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LMI double action rod- maximum safe adjustment?

Posted: Sun Mar 03, 2013 10:28 pm
by Rodger Bryan
My first fretted build, a six-string bass, has gone through 2 1/2 years of seasonal changes and the truss rod adjustments I make (in December and July) are very predictable and it plays like a dream. However, I'm a little concerned that I'm turning the LMI rod a little beyond it's intended range and I am seeking the collective advice from the more experienced bunch here.

The neck: QS maple- .840"-.910" thick, two YUGE (.25"x.375") CF bars, the LMI double action rod, pau ferro fingerboard, snug-fit frets.
It's seems very strong. I'm using medium-light gauge strings. The adjustment range: Winter, at the maximum the rod is tensioned roughly 200-210º from neutral position, and about 150º when summer. The difference of <1/4 turn doesn't seem like much, but I am unsure about the limits of the LMI rod. The threads were given a little lube before installation and it still turns very easily in this range- I also give the rod a little help when tightening. Many thanks in advance for your advice!

Re: LMI double action rod- maximum safe adjustment?

Posted: Mon Mar 04, 2013 7:02 am
by Greg Robinson
Rodger,
Nothing to worry about, so long as you're "helping" the truss rod when you adjust it (bending the neck to the desired relief before adjusting the rod).
I wouldn't be worried about the LMII rod unless you had a neck that was undergoing severe plastic deformation and you had to put around 3 full turns on it from static.

Re: LMI double action rod- maximum safe adjustment?

Posted: Mon Mar 04, 2013 7:20 pm
by Rodger Bryan
Thanks, Greg! For my future builds, this will be good to know. If I do another 6-string, I may consider further counteracting the effect of the tension with compression fretting or maybe compensating when I do the initial leveling. peace, R