truss rod on neck through

Discussion in 'Luthier's Corner' started by bassmanatlarge, Jan 30, 2003.

  1. bassmanatlarge


    Jan 30, 2003
    I'm designing my first neck through and will use a pair of dual action truss rods(stewmac hot rods)

    My concern is that they may be a bit short for a 35" scale.

    I also notice they usually don't extend into the body, but start part way up the neck. Would it not make things stronger and avoid problems at the 24th fret area to extend it? Or would that cause other problems?
  2. First, if youre not building a 6+ string, you won't need more than one trussrod. And the stewac rods were designed for 34" necks.

    Now I assume(from your post) you want to have them headstock-adjustable, but if you look around, most multi rod basses (all that I have seen) are body-adjusted.

    If you want to build a 35" neck, use one trussrod, and add 2-3 CF rods to strenghten the part of the neck the trussrod doesn't.

    Oh, and by the way, it can take a few days to get a reply around here, it's not cause were mean, it's just that your post was a bit abrupt and not that descriptive. If you put a bit more detail, and perhaps a few niceties in your posts, you'll get more replies.
  3. bassmanatlarge


    Jan 30, 2003
    Thanks for your help on that. I really thought my question had all the info needed, and if it's abrupt it's only because I didn't feel a need to fill the post with meaningless babble. As a new comer to this forum, i find it intimidating, and since I'm not a regular poster I feel I don't know any of you well enough for socializing. Surely with time I can get to know some of you and feel more comfortable. Your post tho' helpful doesn't really make me feel welcome.

    niceties aside...

    The neck has two purpleheart stringers making up 20% of the width of the neck with the othe three laminates being beautifully straight grained honduras mahogany. This and the dual rods are at the request of the person for whom I'm building this bass. Whether they are adjustable at the headstock or body is yet to be determined. I lean toward the body and he leans toward the headstock. Structurally I don't see it as being an issue.

    Back to my earlier question...Ideally, how far into the body should the rods extend? We're using lightwave pickups, so it would be possible to extend from the bridge to the nut. I can make the rods any length at all. My concern is that I get support near the heel to avoid a bend developing in that area over time.

    When I see the impressive list of guest luthiers, I assume somebody has already addressed this and can give me some advice on the matter. Certainly if it was something I new about I would be happy to pass it on. While I may be new to this forum, I do build basses professionally and have been a woodworker for 51 years. I'm here to share the knowledge I've gained with this experience and hopefully to learn what I can from the vast knowledge pool that exists here.

    I've lurked here occasionally, and don't see a social club atmosphere. If I find I'm mistaken, I'll spend more social time here. Until I feel comfortable and welcome, I'm not the kind of person to be involved in idle chatter.

    Sorry if this sounds like a rant, I'm not even sure if it is or not myself.

    Thanks once again for your assistance
  4. Hey BMAL,
    Welcome to TB.

    I have used the Stew Mac truss rods on a 35" scale 7 string bass, dual truss rods like you are planning. I used a wenge/purpleneart 11 piece neck.

    I don't think that the rods really need to extend into the body. As long as you can adjust them from the body end, if that is how you decide to do it should be fine. The thing with the bass neck is that it is generally going to bend over the entire length, so I don't see 34" vs 35" as a problem. If you adjust it from the headstock end, I also don't see a need to have them go all the way to the 24th fret. That is the area where the neck is strongest anyway.

    Besides, with the purpleheart stringers, you should be adding stiffness to the neck. I don't see it as being a problem either way.

    Hope this is of help, or sparks an idea.

  5. FBB Custom

    FBB Custom TalkBass Pro Commercial User

    Jan 26, 2002
    Owner: FBB Bass Works
    What Geoff said.

    Seriously, though, the neck is widest, and thickest at the heel. The neck flexes most as you approach the nut.

    Most of the time, the center of the rod is pushing up against the fingerboard and the feet of the rod are pushing back against the neck. The key to good neck relief is to locate the pressure points where they will do the most good.

    The Hot Rods could be an inch or two longer and be perfect for a 35" scale, in my opinion, but then they would start getting too long for medium scale basses, and I would whine about that. As they are, they do a good job on 32-35" scale basses.
  6. bassmanatlarge


    Jan 30, 2003
    Thanks guys...that truss rod length always puzzled me.

    25 1/2" looks optimal to me from your least so far

  7. DP Custom

    DP Custom DP Custom Basses

    Feb 7, 2001
    NC, USA
    First of all, your original post was just fine IMO :p

    Anyway, I aggree that the Stew-Mac rods should be an inch or so longer to at least extend better into the thicker heel area on longer scale basses (35-36")..

    as long as the bottom end of the rod is in the heel area, where the wood is much thicker and resistant to bending, I don't think you need to worry. After all, you don't necessarily want bending pressure on the neck section within the body region!

    good luck

    Dave P.