My neck on my mim jazz bass

Discussion in 'Hardware, Setup & Repair [BG]' started by Figjam, Aug 7, 2003.

  1. Figjam


    Aug 5, 2003
    Boston, MA
    My neck is slightly crooked in the body, like, tis a bolt on, but it isnt striaght. it isnt bent, it just slid sideways in the body, should i fix itjust by un screweing, straightening, and tightening?
  2. Yes, that's how it's done.

    For your purposes, detune and leave the E and G strings on the bass and only loosen the neck screws. Then align the neck so that the strings are equally spaced and parallel to the edges of the neck. Once you've got the alignment, tighten the neck screws and that should be it!
  3. should u shim the sides too.
  4. I don't think that would be necessary. The sides only touch the neck while the flat base is in compression contact with the body. Besides, it could be that the neck is tight against the sides of the neck pocket when it's aligned to the body.

    If it isn't possible to tighten the neck screws enough to eliminate movement, you can take some other action. What you need to do is increase the friction between the neck and body. This can be done several ways:

    1. Spray a quick blast of hairspray in the neck pocket and sprinkle a thin, sparse layer of sand grains in the cavity. Quickly bolt up the neck in position and tighten until you don't get wobble. The sand grains imbed themselves in each wood surface making it very difficult for the surfaces to slide against each other.

    2. Glue a patch of 220 grit sandpaper in the bottom of the pocket for the same effect as above.

    3. Cut a small patch of metal door screen and torque it up between the neck and body. This does the same thing as the other 2 methods.

    4. Convert your neck mount system to machine bolts and threaded inserts. This combination can take a lot more torque than screws and wood. You should be able to tighten this to the point that the neck will never move.

    5. A piece of the thin double sided carpet tape will keep a neck from sliding also.

    Hope this helps.
  5. dude i love ur ideas,
    glueig snad papper in the neck pocket. i have a gap on my fender jazz but the neck doesnt move i use it to hold pics.

    4. Convert your neck mount system to machine bolts and threaded inserts. This combination can take a lot more torque than screws and wood. You should be able to tighten this to the point that the neck will never move.

    i wanna do this to my jazz bass i love this setup on my warwick, and it would alow me to shave the heel/neck joint on the body so it would feel better, not justa square block. how would i go about this.
  6. kipsus

    kipsus Physicist

    Sep 18, 2005
    Vilnius, Lithuania
    These ideas are just crazy enough to work!
    By "threaded inserts" you mean this?
    If so, I've been thinking about it for some time but haven't got the courage to drill holes in the neck that large. Might ruin something. Does anyone have experience with such mods?
  7. jacobmyers


    Aug 28, 2007
    Jackson, MI
    Last night, I installed steel inserts and machine screws in both the neck and bridge of my Hohner PJ Bass F1. It wasn't as easy as I thought it'd be; took about three hours from start to playable (including tuning). I have some pictures (I didn't take as many as I had planned to) but they're on the wife's camera and she has it with her.

    As soon as I get them uploaded, there will be pictures but, for now, you'll have to deal with text.

    I got the inserts and machine screws from the downtown hardware store. I got eight steel inserts (coarse thread outside, fine thread inside, installed with a standard screwdriver), four panhead 1 1/2" screws (for the neck) and four 3/4" screws (for the bridge). I got the smallest drill bit recommended for the inserts based on thinking that it's better to have to drill more than to have drilled too much the first time. The bill (including tax and four 1/2" screws that I bought in case the 3/4" were too long) came to less than $10.

    Figuring that the bridge would be the most difficult process, it's what I did first. I followed NorCal Dog's method of maintaining component alignment. I left two screws in and drilled. The first bit I used was barely larger than the new screws. The new screws are two sizes larger than 'stock' and I had to drill out the bridge to fit them.

    As I expected, the heads of the new screws 'rode' the tail of the bridge. Without reinstalling the bridge, I drilled out the rest of the holes in the bridge. Then I measured the depth of the insert against the #1 drill bit that I used to drill for the inserts. I added 1/8" and wrapped the bit with duct tape at that point to provide a visual 'stop'. Then I drilled all four holes for the inserts.

    I carefully screwed the inserts into the body of the guitar. The #1 bit was a little small and the finish cracked as the wood 'stretched' to accommodate the inserts. This didn't matter much to me, because the cracking is covered by the bridge.

    Because the heads of the tail-end screws 'ride' the bridge, I installed those first. As I tightened them, the bridge flattened out against the body. When I installed the other two screws, it pulled down tight. The inserts allowed me to put far more torque on the screws than before. Everything fit together perfectly and it feels rock-solid now.

    The screws for the neck were about the same size as the originals so I just ran a screw-sized drill through two of the holes to make the pilot holes for the #1 bigger. After this, I removed the neck entirely. My confidence was boosted by my success with the bridge, so I didn't reinstall the neck after putting the first two inserts in.

    Using the same 'tape drill stop' method as before, I carefully drilled into the neck with the #1 bit. I used a 15/64" bit after the #1 to remove a little more material. The maple was too hard to accept the inserts with #1-sized holes.

    The neck inserts cracked the finish on the underside of the neck (there was a bit of the lacquer the back of the neck's finished with between the neck and body) and the wood deformed slightly on the surface. In retrospect, I probably should have used a 1/4" bit to drill the holes. I was tired of messing around, though, and wanted to play the darn thing! Ah, well. Lesson learned (and shared).

    Reinstalling the neck was far more difficult than the bridge. The screws tended to cross-thread unless I backed the screws off until the threads lined up. That's harder to explain than it is to do. Anyway; once I got them threaded right, they went right in.

    I set the neck relief screw to the proper depth and tightened everything up. The stiffness of the insert/screw combination made the flimsiness of the neck readily apparent. Before I got the strings tensioned, the neck bent easily when I held the bass by the body and pressed on the headstock. I'd never noticed this before. I guess the wood screws had some 'give' that covered it up or something.

    I tuned up and played around for a bit. There is a noticeable improvement in sustain but other than that I didn't hear anything spectacular. The biggest plus of this mod is that the screws and inserts can be replaced if they strip out. Not so for wood. Swapping necks would be a breeze with the inserts and you won't have to worry about wearing the wood to the point where the screws no longer 'bite'.

    Every bolt-on-neck should be put together like this.

    I don't advise anyone to try this at home unless they're a competent finish carpenter to start with. It's not hard, if you're not careful, to drill too deep or let the bit 'walk' the hole off-target. If either (or both) of those things happen, you've (for our purposes) destroyed the instrument (or at least the neck). Don't say I didn't warn you..
  8. 62bass


    Apr 3, 2005
    Basically the same method I use. However, when lining up the neck holes I clamp the neck in place and install the two outside strings just tight enough to keep them straight, then tap the neck into alignment so the strings are properly positioned, then mark the holes with a drill bit. Then remove the neck and drill for the inserts. I fill the old neck screw holes in the neck with dowels before doing this. I use a drill press when drilling the final holes.

    It does seem to improve the sound somewhat and seems to help with the ever annoying dead spots on Fenders. The inserts I've found in hardware stores are threaded outside and inside and screw into the wood with an allen key.