Neck relief with feeler gauges question.

[azfryguy]

From all I have read you need a capo or straightedge to check the neck relief in addition to feeler gauges. I have my gauges but thats it, I was think about this last night. Correct me if I am wrong but, the string already perfectly straight without a capo right? So Instead of the the distance between the string at the 8th fret with a capo on the first and fretting the last fret with your right hand, why not take the capo out of the equation and just messuse the distance with out it? Also why the 8th fret does the truss rod end there, or is it strongest there, or what? It seems like you would want to messure it at the 12th fret. Please explain how I am wrong, assuming I am.

Thank you
Garret Fry

[JTE]

You can just fret the E string at the first fret and the last fret (or the fret where it joins the body- there are valid reasons for doing either one). That makes the string a serviceable straight-edge. You measure at the 7th or the 8th fret because that's the MIDDLE of the area the truss rod works on.

I don't use feeler gauges, and seldom a capo. Just fret the string and look to see what you have. I eyeball mine now, but I've been doing it since '77 and know what I want mine to be. I've never used a feeler gauge, just a small machinists' ruler marked in 64ths of an inch.

John

[Growly Lytes]

I used a piece of paper to measure gaps around the first 3 frets & just eyeball around the 8th.
I saw it on Youtube.It works great.

[Zooberwerx]

You need the capo if you haven't yet grown a third arm. Capo the 1st fret (directly on top of the 1st fret) then depress either the last fret or fret nearest the neck / body junction...two schools of thought on that issue. The degree of relief is not consistent throughout the length of the fingerboard; it is most pronounced @ ~8th fret.

Riis

[202dy]

Originally Posted by azfryguy

From all I have read you need a capo or straightedge to check the neck relief in addition to feeler gauges. I have my gauges but thats it, I was think about this last night. Correct me if I am wrong but, the string already perfectly straight without a capo right? So Instead of the the distance between the string at the 8th fret with a capo on the first and fretting the last fret with your right hand, why not take the capo out of the equation and just messuse the distance with out it? Also why the 8th fret does the truss rod end there, or is it strongest there, or what? It seems like you would want to messure it at the 12th fret. Please explain how I am wrong, assuming I am.

Thank you
Garret Fry

You are correct. The string is straight. However, without the capo in place you are not measuring the relief. You are measuring the relief plus the height of the string off the first fret plus the height of the string off the last fret. For example, the clearance at the first fret may be .035" and .110" at the last fret plus the amount of relief at the seventh fret. Each measurement introduces a greater margin for error. So if the measurements at the first and last frets are off by say .003" each (the thickness of a sheet of notebook paper) the relief measurement will be off by .006". If average relief is .012", the error is a whopping fifty percent!

A precision straight edge is quicker and less fussy, by the way. It is easier to "feel" with the feeler gauges against the straight edge, which is how they supposed to be used. Those of us with aging eyesight do not have to look for string deflection caused by the feeler gauges, either.

As far as measuring relief at the eighth (or seventh or ninth) fret goes, this is the location at which the truss rod creates or corrects the greatest amount of deflection. The truss rod does not extend the entire length of the neck. Some necks have curved truss rod channels, with the greatest depth somewhere between F7 to F9, depending on the maker. The truss rod has little discernible effect beyond the neck body joint. So folks who use a straight edge tend to measure at the seventh fret. String and capo method at eight or nine.

[Pilgrim]

Originally Posted by 202dy

A precision straight edge is quicker and less fussy, by the way. It is easier to "feel" with the feeler gauges against the straight edge, which is how they supposed to be used. Those of us with aging eyesight do not have to look for string deflection caused by the feeler gauges, either.

Boy, do I hear that! I have a nice Stew-Mac gauge marked in 64ths, but unlike JTE (may his eyesight never fade), my eyes can't see the marks well any longer without a LOT of light from an intense flashlight trained directly on the ruler.

[azfryguy]

Originally Posted by 202dy

You are correct. The string is straight. However, without the capo in place you are not measuring the relief. You are measuring the relief plus the height of the string off the first fret plus the height of the string off the last fret. For example, the clearance at the first fret may be .035" and .110" at the last fret plus the amount of relief at the seventh fret. Each measurement introduces a greater margin for error. So if the measurements at the first and last frets are off by say .003" each (the thickness of a sheet of notebook paper) the relief measurement will be off by .006". If average relief is .012", the error is a whopping fifty percent!

A precision straight edge is quicker and less fussy, by the way. It is easier to "feel" with the feeler gauges against the straight edge, which is how they supposed to be used. Those of us with aging eyesight do not have to look for string deflection caused by the feeler gauges, either.

As far as measuring relief at the eighth (or seventh or ninth) fret goes, this is the location at which the truss rod creates or corrects the greatest amount of deflection. The truss rod does not extend the entire length of the neck. Some necks have curved truss rod channels, with the greatest depth somewhere between F7 to F9, depending on the maker. The truss rod has little discernible effect beyond the neck body joint. So folks who use a straight edge tend to measure at the seventh fret. String and capo method at eight or nine.

Thank you very much for explaning that to me I was truly lost. I am 18 but my vision is so bad I cant read my computer screen without my glasses! Im gonna get surgery