Slight twist to neck

[wa3jpg]

Just curious, when does a "twist" in the neck become a real problem for a guitar (or mandolin, or...) I've looked down the neck of several instruments, sighting down the neck with the nut flat on the horizon, and I can see the saddle/bridge and note that the bass (or treble) side is a little higher. I have one guitar where my saddle height doesn't really go down on the treble end like it would on many guitars, I wanted a little extra height on that side (seemingly) due to a slight difference in the fretboard height at the nut.

Is playability the only criterion here (its fine! Sounds great!) If it's stable, I'm guessing its no big deal at all (how I want to think about it), but is there anything I ought to watch for indicative of greater problems down the line?

Thanks for any thoughts.

Clark

 

[Mingus]

I'm just wondering if you're confusing neck-twist with bridge/saddle height. It's not uncommon (in fact it's factory spec with most brands. . .and how I set up my instruments) to have the bass side higher than the treble side. If you sight down the neck the way you are right now, look at the frets. . .they should look more or less like railroad tracks. If, at first glance, they look like they start to be not-parallel or all messed up, then you have a twisted neck. (don't look too hard or too long. . .the optical illusion would kick in and even the straightest neck would look twisted!)

Another thing to look for is neck relief. Neck relief is checked by fretting the 1st and 14th frets (or using a capo on one or both) and checking the clearance around the 7th fret or so. Clearance should be close to identical on both the high and low E strings (by fretting the 1st and 14th frets, you're taking nut-slot height and saddle height out of the equation). If they're close, then you're ok. If they're WAY off, then you have a twisted neck. . .and trouble!

Hope that helps!
-James

 

[jp]

I've actually had this problem before on a neck-through-body electric. It seems to me that this problem is perhaps indicative of wood that was not dried or de-stressed properly, or a reaction to humidity variations. A competent luthier can fix this by a few methods, and they're rather involved and pricey.

I feel that the best method is careful sanding to get it to what it should be. This can involve removing the frets and sanding the fretboard to compensate, or completely removing the fretboard to sand the neck plane.

Heat bending is a common fix. The neck is heated up slowly and pressure applied under duration to twist the neck into the desired shape. The problem is that there is no long-term guarantee that it will stay this way. I had this done to my electric, and it eventually went back to its original twist.

I've also read that if the twist isn't too extreme a good luthier might be able compensate for the twist with a careful refret.

It wouldn't surprise me if there might be another solution involving the installation of a dual truss rod, which could possibly compensate side-to-side twist. I don't know too much about dual truss rods, though. If this is possible, the neck channel may need to be routed. This might be the easiest least expensive fix.

 

[Mingus]

It wouldn't surprise me if there might be another solution involving the installation of a dual truss rod, which could possibly compensate side-to-side twist. I don't know too much about dual truss rods, though. If this is possible, the neck channel may need to be routed. This might be the easiest least expensive fix.

A dual truss rod would CERTAINLY solve this problem, but unfortunately I think it would be the MOST expensive option. The original truss rod runs straight down the middle of the neck. If the neck is twisted, it's twisting right around the rod. In order for "dual truss rods" to be effective, they'd have to be centered as a pair. . .which means the original truss rod cavity would have to be filled and two new cavities would have to be made on either side of it.

The other reason why this would be the most costly option is because you would STILL need to remove the fingerboard to get at the truss rod. the slot isn't "drilled" from one end to the other (as it would appear). . .it's actually routed out. In a lot of cases, the rout is done from the fingerboard side. Some (like fender electrics) have that "skunk stripe" down the back of the neck where the rout took place.

I still think that wa3jpg probably doesn't have a twisted neck, though. Let us know what you find!

-James

 

[Mingus]

Just curious, when does a "twist" in the neck become a real problem for a guitar

Just realized that I never addressed the actual question!

When does it become a problem? If it's your guitar, it becomes a problem when you say it does! I've got an acoustic that's in DIRE need of a partial refret. The dents in the first few frets are so low that I can't have the neck razer flat like I like it. . .if I play too hard it gets real buzzy. Is it a problem? It would be if I needed to play harder on it. The fact is, though, that it's still quite comfortable to play (light fingerpicking) and the intonation is still quite good. I've got other instruments that I can play harder on when I need to.

Does it need to be fixed? You betcha. . . Is it a problem? Not until I decide it is! Bottom line is that if it's comfortable for you to play and the intonation is good, then it's probably not a problem.

-James

 

[wa3jpg]

Thanks for all the questions and info. I enjoy this guitar a whole lot (it is my "cheapest" guitar, but gets most play for the last few months, something about the punchy midrange just floats my boat!) I don't find the "problem" to be a big deal, so there is no rush or urgency, it is just my inner "luthier" that is very curious and interested. I enjoy learning about this stuff and I enjoy investigating how my guitar is put together, the stresses and how they interact, stuff like that. Then, there's making music!

I'll attach two photos I took. The first one shows a simple straightedge slid across the fretboard at the nut, under the strings, with the background of the top of the guitar. If you look at the straightedge and compare to the edge of the top, you can see the "tilt" and observe what I call the "twist" in the neck. It is not much more than the other guitar I have in my room right now (Martin D-18GE) but it is a bit greater than that one. I've looked at all my instruments, they all have an observable difference with perfect horizontal of the guitar body, but usually are not far off. Here is the photo, it may exaggerate things a bit, but you can clearly see the slant -

And here is the second photo, maybe a side issue, but it made things a little harder to figure out once I realized it. There is a "belly" in the top as though the top is pressed or carved a tiny bit to make a slight arch. I suspect it could just be the upward pressure of the strings / bridge pulling back on the top, but it seems pretty evenly distributed as I measure it further from the bridge, it makes me thing the arch is there on purpose. It is a bit greater than I expected, but not too much more than my Martin D-18GE I compared it with. The Martin seems to have a flat top and the bridge creates a belly, but the Guild seems to show the belly evenly distributed out towards the edge of the guitar, so that the arch is apparent even inches away from the very sides at the "bottom" or "end" edge of the guitar top ( near where the sides join and where the strap button is.)

Thanks again for all the ideas. This is interesting. I'll go play it now.

Clark

 

[wa3jpg]

Oh, I forgot to mention, and it may be obvious in the second photo, the bridge is slightly asymmetric. Notice that the "left" side (the treble side) has less rosewood showing above the top than the right side (the height of the saddle itself is lower on the treble side than the bass side). It is very slight, but I noticed it. I've carved my saddle so that the treble side is about the same height above the bridge edge as the bass side to kill any tendency to buzz (I play hard sometimes and I require a bit of height. I'll go measure it now.)

Clark

 

[wa3jpg]

My action is about what I like, I measured string clearance with a capo at the first fret and then measured the distance from the top of the 12th fret (right on the fret) to the top of the string, it is about 6/64 th inches. The high E string gives me about 4/64 th inches from the very top of the fret (the crown) to the top of the string itself. I can get a little buzzing on the B string when I pound on things but it is about right. I also note that the neck has a little relief, but not much, it is farily flat when I sight down the neck. (Not much clearance, but a tiny bit, when I have the capo on the first fret and I hold the string down at the 14th fret, I look at the 7th fret and can just see the gap.)

Clark

 

[Mingus]

When measuring string "clearance" you should measure to the bottom of the string. Also, I can't really tell what you're doing with the straight edge in that first picture (reflections). Is it under the strings? Behind or in front of the nut? Below the strings?

Bottom line is still that as long as it's playable for you, it's OK.

-James

 

[ce blues]

clark,

you mentioned that your guild had an "arch" to the top....all of my dreadnaught guilds are quite flat on top, the arch is on the backside. the figures of merit (in my repair books) for acoustic guitar string height is: 5/64" on the bass side strings and 4/64" on the treble side. actually, IMO, anything within those rough ballpark numbers and if they are comfortable for your playing style is the correct height above the fingerboard (as someone stated, measured from the top of the fret to the bottom of the string) and if the instrument tunes-up satifactorily.

ce

 

[capnjuan]

... And here is the second photo ... There is a "belly" in the top ... I suspect it could just be the upward pressure of the strings / bridge pulling back on the top, Clark

Hi Clark; the top of your guitar is supposed to be crowned; its center slightly higher than its edges to strengthen it and, by increasing the tension on it (compared to dead flat), increase its responsiveness.

The term 'belly' is usually reserved for excess 'bulging' of the top in response to the failure of one of more glue joints; bridge-to-deck, plate-to-deck (underneath), or brace-to-top acting together with string tension. Not enough experience w/ the neck 'twist' to offer any comments but the top looks fine. CJ

 

[hideglue]

Clark,

I'm a bit more perplexed by the toe-nail polish (?)

 

[capnjuan]

Clark, I'm a bit more perplexed by the toe-nail polish (?)

... Revlon's Strawberry Sizzle?

 

[West R Lee]

Clark,

I'm a bit more perplexed by the toe-nail polish (?)

:lol: Keen eye for detail Hide, that's why you get the big bucks!

West