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Crack due to truss rod adjustment?

Discussion in 'Basses [BG]' started by kaoz, Dec 16, 2018.

  1. kaoz


    Jan 15, 2010
    I did my own neck relief a couple of weeks ago on my classic 70s jazz bass (first timer) and today i noticed these scratches (cracks??) on the back of the neck right where the skunk stripe ends. Can it be from the truss rod adjustment I did??
    IMG_20181216_205028. IMG_20181216_205039.
  2. king_biscuit

    king_biscuit Supporting Member

    May 21, 2006
    Just looks like scratches in the finish to me. How much did you have to "work" the truss rod to get the correct relief?
    nilorius and bobyoung53 like this.
  3. kaoz


    Jan 15, 2010
    I adjusted two times by almost 1/8 of a turn or so each time
  4. Bikeguy57

    Bikeguy57 Supporting Member

    Highly unlikely. That’s a conservative adjustment.
    rtav, sharpbass, Mister Boh and 4 others like this.
  5. Maxdusty


    Mar 9, 2012
    Michigan USA
    looks like a minor finish crack ...maybe from some kind of wood compression cracking the finish above it from adjusting the truss rod? Maybe the stripe isn't as secure as it should be and lifted up a little when adjusting the truss rod cracking the finish. It doesn't look like it's on the wood itself from what I can see.
    nice_hat likes this.
  6. kaoz


    Jan 15, 2010
    This is what I was thinking, because I dont remember hitting the bass anywhere, so it would get this crack. If a neck cracked because of the truss rod adjustment where it would crack?
  7. JRA

    JRA my words = opinion Supporting Member

    probably the high positive correlation between doing something for the first time and then noticing something 'different'.
  8. Rabidhamster


    Jan 15, 2014
    That is an incredibly common place for this to pop up, so common you might almost call it average. Generally no big deal, its just the different expansion/contraction rates of the different types of wood causing finish cracks. Most Jazz basses develop this over the years, and many P basses. I've got a VNM condition USA Fender Jazz '76 reissue with the same thing. I've seen it so many times I don't even consider it a condition ding when I buy an instrument - because someone else had to watch it happen not me, its just there now no big deal.

    sometimes basses have cracks in this area and it is a problem with the wood, but the vast majority its no big deal, like in this case, just an inevitable design-related finish blemish. The ones where it is a problem with wood, it will be much more severe than what you've pictured.

    The same seasonal changes that likely caused you to need to adjust your neck are the same ones that caused the skunk stripe to expand or contract at a slightly different rate than the maple.
  9. kaoz


    Jan 15, 2010
    Thanks a lot for the replies. Should I pay attention to something next time I adjust the neck relief?
  10. James Collins

    James Collins

    Mar 25, 2017
    Augusta, GA
    Does the skunk stripe feel raised in the area of the scratch? From the picture it looks like a surface scratch. If it was from the truss rod, I would think the skunk stripe would feel like it was pushed out, not a crack in the neck.

    Also, that would only even be a possibility if you were tightening your truss rod to remove relief. If you were loosening the truss rod to add relief, then it would have taken stress off the wood.

    I think you just have to adjust the truss rod to where it needs to be for proper relief or play with a less ideal setup. If it breaks you can fix it or buy a new neck.

    To make the adjustment easier on the truss rod take off the strings and use a straight edge to measure relief. You may also want to consider bending the neck with your hands then having someone else tighten the truss rod to resistance.

    My last piece of advice is a 1/4" turn is a very small turn. It will probably take out 0.25mm of relief. Don't be afraid of future adjustments. I've seen a lot of bad setups, and I suspect fear of turning the truss rod.

    A lot of videos and articles say, "turn a quarter turn, wait 3 or 4 hours, then check and repeat as necessary." The adjustment will be instant, especially if you manual bend the neck with the adjustment. You don't need to wait.
  11. You would REALLY have to crank the truss rod to crack a neck, you would most likely snap the truss rod before you could crack a neck. Make sure you take the tension of the forward pulling strings off the neck especially if you are tightening it, in other words lay the bass flat on your legs sitting down and push down on the headstock or something that does the same thing before tightening the TR although you still wouldn't crack it.
  12. Ronen


    Feb 9, 2003
    Milky Way Galaxy
    As mentioned it's nothing to worry about. If you feel it and it bothers you, you could just lightly sand it with a 600/800 sand paper, then 2000 and forget about it.
  13. nilorius


    Oct 27, 2016
    Riga - Latvia
    I think this is a little finish crack. Do you hear a big difference in sound ?
  14. Maxdusty


    Mar 9, 2012
    Michigan USA
    taking a closer look at the photo from my computer- it looks like a finish crack (on the varnish ) and not a crack on the wood which is a good thing and probably nothing to worry about. You can see an opaque kind of crack in the picture rather than a darker, more defined crack (you'd normally see if it were a crack in the wood) so to me, it looks very much like a crack in the top layer varnish finish and again, no biggie.
    What caused it? Either it was there before you adjusted the neck and you just didn't notice it, could be caused by the stripe wood expanding a bit and lifting against the finish. Could also be caused by as I mentioned a little bit of wood compression near that spot when you turned the truss rod pushing against the stripe causing it to lift slightly against the finish and cracking it.
    Last edited: Dec 17, 2018
  15. Chrisk-K


    Jan 20, 2010
    Maryland, USA
    A finish crack doesn’t affect the tone.
  16. Paulabass

    Paulabass Supporting Member

    Sep 18, 2017
    Not the truss rod adjust. I'd guess the two types of wood expanded or contracted seasonally at slightly different rates, and the finish cracked a bit. Nothing at all to worry about.
  17. Yeah, I think it's just a small finish crack(s). I was really tweaking mine a couple days ago (trying to get rid of a high register buzz)... darn! Better take a look at my neck!
  18. Ric5

    Ric5 Supporting Member Commercial User

    Jan 29, 2008
    I grow organic carrots and they are not for sale
    That looks like cracks in the finish … also called checking … possibly due to temperature and humidity changes
  19. JIO

    JIO Gold Supporting Member Commercial User

    Jun 30, 2010
    Oceana (Pacifica) CA
    musician/artist/owner - Gildaxe
    step away from the magnifying glass... ;)
    charlie monroe and bobyoung53 like this.
  20. Maxdusty


    Mar 9, 2012
    Michigan USA
    I've since adopted the philosophy of mojo and I'm far less worried about such things as finish cracks. :)
    JIO likes this.

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