Help me understand nut width spacing

[Rosewood99]

I have three guitars with 1.75 nut width that seem to have different string spacing at the first fret. One of the guitars was just to narrow for me so I took it to my luthier to widen it a bit. He said he would but that I might occasionally get high e string slippage (which indeed sometimes happens).

What I can't understand is if they all have 1.75 nut width why would that happen?

The guitar in question had 2 3/16 string spacing at the saddle and the other one had 2 1/4 string spacing. Should that make any difference if they both have a 1.75 nut width?

This has befuddled me for years.

[John Arnold]

String slippage is affected by the bevel on the frets. If the frets are beveled more, that reduces the effective playing width of the neck. When I fret a guitar for a player who requests wider string spacing, I try to keep the fret bevel to a minimum.
Another factor is fret height. Strings tend to slip off the edge more with taller frets.
Fretboard radius also can affect it.
To a lesser degree, bridge spacing matters, but that is also dictated by the taper of the neck. Just because two guitars are 1 3/4 at the nut does not mean they are the same width at the 12th fret.
The formula I use most of the time is that of 1930's Martins:
1 3/4 nut
2 1/4 12th
2 5/16 bridge
Very often the bridge spacing is the same as the neck width at the 12th fret, but the above works just fine.

[charles Tauber]

Simple answer: one can space the strings however one wants, including if you are a manufacturer.

The nut width - actually its length - is just that, the length of the nut. For that given length, you can have more or less space between each edge of the fingerboard and the outside strings. Often, fingerpicking guitars tend to have more space between the edges than non-fingerpicked guitars. The distance between the edge of the fingerboard and the 6th string can be a different distance than from the edge of the fingerboard and the 1st string. It is preference.

How much bevel it put on the fret ends influences how close the outside strings can be to the edge of the fingerboard before the strings slide off the un-bevelled portion of the fret. One can make the bevel more or less. Again, personal preference.

Whatever is left after one subtracts the distance from the edges of the fingerboard to the strings, can then be divided into equal or unequal parts. Some people make the centers of the strings equidistant, others make the distance between edges of strings equidistant. Again, personal preference.

The string spacing at the saddle is independent of the string spacing at the nut: you can make a guitar with whatever string spacing you want at the saddle and make a guitar with whatever string spacing you want at the nut. Add the clearance between edges of outside strings and you define the fingerboard width.

In short, nut width doesn't mean much as far as player preference goes: string spacing does. If one assumes that all nut widths of a given size have the same string spacing, one will be disappointed or confused.

[blindboyjimi]

You have 2 very good replies. I’ll add my $.02 since it’s worth just that with John and Charles already answering. Most 1 3/4” nut guitars have a 1.5” string spacing, but that’s assuming a few things. With a 1.5” spacing, that leaves 1/8” on either side of the e’s. Some of that is taken up by the fret bevel and some giving you actual real estate to push down on the string. Read about the center vs equidistant spacing. I don’t worry about any of that, but I am partial to a particular style and I have custom nuts made every time I do a re-fret or re-set. I ask my tech/luthier to square the fret ends on the bass side and their usual taper on the treble side. I also shift the spacing so that I can easily thumb wrap my F chords quickly and cleanly and I don’t care about the treble e as my hands will find it somehow. I switch between 1 11/16”-1 13/16” nuts so I’m only particular about the bottom bass E string. Sometimes I just shift the nut as is a few mm bass-ward and that works too. I can’t recall what my tech charges for a nut - maybe $45-60 so have your tech make you a couple or if you have similar brands just pop out the nuts and see which one you like and have your tech duplicate that one.

I just had one very high end luthier built guitar back to its birth place. He called me and said my nut was not centered. I told him that’s how I liked it, so he made me a new one as he didn’t want the guitar to leave his shop like that. It arrives on Monday. Well I’ll just take the old one out of the case pocket and pop it back in and now, I guess I have a spare. Hopefully, he didn’t bevel the bass side frets. Everyone is different, find what you like and play it.

[ChrisN]

I notice that kind of slippage more with curvier fretboards, including 9.25 vs. 12 radius. If the frets are excessively (subjective) beveled, and it's a 9.25 board, then I have to think about more precise finger placement on E and e.

[Rosewood99]

Thanks for all the replies. I sort of understand what you are all saying. However the two guitars in question have the same radius. Maybe it's the fret bevel that is the problem.

So is that something I could take back to a luthier and have it adjusted?

[charles Tauber]

Originally Posted by paulzoom

Thanks for all the replies. I sort of understand what you are all saying. However the two guitars in question have the same radius. Maybe it's the fret bevel that is the problem.

So is that something I could take back to a luthier and have it adjusted?

Start by measuring what distance you have between the outside strings and the edge of the fingerboard. Do so for each of your guitars. From your description, they aren't likely the same. Note that the distance can be different for the low E and the high e on a particular guitar.

To make the fret bevel smaller, you have only two choices: cut down the fret height, with minimal result, or re-fret and bevel the frets less. The re-fret will cost you $200+. Before going that route, first check the distance to outside strings. If nothing else, that will tell you what's different between the guitars.

[Rosewood99]

Originally Posted by charles Tauber

Start by measuring what distance you have between the outside strings and the edge of the fingerboard. Do so for each of your guitars. From your description, they aren't likely the same. Note that the distance can be different for the low E and the high e on a particular guitar.

To make the fret bevel smaller, you have only two choices: cut down the fret height, with minimal result, or re-fret and bevel the frets less. The re-fret will cost you $200+. Before going that route, first check the distance to outside strings. If nothing else, that will tell you what's different between the guitars.

They are the same now since I took one to a luthier. However one occasionally get e string slippage and one does not.

[Mycroft]

Originally Posted by paulzoom

They are the same now since I took one to a luthier. However one occasionally get e string slippage and one does not.

I get that as well, Paul. My McAlister and Froggy both are 1 3/4" nuts, but the Mac has more of a bevel of the fret ends than the Froggy, on which the fret ends are just slightly rounded. The 1st string on the Mac slipped off occasionally while the Mac does rarely. I do notice though that the Mac feels "smoother" against my fingers when moving my hand along the neck than the Froggy does.

Ah, trade-offs...

[mercy]

unless specified a luthier will bring the E strings 1/8" in from the edge of the fretboard. I like 3/16 for the e string but dont want to widen the fretboard so I accept 1/16 for the E string. Because the E is pretty stiff I almost never slip that string. As youve noticed there is no standard that all follow, its just that 1/8" is common.
For the rest of the strings the modern spacing at the nut is equal spacing between the strings but I like equal CC. That gives just a tad more for the treble strings with I do my melody playing.
I do other non standard things also beyond the OP which I have come to from years of playing and many guitars.