Adjusting a truss rod - question

[pete12string]

Looking from the headstock down to the bridge, which way do you turn a truss rod to add relief (forward bow) to a neck? The truss rod nut is located in the headstock. I always get confused on if clockwise adds or removes forward bowing (relief).

Is this correct?

• To correct a forward bow (remove relief), turn the truss rod nut clockwise.
• For a back bow (add relief), turn the truss rod nut counter clockwise.
• The truss rod should only be moved a 1/4 of turn at a time. Re-check, and re-adjust if necessary.

Thanks!
Pete

[charles Tauber]

You've made it more complicated than it needs to be.

Generally, a (single-acting) adjustable truss rod consists of one or more rods and a nut. As one tightens the nut, it increases the tension in the rod, straightening it or bending it backwards and taking the neck with it. Tightening the nut straightens the neck, removing relief.

Loosening the nut reduces tension in the rod, reducing the effect. The result is an increase in relief.

It's a standard threaded nut on a threaded rod. Nuts are tightened by turning clockwise, loosened by turning counter-clockwise. (Unless it is a left-hand thread, which we don't need to get into.)

If all else fails, the internet is down and your stranded on a desert island with just a guitar and an Allan key, try turning the nut one way a 1/2 turn and observe what happens.

[pete12string]

I should have mentioned that I am asking about a two-way adjustable truss rod. Does that make a difference?

[bnjp]

Righty-Tighty...Lefty Loosy. Loosening ADDS relief (forward bow). Tightening reduces relief. So if you are standing above the guitar looking down at the truss rod nut, tightening the nut is clockwise.

[Tone Gopher]

Standard thread for MOST but not all - exceptions do exist.

Use only 1/4 - 1/2 turn and see which way it goes. If it's really hard to turn and shows no effect, either try the other direction or take it to a guitar tech - if you mess up a frozen/jammed truss rod nut, it can be difficult ($$) to repair.

[pete12string]

Thanks everyone!

[ac]

If I'm not mistaken, a double action truss can be placed "upside-down" in some guitar necks. That would reverse the direction of bend for a clockwise turn. Is this correct?

[John Arnold]

If I'm not mistaken, a double action truss can be placed "upside-down" in some guitar necks. That would reverse the direction of bend for a clockwise turn. Is this correct?

Yes, but it is not likely to be done in the case of a soundhole adjustment location on a flat top guitar, because the soundboard would interfere with the adjusting nut.
With the 'conventional' placement, the adjustable rod is underneath the fixed one.

[ac]

I only mentioned this because I recall an article where a luthier mentioned something about this with a neck he was assembling. It had a headstock adjustment but was unconventional in that the truss rod was upside down to fit his particular design the best.

I haven't needed to adjust my dual action truss rod (headstock opening) but have wondered if the time came how I'd determine the direction. It's carbon fiber so generally it's necessary to put pressure on the neck in the desired direction and then turn the nut the proper direction or it will be very difficult to turn at all because of the extra stiffness compared to wood.

I'll probably just need to cross that bridge when I get to it using heavier strings, etc.