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So what do you do when you need less relief but the truss rod nut won't budge any further. I'm working on a 70's ibanez musician neck-thru 4string bass, relief is about .030"(measured at 8th fret, fretted at first fret and where neck meets body). i tried backing the nut off completely and clamping the neck to a very straight piece of steel leaving it overnight, unclamped it next morning, bounced right back to where it was, even with TR nut tight as possible, relief is still way too much, i repeated this clamping process two more nights, these times clamping until there was back bow in the neck and still the next day i would string it up and it would go right back to .030". any suggestions on straightening this banana out? should i try clamping with more pressure or for longer? apply heat?

^^^^ This ^^^^

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"Act your age, not your shoe size" - Prince

Sometimes things simply just don't work right, so there can be reasons to consider more drastic measures, but before declaring the truss rod at its limit, I' consider taking the nut off completely, lubricating the threads and replacing it before tightening it up again. That way, at least you're not fighting the friction of corrosion as you determine how tight it's getting.

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Frank Ford

FRETS.COM
HomeShopTech
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Heat is probably the correct way to go, but I would consider FF's suggestion and add that maybe a small washer might get you enough travel to pull it straighter. It's from the '70s, so it's probably not going to settle any more and once you get it where you want it, it will stay there (apart from the normal seasonal stuff).

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"Real guitars are for old people, Mr. Marsh."

Eric Cartman

When I run out of truss rod threads, I use a Team Associated bronze bushing as a spacer under the TR nut. Each one is 1/8" thick, so with two you can add up to 1/4" of threads, which should allow you to adjust the excess forward bow out of the neck.

See: Associated Bushings 3/16x5/16" (2)

Here's what it looks like in place.

I have found heat at best a short term fix.
When you look at how the truss rod works there are a few designs.
A the compression rod.
This is often used by Gibson, you tighten on the nut this force is applied to the neck as a compressing force that springs the neck.
as time goes but the wood at the working area becomes compressed. You can add a washer to help .
B Springing or flexing rods
Martin uses these and as you work the rod it presses and flexes a carried that will work the neck. These are both 1 or 2 way rods.

As I stated before heat may work but it won't be permanent. If you have a compressing rod Like Frank Ford just stated above Pull the nut clean the threads add a little lube and place a washer or 2 on it. This may be the easiest fix.

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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

And it wouldn't hurt to tighten the nut with the neck clamped into a little backbow.

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A man hears what he wants to hear, and disreguards the rest. Paul Simon