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MIM Jazz neck problem

Discussion in 'Hardware, Setup & Repair [BG]' started by Rick Martin, Apr 2, 2001.


  1. I bought my MIM Jazz one year ago from Mars. For the first few weeks, it needed several truss rod tweaks to get the neck relief reduced for low action. I would loosen the A and D strings to move them aside and I would turn the truss rod a quarter turn clockwise and then leave it over night. I would tune it back up and the results were great. Nice low action. Over the year I have had to do this at least 30 or more times and although I never heard any sort of loud cracking sound or anything like that, the truss rod now turns with very little resistance. I think it must be stripped or snapped or whatever. At this point the neck wants to go towards too much relief causing the resutant high action. It's not way out of line, but I like it lower. Every two days, I loosen all of the strings and gently, but firmly bend the neck back flat by pushing with my hands. I leave it alone for a few hours and then tune it back up and the neck stays nice and flat like that for another two days or so. This is a nuisance and I suppose the answer might be a new neck. I see that Warmoth has necks for $150 and I see those Maple/maple necks on ebay from Magic Dragon go for $75 or less. Has anybody ever handled one of those?
     
  2. pkr2

    pkr2

    Apr 28, 2000
    coastal N.C.
    That don't sound good, Rick. 30 quarter turn adjustments would add up to around 1/4" of stretch in the rod which would break it every time.

    Since you didn't hear or feel it break, the threads are probably stripped on the nut, rod or both.

    Definitely a job for a good repairman. Sorry about your bad luck.

    Pkr2
     
  3. Yep, sounds like you've got one of the reasons I haven't messed with the MIM's and probably won't ever.

    I own one of the necks from magic dragon. They are fine pieces of work, certainly as good or better than the fender product. They are worth every penny you pay for them. As a matter of fact this one is tapped for one of the new project basses that I will be building this summer. BUT, they are P width and don't have the profile the J necks have. IMO you can't go wrong with the Warmoth product. I just corresponded with Ken Warmoth and found out that they do indeed offer a maple/maple Jazz neck. They don't show one on their website. They get $147 for one and that is more than a fair price. Understand that it will need some dressing to work on the bass but it's quality should more than make up for the extra effort required to do so.
     
  4. What sort of dressing would the neck need? Since I live in an isolated area and don't have a pro guitar tech for help, this, as all projects will have to be a do it myself. I can see how the neck is bolted on, but I wonder how you determine the angle of the neck in the pocket. I've read about putting pieces of matchbook cover or even window screen (for traction) in the pocket as a shim. Is there some sort of jig or tool for this or is it trial and error?
     
  5. This is trial and error. But if your old neck didn't need a shim, chances are that the new one won't either. It's a simple matter to determine if one is needed though - just bolt the neck on, string it up and tune. When the neck has time to adjust, your first indication will be that the frets buzz only above the 12th fret (usually) when fretting below the 12th. That's just an angle correction. The other extreme is if you can't get the lowest action you want. Then you would have to shim in the other direction. Just remember - shimming has a large effect on the nut location in relation to the bridge. Saddle adjustment is the opposite.

    Dressing might include fret leveling, polishing, or tweaking the ends of the frets for comfort. My Warmoth fretless neck needed to be rounded over a little on the edges, they could have cut me! It won't be much and it could be nothing has to be done at all. YMMV
     
  6. Where can I learn about fret leveling?
     
  7. pkr2

    pkr2

    Apr 28, 2000
    coastal N.C.
    "Just remember - shimming has a large effect on the nut location in relation to the bridge. Saddle adjustment is the opposite."

    I'm sure hambone meant just the opposite of this quote. Not meaning to nit-pick, Hambone. :)

    Rick, this is where most of the "how to" setup guides stop.

    Edge dressing is just smoothing the ends of the frets so they don't stick out past the slots. Easy and straight forward.

    Fret leveling, on the other hand, is best left to a good repair person.

    Fret leveling is best accomplished by using a jig that holds the neck straight while the frets are sanded level.

    The equiptment requirements to do the job right are just not practical for an occasional repair.

    The truth of the matter is, if the neck is built properly, fret leveling probably wont be absolutely mandatory, although it could be. A profesional fret leveling would be an improvement but the Fender that you own was never levelled by hand. Heck, they aren't even set up out of the box.

    My advice would be to just put the replacement neck on and go from there. If it should need shimming, there are lots of people on here that can fly you through it.

    Since you can get a neck for less than $150.00, I wouldn't even consider a truss rod replacement. You would be upgrading the guitar for less money than the repair would cost.

    Pkr2
     
  8. No, I think I had it correct - here's why:

    If you put a shim under the heel of the neck (at the rearmost postion) the nut end of the neck will "lower" considerably in relation to the bridge especially if the 2 outermost neck screws are used as a pivot. A business card thick shim will have the effect of lowering the headstock about 8 times that thickness. Same would hold true with putting the shim in front of the rear neck screws but it would "raise" the headstock in relation to the bridge.

    Adjusting the height of the bridge saddles or the bridge itself only increases (or decreases) the string height that amount of change. The reason is that neck shimming acts like a fulcrum and a shims thickness is multiplied over the length of the neck. This can be observed at the nut - a long way away from where the adjustment was made. That's why very thin shims have such a large affect on getting a proper string height.

    I guess I didn't 'splain myself very good the first time :)
     
  9. pkr2

    pkr2

    Apr 28, 2000
    coastal N.C.
    I understand now. Sorry for the correction. I was reading with tunnel vision when I read your post the first time. :)

    Pkr2
     
  10. This shim talk is interesting. I sort of figured out the physics on my own, but the business card idea gives me a good idea of how thick is thick for neck shims.
    I'm saving my pennies for a new neck. I hear good things about Warmoth and I suppose that might be the way to go. I see a web site for WD Music Products that has Fender authorized replacement necks for Jazz bass. Anybody have any opinions on where to buy the neck?
     
  11. Warmoth's construction is different from that of WD. Warmoth uses 2 parallel rectangular steel rods alongside the truss rod for stability and to eliminate dead spots. You will NOT be disappointed in the Warmoth. And for $147 I doubt that WD is going to touch it.

    As for the Fender licensed parts angle, Warmoth is that too. They've just been doing it longer than anyone else.

    Try www.warmoth.com and see what we've been talking about here.
     
  12. Steve Cat

    Steve Cat

    Mar 19, 2001
    Yah, know I just don't get this whole neck angle deal. It seems to me that it is only important if you want to adjust beyond what can be adjusted by the bridge, or maybe the pups. That within those limits you have two "legs" of an angle with the nut being the pivot point. Moving either leg, the fingerboard or the strings round the nut axis makes no difference assuming that the angle is the same.

    Right?
     
  13. Steve Cat

    Steve Cat

    Mar 19, 2001
    Another thing, depending on where the truss rod is broken it may be possible to fix it. My dear departed father in law (I miss him) welded the truss rod on my american standard strat. Now I don't know whether the truss rods are at all alike but it did work and I have even (yes I admit it) made MINOR adjustments when strung to full tension and it hasn't broken in five years. Just something to think about if you know a welder.
     
  14. pkr2

    pkr2

    Apr 28, 2000
    coastal N.C.



    I'm just curious. Why would you weld a truss rod?

    you obviously had it out of the neck to weld it. Why didn't you replace it with a new one? They cost less than $10.00 (cosiderably less) brand new.

    To be perfectly honest, I'm not sure whether the truss rod in Ricks particular bass is removable without major surgery.

    Pkr2
     
  15. Steve Cat

    Steve Cat

    Mar 19, 2001
    It never really occurred to me to buy a new truss rod. I was so upset that I snapped it, by trying to flatten an already flat neck fully strung with 11's and felt so stupid for doing it on my favorite axe, signed by Buddy Guy no less, that I was just bummed. I told my father in law and he was the kind of guy who liked to weld anything so that's the story on that.
     
  16. I sure don't see how the truss rod could be removed from a MIM Jazz. I've got my eye on the Warmoth neck.
     
  17. Steve Cat

    Steve Cat

    Mar 19, 2001
    Since the neck on the strat was "wrecked"anyway I drilled about a 1/2" hole in the other end and pushed the truss rod through with a center punch. Now granted if I took the neck off someone could see the pilot hole, but when its on the guitar who knows.

    BTW I have also MIM jazz, it looks similar to a strat(I mean the truss rod adjustment device). Since your neck is "wrecked" anyway, why not give it a try........unless you have an attack of GAS for which there is no relief other than to buy.
     
  18. pkr2

    pkr2

    Apr 28, 2000
    coastal N.C.
    Steve, that sounds like a good technique to know but there are a couple of points that aren't clear to me.

    I dont understand how you get all of the rod out of the channel at the anchor end. When you drill the half inch hole from the body end of the neck, doesn't the anchor plate interfere with punching the rod out? The rod is threaded into the anchor plate and punching it through seems like it would destroy the anchor plate.

    Thanks, Pkr2
     
  19. I called Warmoth on the phone today and spoke with a very knowledgeable and helpful guy. We talked through the installation process and we talked about clamping the neck to the body and checking around with a straight edge befor drilling. We talked about the possibility of a shim being needed and he said that if he needs to shim a neck he uses a thin piece of brass like you can buy at a hobby shop. He said many people have used pieces of matchbook or busines card, but he thinks the shim should be something solid like the brass. The rosewood neck is $151 plus $11 for shipping. The guy said the neck needed to be finished in order to be under warranty. He said they can finish it for $60 or I could do it myself. He suggested several coats of polycrlyic, but not on the rosewood board. With the maple board, he said you finish the board too.
     
  20. Steve Cat

    Steve Cat

    Mar 19, 2001
    The strat didn't have anchor plate on the neck. Not to sound insulting but I do mean parallel to the finger board, not perpendicular to it like the screws that bolt it on the neck. I haven't had the neck off my MIM Jazz so there may be a difference due to the high neck tensions on a bass.