Neck Relief, Neck Angle, Bridge Height and Action question

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RocknRollShakeUp
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Neck Relief, Neck Angle, Bridge Height and Action question

Post by RocknRollShakeUp » Thu Jul 04, 2019 9:45 pm

A recent conversation about this with another member here got me thinking about this and I would like to get your thoughts, as I think it would be a good thought experiment and learning opportunity for all, when trying to set up JM’s.

When setting the neck relief very straight, let’s say .006”, which is pretty darn straight and I’m not sure how much straighter you’d want to set it, it will typically allow you to raise the bridge, which will help increase the break angle over the bridge and decrease buzzing, especially of that pesky low E string which seems especially susceptible to buzzing in JM’s.

However, if the neck is that “straight”, and with the bridge set higher to compensate, then despite the advantage of the increased break angle and decreased buzzing, some may then encounter an ever increasing action height in the frets beyond the 12th fret which may decrease playability. Is this phenomenon unavoidable for most JM’S when setting up such a straight neck? Or if one had the perfect neck angle this would allow a very straight neck and still allow low action all the way out to the highest frets. And if a low action out to the highest frets is not maintained once the relief is set very low, does this mean that really, at that point, a small shim should be considered in order to lower the action in the frets beyond the 12th fret as well?

Of course the whole thing is a balancing act, but I’m wondering what your thoughts and experiences are on this because this interplay between the neck relief, neck angle and bridge height and the resulting bridge break angle is at the heart of all the common JM woes it would seem, and getting it right can theoretically result in a perfectly playable guitar with no buzzes even when using light gauge strings.

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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by adamrobertt » Fri Jul 05, 2019 6:41 am

A shim solves the problems you're experiencing. Then you can set the neck relief however you need, raise the bridge a tad, and eliminate most issues. I've had very playable Jazzmasters with no buzz or issues with just a good Mustang bridge with the neck shimmed and the bridge raised.

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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by Danley » Fri Jul 05, 2019 7:09 am

Agree there’s a need to shim most Jazzmasters. But I think the easiest solution to eliminating saddle-buzz is to use a stiffer/longer intonation spring to hold the saddle better in place (also helps if your bridge baseplate has very tight holes- not the loose ones some MIJ/Squier have.)
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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by jorri » Fri Jul 05, 2019 7:29 am

Shims dont change the general string height, it raises everything pretty much together-if you were suggesting that.

6 thou neck relief might just mean buzzes lower down the neck. Geometricall if you had 012 and 2.5mm, you then would have 006 and 5mm to clear the lower frets, which would be ridiculous. 010 is probably a limit when ive tried. Maybe extremely good fretwork and light playing 008.

Id go with a shim, then, but dont expect miracles with break angle either. Its never goin to be 90 degrees lol. We're talking 6-7 degrees. I found a small shim helped, but i then tried a massive shim and it didnt really help any more than the initial increase in break angle.

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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by RocknRollShakeUp » Fri Jul 05, 2019 11:04 am

Thanks for your thoughts and tips good people.

So to crystalize this in an algorithmic way if you will:

Set the neck relief as flat as you are comfortable with, which should allow you to raise the bridge a bit, which will allow you to get a better break angle. Hopefully this will resolve loose, flopping, derived string buzzing in the saddles.

Of course compounding this, is your particular bridge, and whether or not you have loose saddles which will also cause buzzes. Going to stiffer intonation springs (great idea btw), or loctite, or a springless design, etc. may be needed as well.

If setting a flat relief and raising the bridge does not solve the buzz, or if it does, but now your high fret action is too high, or if you are just hating life with a real flat relief (strings buzzing against frets, action too stiff, etc.), then a shim is pretty much thee to to remedy, and a good one at that.

Would you all agree with the above? Feel free to interject.

Interestingly with my JM CS Closet Classic that has a typically low neck angle, flattening the radius to around .008-.010, raising the bridge a bit, and using a Mustang bridge that had the 55mm spacing worked really well, although I had to file down the round tremolo screws a bit so that the E strings didn’t touch them. But the point I want to make is that the extra lateral angle that was created in the string slot by the wider spacing of the Mustang bridge was effective at preventing string buzz that was uncovered when I went to a Staytrem with the narrower spacing, on the same general set up! The lateral string pressure on the Mustang saddles also compressed them a bit I think and reduced rattling. This was with 10 gauge strings. With the Staytrem or even Mastery the strings just go over the saddles without any additional lateral pressure, so the only thing that will keep strings tight is string break angle over the saddles/bridge it seems to me. However, I greatly prefer the narrower string spacing of the Staytrem. With the Staytrem and that relatively low neck angle, the guitar had a buzzing low E string even with 11’s to a small degree if I remember correctly, whereas no buzzing with 10’s and the wider Mustang bridge. The Staytrem itself didn’t seem to contribute any buzzing, but it was that floppy E string from not enough break angle. Anyway, a Stew Mac .5deg shim and Thomastik 12 gauge flats cured that guitar any buzzes for good. I’ll likely try 10’s on that guitar soon to see if I get any buzzing with it shimmed, as I’m needing to do country pedal style bends at the moment.

For contrast, my Wildwood 10 JM came with a neck pocket that produces an increased neck angle without a shim and also came with an RSD bridge. Out of the box the relief was .011” with low to medium action height and had 10 gauge strings. Basically no buzzing. Once I lowered the action to a pretty low action however I could just pick up a small low E buzz across the saddle when hitting the low E on the harder side. No noise from the bridge however which is great. Plucking the low E behind the saddle now produced a floppy splatty sound, not a nice harmonic ping, at that point. So I straightened the neck, to a .006” relief, raised the bridge to compensate and now there is no buzz to be heard. However, if I had to nitpick, the action starting at the 15th or 17th fret is a little high now, still totally playable, but a touch high if I get prima donna about it. So interestingly If I wanted to keep a super straight neck relief and very low action, a very small shim would likely improve things even in this guitar .
I’ll probably drop the relief down to around .008-.009” and see if that will be the happy compromise in this guitar. 11’s would likely fix a floppy and buzzing low E string regardless of what my neck relief and action would be in this guitar, within reason, I think, but I want to keep 10’s on it.

EDIT: I kept the relief of the Wildwood 10 JM at .006" and put the action at .070-.075" at the low E and .060-.065" at the high E, which is pretty low action and no buzzing whatsoever, with nice pinging when plucking the Low E behind the saddles. The action starting at the 15th-17th fret is only negligibly higher, maybe like .005" higher, and very playable, and I'm very pleased with the sound and playability of the guitar. I have to say that the very flat relief makes the guitar sound better too, more harmonically rich and livelier somehow. So for what it's worth I strongly recommend starting one's set up with a fairly flat neck relief! Maybe no more than .008-.010", and try even .006".


Anyway sorry about the saga, but JM’s are so fascinating with all of their build and set up quirks. Once they are dialed in though, man I think there is no better guitar out there…well unless you are into Jag-U-Ahhhrs...or other offsets :) !
But I hope that this exploration will help others like me that aren’t JM experts in setting up their guitars.

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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by adamrobertt » Sat Jul 06, 2019 5:14 am

Honestly I always shim my JMs as part of a standard setup. I'm not into having ultra flat necks though, I'm OK with a little relief if needed. Still, I've had JMs with pretty low action and very good playability. Just takes some tweaking, and they can seem finnicky if you are used to setting up simpler guitars.

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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by RocknRollShakeUp » Sat Jul 06, 2019 6:55 am

adamrobertt wrote:
Sat Jul 06, 2019 5:14 am
Honestly I always shim my JMs as part of a standard setup. I'm not into having ultra flat necks though, I'm OK with a little relief if needed. Still, I've had JMs with pretty low action and very good playability. Just takes some tweaking, and they can seem finnicky if you are used to setting up simpler guitars.
Yeah I totally understand. I seem to also remember all of a sudden the rounder the neck radius the more relief one needs. So for most Jazzmasters optimizing the neck angle first with a shim, esp if they have 7.25” radius necks is probably very smart and practical.

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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by Danley » Sat Jul 06, 2019 7:06 am

RocknRollShakeUp wrote:
Sat Jul 06, 2019 6:55 am
adamrobertt wrote:
Sat Jul 06, 2019 5:14 am
Honestly I always shim my JMs as part of a standard setup. I'm not into having ultra flat necks though, I'm OK with a little relief if needed. Still, I've had JMs with pretty low action and very good playability. Just takes some tweaking, and they can seem finnicky if you are used to setting up simpler guitars.
Yeah I totally understand. I seem to also remember all of a sudden the rounder the neck radius the more relief one needs. So for most Jazzmasters optimizing the neck angle first with a shim, esp if they have 7.25” radius necks is probably very smart and practical.
Basically with a ~7" radius neck, the fret sections under the outer strings will go flat while the inner strings might still have some relief - Since the concavity is concentric to some imaginary point in front of your neck, and the middle string portion of each fret is closer to that point than the outer string, it will really never be consistent relief between strings.

But the need for the shim doesn't really arise from that, mostly you just need the shim either 1- Because you can't adjust your bridge low enough, or 2 - Want more break angle. If you have one of the less sloppy-made Jaguar/Jazzmaster bridges (such as vintage, which have thicker intonation springs/better fitted holes etc.) you can get away with very little break angle.
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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by jorri » Sat Jul 06, 2019 9:12 am

Basically i just adjust as needed in reality. If 008 works for you it work, but i always like the resistance with playing.

eg.
if it buzzes on open strings its the nut
if it buzzes on lower frets but not high its the truss rod
if it buzzes on higher frets more than low its the action
if it buzzes everywhere its both
if the bridge can't go any lower or touches the pickguard, you need a shim.
if the bridge rattles, a shim might help but probably needs some other solution too. Usually its between my saddles so i lean them into eachother a bit.

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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by RocknRollShakeUp » Sat Jul 06, 2019 7:07 pm

Danley wrote:
Sat Jul 06, 2019 7:06 am
RocknRollShakeUp wrote:
Sat Jul 06, 2019 6:55 am
adamrobertt wrote:
Sat Jul 06, 2019 5:14 am
Honestly I always shim my JMs as part of a standard setup. I'm not into having ultra flat necks though, I'm OK with a little relief if needed. Still, I've had JMs with pretty low action and very good playability. Just takes some tweaking, and they can seem finnicky if you are used to setting up simpler guitars.
Yeah I totally understand. I seem to also remember all of a sudden the rounder the neck radius the more relief one needs. So for most Jazzmasters optimizing the neck angle first with a shim, esp if they have 7.25” radius necks is probably very smart and practical.
Basically with a ~7" radius neck, the fret sections under the outer strings will go flat while the inner strings might still have some relief - Since the concavity is concentric to some imaginary point in front of your neck, and the middle string portion of each fret is closer to that point than the outer string, it will really never be consistent relief between strings.

But the need for the shim doesn't really arise from that, mostly you just need the shim either 1- Because you can't adjust your bridge low enough, or 2 - Want more break angle. If you have one of the less sloppy-made Jaguar/Jazzmaster bridges (such as vintage, which have thicker intonation springs/better fitted holes etc.) you can get away with very little break angle.
Got it, I totally understand and agree!

I was just trying to get at the fact that with a 7.25" radius, more neck relief is typically needed, and the higher the relief, the lower the bridge height, and the lower the break angle across the bridge, hence indirectly a guitar with a smaller radius would more likely benefit from a shim at the end of the day. I hope that made sense.

But yeah, bridges that mechanically rattle just compound the problem. However it is clear that if there isn't enough break angle, or if the string gauge is not thick enough to increase the tension to a critically needed level, the string itself will buzz on the saddle even if the saddle makes no noise in and of itself. A floppy string across an otherwise silent saddle under enough string tension, will also compound any potential for buzzing in said saddle.

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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by RocknRollShakeUp » Sat Jul 06, 2019 7:22 pm

jorri wrote:
Sat Jul 06, 2019 9:12 am
Basically i just adjust as needed in reality. If 008 works for you it work, but i always like the resistance with playing.

eg.
if it buzzes on open strings its the nut
if it buzzes on lower frets but not high its the truss rod
if it buzzes on higher frets more than low its the action
if it buzzes everywhere its both
if the bridge can't go any lower or touches the pickguard, you need a shim.
if the bridge rattles, a shim might help but probably needs some other solution too. Usually its between my saddles so i lean them into eachother a bit.
BTW, thanks for the high quality input y'all! Very educational and enlightening.

Just so we are clear, .008" referred to the neck relief, I like 10 gauge strings on 25.5" inch instruments typically.

When I flatten the relief, say from .012" to .010" and lower, I notice that the string tension feels noticeably stiffer, and the tone much better. At .012" ( and above) the string tension feel is noticeably lower, bending is easier, but the string feels "splatty" and loses harmonic zing, or ping, if you will.

Typically I set relief for .008-.010 on my guitars. On my Wildwood 10 JM I set it on .006" and so far I'm really digging it from a tonal and set up and playability point of view.

To circle back though, I think if one bends strings a lot and has a 7.25" radius, .006" will be far too flat for proper playability because I think one is much more likely to fret out when doing bends, but if no bends are done, it may work fine possibly.

Thank you very much for that diagnostic list of buzzes, that is very helpful indeed!

What the hell does one do if the truss rod is buzzing though?! Loosen and retighten?

Speaking of buzzing, I think my Wildwood 10, which is very resonant and loud acoustically was causing a bit of buzz from the pick guard, I think it may be the pickup covers vibrating against the pickguard contact point!? It cannot be heard when the guitar is plugged in, and it got better to disappeared when I screwed in the pickup mounting screws just a tad, securing the pickup covers better..I think the tight fit of the pickup covers kept them from coming up with the adjustment screws, if that makes sense.
Last edited by RocknRollShakeUp on Sun Jul 07, 2019 12:39 pm, edited 1 time in total.

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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by kgbAttack » Sun Jul 07, 2019 7:25 am

So my Jazzmaster has a 9.5" radius. I have no buzzes whatsoever, and my neck relief is .010". My only complaint is that the action is somewhat high from the 12th fret onwards (approx .080" on both 6th and 1st strings) higher than my Jag and my Tele). The guitar came straight from Custom Shop (I bought it online) and so far I haven't made any change. I don't think I can lower the bridge, or maybe a tiny bit (but that might lead to reducing break angle and buzz) - I'm positive there is no shim...would adding one be the correct thing to do in this case?

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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by RocknRollShakeUp » Sun Jul 07, 2019 12:34 pm

kgbAttack wrote:
Sun Jul 07, 2019 7:25 am
So my Jazzmaster has a 9.5" radius. I have no buzzes whatsoever, and my neck relief is .010". My only complaint is that the action is somewhat high from the 12th fret onwards (approx .080" on both 6th and 1st strings) higher than my Jag and my Tele). The guitar came straight from Custom Shop (I bought it online) and so far I haven't made any change. I don't think I can lower the bridge, or maybe a tiny bit (but that might lead to reducing break angle and buzz) - I'm positive there is no shim...would adding one be the correct thing to do in this case?

Image
I think adding a shim is a very reasonable thing to do with your particular guitar. Since you don't have buzzes now despite what looks like a pretty low neck angle, possibly because you use thick enough strings, you shouldn't have to shim it very much either. Since I like the simplicity of the StewMac shims, I'd start with a .25deg Stew Mac shim, but you can also use cardboard like Fender in the old days.

Now you can at first try to flatten the radius to .008" (maybe like an 1/8th of a clockwise turn), or a bit more, which should straighten the neck out just enough to lower the action a bit, and it may drop you down to acceptable levels. However that looks like a typical low neck angle JM that you may just want to address with a shim and get it over with once and for all, since you have to take the neck off anyway to adjust the neck relief.

But your guitar would make for a great case study to just use neck relief flattening to see if you can just lower your action enough to your liking. If the guitar definitely needs a shim, flattening your relief may lower the action up to the 12th fret or so to your liking, and even more then you want, which will then necessitate raising the bridge, but then either way you may find that the action is still too high in the higher frets beyond the 12th fret, and if that's the case, then you'll have pretty much proven that you need a shim.

I hope this helps! Please do an update after you tinker with it.

BTW, does anyone know what fraction of a degree one gets with the use of a single ply of the typical cereal cardboard box shim? Probably not, but some hardcore dudes out there have those apparatuses that can measure neck angles and could have measured pre and most cardboard shimming :).

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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by adamrobertt » Sun Jul 07, 2019 5:08 pm

kgbAttack wrote:
Sun Jul 07, 2019 7:25 am
So my Jazzmaster has a 9.5" radius. I have no buzzes whatsoever, and my neck relief is .010". My only complaint is that the action is somewhat high from the 12th fret onwards (approx .080" on both 6th and 1st strings) higher than my Jag and my Tele). The guitar came straight from Custom Shop (I bought it online) and so far I haven't made any change. I don't think I can lower the bridge, or maybe a tiny bit (but that might lead to reducing break angle and buzz) - I'm positive there is no shim...would adding one be the correct thing to do in this case?

Image
Yes, I would shim the neck in this scenario. You'll have to raise the bridge, but you should be able to fix the problem that you're having.

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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by timtam » Sun Jul 07, 2019 5:40 pm

RocknRollShakeUp wrote:
Sun Jul 07, 2019 12:34 pm
BTW, does anyone know what fraction of a degree one gets with the use of a single ply of the typical cereal cardboard box shim? Probably not, but some hardcore dudes out there have those apparatuses that can measure neck angles and could have measured pre and most cardboard shimming :).
Trigonometry ....

tan(angle) = rise_in_pocket / pocket_length

eg
rise_in_pocket = 1 mm (ie 1mm thickness, uncompressible, at one end of pocket)
pocket _length = 76mm

angle = atan(1/76) = 0.75 degs

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