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Duel Truss Rods


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Hi. I'm making a solid body 12 string, with a hard maple neck. I'm routing in two truss rods, ( from LMI, 1/4 inch wide and 3/8 inch deep.) The overall fingerboard width at the nut is 1 and 7/8 inches. How far from the centerline should the trussrods go? ( I got the smallest duel action trussrods I could find to keep the neck depth as small as possible.) Thanks

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Hi. I'm making a solid body 12 string, with a hard maple neck. I'm routing in two truss rods, ( from LMI, 1/4 inch wide and 3/8 inch deep.) The overall fingerboard width at the nut is 1 and 7/8 inches. How far from the centerline should the trussrods go? ( I got the smallest duel action trussrods I could find to keep the neck depth as small as possible.) Thanks

do you really need 2 truss rods? I think one would work just fine.

maybe some carbon fiber reinforcement.

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Hi. I'm making a solid body 12 string, with a hard maple neck. I'm routing in two truss rods, ( from LMI, 1/4 inch wide and 3/8 inch deep.) The overall fingerboard width at the nut is 1 and 7/8 inches. How far from the centerline should the trussrods go? ( I got the smallest duel action trussrods I could find to keep the neck depth as small as possible.) Thanks

do you really need 2 truss rods? I think one would work just fine.

maybe some carbon fiber reinforcement.

If a situation arose where two truss rods could or should be used, is there a way to synch up the adjustment to avoid twist? I'm just curious because if olddog does use two I wonder if that would be a better way to go, if possible.

From my neck I was building a while ago, I was using CF rods and one person posted that there was no reason for it with a hard maple and jatoba laminate and a number of the great luthiers here stepped in a said it never hurts to have some CF. I would imagine that it would be extremely useful in this situation and might prevent any problems that can occur with two truss rods.

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The whole idea, aside from neck stiffening, for 2 truss rods side by side is to straighten neck twists. Rickenbacker been doing it for years on their 330 / 360 hollowbodies and 4000 series basses. Hagstrom does similar with an I-beam (looking endwise) shaped truss rod. The neck consists of two halves glued together around the truss rod.

The best info I could find regarding how far apart for your dual truss rod system is from a Rick bass repair site. Scroll down a bit and you will see pics of a Rickenbacker 4002 bass truss rods at both ends.

http://www.nortonbassplace.com/11repairshop.htm

But you will have to judge for yourself with your 12 -string.

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In using two truss rods, if the neck doesn't twist on you, would you run a higher chance in twisting it yourself adjusting for relief? Is one or the other a better way to go for a twelve string or just preference? I am just curious of what the deciding factors are between the two or if it is just a preference of preventing twist or fixing it if it occurs?

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Regardless if its a single or dual everything is checked with a straightedge after adjustment, otherwise how would you know if you got it right? :D I would think the best application for a dual truss rod would be for a shallow neck which can be more prone to twisting. And would work better in a neck where the wood is symmetrical to the centerline ie. a laminated neck or a VERY uniform one piece. If you can minimize the thickness of the usual blocky neck on a 12 string by using 2 truss rods to compensate for the extra string tension then I think its worth the effort. The benefit is having the ability to keep it balanced.

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Regardless if its a single or dual everything is checked with a straightedge after adjustment, otherwise how would you know if you got it right? :D I would think the best application for a dual truss rod would be for a shallow neck which can be more prone to twisting. And would work better in a neck where the wood is symmetrical to the centerline ie. a laminated neck or a VERY uniform one piece. If you can minimize the thickness of the usual blocky neck on a 12 string by using 2 truss rods to compensate for the extra string tension then I think its worth the effort. The benefit is having the ability to keep it balanced.

I got ya on the adjustment, I was just curious if you could have long term problems with twist in using two rods, I believe someone had this problem, but I suppose they could have been inexperienced with the whole adjustment concept, which could be a tad tough with two. I know Ibanez has a Gio series that I have heard from many people often have neck twisting issues, and I believe the neck is a quite shallow one piece. Overall on a 6 string shallow neck 3piece laminate, if you weren't worried about time or money would you do the two trods or a trod and two CF rods? I have always been quite fortunate to avoid any twists in the guitars I have, hence the reason I have always drawn toward CF to prevent problems rather than being able to correct them. I swear there was a topic about this subject a year+ back that we talked about this, maybe I will look for it later. Thanks for the input.

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Hi. I'm making a solid body 12 string, with a hard maple neck. I'm routing in two truss rods, ( from LMI, 1/4 inch wide and 3/8 inch deep.) The overall fingerboard width at the nut is 1 and 7/8 inches. How far from the centerline should the trussrods go? ( I got the smallest duel action trussrods I could find to keep the neck depth as small as possible.) Thanks

I started reading this thinking 12 string bass, but then I saw 1-7/8" and a thin neck. Personally, I would not do this(just my opinion FWIW). If you are doing it though... Make a full scale section of your neck at the 1st and 12th frets. Show the routes and truss rods(be sure you leave about 1/8th inch of material behind the truss or you run the risk of cracking through the back of the neck. I think you will note your neck profile is going to be quite thick compaired to a common neck(thin profile modern necks with the smallest off the rack truss rods have just about 1/8" behind the truss when it is centered on the thickest part of the neck, and of course you get thinner as you move to the outer edges). It seems to me that two carbon fiber rods placed on either side of a truss rod is good insurance against twisting(carbon fiber has no memory) and would add stiffness and strength if needed. This in conjunction with a single double acting truss rod is a wonderful combanation. Careful selection of well dried straight, clear, well quartered or flat sawn neck stock will also provide good insurance against warpage. Choosing string gauges that will require very similar tension when tuned to pitch will also help prevent warpage. If you are planning headstock access for two rods on a 1-7/8" nut neck. You best look at the headstock breakage potential also(you dont have much material to begin with and now you are taking away a lot of that wood for truss access(and the rods add no strength to the beyond the nut).

Peace,Rich

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I have a Rickenbacker 260jg model from the 80's that I love. The one real issue with it is the dual truss rods. They work very well but are far more difficult to adjust and setup than a single rod neck. If I had the option, and performance was equal (which I believe it is), I would go with a single rod and CF re-enforcement. As far as I can tell, the concept behind dual rods is to have the strength and a far more precise level of adjustment. In theory each half of the neck is independently adjustable. But in reality, they interact and make it far more difficult to adjust properly. It gets great results, not vastly superior to a single rod, but twice (at least) the work.

Peace...Rog

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