Problems with back bowing necks on Martin guitars with Micarta fretboards
 

I recently bought a used 2001 Martin JC-16gte with Micarta fretboard and I was informed when I took it for a pro set up that the neck was back bowed and that the truss rod was already completely loosened and could no longer compensate for the problem. I had noticed the back bow but figured it could be fixed with a truss rod adjustment. The guitar tech also informed that he has seen a lot of the Micarta fretboard Martin's having this problem. He said that Martin immediately replaced back bowed guitars that were under warranty but never publicly acknowledged the problem and have since used double end adjustable truss rods on necks with Micarta fretboards. What about all those 16 series guitars out there already like mine? Anyone have any info or thoughts on this?

I have never heard of this. Interesting. I bought a D-16GT last summer and to date have no issues. I have no idea if mine has a double end truss rod.

I'm hoping some of our Martin experts will weigh in but I'd be surprised if Martins guitars with Micarta fretboards do indeed have this problem.

Was the tech saying the the problem was due to the micarta?

I have a 2002 Martin 000-16SRGT. Whether it is more stable due to the shorter (12-fret), thicker (mod. low oval), or wider (1-3/4") neck, I don't know, but the neck is straight. The guitar has one truss rod adjustment.
When I first got it (last year), I noticed some string buzz on the lower frets, but I now use strings with the recommended top tension (PB 12-54), and the problem has disappeared.
Micarta is less likely to swell, shrink, or crack than ebony. As guitar necks tend to bow forward with time, I'd like to understand what would cause the back bowing that you describe.

Martin may be doing the fix under warranty, the problem is you are not the original owner. If you know the first owner well enough, maybe he could contact Martin and get the work authorized. Otherwise its you dime.

Sorry to hear it.

I own a D-06GT and I've adjusted the neck to the point that its almost flat with no buzzing with no problems.

I'm confused though, if the neck is bowing backwards, it should be able to go the other way by tightening the rod (clockwise). What am I missing?

usually not the case. like here you need to loosen the rod (counterclockwise) to go the other way, and the OP said the rod is completely loosened already.

Something is not making sense here. Back bowed means the neck has a "hump" versus a "valley" and that is corrected by tightening the truss rod not loosening it, so the tech saying it's already as loose as it can be makes no sense.

What am I missing, and I have heard nothing about a Micarta problem and "double end adjustable" truss rods??

I was hoping you'd post Rich - you were the 'Martin expert' I was referring to in my post.

Whichever direction is turned to compensate for the back bow has been done completely. I believe it is loosening to relieve the neck as opposed to tightening to bring down an upward bow. Anyway these guys at Gryphon Strings in Palo Alto are an authorized Martin service center and work on a lot of them. He said it is something about Micarta not adjusting itself to the change that obviously happened in the neck wood for whatever reason. Martin has since started using 2-way truss rods so that forward bow can be put into the neck by turning the truss rod backwards.

Back bowed means a reverse curve meaning the neck is curving downward to settle any confusion.

in which case what i would call loosening the neck would solve the problem right?

Also, go to heavier strings, only solution you have

I do not have any information about this particular problem, but I can think of two possibilities that might be going on:

1. On the regular Martins (as well as other brands) the fretboard is made of wood (typically ebony, but on lower priced models you see rosewood). When you have a wood fretboard on a wood neck, the two move in unison (more or less) with humidity changes. When you have a plastic fretboard (micarta is a kind of plastic) it is not affected by humidity, but it could be affected by heat. In either case, you have a fretboard glued to a neck where they do not behave in unison and you might get some bowing - either up or back - with changes in humidity or due to high temperatures (from things like being left in the sun or in a hot car or above a heating radiator or such.

2. Martins made with Micarta fretboards are not their top end models. Martin is like all other guitar companies in that they use their best woods on their higher end models and what is left on their low end models. Lower quality woods are often not as dimensionally stable as higher quality woods (wood quality is not only about how it looks). As such their lower end guitars may have less stable necks that result in this kind of twisting around. I am sure it is much cheaper to simply replace a few necks that to use high quality woods on their entry level models which would significantly bump their prices well above their lower end price points.

A single action truss rod will act to induce backbow only...if the neck is already backbowed without truss rod tension, adding truss rod tension can only make the problem worse.

If the backbow is slight, it might be an option to mill the frets to bring things to playability...figure an hour to an hour and a half to do a full level/crown/polish. This would work only where the removal of fret material will be fairly moderate.

Another option might be to relevel the fretboard & refret. For 3-4 hours of labor, the frets could be pulled, the board leveled to remove enough material to eliminate the backbow, and the board refretted. This approach would work if there is no more than .030 to remove....more than that, and the edge of the fretboard will show a distinct scallop.

Might be time to look at a refret or fret mill on a 10 year old guitar in any case, so might not be all that much more than the cost associated with normal wear and tear.

I won't argue the semantics of "back bow" I can see both points of view so lets talk "relief".

With Martin to increase relief, move the fretboard away from the strings, you decrease truss rod pressure by turning counterclockwise, and tighten the truss rod to raise the fingerboard.

Martin went from the single adjustment to dual adjustment truss rods around 2005-6, the old 5mm truss rod tools are too short for the new truss rods which are recessed deeper, you need a longer truss rod tool.

I have never heard the change to the new/better truss rod was driven by problems with Micarta ftreboards, that may be true I don't know, but Martin certainly doesn't use the new truss rod only on Micarta models, all my post 2005 Martins have the new truss rod.

Regardless good luck with your guitar..........:)

Attibuting to micarta seems odd since it would be more inert than either rosewood or ebony. Have you called Martin and asked them?