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Yes I've done this before but this time around it's bogging me down. I reviewed the R O'Brien TD tutorial. Think I'm going to access it through the soundhole but I don't completely understand if the caulking is that necessary...won't it stick to the threads and make it a little harder to turn??? And the wood shim on top, I do like that idea but does the rod have to be pushed down in the center?

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Mike McNerney

I haven't seen the O'Brien tutorial but what I do is wrap the truss rod in Teflon tape that plumbers use for threaded fittings and glue the wood filet on top of it. If I want to put a bend in the rod I will glue tapered wedges in the bottom of the channel before installing the rod, but generally I cut the channel with a tablesaw and access the rod through the soundhole so the channel naturally curves up at the peghead end of the neck.
I push the wood filet tight to the Teflon wrapped rod making it tall enough to be proud of the channel and then plane it off flush. It needs to fill any gaps so the rod doesn't rattle and will work properly.
I use the old fashioned single action rods, so if you are using something else someone may know better ways to install it.

Haven't seen the O'Brien toot either and I never caulked OR inserted the spacer strip. I just made sure that I had a rattle-free, press fit of the rod in the channel and I've had no issues with the 54 1/2 that I built. I used the Blanchard rod after always testing the adjustor in a vice and the rod has functioned flawlessly and perfectly on all of mine.

I figured that wood shrinks over time for the most part, it can expand but for the most part we see that horrible word..... shrinkage... Now if I was using another rod that did not fit snuggly in my milled channel organically I wold consider caulk or spacers.

FYI too Mike injecting caulk into a truss rod cavity of an already completed instrument with a rattling truss rod is one of the escalatory remedies that we employ to repair guitars with rattling rods. We of course avoid threads with the application of said caulk. It is believed however that the caulk if it gets on threads is not going to be like glue on threads and we should be able to still turn things. So caulk on threads may not be the end of the world and good on you for playing this out forward and anticipating that it might. That's great thinking and that produces great guitars Mike.

You considered the "serviceability" of the instrument going forward and that makes my day! Thanks man!

So long answer short it depends on your truss rod selection, your fitment and your faith in physics.

A long time ago someone here that seemed to have credibility recommended toilet seating wax ring material as a filler to prevent rattle. I actually used it on quite a few before I switched to the Blanchard rod and a filler strip per his recommendations.

I make sure each end of the rod is a snug fit using thin shims if needed and make sure the filler strip creates some downward pressure on the center of the rod. So far so good on a lot of guitars.

A couple of my early guitars where there was no filler strip, caulk, or wax rattled. Per Frank Ford I injected rubber cement into the cavity and it worked.

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It's not what you don't know that hurts you, it's what you do know that's wrong.

I always figured that the fretboard was a good enough filler strip. I like the Martin style rods and I get them either from Martin or Bitter Root. I like to make it so they are removable, so no caulk or anything like that which would make it difficult to slide out. These rods are already wrapped in some sort of shrink fit tape stuff and rattle free. With the proper sized rout they are in tight enough that it requires pliers to pull them out but enough to stop vibration. I've yet to see one break but if one does I can remove it.

You know too simply engaging the rod and making sure it is not in the neutral position often, usually will kill any rattle. Not always though and that when we may inject caulk or see below.

There is another fix we do for those interested and that is to on a Fender remove the dots, some of them, drill and thread for a set screw, install said set screw and crank it down to engage the rod and stop it from rattling and then reinstall the dang dot. Works like a charm.

Another cool fix for truss rod rattle is a product that used to be called Chair Lock. If you Google that then you will find out what ever the new stuff is called which I forgot. Anyway it was made for loose chair rungs. It's not a glue rather it swells the wood. So when you inject it into the chair rung joints it swells and no more loose and squeaky rungs. It's water thin. Just remove a dot and drill into the truss channel and squirt it in. It swells the wood that the liquid touches and fills in the space causing the loose rattle. I only ever used it once but it worked like a charm.

for me I tried about everything and about everything will work. My favorite is tite bond in the slot not so much as an adhesive but as a filler.
all you want to to be able to control the movement of the rod so it won't buzz.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

No caulk or filler strip and no rattles here.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

There are some real gems of posts above guys this is a good thread!!!

Thanks all. The rod is in

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Mike McNerney

Late to the game, I know, but I didn't do anything for a while and then had that customer who found a certain chord, half way up the neck that caused just the right vibration and made the truss rod rattle. I eventually had to remove one of the frets (around 12 I believe) to drill a small hole into the truss rod area and inject some sort of non-hardening glue (forget what it was) into the channel to get the rod to stop vibrating.

Since then, I have done what I have seen Greenfield do, which is to press the truss rod channel filler strip (assuming you use one) into the neck a little deeper in the center to put the rod under some mild tension at install. I guess this is similar to the wedges mentioned above, but without more info I can't say for sure. In any case, this seems to have prevented the problem, as the rod is under a mild bend even when the rod isn't tensioned in either direction. I use LMI truss rods, which have a plate on the "down" side and a rubber-coated rod facing toward the fretboard.

Seems almost counter-intuative, but if you do everything "perfectly" in your guitar build (based on your target string tension) the truss rod could actually be an insurance policy, rather than an integral part of the guitar's ability to perform. Yea, almost never happens, but on that particular customer's guitar I mentioned, it was. So, I couldn't just tighten up the rod one way or another to eliminate the rattle.