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Scale Length Off?


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First, I would like to thank everyone that answers and that I'm sure this is a basic question for virtually everyone here. A while back I bought a cheap DIY guitar kit figuring it would be a good place to start and to learn from before I spent alot of time and $$ on a scratch build. I have it build and it sound like what you would expect from a cheap kit in beginners hands (like crap) but I have learned alot. but, there is one problem I have yet to figure out for sure. The scale length is suppose to be 25.5". I can tune the open strings to standard and adjust the intonation at the 12th fret just fine. The problem is that at the first fret, it is sharp and progressively gets better till I get to the 12th fret. After which, it will start to go flat from the 13th fret on. I am pretty sure this is an error in scale length but have no idea as to whether it is to long or to short. If I am right in that it is the scale length, would it be better to adjust at the bridge or where the neck bolts to the body? Again, thanks to all that answer.

Ken

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I checked the nut height according to the tutorial here. It's right. I also checked the location of the first fret and it is correct for a 25.5" scale length. As is the 2nd fret and the 12th. What is happening is that as you fret any string, it will go from sharp (1st fret) to flat (22nd fret). The only fret that is correct is the 12th.

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I still think its the nut, a well cut nut can leave less than the thickness of a high e string (.010) between the strings and the top on the 1st fret, a bit more for the thicker strings. the final height of the action affects how low the nut can be cut without (open) string buzz.

To eliminate the nut from the equation, put a capo on the 1st fret and tune up (to F)

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Lets go back. You intonated the open string to the 12 fret right?

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I have one thing to point out... the fact that the octave is in tune means that the bridge, nut, and 12th fret are in the right places relative to each other (depending on how good your ear is).

If this is a guitar kit, is it possible that the fret positions are wrong?

Edited by Geo
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Thanks for the replies. Fret distances from the nut to the 1st and 2nd frets are spot on using a dial caliper. The 12th fret also appear spot on but only using a tape measure. I don't own a capo so I tunes the high E string to F just by fingering at the first fret. With that tuning, all the following notes down the neck got flatter as I went. I also remeasured the nut height and it is too high. About .025" with a open E string at the first fret and around .012" with the string fretted between the 2nd and 3rd fret, measuring at the first fret. The low E string is much closer to the finger board (about .017"open and .005" with fretting as described above) but exhibits similar problems as the high E string. open tuning good and goes sharp at the first fret. From there, down the fingerboard, gets progressively sharper. With the 12th fret intonation spot on. The low E doesn't have this problem to the same degree as the high E string.

One side of my head tells me "Ya get what ya pay for" while the other side says"This should be simple. Just figure it out"

I will adjust the nut height on the high E side and see where that leads me.

BTW....I did replace the cheap plastic nut in the kit with a better Fender nut.

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Thanks for the replies. Fret distances from the nut to the 1st and 2nd frets are spot on using a dial caliper. The 12th fret also appear spot on but only using a tape measure. I don't own a capo so I tunes the high E string to F just by fingering at the first fret. With that tuning, all the following notes down the neck got flatter as I went. I also remeasured the nut height and it is too high. About .025" with a open E string at the first fret and around .012" with the string fretted between the 2nd and 3rd fret, measuring at the first fret. The low E string is much closer to the finger board (about .017"open and .005" with fretting as described above) but exhibits similar problems as the high E string. open tuning good and goes sharp at the first fret. From there, down the fingerboard, gets progressively sharper. With the 12th fret intonation spot on. The low E doesn't have this problem to the same degree as the high E string.

One side of my head tells me "Ya get what ya pay for" while the other side says"This should be simple. Just figure it out"

I will adjust the nut height on the high E side and see where that leads me.

BTW....I did replace the cheap plastic nut in the kit with a better Fender nut.

If your open string and 12th fret is spot on, neither sharp or flat then the guitar is intonated properly. Weird. recheck the string height using a spare string as a gage. Buy a capo and check fret heights at different positions. Remove all excess material above half the strings height on the nut (where the string sits). Make sure the string angles back from the front edge of the nut or isn't sitting on a hump.

If the fret positions are correct then it is most likely a problem with the nut you made.

Pictures of the guitar and the nut would be helpful.

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I use a Korg Chromatic CA-30 tuner. Set at std. 440hz. I use it to set both the open strings and intonation.

When I tune, I don't look at initial reading but will give it a sec to settle. The initial reading is always sharp no matter what I plug into it.

Edited by sockwalker
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I use a Korg Chromatic CA-30 tuner. Set at std. 440hz. I use it to set both the open strings and intonation.

When I tune, I don't look at initial reading but will give it a sec to settle. The initial reading is always sharp no matter what I plug into it.

Are you using the harmonic at the 12th fret or just fretting the 12th fret?

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It's puzzling to me that each fret 1-11 gets sharper , and that the octave is then spot on. So you must have a very tiny half-step between frets 11 and 12. Or maybe I misunderstood. I would expect the sharpness to decrease as you approach the octave... but maybe that's what you meant.

But essentially, it sounds like the problem is your nut height--more severe on the treble E, less severe on the bass E.

And as someone else suggested, make sure the slot is angled down properly so that the string is beginning to vibrate at the very front edge of the nut, not somewhere behind that.

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Let me try to explain it better. Lets say that 1.00 is the correct note at a given fret and anything above 1.00 is sharp and below is flat. From there it goes..

Open) 1.00

1st) 1.11

2nd) 1.10

3rd) 1.09

4th) 1.08

5th) 1.07

6th) 1.06

7th) 1.05

8th) 1.04

9th) 1.03

10th) 1.02

11th) 1.01

12th) 1.00

13th) 0.99

14th) 0.98

15th) 0.97

And so on through to the last fret. Does that help explain it better? It's hard to solve a problem if it isn't explained well. Sorry for any confusion.

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Like this one. Frets where already installed. I pulled the nut and lowered it. It seemed to get a bit better but still has the same issues. I'm going to play with the nut height some more and see where it leads. Worst case, I'll mess up the nut and have to get a new one and start over. It also seems like the fret board is a different radius than what the nut is cut at. A set of nut files would take care of that but for what Stew-Mac wants for a set, I can't do that right now.

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Does that help explain it better? It's hard to solve a problem if it isn't explained well.

Yes, that's what I thought--my mistake.

It also seems like the fret board is a different radius than what the nut is cut at.

That might be the problem, if some of the strings have to stretch farther to be fretted than others. Given the in-tune-ness of the octave and twelfth fret, it seems to me that there are only two other possibilities:

1) All frets except the octave are out of place (but you already ruled that out)

2) The strings are stretching too far to be fretted (but then, why would the 12+ frets be FLAT? They should be right on, because the stretch from a high nut would be less significant that far away from the nut).

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2) The strings are stretching too far to be fretted (but then, why would the 12+ frets be FLAT? They should be right on, because the stretch from a high nut would be less significant that far away from the nut).

That's the part that is throwing me off as well. I can understand the nut height influencing down to the 5th or 7th fret but, after that, it should stay relative and not continue to get flatter the father down the neck you fret. This is why I was originally questioning the scale length and is it off for the fret spacing.

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