Jazz Bass neck alignment.

Discussion in 'Hardware, Setup & Repair [BG]' started by SGT. BAKER, Nov 29, 2016.

  1. Hey, folks!

    I introduced you this bass in some older thread yet, where we talked about the beat basses.

    This is one of those cheapest jazz bass copies made in China, finished in sunburst, and thought for beginners with a tad budget:


    It has enough things to realize oneself at first sight that ´s not a good bass. It´s built poorly and with cheaper materials (nut, tuners, pickpups, knobs, cavities, pickguard, fret job…, all it sucks!) So as you may have guessed this bass it has a tight decent sound. Regardless I liked the neck, the sense of feel of the back side, the shape and the size.

    This bass it came from factory with an awful set up. It had one of the highest string action that I´ve seen in my life, so the bolt on job was not very good either. The thing is that the neck pocket it was a bit broader and too deep for the neck heel. So much than even lowering the bridge saddless to maximum it was impossible to get a normal string action, even when it was fretted. This fact it made me shim the neck with a maple wood´s piece. Honestly I might have made it more polished in this work, but I focused all my attention for the defretting process.

    As you can expect the woods are of low quality too. Just take a look to the neck´s grain:


    I´m not sure what kind of woods have this neck bass. Although they look like maple and rosewood of low quality, these woods they aren´t worth a hassle to think making a replacement of the entire hardware and electronics.

    As I said before, that the lonely thing that I liked of this bass it was his neck. His size it´s closest of a PB (type B) instead a JB, and surprisingly the condition was really straight with no twist. This was the main reason wich I purchased it used, though really in great condition in the past and with a priced of laughter, ´cause I had in mind to defret it. So it was a good chance to learn playing fretless too. Sorry, but I haven´t pictures of all the defretting process, so I keep on mind show you the next time.

    One time defretted I removed the awful logo in the headstock. I removed the plastic nut into one of bone, the volume and tone knobs and the capacitor. I strung it with flatwounds, ´cause I didn´t wanna do scratches in the fingerboard, and it become in my main bass for practice in home.

    After spending some months playing with it I tried removing this fretless neck into a PB body. It´s a matter of taste but I prefer better the shapes of PB basses instead the JB shapes. Though I must to solve the issue of the length. This JB neck it has 21 “frets” and the neck pocket of the PBass it was thought for a 20 frets´ neck. So I copied the heel´s size and shape of this traditional neck of 20 frets of my PBass. It was necessary removing a little of wood in the JB neck heel, under the 21th “fret”, for keeping the same 34 inches between nut and bridge line, when I was putting this JB neck in this PB body. Of that way the last fret it stayed floating on the neck pocket of the JB body, and resting on the pickguard of the PB body. Sorry but I haven’t picture of the last one:


    And I had to do new holes in the neck to bolt on this fretless neck into the PB body. I must say that the neck it fitted into the PB body easily and with no issues.

    Once done I played it for a while and it worked fine. But I realized that I missed the sound of the bridge pickup. I did not want routing a new bridge pickup cavity in this old PB body, so I ended up removing again this neck into his jazz bass body. I thought that surely I should fill this hollow under the 21 “fret”, but as this bass it´s so cheaper I didn´t mind it. And I kept practicing and playing so.

    After this, a closer friend of mine asked me if I could lend him this bass. He wanted to try learning fretless without buying a new bass. Despite being a poor instrument this bass was a challenge for this purpose. He realized the difficult to play fretless and the effort envolved to entonate properly and working the vibrato for giving sustain while he played. After eight months roughly playing with it, my friend returned my bass with some several war signs: chips and scratches in body, neck, even the fingerboard. The appearance is like a natural soft relic:


    The body wood it´s so soft that if you press a tad high it´s possible leaving some marks. Even in the fingerboard. The picture shows how the E string made a mark on the fingerboard on the 3th, 4th and 5th “frets” in the E string. (Also you can see the bone nut):


    My friend told me too that the neck it tends bugging towards the G string side. And he was right! If we compare the E and G strings we realize that the G string was closer to the edge of the fingerboard.

    This picture it shows fairly how it affects to the margin string in the upper frets of the G string side:


    This bad alignment of the strings with the neck this resulted a misalignment with the pickups piece poles too. Check how the E string it was passing through mostly on the top of one of the pickups´ pole piece, while the G string it was passing through between both poles pieces:


    This is the evidence of a mediocre neck pocket work from factory. Just take a look to the gap between neck and body. (You can check part of the defretting job and how I filled the slots with maple wood too):


  2. I found that the other issue was the size of the body´s holes. They have widened. With this fact and the gap between neck and body, it was possible pushing a little bit the neck towards the E string side without loosen their screws, and even strung and staying in tune.

    This is what it happens when there´s not any gap between neck and body in the E string side. Logically I loosen strings and screws for getting this neck position, and I tighten them after to make sure for getting this picture:


    All this it made me thinking and suspecting that maybe if I had not remove in the past this small portion of wood under the 21th “fret”, probably I had not had this problem of misalignment. I didn´t care too much ´cause it´s just a beat bass, and with this range of price you can expect anything.

    Well. The first step I had to do it was measuring the bridge and pickups locations with a steel rule. It seemed to me that their locations they aren´t absolutely perfect though good enough. The bridge´s alignment with the pickup polar pieces it wasn´t so bad. And it was the same of a bunch of basses that I´ve seen, like Fender and Ibanez for instance.

    So the next one it was measuring the neck. I tried drawing a line through the centre of the whole neck (from the headstock to bridge) and I got a really a bad result. Certainly it was necessary to place it/relocate the neck in his right position. Loosen the strings first for reducing the string tension and the screws slightly after, it was possible getting a right alignment of the neck with the bridge and the pickups. The right neck position was so close, but it wasn´t stable.

    When I tried re-tighten the screws a little bit more, just an screw it broken:


    Damn! This gave me an extra job.

    Finally I get it taking off:


    I filled this new hole with a wooden piece made myself by hand, ´cause I haven´t wooden dowel rods of this size:


    And I took advantage to fill the neck holes too with small pieces of maple wood, that I built them myself, and I glued too:


    One time I removed the strings and the neck´s screws, I measured the gap of the neck pocket for knowing which would be the size and the shape of the new shim in the E side.

    The main problem was located in the neck pocket area. It was broader that seamed. So I needed working in it to fit the neck so tight as possible. Really it had a huge neck pocket:


    I started working in the pocket. A view of the pocket´s depth without shim it:


    Having in mind the centered line that I took for getting a good alignment with the body, I had working to reduce the width of the heel of the neck in the E side to get it tight, and finding a good angle for avoiding that the strings they was too close of each the edge of the neck. For filling this gap between neck and body I built/made a small piece of wood to glue it in one of the neck´s pocket in the E string side. The G string side it´s so short for holding the neck, and it seemed to me that the neck it fitted good enough in this zone.

    I took a lot of care for no cracking this G side:


    I leveled and I sanded to get closer of the final width. I spayed the sides of black.

    After this I filled the body holes too with wooden dowel rod and glued with Titebond. I had to do an small hole again to guide the screws in their new positions.

    Time´s up to put the neck. I took the steel ruler to follow the centered line. As you can think I worked slowly, measuring and checking often, and taking too much care for avoiding some cracks in the body. After a few tries and sanding the neck pocket with patience, I found the right position for the neck:


    Well done: A good neck alignment that it fitted tight with no screws!

    Once the alignment was right I need holding neck and body. I strung the G and E strings with a low tension just for checking it all. It seems that the new position it´s right. Check like the strings margin at the fingerboard end in G and E neck´s sides it´s has the same size:


    And holding it all with the the neck plate and screws:

  3. Bolt on and strung. The pickguard´s edge don´t reach the neck, though it´s so close:


    It seems that the shim it´s hidden.

    And finish, and perfectly straight!


    No miracles of course! But just check that now it´s better that before.

    In terms of sound really there isn´t a huge difference. When I plugged it I noticed that now this bass it sounded a tad better that before. Now the strings they seem having a sligthy better balance in terms of volume; it has a little of improvement in the sustain; and it seems that this bass it had won a little bit more of punch. It is not like to become mad, but it is there.

    Actually, one year after, the neck keep on staying with the same right alignment. I know that the ideal thing would be to refill this hollow under the 21 “fret”, but I wanted daring the neck alignment. It´s not a hardest work, so I keep in mind filling this hollow with maple wood in a near future.

    I hope this can be helpful. Thanks for reading.

    Any comments, tips, suggestions or whatever they´ll be welcome!
  4. sissy kathy

    sissy kathy Back to Bass-ics Gold Supporting Member

    Apr 21, 2014
    Arbutus, MD
    What's done is done so it's a little late to be giving advice or tips. For future reference, a cheap neck should be modded rather than the pocket of a decent body.
    SGT. BAKER likes this.
  5. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician
    You really should be using plugs rather than dowels for the neck where the screws are to go in. Now the screws are going into end grain which is weak for holding screws. Next time use plugs so that the grain of the wood is oriented in the same direction as the neck grain.
    Lownote38, dxb, Low Commotion and 2 others like this.
  6. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician
    Though I can't say for sure that it's actually maple, it sure looks the part. And it's a particularly nice cut - no runout to speak of. The colour of the wood might bother some folks, but it actually looks decent in terms of quality. It shows a pretty even growth pattern, nicely cut on the flat. Stiffness is not measurable from a pic, but otherwise I would not be calling it poor quality.
    Lownote38 likes this.
  7. I´d thank you that you explain me like to do it.

    It seems that the neck is that what it works the best in this bass. And as I said before the body pocket it was really wider for this neck. So I chose working in the pocket.

    Thanks for comment!
  8. It seems a great advice. Please, I´d thank you a picture showing a plug, ´cause I´m not sure to understand you.

    I said poor quality ´cause the wood grain is not so tight like another necks, and it has finished so tight. And you are not wrong saying that it looks decent in terms of quality. The stifness isn´t the best, but good enough. But remember that this neck it´s a tad fatter and widder than other Jazz Basses too. And I liked too much that it wasn´t twisted. So I had two good reasons for purchasing this bass.

    Thanks for comment!
    Last edited: Nov 30, 2016
  9. Last edited: Dec 1, 2016
  10. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician
    I guess you don't understand how wood screws fail to hold in end grain. And just because others do it doesn't make them hold any better.
    sissy kathy and Lownote38 like this.
  11. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician
    Fibers run along the length of a dowel. They are long strands of cells. When you drive a screw in along the path of the fibres, the screw threads sever the fibres at each thread of the screw. So you only have a bunch of fibres severed into little pieces holding the screw, and the fibres are relying on their bond with neighbouring fibres to keep attached. However, if the screw is going across the grain, each fibre is only severed at one point and thus retains most of its bond with its neighbours, and because you are going across the grain, you have many more fibres actually holding the screw. That's why screws hold better across the grain than along it.
    Lownote38 and SGT. BAKER like this.
  12. I was very impressed by your response! Is really a very convincing explanation of how I should driven the screws across the grain instead than along. I haven´t enough words to thank you.

    So if I haven´t missunderstooth your explanation, it would be possible putting a wood piece with the grain across for refilling (wood grain in horizontal direction rather than vertical direction like my picture), isn´t it?

    And I realized that the fact of putting wooden dowels rods it´s a very common mistake in some people when they try repairing widened holes in the heel´s neck.
  13. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician
    Yes, a plug would have the same grain orientation as the wood in the neck.
    Lownote38 likes this.
  14. walterw

    walterw Supportive Fender Commercial User

    Feb 20, 2009

    "plug" is the word for a special wooden dowel that has the grain going sideways so it's stronger.
    SGT. BAKER likes this.
  15. I was quite confused about the meaning of "plug". But now I haven´t doubts!

    Surely, you guys, are so used to employing this and another words easily in your dalily/everyday "slank" lenguaje here in TB. So there are some specific words that they scapes to my aknowledge. That´s the reason I was not sure about it.

    But your answers it help me a lot to understand this technical words to name some specific pieces for repairing.

  16. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician
    Yes, at times we forget that the terms we use may be common in our trade, but not necessarily understood by others. And for those who are still unsure of the difference between a dowel and a plug, perhaps a diagram would help:

    sissy kathy and SGT. BAKER like this.
  17. 202dy

    202dy Supporting Member

    Sep 26, 2006
    "Plug" isn't slang. It is part of basic (English) woodworking terminology. The excellent diagram submitted by Turnaround highlights the difference between dowel and plug. In this usage it is a noun.

    "Plug" can also be used as a verb. For example, "He plugged his cable into the amplifier."

    Another example:"After counter-boring, he used a dowel rod to plug the hole."
  18. Of course, 202dy! I said "slang" ´cause it was the way to describe this woodworking terminology that it was unknown for me.;)
  19. 202dy

    202dy Supporting Member

    Sep 26, 2006
    Ah! You meant "lingo." That is the usual term for specialized or technical language.

    "Slang" is usually thought of as informal, often vulgar, use of language. However, it can also be interchanged with "lingo" but sometimes the message will be misconstrued.
    SGT. BAKER likes this.
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