I have bought a second hand accoustic guitar. When I saw the neck is little curved I wanted to turn the truss rod bolt counter clockwise to get some relief. I was able to move it 360 degrees before I felt the bolt is loose, i.e. if I go on turning, the bolt would be moved out. But if I turn the truss rod bolt clockwise it holds the tension. So, why is it? Is this truss rod broken?

Thanks a lot for your help.

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Revision two. I was half asleep the first time & gave poor advice.

Looks like it's bent backwards from that photo, but that may depend on the camera lens & angle the picture was taken, so be certain before you make any adjustment.
Use a steel rule laid edgewise down the neck, or hold a string down at the 1st & 12th fret to judge.

Don't start before it's strung & in tune.

If it's been unstrung for a long time, string it, tune it & let it rest a week before you even start. Your early random attempts will not help this. You really should have strung it first & let it rest. As you've apparently dropped all the tension off the truss rod without it strung, you've made the job harder, so now you have to be patient.

Clockwise to pull it back, counter-clockwise to allow it to be pulled forwards by the string tension.

If all you have to adjust it is an Allen key*, you may need to keep alternately tuning & slackening at least the centre strings to give you room to work & also check how it's sitting.
That's not a fast job.
Once it gets anywhere close, leave it to rest a couple of days before continuing. If you have to drag it a long way, the neck movement will take from hours to a week to finally settle; you can make finer adjustments as it starts to come to an equilibrium.
Don't try to get it right all in one go, & make sure to leave it in tune between attempts.

If, even after a couple of weeks it still bends back with no tension at all on the truss rod [assuming a correct guess based on the photo] then you will have to take it to a luthier to be straightened.

*What you really need is a long-shaft screwdriver with interchangeable hex bits & a universal joint. Then you can do it without having to drop the string tension.

  • O, Tetsujin, first of all, thank you so much! It is so kind of you, giving me so good and detailed suggestion! So, it is a BACK BOW! And I need a CLOCKWISE turn to straighten. Before I thought just the opposite! The biggest mistake I made, as I understood, is that I adjusted it when it's not strung and in tune. This I should remember and avoid in the future. So I restrang it and left the guitar in rest. I will report the result the following days. I understand now it is not a fast job. So I should be very patient. Thank you again. I really appreciate your help. Jun 1 '20 at 19:39
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    @Tetsujin If it has back bow the truss rod should be loosened, counter clockwise, not tightened right? Regardless the pic may be deceiving because many cameras have a bit of a fish eye effect to them. Also the neck should be checked under string tension because the tension will affect the neck angle. Jun 1 '20 at 21:16
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    Ugh - sorry guys! Serves me right for trying to write an answer at the wrong end of the day. Sorry, brain not in gear, should be loosened.. but after the strings are on & allowed to settle. I'll fix this once I'm fully awake. Aplologies.
    – Tetsujin
    Jun 2 '20 at 7:21
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    So sorry guys, fixed now. Paul. Yes, let it rest fully strung for at least a week. You can't judge the neck's straightness without it strung & as you have changed the tension, we don't have a good start-point, so more patience will be required.
    – Tetsujin
    Jun 2 '20 at 8:26
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    Let the strung guitar rest for some days, and now the neck is almost straight. I am satisfied. Thank you guys for your help. Cheers! Jun 6 '20 at 14:35

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