Questions about truss rods

[markdavid]

Hi all

Despite having played bass for a while now i would not really describe myself as technically savvy when it comes to setups, I can adjust intonation, action, the easy stuff basically , truss rod has always been a bit of a mystery to me. 

With that out of the way I have a couple questions, firstly what is the usual range of truss adjustment available, I have a Squier I have been using as my setup guinea pig and I get probably 95% of a complete turn of adjustment in total , I am using standard Allen key to adjust so possibly that may restrict access a little bit vs a specialist truss rod adjustment key

Secondly is there an easy way to measure relief, try as I might my eyes are not the best and I struggle a little to read thousandths of an inch 

Many thanks

 

[lownote]

Q1: Not sure how many turns you get at full range but you should aim to make adjustments of no more than 1/8-1/4 full turn of the Allen key at each tweak.  Let the bass adjust, measure relief and tweak again if needed. Don't forget to slacken the strings for the tweak and then retune before measuring the relief. 1b:  an Allen key is the correct truss rod adjuster TMK - that's  what bass makers issue with them.

Q2:  Thousandths of an inch don't come into it, that's far too precise. People have different ways.  Mine is to press down on the E string at the first fret and again at the last fret and then measure the clearance of the string from the 8th fret.  This should be around 0.3mm-ish measured with automotive feeler gauges, or simply a business card or plectrum. Place feeler/car/pick twixt string and fret (or fingerboard if fretless) and wiggle it.  If the relief is too slight your measurer will lift the string, if the relief is too much the measurer will flap about.  Just right is when the measurer slips smoothly and firmly between string and fret/fiingerboard.  Unless I have a friend to help I use a guitar capo to hold the string down at the 1st fret, my elbow to hold it down at the last fret and my fingers to do the measuring.

Edited February 19, 2020 by lownote12

[hooky_lowdown]

To view truss rod adjustment, hold the bass flat (horizontal) up to your head so you look from the bridge end down the strings, with headstock in the distance, then move the bass closer to one eye so that one eye views the neck from one side from heel to nut. You should then see if the neck is dead straight, though there should be a tiny amount of relief (very tiny amount of upward bow).

When you turn the truss rod the amount of bow should either go up or down depending on which direction you turn the truss rod.

If your strings are loose the neck should bow backwards, then the tension from the strings will bring the neck upwards once tuned.

[nilebodgers]

For a standard Fender-style bass: capo on 1st fret, hold string down at 17th fret and a 12thou / 0.3mm feeler gauge should just slip in at the 8th fret when the truss rod is adjusted correctly.

Some people prefer more or less relief than that, but it’s a good starting point.