Changing String Height Above 1st Fret
 

I understand it's best to not bury strings in the nut, that the string slot depth should be about 1/2 the string diameter so that the string appears to be sitting almost on top of the nut (let me know if that's incorrect).

It would seem to me (who's not done it, but wants to) that the proper way to reduce string height above the first fret is to take material off the nut's bottom, and leave the slots alone. I've got new guitars with original nuts that appear to be done this way, and which are reduced more on the treble side to get those strings closer to the fret, so the saddle appears a bit tilted down on the treble side.

Notwithstanding that assumption, I see pros regularly deepen the nut slots, eg http://www.bryankimsey.com/nuts/nuts3.htm to adjust 1st fret string height.

What's the best drill on this process?

The best procedure is the way the pro's do it as you mentioned, they are pro's after all and that's what they do. It's next to impossible to get the proper heights by removing material off the bottom. We use special files that leave a circular profile to the nut slot so that's not an issue. once you get the slots cut you can then remove some of the top off to get the strings set in the slots as you described. I like to bury the two treble strings in full depth then gradually increase to the low-E string which is set in just past half it's diameter.

I'm confused .... the depth of the nut slots has nothing to do with the slant of the saddle ...that's a totally different issue.

I intended to say "nut," not saddle. Apologies for the confusion.

That makes sense - it didn't occur to me to sink the strings as needed, then remove some of the nut's top to expose the string diameter desired. I thought that if I sank the strings as needed, they'd just be buried, but I was sure there had to be a way out of that box. Thanks

The best way to lower a strings height is simply cutting the nut slot deeper, but, not everyone have nut files and correct tools.

I work for 12 music stores and not all of them have the correct tools, so I manufacture in house nuts for them, they are all pre-radiused, slotted with the correct spacings and so forth, all the store has to do to make it fit is sand the bottom. It's not the best option IMO but it does work.

We change the way we do things to meet the challenges with the tools we have at hand.

Steve

If it is important to you that the nut slot depths are only half the string diameter, then all you have to do after deepening the slots is to cut some off the top of the nut.
I never measure string height over the first fret. The nut height should be the same as the frets, which can be checked by pressing the string against the second fret. It should barely clear the first fret.

I'm new at this, so the only reason it's important to me re: nut slot depth is because I read it somewhere - I'm open to alternatives, for sure. I thought I read that burying the string in the nut killed something (sustain?).

What's your preferred method for removing some off the top of the nut?

As to your last point - I want to make I understand it - if you can see light under the string at the first fret when you press the string against the second fret, doesn't that mean the nut is slightly higher than the first fret? If they were the same, then it seems that pressing the string at the second fret would cause the string to touch the first fret, not have a slight gap. Sorry if I'm over-analyzing this, but I'm learning!

No .... think about it .... the nut can only make contact with the string over the semicircular area of the bottom half of the string. After that it doesn't matter whether the nut is fractionally higher or 2" higher ...it will have no effect on the sound, or the sustain, or anything else. It becomes purely an aesthetic consideration.

Can't speak for anybody else, but my disk sander is the go-to method for me. I can't understand why anybody would want to file or sand with the nut in situ , but hey ... it takes all sorts.

No , you are not over-analyzing this, it is a very pertinent observation. Let me just say that you will see an addition to the signature in my posts over the next couple of days which might be of interest to you in regard to this issue.

Thank you for the info/clarification, and I look forward to the sig addition.

I use a file and sandpaper to remove material from the top of the nut. I sand up to 600 grit, and then polish. I generally don't do that with the nut installed.....it is in a vise on the bench. The slot depths are done with the nut in place and the strings tuned up close to pitch, but the nut is not glued until after the top is fully shaped and polished.

The reason that I generally don't remove material from the bottom to lower the nut is that it is very difficult to control. I have found that it is better to fit the bottom of the nut first, then lower the slots individually to the proper height.
You should see a very small sliver of light between the string and the first fret because the string rises a bit at the nut due to the fact that it is being bent at an angle. While you can sometimes get by with having the string touch the first fret, it must not touch before the string is all the way against the second fret, and that can be difficult to determine.

What kills sustain is having an improperly cut slot....one that is binding the string or is too loose or flat-bottomed at the exiting edge. The string must be free to facilitate tuning, but not so loose as to move laterally or vertically in the slot. The amount of nut sticking above the string may hamper the formation of a proper slot (that depends on the tools used and the skill of the luthier), but it has no direct effect on the performance.

The thing about having the string slots at the nut cut to a minimal depth, just enough to hold it in is more for playability then anything else. Nothing like hitting your hand on the sharp corners of a tall nut ;)

I think I remember years back some how the idea that it improves tone came about but when you think about it, the file that you use for a particular string is going to be thick enough for the string to seat down to the bottom, or not. So it's not like there is any nut material grabbing or crowding over the top of the string deadening it. The string is going to sit at the bottom and a properly cut nut slot will hug the lower half diameter of the string weather it's too deep or not.

It is rarely a good idea to lower a nut from the bottom.

Cut the nut slots with a slotting file of preference.

If the nut needs to be raised, then shimming and subsequent touch up of the slots with files is a good idea.

The string height above first fret is affected BOTH by nut height as well as saddle height (and truss rod adjustment, to some extent).

And BTW, I usually go for at least 3/4 of the string in the slot, especially on LOW BREAK ANGLE headstocks, to avoid strings accidentally being knocked or pulled out of the nut slots. Especially high E and B --- it is really best to prepare a slot more than 1/2 the string diameter.

Thanks Ned. I think the most frequent arrangement I've seen (until your observation here) is the 1/2 diameter notion applied to the thicker wound strings, while the unwound are fully sunk, but not beyond.