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Hi Folks,
I thought I would post this question here in hopes that someone might
have more insight than I.

I will be switching from LMII's TRSD truss-rod to a compression style
truss-rod. I had one of their rod's break on me inside a guitar earlier this
year. After much thought and research, I realized that if a neck is well
made and you pre-tension the compression rod, you end up with
something that is very functional and not prone to breaking. I just think
these dual-action rods are much more delicate than the tried and true
compression rod.

So my question is this: I want to adjust thru the soundhole (not the
headstock), is this possible with a compression rod and can you
recommend a good rod to go with?

Thanks,
Simon

Simon,

I don't know about the compression rods, though I'm sure someone has the answer.

Where did the dual action rod break? Any idea on what happened?

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53% of all statistics are made up on the spot
http://driftwoodguitars.blogspot.com/

Wayne,
The TRSD rod broke at the adjustment nut - it didn't necessarily snap, but
it became very loose in the threads for some reason and began to rattle.
Maybe the threads got mangled somehow - although, the customer said
he released the string tension and only adjusted the truss rod a small
amount - so I am thinking the truss-rod is to blame.

I am sure the TRSD rod is a good one - however, I think I will feel much
better going with something that is well-known for being reliable. There
has to be a reason why Taylor and Gibson still use it.

Peace Out,
Simon

I like compression rods too, for one thing they are lighter than dual rods. I make them with a right angle at the heel end and the standard Gibson type headstock cavity for the nut. This weakens the neck in this area, so it is a good idea to make the cavity as small as possible. Scarf jointed headstocks and back strapping are good ideas with this type rod. The repair people get a lot of broken Gibson headstocks... Oh, and a curved rod channel and relief planed into the fingerboard also makes it work smoother.

You could make the truss rod adjustable from the heel end I guess, but one thing to think about is how you will anchor it at the nut end of the neck. You don't want to take away too much material here, perhaps a barrel bolt (which is often used with these rods for heel end anchoring) will also work in your situation. You will need a long nut to be able to reach it through the heel block too.

I know I have seen guitars with rod adjustment from the heel end, but for the life of me I can't remember any names now...Arnt38986.2610532407

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Rian Gitar og Mandolin

Fender uses this method on most of their electric guitar necks. I believe that they use a small block of aluminum alloy at the headstock end under the fretboard, and the trussrod is threaded into the block then peened to keep it from backing out.

Al

On that TSRD did you put silicone caulking in the bottom of the slot as recommended by LMI. If not this rod has a bad habit of rattling. it is actually the round rod rattling against the lower rectangular rod and or the rectangular rod rattling against the channel. In particular when the rod is tensioned for anti-relief and or free of tension all together. This is easily fixed by removing the FB, nut and rod and laying in a single bead of silicone prior to reinstalling the rod.

I have used this rod almost exclusively for several years on at lest 15 guitars with zero thread outs but the first two I had the rattle and this solved my problems.MichaelP38986.6802777778

The other thing I do with this rod that may not occur to all is I rout the channel only as deep as the rod pair itself and then notch the bottom of the channel for the nut blocks at the ends. That way it fits pretty good all the way down. I also add a few blobs of calking in the channel before installing the rod.

_________________
Tickle your guitar daily, and it'll tickle you back.

Michael,
I hadn't been using the "silicone" trick but fortunately, hadn't encoutered
any trouble with rattling. I would strongly advise anyone who uses the
dual-action rods to use some silicone caulk - because it is an excellent
precautionary measure.

It seems from my research that the compression rod has to be adjusted
thru the headstock - bummer. I am switching to it nonetheless, because I
feel that it is much more reliable long-term solution than the dual-action
rods - even though they might not be quite as effective or offer as much
control.

Actualy Simon, they do offer control both ways but you must build that in your neck. You can introduce relief when you attach the fingerboard with the truss rod lose, so the when you tighten it it goes flat and loosen it the relief comes back. It just requires a little planning and carefull execution.

_________________
Tickle your guitar daily, and it'll tickle you back.

I ran into the rattling problem on an electric bass, because the trussrod had no tension. Just a bit of a turn to pull everything tight took care of the problem.

Al

Yes I run a 1/16" bead of silicone caulk in the channel from just short of one end of the rod to the other end of the rod, before installing the rod.

I have been using the TRSD rod for a while now. I like them. There is nothing wrong with the rods design or fabrication. 90% of all the issues that have popped up with this rod have been due to the channel not being caulked as recommended by LMI or owner that over crank the rod. If a few have had threads strip, well threads are going to strip some times no mater who makes the rod or what design the rod is. I have had Martin style channel rods fail. I have seen and repaired sheared and striped compression rods. When building with any rod. inspect it prior to installation, and pray you don't sell it to someone that likes to crank on bolts for kicks. My educated guess is that 80-90% of all rod failures come from over tightening and the rest is MR Murphy's falt.MichaelP38987.4012615741

[QUOTE=A Peebels] Fender uses this method on most of their electric guitar necks. Al[/QUOTE]

Right, I think I heard about those...

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Rian Gitar og Mandolin

As Michael said, CHECK 'em before the installation!

I built a neck-thru electric bass a few years back, using S-M's dual truss rod. I strung it up only to find that the truss rod wheel wouldn't turn (I'd wiped a very little bit of vaseline over the threads prior to gluing, to keep glue & caulk from sticking, so I'm guessing the threads were gauled). I figured I could force it & ended up shearing the truss rod - from much less pressure than it should've taken.

After I'd had a good cry, I steamed the fingerboard off, replaced the truss rod with a new one, and reglued the fingerboard. It was a lot of avoidable work, but I seem to learn best this way...