Action on J45

[jimydrmz]

Just feeling lately that the action is a bit high on the upper frets of my J45. I look down the neck and don't see the need for trust rod adjustment. I've recently had my guitar tech give it a good going over. I also keep it humidified and in the case. Last weekend I picked up an acoustic at a Christmas party that had insanely low action, so I'm wandering if it's just me.

[Leonard McCoy]

How high exactly is the action if you measure it at the 12th fret on both the treble and bass side from the top of the fret to the underside of the E string?

[jimydrmz]

As near as I can tell, 3/16?

[Dave F]

I hope you mean 3/32

[MorrisrownSal]

Seems you live in Canada, and recently got a humidifier for your case....

 

Could it be over-humidified? I love my guitars feel when the RH is 40-45%.

[jimydrmz]

Okay, I re-measured the low E string at about 4/32 from the neck surface to the bottom of the string. The humidity in the case is around 40 percent.

[jvi]

seems too high to me, 6-7/ 64s is right for me , (3/32) tho a bit lower feels so good its tempting, I think the tech missed the mark by a little

[zombywoof]

I agree most folks would probably find 8/64 on the high side of "normal."

[jimydrmz]

Thanks for the info. guys. Just got a hold of my guitar tech. and he will take a look.

[j45nick]

Okay, I re-measured the low E string at about 4/32 from the neck surface to the bottom of the string. The humidity in the case is around 40 percent.

 

 

Measure from the top of the 12th fret, not the top of the fretboard itself, to the underside of the string.

[Buc McMaster]

On acoustic guitars what's possible with the action is all about the neck set. Bad neck set angle, bad action that is likely to remain so without a reset. Good neck set angle, all things are possible. My J-45 Vintage has a most excellent neck set and the action is electric-guitar-low the length of the fret board without rattle. Neck set is critical on acoustic guitars.

[kidblast]

I agree most folks would probably find 8/64 on the high side of "normal."

 

 

yea,, or just "high"...

 

mine are all around 5/64s (low E) and 3~4/64s (high E)

[jimydrmz]

On acoustic guitars what's possible with the action is all about the neck set. Bad neck set angle, bad action that is likely to remain so without a reset. Good neck set angle, all things are possible. My J-45 Vintage has a most excellent neck set and the action is electric-guitar-low the length of the fret board without rattle. Neck set is critical on acoustic guitars.

[jimydrmz]

Are you referring to truss rod adjustment?

[blindboygrunt]

No jimy, he’s talking about the break angle over the saddle

A sharp break angle , initially on the guitar from the factory , leaves more scope to get a nice action

 

Lowering the saddle (along with the nut to a lesser extent) can only be done so much before the strings are left with no angle over the saddle

 

You’ll not see many gibsons with a sharp break angle

[BigKahune]

Neck set or neck angle to the body. This is formed when the neck is set into the body and glued - angle is pretty critical.

 

 

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[jimydrmz]

Hey great example thanks...

[BigKahune]

Yer welcome. I agree with Buck. The steeper neck angles cause a need for a taller saddle. The shallower neck angles cause a need for a shorter saddle. The height of the saddle gets into what BBG is talking about.

 

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[blindboygrunt]

If you get your hands on a straight edge long enough to run the fretboard and head towards the bridge then the line (shown above in bigkahunes diagram) should go over the top of the front of the bridge (the side nearest the hole in the top)

If it hits the bridge face then you’ve a slight problem

[Buc McMaster]

Are you referring to truss rod adjustment?

Not at all. As others have shown and explained, the neck set is a whole nuther critter from rod adjustment. With a glued neck joint (as most acoustic guitars have) there is no user friendly adjustment available......it is what it is when assembled by the builder. Set neck electric guitars like the Les Paul have a seriously adjustable bridge height to work around neck set issues. Strats and Telecasters are bolt necks and easily shimmed for a correct neck set. Not so with set neck acoustics.

 

As BKs' diagram and BBGs' explanation, a straight edge laid on the frets should ideally point to just above the bridge (not the saddle), perhaps a 64th or 32nd of an inch clearance. This indicates a very good neck set and allows for a wide range of action adjustments at the saddle. A trained eye can sight down the side of a neck and follow an imaginary line of sight to the bridge to get a pretty good assessment of a neck set while guitar shopping.......it's one of the very first things I do when evaluating a potential purchase.

 

Hope your situation turns out to be just a tweaking of the setup.

[Leonard McCoy]

Every musician can learn to set up his own instruments if he puts his mind to it. But until you're there (I recommend Erlewine's Guitar Player Repair Guide), I think it's wise to turn the guitar over to a tech.

[kidblast]

Every musician can learn to set up his own instruments if he puts his mind to it. But until you're there (I recommend Erlewine's Guitar Player Repair Guide), I think it's wise to turn the guitar over to a tech.

 

yea, it's not rocket science, but then again, not just know how,, the right tools are key.. Good nut files are a big expense, but without them, you just can't set the nut, which is a key part of any setup, factory setup usually leaves them too shallow.

 

If you're doing fret work, (leveling, knocking down high frets, etc.. ) need the right tools for this too. It's often times easier just to have a few contacts in your pocket that you trust, and can turn the setup job around in a reasonable time. nothing like dropping off a new guitar for a setup and it's at the shop for a month.

[BoSoxBiker]

Wouldn't it make sense to at least measure the neck relief before jumping into anything else? If the relief is too big, the relative effects on even 12th fret string height are felt. A Capo and a set of feeler gauges are all that's needed. The gauges are cheap. I would first pay attention to this,

 

Then the humidity factor. Not the current humidity in the case, but rather the condition of the guitar. Is it a "wet" guitar or a "dry" guitar. Do the top and back appear swollen(raised) The neck angle can also have an appearance of being off. Look at this. Taylor Wet Guitar (I wish Gibson had a page for this.) I live in a humid area. My guitars play like a dream until it rains, and then for a few days after if there was a lot of rain. I use a drying strategy in the case when affected. (silica gel packs)

 

Will de-humidifying a "wet" guitar bring you from 8/64 to 5/64? Probably not, unless it was really, really wet. Neck relief brought down from .011" to .007" might get a whole 1/64 by itself. The combination could be in effect. Also note that the neck relief itself can be affected by humidity and temps, though I forget which way.

 

Heck, a humid guitar can even feel off with good string height and neck relief specs. I'm dealing with that right this moment. This guitar has been on the stand for a few days, including a bunch of rain yesterday. Mild day, minimal heat. Poof! Up near 60% humidity in it'a corner.

[jimydrmz]

I have a measurement of 2 mm at the 12 fret under the low E string. From what I have heard, this should be about right? Still feels too high to me...

[j45nick]

I have a measurement of 2 mm at the 12 fret under the low E string. From what I have heard, this should be about right? Still feels too high to me...

 

 

Gibson's generic action specs for acoustics is 6/64" under the low E String. That translates into 2.38 mm. By that, your action is not high. That doesn't mean you can't try to lower it, but depending on how the neck relief is set, you may be getting into fret buzz territory if you go much lower.