Truss nut stripped: what replacement nut should I get?

Discussion in 'Hardware, Setup & Repair [BG]' started by joelb79, Jul 25, 2013.

  1. hdracer


    Feb 15, 2009
    Elk River, MN.
    I brought the nut I removed from my MIM neck into work with me this morning to do a little testing. I also stopped at a music store and got a new two pack of Fender nuts.

    After close inspection the quality of these nuts is very low.
    The threads are fair,at best.
    The nut is extremely soft with a Rockwell hardness of B38 (not even qualifying for a Grade 3 bolt)

    The broaching of the key hole is atrocious.
    All three are different.
    My used one measured .1938 at the top tapering down to .1942 on the bottom

    New nut #1 measured .1918 at the top to .1945 at the bottom

    New nut #2 measured .1885 at the top to .1956 at the bottom. It has a burr or roll over on the top. .050 down from the top it jumps to .1935

    I measured the ball end of the 5mm wrench I used and the ball measured .1928. It is a well used wrench that I keep at home.

    My conclusion is that because of the extreme softness of the nut combined with the sloppy broaching these nuts are very prone to failure.
    I believe they are designed to be 3/16 but they are so soft and over broached that a under tolerance 5mm wrench can be tapped into most of them.

    Use care when adjusting them. A 3/16 wrench and moderate amount of torque will round them out.
    I would remove tension from the strings and induce back bow to the neck and then adjust the nut to be safe.
  2. hdracer


    Feb 15, 2009
    Elk River, MN.
    I just did one more test.
    I sacrificed my used nut in the name of science.
    I put the nut in a vice and used a ball end 3/16 Allen socket and a torque wrench to see how much force it would take to round it out.

    It let go at 48 inch pounds
    That isn't much force at all.
    Combat Wombat and jazzbo66 like this.
  3. joelb79


    Mar 22, 2006
    Lansing, Michigan
    No kidding, i wasn't going about adjusting my nut in a violent fashion. The last thing I would want to do is hurt my nut..


    Thank you for sacrificing your nuts in the name of science.
  4. Musiclogic

    Musiclogic Commercial User

    Aug 6, 2005
    Southwest Michigan
    Owner/Builder: HJC Customs USA, The Cool Lute, C G O
    See Joel, if you would has shot me a message on FB, I was in Charlotte yesterday, could have dropped one off to you with the proper wrench/Allen key.....I did get some cool bubinga though.....LMAO
  5. joelb79


    Mar 22, 2006
    Lansing, Michigan
    Rats. When are you going to be wood shopping again? We could meet for Big John's of course like you mentioned almost ... 4 times. I'm hungry just thinking about it. :)
  6. walterw

    walterw Supportive Fender Commercial User

    Feb 20, 2009
    awesome that you did actual tests like this!

    i avoid using the ball-end for just this reason, the tolerance slop and soft metals involved lead to easy stripping.

    3/16" is indeed the correct size, just be sure to use a fresh, sharp one and don't use the ball-end.

    the american standard bass nuts are nicer, and sharper, but i still avoid that T-handle ball-end wrench fender provides; i took a regular allen key and chopped it off just past the bend so it will fit and still provide a proper flat-sided hex shape to drive the nut.
  7. Thanks for the great info!
    The nut is likely made of soft metal to give way before the truss rod.
    Stripping a nut is an inconvenience, breaking the truss rod is neck replacement!
  8. joelb79


    Mar 22, 2006
    Lansing, Michigan
    Much better than breaking the truss rod. I was able to repair this bass without issue and set the relief too low after. Gave it a proper setup and played it for months. Simple repair for those who did the same.
  9. GIBrat51

    GIBrat51 Innocent as the day is long Supporting Member

    This is very simple, and works for any hex nut, or hex head bolt. If you can move the hex key left and right in the hole, it's TOO SMALL. The Correct key will be a tight slip fit, and have almost no play. Period. Any key that can wiggle around in the hole - like, say, a 3/16" key in a 4mm hole - will work; for a while; if the the nut isn't too hard to turn. But, you WILL ruin the nut - eventually. The correct hex key will not wiggle around; and it will not strip the hole out. Well... not unless you're a gorilla, and the hex key is about 3 feet long, anyway...;)
  10. joelb79


    Mar 22, 2006
    Lansing, Michigan
    Pre-stripped holes, nuff said. Not a mistake I make myself but one made before I bought the bass.
    Last edited: Apr 20, 2018
  11. GIBrat51

    GIBrat51 Innocent as the day is long Supporting Member

    Yeah, I understand that; you were gooched from the get-go. My little rant was for the people who seem to think that if it "sorta" fits, then it must be good to go. And just because Bass X has "always" used a particular sized nut, doesn't necessarily mean yours does.. especially if you bought it used...:thumbsup:
  12. THANK YOU. Someone said it. This is the way it should be done!! You should always counteract the string tension when making adjustments. Think of it as a push button toggle. If the neck is cranked but the strings are loose, still bend the neck back (anchoring body and headstock) to make an adjustment. the only thing causing relief on a neck should be string tension.
  13. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician
    I think you have just identified an untapped market - pre-stripped TR nuts. Saves the user all the trouble of finding an ill-fitting hex key and working the hole to round.
    Paco Leon likes this.
  14. Lownote38


    Aug 8, 2013
    Nashville, TN
    There's another thread in this section about the truss rod nuts in this model bass. Read it. Fender used junk metal that easily strips and literally cracks. You can get that old one out and get a new one.