Truss rod adjustment... trial and error, or scientific methodology?

[Spidey2112]

I wanted to put some fresh strings (GHS Pressurewounds, med/light) on my USA Geddy Lee Jazz... disclaimer: truss rod adjustment at heel.

I had medium gauge Pressurewounds on prior, and the relief wasn't exactly to my liking... with a capo on the first fret, and a string depressed at the last fret, I like seeing just a bit of daylight (see scientific methodology ), and of course, I wasn't with the mediums.

Even knowing I would be installing med/light gauge strings, I gave the truss rod about an 1/8th of a turn (clockwise), put on the strings, thinking that should put me about where I want. Nope.

Still seemed to be a bit high, for me. Using a Baroque gage, I'd estimate relief at about .020" at the 8th fret, 4th string.

My question is... between string changes, what factors in your decision to either leave the truss rod where it is, or adjust based on a change in string gauge/tension?

I hope this makes sense... so frustrating, especially with the adjustment at the heel.

TIA, for input and suggestions... and humor, or course.

 

[sissy kathy]

I don't attempt to adjust the rod until after the new strings are installed. I can't remember the last time I installed any; well I put some on after my last build was completed about 8 years ago. I put the minimum relief necessary so there is no buzzing when I play; I've a light touch and am willing to let the amp do the heavy lifting. Pretty simple really. YMMV

 

[-Stingray]

I use feeler gauges. I know exactly where I want my neck relief set (.010" which is roughly .25mm).

Edit: If I get buzzing at that setting (with my string height set correctly at the last fret) then I start looking at other things, like whether the frets are level, and whether the nut is cut correctly, etc.

 

[Spidey2112]

I don't attempt to adjust the rod until after the new strings are installed.

That'd be nice, wouldn't it?

Stock USA Geddy... adjustment at the heel, with the body bisecting the truss rod adjustment... in my case, neck has to be off, to adjust.

 

[Zooberwerx]

That'd be nice, wouldn't it?

Stock USA Geddy... adjustment at the heel, with the body bisecting the truss rod adjustment... in my case, neck has to be off, to adjust.

Do the mod so you can adjust that rat-bast*** at full string tension.

Riis

 

[Lobster11]

That'd be nice, wouldn't it?

Stock USA Geddy... adjustment at the heel, with the body bisecting the truss rod adjustment... in my case, neck has to be off, to adjust.

I still think it's a good idea to install the strings before adjusting the rod. In fact, it's probably ideal to leave the new strings on for 24 hours or so before making any adjustments, to give the neck time to settle into whatever new position it wants to be in with the new strings.

 

[ThomasTronics]

No science here.
Just adjust the neck till you get the right amount of rasp (or not) between frets 1- 7.
I was able to a thin Phillips that i can squeeze into the small heel opening.
Obviously there's guides and you should work of that but i find every neck and relief is different. Some basses like relief and some can go very flat.
I personally like factory relief, not flat but not too much. But i stopped measuring my relief with feeler gauges and started using my ears and fingers. Was a huge improvement than worrying about 0.008" feeler gauges

 

[JRA]

...what factors in your decision to either leave the truss rod where it is, or adjust based on a change in string gauge/tension?

in a word: "feel."

given that every neck is different (the feel, the response to adjustments, other) and that every string set can be different (when trying out different gauges, tensions, 'formulations', whatever) = it's about feel for me. each neck and string set coupling will have its own version of compromises and optimizations, back and forth, until i get settings that feel correct for that ax with those strings.

FWIW: i measure nothing except the way things feel to me. numbers might be good for establishing the 'universe' in which adjustments are made, but the feel of the thing trumps any/all of the numbers. i'm picky about feel, so it might take a few trials/days of futzing to arrive at 'best' for a particular combination of ax + strings.

adjustments at the heel? without the benefit of the little wheel thingy?

 

[byacey]

Adjust by feel offers no repeatability or any indication of the state of the neck and fret level. If you go by the numbers, it'll reveal a lot about how well set up the instrument is.

 

[Turnaround]

There's little point in setting up the bass to a set of numbers that are perfect for someone on a particular bass, but may not be optimum for you on your bass. But once you find the best setting for a particular instrument it's worth measuring it so you can put it back to that spec every time without trial and error. The added advantage is that if it doesn't seem right when putting it back to the numbers you recorded, it's an indication that something has changed - like fret wear, neck twist, etc.