Shaping First Saddle - Question

[mirwa]

No surprise I do things differently, we do things the way we find works for us and our clients.

I will radius the top of a saddle shape to match the fretboards radius, then I will adjust the base of the saddle so I achieve the desired E heights measured at the 12th, this gives a graduated increase of each strings height from treble side to bass side with respect to the fingerboard radius.

I will then intonate each string by filing the crest of the saddle back or forward

Steve

[brianhejh]

Hi Guys.

Within this topic there is mention that the bottom of the nut is to be filed to the same depth/level as the first two fret tops. Sounds logical but different to what I am currently doing. If this is true than the small gap at the first fret required to play without buzz is this achieved by string tension only.?

Thanks
Brian

[mirwa]

Originally Posted by brianhejh

Within this topic there is mention that the bottom of the nut is to be filed to the same depth/level as the first two fret tops. Sounds logical but different to what I am currently doing. If this is true than the small gap at the first fret required to play without buzz is this achieved by string tension only.?

Hi Brian,

Good question, the situation you describe works well with what we call a zero fret application, that is no nut just a fret, we file this fret level with the rest of the fretboard when doing a fret level, then when we string the guitar up that first zero fret becomes our ideal nut height, it works extremely well with a fret as it gives you a really low nut.

With bone and or plastic nuts, I find the opposite, yes you can cut the nut to a height where it is level with the first two frets and achieve an ideal nut height exactly as per the zero nut situation, however, when you do this and change the strings on the guitar once or if your lucky twice thereafter, especially the bass E string, the action of the string moving in its groove whilst being tightened is enough to now ruin your nut, the nut is now too low and buzzes.

Most luthiers that I know off, myself included, when cutting a nut, measure the string height over the first fret with feeler gauges or paper whilst applying pressure on the string between the second and third fret, we cut it to a comfortable playing height that also allows the customer to do string changes without ruining their nut.

Possibly the people / person that promotes the other method may be attempting to sell a tool that works the way "they" advertise they do it.

Steve

[John Arnold]

Just to expound on the zero fret:
The reason it works is clear when you realize that placing a capo on the first fret creates a new 'nut' that is the same height as the frets. At that point, the clearance over the second fret is fixed. Once the relief is set, there is no adjustment for this clearance except at the saddle. If there is no buzz with the capo, then there should be no buzz on open strings when the nut is that same height.
When the nut is set the same height as the frets, the first fret action is determined solely by the saddle height. In fact, first fret action should always be about 11% of the 12th fret action. Anything higher is unnecessarily too hard to play, and anything lower will tend to cause it to buzz more on open strings.

In general - I typically end up with low E will be slightly higher than the high e string at both the nut and saddle. The rest of the strings are progressively closer to the frets. At the nut - it may only be 0.006" higher - but it's still a bit.

Considering the above analysis, there is no reason that the bass strings should be higher at the nut.

BUT......

I do set the bass string slightly higher, but the aim is not to compensate for the string wearing the groove, since I have not witnessed it....at least, not after changing strings a few times. This may be because I slot the nut for full contact over the thickness of the nut.
The reason I raise the 6th string a few thousandths is to prevent back buzzes.

[Rodger Knox]

Originally Posted by charles Tauber

Then I respectfully suggest you haven't understood what I described.

If you "follow" the radius, you will have uniform string height from 1st to last string. It can't be otherwise. That isn't what most people want: they want the treble strings lower than the bass strings. That means the saddle needs to be lower at the treble strings than bass strings. That means it is a different curvature than the surface of the fingerboard/frets. In Erlewine's language, that's a "flatter" radius on the bass side. It's simple geometry. It isn't complicated to achieve.

It's not quite that simple Charles. You're forgetting the strings taper, so matching the fretboard radius doesn't work. The method you use for setting the saddle heights is the best for several reasons.

[charles Tauber]

Originally Posted by Rodger Knox

You're forgetting the strings taper, so matching the fretboard radius doesn't work.

The distance from the 12th fret to the bottom of the string, as defined by the support of the bottom of the string at both nut and saddle, is dependent upon the diameter of the string? I assume that the change in diameter is what you mean regarding the stings tapering.

[murrmac123]

Where is Louie Atienza when you need him? Louie had all this 3D visualization stuff totally down.

He would have been the first to agree that you can't just use the fretboard radius on the saddle top ... not if you want optimum results for professional players. Quick and dirty for amateurs? ...'spose it would be OK.

[Rodger Knox]

No. from the nut to the saddle. The spacing at the nut is narrower than the saddle. so a uniform saddle radius matching the fretboard does not produce uniform string heights.
We're getting into compound radius discussion territory...
edit:Murry posted while I was typing, and Louie has been a major contributor to the compound radius discussions. He's designed several jigs for making compound radius boards.

[murrmac123]

Originally Posted by Rodger Knox

No. from the nut to the saddle. The spacing at the nut is narrower than the saddle. so a uniform saddle radius matching the fretboard does not produce uniform string heights.
We're getting into compound radius discussion territory...

Absolutely right, Rodger.

At this point it might be as well to reaffirm that for all practical purposes, none of this matters ... we all know that we can file from the top to give the required result. We also know from experience that setting the saddle top to the fretboard radius doesn't give best results.

But it's still an intriguing subject , so, going from the practical to the theoretical ... yes, as Rodger says, the taper of the string paths does indeed mean that using the same fretboard radius for the saddle will result in the E-e string action being too low, or the intermediate string action being too high, depending on which way you interpret it.

However ... this is true for the case where the top of the saddle is symmetrically aligned with the fretboard, but of course this is never the case in practice ... so what happens when the saddle top is tilted to give a lower height for the treble strings?

This is where I do not have the mathematical expertise to figure it out in terms of co-ordinates ... but what I do know from hands-on experience (and accurate measurement) is that the saddle top "curve" has to be flattened in order to get the correct increment in string height from treble to bass. Or as I prefer to think of it ...the correct decrement in height from bass to treble.

[charles Tauber]

Originally Posted by Rodger Knox

No. from the nut to the saddle. The spacing at the nut is narrower than the saddle. so a uniform saddle radius matching the fretboard does not produce uniform string heights.

I stand corrected. For a single radius fingerboard, that is true.

We're getting into compound radius discussion territory... He's designed several jigs for making compound radius boards.

Every fingerboard I've made is a "compound radius". I just assumed that's what we were discussing. My mistake. Obviously one cannot make a saddle to THE radius of a fingerboard if the radius of the fingerboard is constantly changing along its length. That's part of the reason I determine the curvature of the saddle as I do.

I use a handplane that takes me about 10 minutes. I don't make enough of them that saving a few minutes on each one will make much difference to me. Still, I appreciate his ingenuity.

[mirwa]

Originally Posted by murrmac123

you can't just use the fretboard radius on the saddle top ... not if you want optimum results for professional players. Quick and dirty for amateurs? ...'spose it would be OK.

Bwahaha you so funny, love it.

Appreciate an expert setting me straight. Where's that wink wink emoji.

Steve
(Amateur Luthier....)

Warranty repairer for Taylor, Gibson, Epiphone, Yamaha, Martin, PRS, Esp, Music Man, Ernie Ball, Ibanez, Kramer, Ovation, Line 6, Laney, Ashton, Cole Clarke, Maton, Luna, Tanglewood, Kayne, Axl, Johnson, Admira, Fernandes, Walden, Hawthorn, Onynx, B.C Rich, Fiesta, Rhapsody, Aria Ukes, Kealoha Ukes, Lanikai Ukes, Monterey, Jose Ortega, Cort, Eastman, Electra, Suzuki, Five O, Oakridge, Katoh, Alvarez, Schecter, Spector

[Howard Klepper]

Compound radius is not really relevant to whether the saddle must be flattened to get the action lower on the high E than it is on the low E. We can do away with the compound radius part by assuming that the saddle radius is that of the conic surface described by the compound radius projected to the saddle location.

So to the question whether one must flatten, i.e., increase the saddle radius to get an action differential between high and low E: no, it is not necessary. I do the saddle adjustment (and Steve, too, if I read him correctly) by first radiusing the top of the saddle, and then moving the center of the circle of which the saddle top is an arc down and towards the low E. Put more simply in terms of method, first arc the saddle top to the radius of the projected cone. Then lower the treble side of the saddle bottom more than the bass side. The radius of the top of the saddle remains the same, but it no longer lies on the same conic surface as the fret tops. All you have to do is mark the amount that must be taken off under the two E strings to get the desired action, draw a line connecting the marks, and sand to that line. Works a treat, and puts all the intermediate string heights right in proportion.

[mirwa]

Originally Posted by Howard Klepper

(and Steve, too, if I read him correctly)

[Ned Milburn]

I'm right on track with Howard's description above. Same here!

FWIW, I do not like it when middle strings are too high. Uncomfortable playing and tough for bar chords.

Also, it is important to mention that there is NO perfect setup "one size fits all". Each guitar should be set up to the needs of its owner.

A perfect example: When I was cutting my teeth with guitar repair/setup in the 90's, my former boss showed me how to set up Bruce Cockburn's guitars. Bruce has a strong right hand, especially his thumb picking. So we set up the low A and E a bit higher on the nut than a "standard" setup, and a little bit higher at the saddle, too.

So, although there are standard practices, tweaks should be made to individualize for player's needs. It is important to understand the principles, but not be dogmatic about them.

Cheers!

[Rodger Knox]

Originally Posted by Ned Milburn

I'm right on track with Howard's description above. Same here!

What I do is also pretty close.