Do I really want my neck straight?

Quexoz

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Now let's add .010" of relief. The action at the 12th fret comes up to just a hair over 5/46". So we lower it back to 4/64". Guess what the action at the 19th fret is: 4/64" (I measured this too).

Seems good, right? But... Where is the widest part of the arc of the string's vibration? It's halfway between the fretted note and the saddle, or at the octave. And that's where we need the greatest distance between the string and the fret. Adding relief actually made that distance smaller, though.
Bingo! On my Tele, I found ~.008 of relief caused a slightly greater amount of fret buzz when fretting around 2-5. Straightening to maybe ~.002 relief reduced the buzz. I find 25.5 scale to be much harder if not impossible to completely eliminate buzz, 24.75 is easier, less buzz-prone. I think of it like the portion of an 18 wheeler trailer that sticks out past the rear axles (the frets beyond 12-14) that acts like swinging a very large baseball bat at nearby cars when you turn.

I assume what was happening is fretting at 2-5 puts the halfway point right around frets 14-20 where the relief has least effect. Which brings us to fret leveling with "fall-away", but that is another can-o-worms.
 
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ghostchord

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Two things here:

1. Players can indeed feel very small differences in things like neck relief. Our fingers are much more sensitive than people realize. Think of this: The biggest frets available are .058" tall. Typical frets labeled "medium jumbo" are around .047" tall. Just that .011" difference makes those big frets feel like railroad ties to some people.

2. Let's say you like your action at the factory standard 4/64" at the 12th fret and the neck is flat. The action at the 19th fret is about 5/64". (I just measured a Strat I had handy.)

Now let's add .010" of relief. The action at the 12th fret comes up to just a hair over 5/46". So we lower it back to 4/64". Guess what the action at the 19th fret is: 4/64" (I measured this too).

Seems good, right? But... Where is the widest part of the arc of the string's vibration? It's halfway between the fretted note and the saddle, or at the octave. And that's where we need the greatest distance between the string and the fret. Adding relief actually made that distance smaller, though.

People think that you need to add relief so the curve of the neck matches the arc of the vibrating string, but it doesn't work that way. The two curves are not parallel. Adding relief actually has the opposite of the intended affect, and increases buzzing in the upper registers.

In my opinion feeling the size of a fret as you run your finger over it is very different than feeling a gradual change like a relief. But do a double-blind test to really answer that. If it was so easy to tell then you wouldn't need the straightedge ;) you'd just be able to tell...

It's not clear to me that the limiting factor is the halfway point since the clearance is going to increase as you go down the neck. So presumably at least some of the time the limiting factor are the frets closer to the fretting point where the clearance is much smaller?

Sounds like we agree though that you can get more buzzing on the higher frets. Presumably that's why putting a slope on those higher frets when levelling is common to counter that?

It's certainly possible that the standard of putting a relief in is counter-productive. My guess is that it's more of a tradeoff. You also gotta wonder what's the impact on intonation. This could all be tested if we cared enough ;) It's also possible this practice allows for more manufacturing tolerances or something along those lines...
 

Boreas

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I like a touch of relief because I am lazy. If I dial in a neck until it is flat under string tension, there is a good chance that with a minor humidity change, I'll have to adjust it again tomorrow because of string buzz. So I straighten it tomorrow, then I have relief the next day. So, I just make the neck straight, then add string tension, then go with the amount of relief created. It is typically enough that it is rare the strings will start buzzing on me.
 

ghostchord

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This is pretty interesting, but a bit of a long read.


Interesting. I didn't really try to grok all the data but I think the experimentation did not include nut adjustments. The other question is if a flat neck is better, maybe an inversely bowed neck is even better! All these numbers can be determined without measuring on a guitar, it's just geometry. If we want something super conclusive we have to vary the height at the nut, the height at the saddle, the relief and then fret *all* positions and compare. I'd try to set the action to the lowest possible with different parameters and then see where we are.
 

Wallaby

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I took the point that increasing relief can reduce the next fret clearance at higher areas of the neck below the minimum required for clear sounding. As long as next-fret-clearance at every fret exceeds the lowest height needed at the first fret ( where it would be the least ) less relief allows lower action for a greater area of the neck than more relief, and provides the benefit of a more compliant feel.
 
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Freeman Keller

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This is pretty interesting, but a bit of a long read.



Wallaby, I was going to link that Bryan Kimsey analysis. Bryan had a great influence on how I approach setups, he is mostly an acoustic guy but much of what he does works on electrics too. In that link he uses an electric because its easy to change goth relief and action.

Bryan's setup specs have become my starting point, like him I will modify them for individual players. However the principles are the same - a little bit of relief is desirable, less is better. If I'm going for fairly low action I'll shot for 5 thousands or so assuming the frets are perfect.
 

KokoTele

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In my opinion feeling the size of a fret as you run your finger over it is very different than feeling a gradual change like a relief. But do a double-blind test to really answer that. If it was so easy to tell then you wouldn't need the straightedge ;) you'd just be able to tell...

I can tell. Through experience, I've been able to learn the difference between too much relief and when the action is simply too high. I use a straight edge to measure and dial it in accurately and quickly. (I just use the strings. They're more accurate and convenient than any straight edge you could buy or make.)

Most players can tell the difference, they just don't have the experience to tell what it is that's making it feel "not right."
 

Ronkirn

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the setup, which includes the degree of relief, is a personal aspect of the guitar.. what works for Jeff Beck, probably wouldn't work for you.. that doesn't mean Jeff doesn't know what he's doing, nor does it mean the same for you...

You adjust the guitar to how YOU like it,, and fuggidaboudit..
 

telemnemonics

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Relief at 1/32"- 1/16" indicates heat in winter with no humidifier caused necks to dry out and bow more.
I like close to straight, any relief is more to make sure I don't end up with back bow if the humidity changes.
 

Paul G.

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How do you play? What gauge strings do you use? How low do you like your action? In general you want some relief to allow the string room to vibrate

In general, a "normal" touch, using "average" string gauge (.009-.042, .009-46, .010-.046, .011-.049) -- I start with .008"-.010" relief (measured with a feeler gauge). A business card is usually .008" or .010", so that can substitute for a gauge. Make sure you measure with your guitar tuned up. Capo on first fret, depress fret where it meets the body. Slip your gauge (or business card) carefully under the 8th or 9th fret. It should slip through without moving the string. Move the truss rod in small increments (1/8 turn at a time) until you're there.

Adjust your action to 1/16" at the 12th fret.

Now, play the guitar -- look for buzzing and fretting out on bends. A small amount of rattle is acceptable on an electric, but not on an acoustic.

Now play the guitar, and decide if it's OK. For most players, this should work. If you want a straighter neck, you can try to tighten the rod slightly and check for buzzing and choking from the first through 8th fret. Continue until you're happy.

If you want lower action go ahead and lower it slightly. Play each string from the 12th fret to the last and make sure it frets cleanly and doesn't choke.

That's the long answer. Short answer is for most people, using average string guages, yes, you need some relief.
 

Freeman Keller

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Relief is not just the curvature of the neck and fretboard under string tension, but it is where that occurs with respect to other things going on with the neck. With most guitars that have a well defined neck heel (acoustics, many set neck guitars) relief more or less ends at the neck to body joint. At that one of several things might happen, the fretboard might continue in the same plane, it might drop off, it might curve up. There might be a definite hump at the body joint. All of these come in to consideration as you level frets and adjust the relief. It is not at all uncommon to have buzzes in that area.

This is a very simple drawing but it gives some idea of what might happen at the joint

Neckprofile.JPG


Wallaby mentions "next fret clearance" that is a very important concept in setting relief. If you can fret a string at the first fret and play a clean note without buzzing they you must have enough clearance (duh). It might be too much but it definitely is enough. While fretting it at the first fret measure the clearance at the second. Now fret the second fret and measure the clearance at the third. If it is equal to (or greater than) the last measurement it won't buzz. Now do three and four, same thing. As you move up the neck as long as you have that same clearance it won't buzz.

It will buzz if you have a high fret - that has nothing to do with relief, fix it. It might buzz as you approach the neck to body joint, the little test will tell you what is happening and how to deal with it.

I frequently do the test without actually measuring the gap - I fret the first fret and tap the string over the second, if I hear a little "ping" I know I have some clearance and it must be enough to not buzz. Fret and tap the next fret, same thing I want to hear the little ping. Its a remarkably simple little test but it tells a lot about the condition of the neck and frets.

There is also a little back fret clearance test that I use to check nut slots - if you fret at the third fret you are also holding the string on the second, measure the gap at one. You should have a tiny gap, if you don't your nut slot is probably too low.
 

adjason

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seems like at least originally I make the neck flat then the string tension puts just a hair of relief in it- this usually works for me. some guitars seems to want a bit more relief and some a bit less. If they play well I would not worry about it-but yeah your measurements seems really high
 

Chicago Matt

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I usually just eyeball it down the fretboard from the headstock and leave just the slightest bit of relief. Pretty close to flat, but just that tiny bit.
I do the same, but the only correct answer is Ron Kirn's:

"the setup, which includes the degree of relief, is a personal aspect of the guitar.. what works for Jeff Beck, probably wouldn't work for you.. that doesn't mean Jeff doesn't know what he's doing, nor does it mean the same for you..."
You adjust the guitar to how YOU like it,, and fuggidaboudit..

It seems I end up with just the width of a piece of paper. It's certainly less than .008, maybe .004? I like the action pretty much the same from high E to low E, somewhere between 4/64" and 4.5/64".
 

Freeman Keller

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It seems I end up with just the width of a piece of paper. It's certainly less that .008, maybe .004? I like the action pretty much the same from high E to low E, somewhere between 4/64" and 4.5/64".
A typical business card is about 10 thousands. That is the very upper limit of what I want for relief - I might set a bluegrass dreadnaught to around 0.010 but wouldn't go much above that. For a finger style guitar or a low action shredder I want less. But it does give a quick check when you don't have feeler gauges.
 

jwp333

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I agree with Ron Kirn too. But just realize that with a perfectly flat neck, you are probably going to need to raise the string height a little. You may get string rattle and dead spots with a perfectly straight neck and the "normal" 2/32 string height at the 12th fret. It's all a compromise.
 

Si G X

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Mine are almost dead straight, if I capo at the first and push down on the last, the middle is just barely off the fret.. it's such a tiny amount I don't even try to measure it but I can just feel it if I tap the string.

I just find that's the safest way to do it when you don't have a notched straight edge or perfectly new dressed frets.
 

Boreas

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Mine are almost dead straight, if I capo at the first and push down on the last, the middle is just barely off the fret.. it's such a tiny amount I don't even try to measure it but I can just feel it if I tap the string.

I just find that's the safest way to do it when you don't have a notched straight edge or perfectly new dressed frets.
Unless I suspect a twist, this is also how I check it. I can do it in a couple seconds from my recliner. I check each guitar every so often, but if it gets to be too upbowed and hindering playing/comfort I will crank it back. Oddly, I find my Fender necks oscillate the most - perhaps because they are played the most and usually out of their case.

Much has to do with string gauge, attack, and WHERE you pick. I find lighter gauge strings are just buzzier - I assume because of more string travel due to inadvertently over-attacking the wimpy strings. I just live with it with certain electrics, but abhor it in an acoustic.
 
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telemnemonics

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I usually just eyeball it down the fretboard from the headstock and leave just the slightest bit of relief. Pretty close to flat, but just that tiny bit.
I worked on my own guitars and as a guitar tech without ever using any measuring devices until I was well into my 50s.
Then one day as I squinted down the neck to set relief I concluded that my eyes had stopped working as feeler gauges, so I moved to straight edge and either feeler gauge or whatever was near the top of the tools pile on the bench.
I don't need to know the number of thousandths my relief is set to, but if chasing an odd neck problem or removing and storing a neck to do other work on it or the guitar, I might want the number for reference.
Same with a neck I'm going to do a heat reset to, I want to know how bad it was and confirm I heated and over bent it enough, since that's kind of instinct and doesn't always come out as expected.

I have to admit all the tech chat here also played into my bringing feeler gauges in from my garage mechanics tools to use on guitars.
I set up tons of guitars for other players based on watching them play and setting relief and action to match their technique, but only in the last 5-7 years learned the numbers associated with my relief settings.
 




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