why not put truss rods in bass necks?

Discussion in 'Setup & Repair [DB]' started by PB+J, May 5, 2002.

  1. PB+J


    Mar 9, 2000
    arlington va
    I can't see why not. The neck is more than long enough, the string pull forces are quite high, and the whole instrument is more sensitive to changes in weather than are the instruments that always have truss rods. The difference between good action and unplayability is slight, so why not have a truss rod? There's plenty of room under the fingerboard for an allen-key adjustment nut. If you had one, you could tweak neck relief as needed, with every change of string brand, or even if you were going from mostly pizz to mostly arco

    can't understand why not--any ideas?
  2. anonymous0726

    anonymous0726 Guest

    Nov 4, 2001
    I can think of few reasons.
    • Only about half of the fingerboard is touching the neck.
    • The neck that is there is pretty stout, not sure that you'd get much flex out of it, anyhow.
    • Bending the neck wouldn't change the relief in the fingerboard, rather it would just break the glue seam.

    Gary Karr has a new bass made by some maker in O, Canada!, and this maker has mounted the neck on a mechanism that allows you to move the neck forward and back to the change string height without changing the geometry of the strings/bridge/front of the bass.
  3. pkr2


    Apr 28, 2000
    coastal N.C.
    The neck on an old Ampeg baby bass is adjustable pretty much as you describe, Ray.

    It has an adjustable truss rod on the overhanging part of the fingerboard too. No adjustable truss rod in the neck though.

    Interesting idea though.

  4. sean p

    sean p

    Mar 7, 2002
    eugene, oregon
    the canadian maker in question is james ham, from victoria, british columbia. there's a blurb about his basses winning an award in the latest db magazine (or maybe the one just prior).

    sean p
  5. Bob Gollihur

    Bob Gollihur GollihurMusic.com

    Mar 22, 2000
    New Joisey Shore
    Big Cheese Emeritus: Gollihur Music
    I can't imagine how any truss rod could move the huge mass of a neck and the fingerboard on an URB. There is at least another inch of wood.
  6. PB+J


    Mar 9, 2000
    arlington va
    Well I'm not sure. It's true the mass of the whole system is greater, but I'll bet if you compared the flexibility of a maple neck to the flexibility of a stainless steel rod, the difference in wood mass isn't going to be that big of a factor. I put a martin style trusss rod in a guitar once--and aluminum box with a steel rod in it. It was seriously stiff and controls neck relief like a prussian concert master. True, the forces are greater in a bass neck, but beyond the strength of a steel rod?

    It surely couldn't hurt, and it would add some stiffness and some adjustability. It's not going to pull the fingerboard off, I don't think, since a good glue joint is stronger than the wood around it. The fingerboard extension isn't under any tension, so once you had the "scoop" adjusted there you could use the truss rod to tweak the neck part. I suspect it's mostly tradition, but maybe not.
  7. Chasarms

    Chasarms Casual Observer

    May 24, 2001
    Bettendorf, IA USA

    I don't think it is a question of competing against the strength of a steel rod, it is more that it would be too stiff to be used practically.

    I wouldn't be that comfortable using two hands and a 24" breaker bar to adjust the truss rod on my bass. A 3/4" thick piece of straight-grain ebony is pretty darn stiff. Especially when backed by a glue seam and a fat piece of maple.

    I am no expert, but I believe that most movement you see in a bass from weather changes is in the table and even the entire body box. So, simply adjusting relief on the neck wouldn't fix your problems without significantly changing the playability of the bass. You'd end up using an adjustable bridge anyway if you wanted the bass to play the same all the time.

  8. arnoldschnitzer

    arnoldschnitzer AES Fine Instruments

    Feb 16, 2002
    Brewster, NY, USA
    When I encounter a bass neck that is flimsy, I will sometimes install a carbon fiber rod into the neck under the fingerboard. The added stiffness is remarkable, and sometimes it adds a little to the "pop" of the bass. I've put them in all my handmade basses with good results. An adjustable rod would not work. As the well-informed Mr. Parker said, it would only break the glue joint or worse.
  9. PB+J


    Mar 9, 2000
    arlington va
    Sorry--not trying to be argumentative, just trying to gather info. Why do you say it would break the glue joint? The truss rod could not exert any greater force than the force the strings are already exerting. The rod would be pushing up against the underside of the board, true, but truss rods do this all the time in, say, 8 string electric basses or 12 string guitars and it's been proven durable for 80 years now. Truss rods will break long before the fingerboard comes off. I understand about the need for fingerboard scoop, but the truss rod would only tweak a setup which had been accomplished in the traditional way--at least, so I'm imagining.

    I've built several electric guitars and basses, so i'm not totally clueless, but obviously the double bass is a very different bag, demanding a much higher level of skill and knowledge. But look at the archtop guitar--designed by combining some techiniques from violins with the tradtions of guitar lutherie. Surely the double bass, wonderful as it is, hasn't reached a state of perfection?
  10. Dude, do what I do when master luthiers and experienced players won't fulfill your needs.. experiment. If you've built many electrics I'm sure you've got the tools. Laminate some plywood to the proper width of a neck, band saw out the approximate shape, put your truss rod in, bolt the "heel" to the edge of a work bench, glue on a 1x3 piece of oak or whatever "fingerboard" and bend away. I for one would love to hear your results.
  11. anonymous0726

    anonymous0726 Guest

    Nov 4, 2001
    It would require a drastic redesign of the neck. The current design relies on the stiffness of the fingerboard to support the whole structure. But, hey, go for it. You could be the next thousandaire...
  12. arnoldschnitzer

    arnoldschnitzer AES Fine Instruments

    Feb 16, 2002
    Brewster, NY, USA
    Necessity is the Mother of Invention. But in this case, there's no need. A proper neck/fingerboard set up is quite rigid. And with about half the fingerboard hanging off the neck, bending the neck would screw up the overall camber of the board. Then you would get clearance and buzzing problems. Now, if you had a second truss rod in the overhanging fingerboard...
  13. Jeff Bollbach

    Jeff Bollbach Jeff Bollbach Luthier, Inc.

    Dec 12, 2001
    freeport, ny
    Way too complicated, Ahhnold. I'm thinking two fingerboards. each with different camber attached with industrial velcro.
  14. anonymous0726

    anonymous0726 Guest

    Nov 4, 2001
    Industrial Velcro? You wouldn't want to drop THAT bastard on the carpet accidentally!
  15. Joe Taylor

    Joe Taylor

    Dec 20, 2001
    Tracy CA
    We don't no stinking truss rods!

    We all would spend way too much time adjusting it.

    Get two bass' and have two diffrent set ups.

  16. nicklloyd

    nicklloyd Supporting Member/Luthier

    Jan 27, 2002
    Cincinnati, Ohio
    Contemporary doublebass luthiers, myself included, use truss rods. However they aren't adjustable, and they aren't metal. Graphite rectangle bars, 1/4" X 3/8" X 18", recessed into the maple neck, and below the ebony glue joint. Available from Luthier's Mercantile. They add signifigant stiffness to the neck, with insignifigant weight gain. I have also used them in a neck repair, when the customer can not afford a graft. (They can be cut into smaller sections with a bench grinder.) Also, it doesn't take that long to install one, and at $26 a rod, it's cheap insurance.

    Trade secret.

    And cast my vote for experimenting with your tools and ideas. Improvise, retry, and relax. (Just don't ruin any customer's bass...)
  17. rgarcia26


    Jun 9, 2008
    Miami Florida
    can you please explain how is that you install this rod in the neck? is there is any online documentation that i can check for it?
  18. Rebop


    Jul 9, 2008
    La Honda, CA
    POWERTOOLS!!! :bag:
  19. rgarcia26


    Jun 9, 2008
    Miami Florida
    Lol I never install a truss rod in my life, I know I take a router make a channel in the front of the neck to insert the rod (but the channel is just the side of the rod??? The channel is deep as de rod or deeper???, do you installed like a guitar rod???) I have to use epoxy to set it???
  20. mattfong


    Jan 14, 2008
    Toronto, Canada
    Routers are for wussbags. Be a man and use a chainsaw. Lumberjack style!