you break one of the welds, maybe blow the truss rod out thru the back of the head end.

    If the rod is working it should have an effect on relief. I like to build necks with no relief, let the string tension pull a little in, and then use the truss rod to bring it back to my goals. Most acoustic guitars with standard lights or mediums will go from no relief to 6 or 8 thousands, 1/8 or 1/4 on the truss rod should bring it back to around 4.

    Last comment. Double acting rods usually wedge themselves in tight enough that they don't rattle but single acting rods often rattle when they are loose and it is common to put something like bath tub caulk in the channel to cushion them.

    Last last comment, be very certain that your rod really is broken (it is incredibly rare) because attempts at "repairing" are going to be very invasive.
     
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  8. screefer

    screefer Tele-Holic Silver Supporter

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    Well I'll be.
    I 'loosened' the rod and it went tighter and slightly bowed the neck. Just like you said.
    The rattle is still there but not when being played. Weird

    Thank you for your educating skills!
     
  9. Freeman Keller

    Freeman Keller Poster Extraordinaire

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    Once the rod has just a hair of tension on it its almost impossible for it to rattle in the slot unless it is broken. If it moves the neck it isn't broken. Does your Eastman happen to have a bolted neck joint? Dozens of other things that can rattle and don't always sound where you think they should. If you have a stethoscope start listening all over the guitar. I'm guessing its not the rod.
     
  10. screefer

    screefer Tele-Holic Silver Supporter

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    Understood. Set neck.

    This rattle can be heard from your lap. When I put it to my ear, it 'seems' to be from the middle of the neck. Maybe there is something in the rod cavity. After all the shaking and adjusting, the resonate buzz (when playing) seems to have disappeared but the rattle, when shook, still lives.
    I realize that without seeing this in person it is tough to prescribe.

    So, for now, all is good but I'd hate to have it crop up in the middle of my Carnegie Hall set...:D
    Thanks
     
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