martin D12-20 72 or 73 truss rod reinforcement

[peter meyer]

howdy all,

I'm about to do a neck reset on this Martin  12 string, and while in in there I'm planning to reinforce the truss rod w/ graphite rod Ala Dan Erlewine ,,,seems like a niffy idea. Have any of you tried this approach or have other tried and true approaches you'd like to share ,, thanks

Posted on May 31, 2015 at 8:35am Edit Post  

[Frank Ford]

Offhand, I see no downside to adding reinforcement inside that tube, although I've never felt a NEED to do it on any neck I've reset.

Ol' Dan tells me he believes the tone is improved by the additional mass of the reinforcement, and that StewMac is working on an adjustable truss rod to replace the square tube.  You'd pull the neck, yank the tube out and replace it with a (two-way?) adjustable rod that fits in the same channel.  Lotsa work, but makes sense, I guess. . .

[David Farmer]

I'm curious Peter, how bad is the relief 1-12?

It would be great to hear how much of a reduction you get if you go through with the carbon fiber or key stock thing.

Just to add to the searchable knowledge pool.

It's such a common problem.

I have a hollow tube martin in the shop right now w/.014" relief in the board and a reliable stiffening method would be preferable to the vagaries of heavy compression w/ frets or the tail chasing quality of making  board thinner to straighten it.

Ian, hammering in key stock sounds like it would require a very precise fit. did you fit it? Or does nominal key stock just happen to work?

[peter meyer]

Well Dave,,

the relief as it stands probably around .014 .015,,, id say check out the stew mac sight for explanation/demo that Dan gives  on his graphite epoxied in the tube method and see what you think ,you will find it when you search for  graphite rod material . i will start working on the guitar tomorrow as decide which tack ill take as i work on this thing ,,and let you all know the results ,, i much appreciate all the input so far

                                                                              peter 

[David Farmer]

Thanks  Peter.

Dan's instructions are pretty specific but he does not mention the amount of increased stiffness in terms of relief. I think it needs to be significant to justify the effort. Do let us know how you make out.

[peter meyer]

Well ,,, necks off and i Just epoxied that graphite rod in there ,,ill let you all know how it went when it dries  ,,, happy 4th

[Mark Pollock]

Dying to hear how it turns out. I've heard the advice to do this many times, but haven't actually heard about results from someone who has done it.

[peter meyer]

Hey all ,,just wanted to give a quick update ,,,as i,m refining the dovetail before i glue  er up ,, i placed the graphite in a while ago ( i also added a thin mahogany spline for a nice tight fit w/west system epoxy) .

Well ,,this isn't the definitive test  as i haven't strung it up yet .. but the neck did come out nice and straight :) 

so a plus there/// . I'll be posting the results as soon as she,s strung up and set .

[peter meyer]

the martin 12 string is done ,,here are my thoughts so far ...What the graphite treatment did do

i was able to flatten the neck  just by inserting the rod /spline/epoxy " which had a built in forward bow" , the procedure did not take very long so not adding much time to the neck removal process for reset . the neck remand straight w/ sleight relief  strung up .

what i think now

i consider this idea a success ,,if i had to do it again i may look for stronger quality graphite as suggested by Russel Vance just for extra insurance

So in conclusion 

yet another way to "skin the the cat"  although i really hate the idea of skinning a cats!

p.s. Frank mentioned  stew mac coming up with an adjustable rod for "the square tube"in the future ,,,i like that idea ,we'll see .

[Mark Pollock]

Thanks for reporting back. Good to know!