Can I add a 24 fret neck on a bass which originally had 21 fret neck with no problems?

Discussion in 'Luthier's Corner' started by Float on man, Jun 11, 2018.

  1. Float on man

    Float on man

    Mar 10, 2018
    Will there be any intonational problems if I added a 24 fret neck on my crappy fender j-bass clone which originally had a 21 fret neck. Like, they’re both the same scale length, but since the frets would be smaller to compensate for the 3 extra frets, would that mess up the intonation on my bass?
  2. Fun Size Nick

    Fun Size Nick

    Feb 21, 2006
    London, UK
    Unless the extra frets are on some sort of fingerboard extension that extends past the neck joint, the bass will no longer be the same scale length and it will not intonate properly.
  3. rocmonster


    Oct 31, 2011
    The distance between the nut and bridge should be 34” ( if the new neck is also 34” scale) and the 12th fret should be 17” from the bridge. You will most likely have to shift the bridge position (forward or back depending on where the neck attaches) to be halfway from the 12 th fret if you have any chance of proper intonation. The pickups will not correspond to their original placement of the 21 fret neck.
    Float on man and chinjazz like this.
  4. Float on man

    Float on man

    Mar 10, 2018
    So, just measure from the bottom of the nut to the 12th fret, and then if measurement is, let’s say 4 inches, measure from the bottom of the 12th fret until it reaches 4 inches, and place the bridge there. Is that what you’re saying? I’m still new to this and I don’t really understand much.
  5. rocmonster


    Oct 31, 2011
    Sure, if the original scale was (hypothetically) 8” then yes the distance between the nut and 12 th fret, and the 12th fret and the bridge would be equal.
  6. Mushroo

    Mushroo Guest

    Apr 2, 2007
    I don't think it's going to work. If you try to move the bridge toward the neck, then won't it collide with the bridge pickup? Not to mention installing a longer neck will change the balance of the bass, possibly making it neck heavy. Also it is not necessarily a safe assumption that the neck will fit the pocket without any routing. Since you are "new to this" I recommend you get the proper replacement neck. :)
    Matthew_84 and Fun Size Nick like this.
  7. The TLDR version of all of this: if after the new neck is installed, the measured distance from the nut to the bridge matches the scale length of the new neck, then it will work.

    So if the new neck has 34" scale length fret spacing, and once screwed into the neck pocket the distance from the nut to the bridge is also 34", then you're golden.
    JRA and Brent Arrowitz like this.
  8. yodedude2

    yodedude2 Supporting Member

    Nov 19, 2005
    san antonio, texas
    Yevgeny Bondar likes this.
  9. Float on man

    Float on man

    Mar 10, 2018
  10. Float on man

    Float on man

    Mar 10, 2018
    Huh, neat. Thanks for the shortened version. All of this has been very helpful information.
  11. Lofreck


    Apr 25, 2013
    Even shorter version:
    After installing, the 12th fret of the new neck should split the string in half.
  12. If the 24 frets are only an extension of the fretboard and the heel is the same as the 21 fret,it should fit,unless there is a pickup in the way...
  13. There really should be a sticky for this, this question seems to come around every couple months.
  14. The length of the 21 fret and 24 fret necks are different (the 24 fret neck is longer). The frets on a 24 fret neck are not smaller to compensate. The gaps between frets 20 and 21 are exactly the same on both necks - the 24 fret neck just has three additional frets, which have to be smaller than the frets before them for intonation purposes.

    As mentioned by others, this will not work unless you either make the neck pocket deeper so that the scale length is still 34”, or you move the bridge forward so the scale length is 34”. Personally, I wouldn’t bother.
    Fun Size Nick likes this.
  15. FugaziBomb


    Jun 5, 2017
    It will not work without modifying the neck pocket or relocating the bridge. As other people have said here, the distance from the bridge saddles to the nut must be roughly 34" (give or take for intonation).
  16. brianrost

    brianrost Gold Supporting Member

    Apr 26, 2000
    Boston, Taxachusetts
    Just an example: Danelectro used to make guitars and basses with strange neck designs. There were the "dolphin nose" models where the bodies of both had the bridge in the same location so the guitar necks had 21 frets and the bass necks had 24 frets and extended further out because of the longer scale length. On the "double cut" models, like their doublenecks, the headstocks would line up so the bass bridge had to be much further down the body (about 5") and the neck had only 15 frets.

    rwkeating and Mushroo like this.
  17. Float on man

    Float on man

    Mar 10, 2018
    Okay, so basically whatever I do to the neck length, adjust the bridge and pickups according to how much or less the scale length increases/decreases with the new neck. Got it, thanks a lot.
  18. Fun Size Nick

    Fun Size Nick

    Feb 21, 2006
    London, UK
    I think what most of us are suggesting is that while you could do this, it’s far too much work to do all that to compensate for changing the length of the neck. You’d be routing new pickup routes, drilling wire tunnels, probably reshaping the neck goes on. If there’s something irreparably wrong with the neck, then you’d be better off getting a replacement neck that’s the same length as the old one. If you just really want a 24 fret neck, I would suggest that there are plenty of good, inexpensive Ibanez Soundgears on the used market that would work much better for this purpose.
    Float on man and Matthew_84 like this.
  19. ^ This.

    Also, if you really need those higher notes and what to stay true to a Fender Jazz, you could always get a 5 string and string it to EADGC, or get a low D with D standard tuning (DGCFBb).

    I think there also a couple of odd-ball 4 string Fender Jazz’s with 24 frets, though they’re mostly Japanese Fenders aimed at the Ibanez SR crowd.
    Fun Size Nick and Float on man like this.
  20. MonetBass

    MonetBass ♪ Just listen ♫ Supporting Member

    Sep 15, 2006
    Find yourself a used one of these:
    Problem solved. I love mine.
    CaribooBass and rocmonster like this.