Neck Relief

[darylcrisp]

i like my fretboards as flat as possible with the least amount of relief dialed in. i do the same with my guitars(fingerstyle player).

when i get a new(whether brand new or used) guitar or mandolin, i first check nut slot depth and cut-i will adjust as needed to make sure a smooth path is present and the correct height is obtained, next i remove all relief until the neck is as flat as possible-i have noticed exactly what sunburst mentioned regarding mandolins having a touch of a dip or bow along the fretboard. the 3 best mandolins i've had that came with dead flat fretboards when adjusted are: Collings MT, Northfield F5S, Pava. I made a special ruler to check fretboard flatness for mandolins, without the frets being touched.

once i remove the relief, i adjust action at the bridge(i like it low there also, so any uneven fret work will appear quickly), i keep it as low as possible. i fret right at the fretwire so i'm not pushing to the fretboard, and i don't have a hard driving right hand. i can get away with very low, easy to fret actions. exact same setup goes with my guitars.

d

[sunburst]

I made a special ruler to check fretboard flatness for mandolins, without the frets being touched.

In an ideal world, that would be worthwhile information, but in "the real world" it is the tops of the frets that matter, not necessarily the fingerboard surface. A perfect neck would have a dead straight fingerboard and frets of even and height, exactly the same height. Then, the correct, slight amount of relief could be dialed in with the neck under string tension. If the neck has moved (warped, twisted, or otherwise, even nearly microscopically), if the neck stiffness varies at all, in short, if anything is less than perfect (hint, it's always less than perfect) the fingerboard may show slight unevenness. That's OK, as long as the tops of the frets are milled correctly. Checking the tops of the frets with a straight edge (or a string, as I outlined above) gives us more useable information than checking the surface of the fingerboard beneath/between the frets.

[Mike Barber]

Definitely #1. I have an Eastman 315 that I really like and to my beginner ear, it sounds good. I played a more expensive Weber and it wasn't the sound that grabbed me (though it was good). It was that it was noticeably easier to play. A bit later I figured out that it was the relief. That one was clearly flat. When I finally did adjust my truss rod to be nearly flat it was clearly easier to play. I had just been trying to lower my action at the 12 fret to get the playability. But it was removing most of the relief that made the big difference.

[stevedenver]

flat................but....
I checked all 4 of mine 3Fs and one A
they each 'sight' dead straight

but upon doing the first fret and the 20th fret check as mentioned , each has a hair-like the width of a piece of paper- of relief-didn't get the gappers and actually measure each for you, but truly all are very close but not dead flat as I would have otherwise sworn

I like the same on my guitars, both electric and acoustic, but, I also tend to like my action a touch high at the twelfth fret on all but my archtop guitars.

[DataNick]

+1 to #1: fretboards as flat as possible with the least amount of relief dialed in.

[John Adrihan]

I checked both my instruments and they are both the same, just a little bit of relief between the 4th and 9th frets. SO, How do I take that out? meaning which way do you turn the truss rod? and what does it do. I have been playing for a few years now and I guess it is time I learn. So again which way to turn it, what does it do and how much typically? Thanks

[Tom Haywood]

As flat as possible for me. Dead flat is rarely possible due to vagaries in the frets or neck, or more often due to the manner of playing. Someone who plays hard needs more relief to prevent buzzing. David, you play with a light touch so can play a very flat board. A board that has a twist or hump or uneven frets may require more neck relief as an alternative to fret work or planing. As mentioned above, the closer to dead flat the more regular maintenance is needed. Don't know why, but many mandolins move into greater relief over time as the weather changes. I think most folks don't get their mandolin set up checked twice a year, so you tend to see too much relief in many of them. Cheaper instruments tend to have lesser quality woods in the necks, so the truss rod has a hard time keeping it straight. More relief usually makes it harder to play. That's usually the thing that gets people in to have it looked at. Finally, I see a few where the owners adjusted the truss rod without knowing how it all works, got things out of balance, and didn't take it in for a check up because, well, they wanted to do it themselves. Been there myself. The nut is not really part of the equation here. The slot depths are set in relation to the first fret, then the relief is set, then the action is set. That's how I was taught.

[fscotte]

I can make the fretboard dead flat but I choose to build a very slight relief in them. Basically because you may run into that awful thing called humidity.

[sunburst]

The few people that have checked their necks and reported (thanks!) have confirmed what I suspected. What many are calling flat is what I call slight relief. A paper thickness is enough relief for me to consider it slight relief, and that's all I'm talking about; just enough to keep buzzing at bay.
Those of you who can play a dead flat neck and low action with no buzzing, that's great, but not many can. The lower the action, the more important slight fingerboard relief becomes.

(BTW, sighting the neck is notoriously inaccurate. A neck can look straight or it can look curved, but checking the tops of the frets with a string or straight edge will reveal the true condition of the frets. Sometimes the eye is fooled by bindings, by uneven fingerboard thickness, by uneven fret height, by any number of things, so sighting the neck is not a reliable method of determining straightness.)

[Bertram Henze]

I guess #2 comes into its own with longer scales. I have had both versions on my OM and I have much less string buzz with #2 - I'll stick with that.

[MysTiK PiKn]

Your diagram shows excess curvature immediately in front of the nut. Hence, the diagram causes confusion.
GOOD TOPIC THO !!

The nut will vary slightly because God did not make it - and even then it might vary slightly - but very slightly. So nut slots height, is pretty much written in stone. ( see www.luthiery.net) Paul Hostetter's site, for diagrams of nut slots heights.)
(see Frank Ford's site www.frets.com for detailed info on "relief".

As stated, the straight neck is an illusion, it usually has a trace of relief - and this can often be set that way w truss rod. Frets must be level. Higher action is MAYBE needed by heavy handed insane bluegrass pickers - the one's we love, yeh.

With the nut and the slight relief, you are where you wanna be. But...
You now get to set your action, by adjusting bridge height, and perhaps a slight bridge angle, slightly higher on bass side (maybe).

I had to do a lot of all of the above on my mando. Including fret levelling. I have good setup and action now; but I am still tweaking bridge and truss rod in various combinations - very slight adjustments. I am basically playing with the "point of buzz", and trying to minimize buzz, and maximize low action. (I am talking really picky stuff here. I have one fret that wants to buzz).


= = THANKS to John Hamlett for yet another highly accurate detailed description. = =
If you missed it, read it again slowly. It's all there.

And, mandos setup high relief, high action might come that way from manufacture, OR are deliberately set high to hide neck problems, loose frets, reverse bow, neck hump, twisted neck, roller coaster neck, etc. Mine had most of those problems - the bridge was sky high to hide the truth - and in my case, I KNOW THE SELLER DID THAT deliberately. What I know about this stuff, I learned while fixing my mando, and also from hanging out in the Builders/Repairs forum. Now I can tweak my neck any way I want. But mine now has a hidden problem - the real fix is to plane the fingerboard to delete irregularities - on the agenda, later. I'm ok for now. That job is aka "refretting", since it is an opportunity to do that at the same time. That would yield a perfect neck.

Finally = None of this is about what brand of mando you have.

[OldSausage]

John is absolutely right (well of course he is), even my 'flattest' boards have some paper-thin relief, and I've no doubt that is also the case for all the people who said they like their boards dead flat.

My interest was sparked by the fact that nearly every time when I take someone else's mandolin for a test drive, a friend asks me to adjust theirs, or I buy one second-hand, or even when I try one in a shop, it appears to have rather more relief in the neck than what John is describing as being correct. So until I got his feedback and that from others, I was starting to wonder if it was just me.

So now I'm wondering who really is doing all this bad stuff to mandolins, and if they can be stopped

[pops1]

My E,A,&D are flat, the G has slight relief. Very low action, with arthritis in my wrists this is what gives me the lowest action with good sound and very easy fretting. E is just on top of the 1/32" line and G is 1.5/32.

[sunburst]

...So now I'm wondering who really is doing all this bad stuff to mandolins, and if they can be stopped

I suppose it is "us".
We are the ones who tighten the strings until they are in tune, and it is often the strings that gradually pull too much relief into the neck. Can we be stopped? Hmmmm...

[Buck]

Great topic and information. This is all applicable to guitars as well, but seems to generate much more controversy there. I could (or thought I could) do a pretty good setup. I could at least make many factory instruments better than when they started. Then a little over 10 years ago I got to play my first guitar setup by Bryan Kimsey. I wanted all my instruments to play that easy, so I started researching. Folks like Bryan, John Arnold, Frank Ford and others were very gracious to share their experience publicly, as well as taking time to answer specific questions.

Once I had grasped the concepts of nut slots = fret height and minimal relief, life made much more sense. IME people are generally resistant to these two concepts, which I find odd. I can't explain the issue with nut slots, but I think people resist the idea of minimal relief because they like to adjust the truss rod. It's a little different with adjustable bridge mandolins, but on guitar, you have to accept that raising the action at the saddle takes a little work. Raising the action by adding relief is easy, so people take that route. We know that the truss rod is not there for that purpose, but higher action is a side effect of increased relief. That will stop some buzzes, but at the expense of playability. The real answer of course is to raise the saddle.

I'm not sure if it's still on his website, but Bryan did some experimenting and found that increased relief alone does almost nothing to increase the "next fret" clearance, which is where most buzzing happens. It is the side effect (higher action) that stops the buzzing, but everyone assumes the truss rod is the correct fix. Sometimes easy is attractive.

[sunburst]

... just a little bit of relief between the 4th and 9th frets. SO, How do I take that out? meaning which way do you turn the truss rod? and what does it do.

Unfortunately, the rod will probably not help you. An adjustable rod will adjust the bow for the whole length of the neck and we can't selectively straighten parts of the neck using the truss rod. The quick fix for slight humps and dips is milling and re-crowning the frets. That is perfectly OK, and it will make things ideally playable until such time as a full re-fret is needed. At that time, the fingerboard can be milled straight, and new frets installed. It not advisable to remove perfectly good frets (risking damage) to plane the fingerboard, so simply milling the frets is the best remedy for a slight dip or hump when the frets are in good condition.
Now, remember the straight edge that checks the fingerboard condition between the frets? For the entire time between doing the mill and re-crown up until the frets are worn out and the fingerboard is planed during the process of a full re-fret, that straight edge will still show the dip or hump, but since we've leveled the frets, the dip or hump is no longer a problem. If the frets are stainless steel, that condition could be present for many years.

An adjustable truss rod, when working correctly, will adjust the neck from a bowed condition, to straight, to back-bowed and anything in between. It moves the whole neck from nut to heel but does nothing for the frets beyond the heel (from neck to extender). It also does nothing to correct local variations in fingerboard relief or straightness. That is all up to the luthier; the builder and/or the repair person. As I said before, wood moves, and sometimes it moves unpredictably, so unevenness in the frets anywhere may be something that happened after the builder was done with the instrument. Also, as I said, it is ultimately the tops of the frets that really matter. Leveling the frets is how we correct those minor inconsistencies (major inconsistencies require more work), and that is one of the reasons sighting the neck or checking for straightness any way other than straight-edging the tops of the frets can be misleading.

So, the luthier must establish correct geometry as nearly as wood will allow, and the luthier must re-establish that geometry if the wood moves. The set up person can then adjust string height at the nut, string height at the bridge, and neck relief. If anything in the geometry of the thing is off, that can't be corrected through set up, and a repair is needed. Even if it is a repair as simple as a slight mill and re-crown, that is a repair. This is why many people who can do basic set up work still can't get playability up to the highest of standards; the thing needs to be repaired. A set up is only good when the geometry is correct.

A little relief from the nut to the 4th fret would be much better than relief from the 4th to the 9th fret. If your frets are in good condition, a mill and re-crown will probably fix things, but as I said, the rod probably will not.

[acousticphd]

I'm a fairly obsessive seeker of condition #1 (Virtually flat/no relief), but after a number of years my experience is that it can be difficult to achieve, especially with older instruments. I have one or two newer mandos and guitars each that can be adjusted close to this "ideal". I don't think it is so much that people choose setup #2, but that time, string tension, and infrequent maintenance is moving nearly all instruments towards setup #2.

I think though that there is a 3rd geometry that is actually more typical, at least with my instruments and many others I have seen. High/uneven action on older instruments is not necessarily too much FB relief( ie, curvature), but rather a neck angle that creates one FB plane ramping slightly down to the neck joint, and a second plane established above the joint. Thus the shape is more like a shallow "V", but in either case the action is high and playability poor in the middle of the FB.

I have had the FBs of ~5 vintage mandolins planed/refretted to try to solve and correct this, but it has proved to be difficult because they readjust to the old geometry over time. Even if the FB shows little or no relief, after some time (a few months, or a few yrs), the problem starts to reappear. Of course these are old Gibsons without truss rods, but an adjustable truss rod would not solve the problem either. As John says, fret milling is one compromise to create a more even plane, and I'm now having fretwork done on a couple fingerboards I've already had replaned in recent years.

What I've learned from this (I think) is that some of the truisms you often see, (including here), are not very helpful and not necessarily true, eg: "Mandolin necks are too short to need truss rods"; "This Gibson neck has been dead straight for 80 yrs, so it's never gonna move". I can tell you that my Gibson's neck is on the move, after >90 yrs. So when you pick it up, you shouldn't conclude I "chose" the setup it has, which is necessarily a series of compromises. I'm not sure there is a final solution, but as I plan to play it for years to come, hopefully I can find people to help keep it as healthy and stable as the wood allows.

[sunburst]

... one FB plane ramping slightly down to the neck joint, and a second plane established above the joint. Thus the shape is more like a shallow "V", but in either case the action is high and playability poor in the middle of the FB.

Yes, that does happen frequently. When we build mandolins, we try to compensate for that, and it usually works pretty well. We introduce a little drop-off of the fingerboard from a fret that corresponds to the start of the neck heel (usually #12)*, to the end of the fingerboard. String tension usually levels things out, but a little remaining drop-off can be a good thing because it counters the formation of the "V" over time. We mill one straight surface from nut to 12th (or whichever) fret and another straight surface from there to the end of the fingerboard, so we start out with an inverted V. (We do this for guitars and mandolins, any instrument that has a fingerboard extender over the body.) I haven't mentioned it here because it is not really part of the neck and it is beyond the realm of the truss rod's action or the relevance of fingerboard relief.

Old Gibson mandolins generally have very thick fingerboards, and as long as inlays and fret slot depth are maintained, we can usually plane the fingerboard into the inverted V geometry and solve the "V" problem long term. For instruments with thinner fingerboards, removing the 'board, planing the neck/extender surface and replacing the 'board can cure the problem. One thing's for sure, though- No amount of truss rod manipulation will help (if a truss rod is present) and many instruments have been damaged by those who think it will help.

*The bottom of the "V" is usually not at the neck joint but is at a place somewhat diagonally opposite the start of the neck heel. The neck shaft functions as a cantilevered beam, and the start of the beam is actually where the heel slims down to the neck shaft, not at the neck joint. That is where forward movement is concentrated because of something often known as a stress riser. A loose neck joint can also cause a "V", but that is a different situation from the typical, intact instrument. Also, in old instruments, there can be distortion of the body over time from the constant strain of string tension.

[Mike Floorstand]

The test of holding down the string at the first and 12th fret - i.e. using the string as a straight edge against which to check the curvature or relief of the neck - is standard practice with guitar setups, when I read David's original post I started to wonder whether mandolins were or should be different ...

My mando does have a tiny bit of relief - maybe not even enough to get a piece of paper between the string and 7th fret, but definitely not flat. Phew! (or: That's a relief!).

It is that little bit of relief that allows you to reduce the saddle height to get the lowest possible action without buzzing.

[MysTiK PiKn]

*The bottom of the "V" is usually not at the neck joint but is at a place somewhat diagonally opposite the start of the neck heel. The neck shaft functions as a cantilevered beam, and the start of the beam is actually where the heel slims down to the neck shaft, not at the neck joint. That is where forward movement is concentrated because of something often known as a stress riser. A loose neck joint can also cause a "V", but that is a different situation from the typical, intact instrument. Also, in old instruments, there can be distortion of the body over time from the constant strain of string tension.

Thanks for the ride, John. But I got lost in the last paragraph - I THINK BECAUSE, I failed to notice the "asterisk".
Having noticed it, I can read it again for the first time.

Great info. I was lacking this ditty about the upper regions when I milled frets. (oops). I ended up milling the entire length. I got lucky kinda; but a lot more filing happened. No matter - the real fix or "repair" will come with the FB sanding/planing. For now, I not only have low action; but also low frets, in places where the FB was high. Mine was a roller coaster - there was nothing to lose really - I knew I was headed for milling the FB anyway. Anyway, thanks for all this intense information - wow. That's years of experience talking; and a lot of patience.

Those interested will be well fed. Thanks.

[pops1]

Sometimes you can correct too much relief by refretting with a slightly larger fret tang instead of milling the FB. I have done this successfully several times, lately on an '28 Martin with bar frets, worked like a charm and now plays exceptionally well.

[sunburst]

It works much better with bar frets (though it can be hard to control). My experience with oversize tangs on T-frets is; compression fretting is a more or less temporary solution for forward bow.

[John Adrihan]

This has been really cool. Both my mandolins had a little bit of relief. I checked one and the truss rod was loose. I gave it a little tightening and took the relief down to almost nothing. no buzzing and it looks great. the other mandolin I gave a little turn also and reduced the relief to almost nothing as well, it too looks great. one guitar I have a Yamaha from the 60's is perfectly flat and plays great and a morgan Monroe 28 copy I have has quite a bit of relief. I left that alone. that one needs some fret work if memory serves. when I had someone adjust it before they put the relief in for the buzzing when played hard.

[Bill Baldridge]

This has been really cool. Both my mandolins had a little bit of relief. I checked one and the truss rod was loose. I gave it a little tightening and took the relief down to almost nothing. no buzzing and it looks great.

I bought a used Gibson fern that had a loose truss rod. After putting some tension on the rod I got a noticeable increase in volume. My theory was that with little tension on the rod, the neck was flexing too much during playing and thus absorbing a lot of the energy that would otherwise have gone to the top plate.

I wait to be corrected, and thank those who know what they are doing for educating me.

[John Ritchhart]

You guys just reminded me to lower my bridge for the summer. I had to raise it last winter due to the humidity drop. It buzzed on the 4th string around the tenth fret. I'm kind of interested that it can move that much but I have to adjust it every year. The house is humidified in the winter but apparently not enough and I spent this winter in the desert at about 28% humidity. I used the wet rag in a bag method for the case but it didn't help that much.