Installing a Martin style one way truss rod

[Kevin in California]

Okay here is my question. I have pictures of both rods laying on my neck blank. The long rod from LMI extends way out of the tenon with the other end positioned at about midway between the nut and first fret. The shorter rod from SM does not extend as far, and the other end is positioned right about at the first fret.
Where is the correct placement in the neck for these rods? I'm really wondering why one is 1 1/2" longer than the other. In my previous truss rod installs, using the LMI 2 ways, and even the SM Hot Rod (which failed on me), only the adjusting nut protruded from the tenon.
Thanks for your help on this. I wanted to try this style of rod and hope I like it. I guess I know what to do, but need affirmation.

Kevin

[ken cierp]

Hi Kevin,
I believe both those rods are made by Gotoh -- I have not use the LMII version but indeed have wondered way they call it a "two-way", I will contact Chris Herron today for an explaination. At one time we had a source for the longer version which was actually a little less expensive than the short one --- so that's what we supplied in our kits. For the past several years we have used the short one exclusively. They function exactly the same. The longer version requires a little more prep of the sound board to provide clearance and is a bit easier to access with a shorter adjusting wrench. But other than the wrench issue the short version works perfectly. These truss rods are robust and I have never heard of a failure --- though it has never happend to me, I understand you are not the first to have problems with the two-way failing, was it the weld? Here's the KMG installation guide.
http://www.kennethmichaelguitars.com/ne ... embly.html

[Kevin in California]

Yes, the barrel nut broke off right at the weld. I had installed the rod the same way I'd done all the other LMI 2way rods with just a dab of silicone under the rod in about 3 places. I won't be using that SM rod again.
Thanks for the guide.
I like the idea of this boxed rod and the stiffness I'm sure it adds to the neck.

Kevin

[ken cierp]

Chris Herrod just got back to me "two-way" -- and after looking close at the LMII pictrue of the Aluminum truss rod I can see that it is indeed has two way action. The barrel nut is welded to the inner threaded rod, so when rotated the capture nuts in the rod will cause the channel to bend in either direction -- pretty cool -- but welded barrel still is bothersome to me.

[Kevin in California]

Well that is good to know. I had noticed the weld, but didn't think about the action.
Thanks for checking.

Kevin