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I received great help from my last post on this but I need to ask more questions. Thanks in advance for any help.

Fret guage:
I'm refretting a classical guitar which has quite narrow frets. Narrow frets give better intonation, while bigger frets are easier to play, or is it the reverse? Any other pros and cons on fret guage?

I play on narrow guage and larger guage and don't really have a preference, although I don't care for how jumbo frets feel. My perception is that older classicals, pre-80s, more frequently have quite narrow nickel frets while later guitars have bigger frets. What reason for this trend?


Neck relief:
Should I level the fretboard on a refret job (classical guitar here)? One of my guitars has a some 'relief' (curvature) - put there by the luthier, or warped there over the years. The steel rule in the pictures is bent in at each end and sits on the fingerboard between fret #2 and #13 - strings loosened. In between, you can see the gap, about 2mm, where the middle of the fingerboard is 'lower' than at the ends. Same for the treble side. I have had other guitars with more bow than this.

Another of my guitars has a dead flat fingerboard - no gap at all with the ruler placed the same way. I understand that some builders add the relief, at least on the bass side, to allow room for the belly of the strings to resonate? Is this not accomplished anyway by the vee (string line relative to fret line) between the nut and saddle? Saddle adjustment can take care of bass relief, right?

Leveling the flat-fingerboard guitar with a precision aluminum block looks easy enough - just a fine-grit sanding, followed by a levelling of the fret crowns - therefore, flat fingerboard - flat plane of frets. But what is the procedure with the bowed neck? The plane of fret crowns should mirror the (curved) plane of the neck? Or, if I level the frets on a neck with relief, then there's no more relief - only taller frets in the middle.


Thanks.

Not quite sure what you're showing in the pix. To me, both of them illustrate frets that have been flattened beyond utility.

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Cheers,

Frank Ford

FRETS.COM
HomeShopTech
FRETS.NET

I'm hoping youre planning on replacing those frets. They're extremely low, like frank said, beyond playable

Thanks guys. The frets are higher than they look in the pics. The ruler is hiding them. I placed the ruler on the FB to try and illustrate the relief in one neck vs another. Top shows a flat neck with no gap; bottom shows another guitar with a gap (relief) in the middle.

Can you post another pic that shows daylight between the top of the frets and the fretboard? Right now it looks like the frets are sanded flat to the fret board.

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Brad Hall
Mystic Dawg Guitars

Post some more pics.
Is your ruler truly straight?

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wah
Wah-wah-wah-wah
Wah

The ruler is not precision straight but there is a gap on one neck and not the other, illustrating neck bow. I could post another pic, but all I wanted to explain is that there is bow in the neck of one guitar and not the other. I think it's common for some guitars to have bow and some to be dead flat. I am only interested in opinions about different fret guages and about levelling a bowed neck/frets.

Cat, I think your pictures are very confusing but I'll try to go back to your original post and answer your questions. First, I am not an expert on classical guitars - I have only built one - but I do work on them from time to time. I happen to have a little Cordoba nylon on my bench right now and took some measurements, so based on that and what I built...

The frets on the Cordoba measure 0.079 inches wide and 0.038-0.040 tall. This is a pretty generic medium medium fretwire, similar to StewMacs #0148. Thats pretty much what I remember using on the one I built. Jumbo frets are popular with electric players - remember that they go sharper when fretted by its pretty easy to compensate for that on an electric. People feel that large frets are easier to bend notes - not necessarily something you want to do on a classical.

I'm a believer in a little bit of relief for any guitar. The question is, what is the right amount. Classicals are complicated by (usually) having no way to control relief. The one I built had a small amount planed into the neck, slightly more on the bass side - I frankly don't remember how much. I do remember a discussion that builders could either plane the neck or the fretboard but many people objected to the appearance of a fretboard being thinner in the middle. If you are going to put relief in the neck that is probably your only option.

The Cordoba came to me with the complain of some buzzing - I found two frets that were slightly high and leveled them. When it came to me it had 0.002 inch of relief at the 6/7th frets tapering to nothing at the 2nd and 12th. When I held down each string at each fret and tapped it right over the next fret there was hardly any movement. I increased the relief to 0.004 (Cordoba is one of the modern nylon string guitars with an adjustable truss rod) - now when I tap over each fret I get a distinct "ping". I ended up with the 12th fret action at 0.125 on the high E and 0.140 on the low (I know its traditional to talk about them in mm but I work best in decimal inches).

On your guitar I would measure the amount of relief with string tension on and with none - are the strings contributing any relief. I would then pull the frets, level the board and sand or plane enough relief that when you restring it you will have somewhere in the 0.004 to 0.006 range. If you are lucky, the strings will pull that much and you won't have to put any in the board. The better your fret leveling and dressing the less you need, but I wouldn't go below 0.004.

You can't level frets when you have relief in the board. On a guitar with an adjustable rod I take all the relief out while leveling, then put it back in during the setup. No truss rod is a bit of a Catch 22 - the best you can do is level each three frets with respect to each other - basically rock each trio and level any that are high.

Others with more classical experience probably have a better way to approach this - I'll look forward to their comments.

btw - go buy a good 24 inch metal straightedge and some feeler gauges.

You're not going to get them until you answer OUR questions so that we can help you.

We need GOOD PIX of the fret height.
Get a REAL metal straightedge - not a piece of chipboard.

Thank you.

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"Act your age, not your shoe size" - Prince

Thanks for the detailed reply. Sorry if the pics are not that clear; they are the best I can do. Relative to the 7th fret, the gap between bottom of string and FB is greater than it is at F2 and F13. I placed the ruler on each guitar only to show the gap (from fingerboard to ruler edge) on one guitar and the non-gap on the other. The strings may be contributing a miniscule degree of relief but not any that I've measured. Visibly, the gap difference between the two instruments is the same either tensioned or loose.

Main question is about levelling the bowed neck and I think you answered this nicely.

Makes sense to me, because if you did level them, some would be higher than others. Therefore, any bow of the neck must be matched in the arc of the fret crowns. I wanted the endoresement from a luthier on this technical point. Thanks for that!

My conclusion:

The guitar (or any guitar) with the dead flat neck, I need only to check the level and very lightly sand to clean it up. You suggest adding relief, but I think the fingerboard was intentionally made flat. If there is undue buzzing after the refret then I'll know the importance of relief. I think the current fret buzz is due only to very worn frets, not the fingerboard being flat.

The guitar with the bowed neck, I must check three at a time with a fret rocker.


Would still like to hear any pros and cons about fret guage. You're right jumbos are really for electrics but I've seen them on classicals too. I'm really interested as to why, it seems, narrow nickel was once very popular but now larger frets are almost universal. Guess I'll refret with what's there (narrow guage) unless convinced otherwise.

In my limited experience the only way you can get by with a perfectly flat fretboard plane is if the frets are absolutely perfect and your action is fairly high. Most guitar techs will put some amount of relief into the neck - the question is how much. If you goggle "classical guitar neck relief" you will find articles by Kenny Hill, Yamaha, classical guitar discussion forums and others all recommending relief in the 0.003 to 0.010" range.

I looked at my 1937 Hauser plans and they call for 0.002 to 0.004" of relief with the strings "slack" (this was Segovia's guitar). It is also interesting that they show the thickness of the fretboard as 6mm at the nut on both the bass and treble side, and 4mm (bass) and 5mm (treble side) at the sound hole. Remember too that 2 thousands of an inch isn't very much - that is the thinnest blade on my feeler gauges. You need something better than a wooden ruler and a picture to measure it.

The Hauser plans do not call out fretwire size. I do not agree with you that "larger frets are almost universal" but if that's what you like then go for it. I put medium in all my steel string acoustics (and would use that on a classical) and jumbo on my electrics because thats what most players expect.

Good luck with your refret

The ruler is SS. What you see is just the cork backing, recessed about 2mm around the edges. I could have skipped the pictures - I only wanted to say that guitar A has visible relief, while guitar B appears to have a very flat fingerboard.

I do plan to precision straight edge the fingerboard once the frets are off. There may easily be some relief in the 'dead flat' neck but of course, measuring the frets and measuring the fingerboard are two different things. I will take your lead on adding some relief if there is none. A couple thou removed for improved playability is worth it.





What I meant by that is that older guitars that I see frequently have the original very narrow frets, compared with later to present-day instruments which have larger fretwire (talking of classical here), 'almost universal'. This is only my observation. I could be wrong but I can't remember seeing any new instrument recently with the kind of skinny fretwire that was in vogue a few decades ago. I was just wondering if, why, how, this trend came about.

Thanks for the constructive help!

The best straightedge you can get is a tight guitar string. Put a capo on the first fret, hold it down at the body joint (13th or 14th fret) and measure between the string and the 6th or 7th (both E strings). That will tell you if you have relief and how much. I also do the tap-each-string-on-each-fret test to make sure I have a hair of clearance - sometimes its too slight to measure but I still want to hear that little "ping".