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I'm having trouble understanding an issue of setting the neck angle that I am reading in the Making Master Guitars (Courtnall) book.

Let me start with what I know so far. I have built 2 classicals using the Cumpiano book as a guide. In his method, the workboard from the neck to the upper bout is flat so that the neck when attached to the soundboard is on the same plane as the upper bout of the top. This makes attaching the neck a very straightforward process. Since the neck and the upper bout are on the same plane, the "neck angle", for lack of a better term here, is planed into the fingerboard itself so that the fingerboard slopes downward from the nut to the soundhole.

The Courtnall book approaches this differently (the Bogdanovich does as well). The neck area of the workboard is sloped downward by 2-3 mm so that the neck ends up in a positive angle (the nut will be higher than the soundboard-the exact opposite of the steel string guitar). This is shown on page 165 of the Courtnall book, fig. 11-4. On page 243, figure 19-2 shows a summary of how all of the parts go togther on the workboard.

Here is my question: It seems to me that if you put the neck on the workboard (which has been tilted downward) the neck will rise up where it is supposed to meet the soundboard and it won't lie flat there. In addition, because the neck is tilting up, the slots that were cut into the neck to receive the sides will be tilted back slightly rather than straight up and down as the drawing indicates.

I have not been able to find an explanation of this in either book. I have, however, found a small discussion of this in the Middleton Book (A guitar Makers Workshop) on page 85, where he briefly talks about "cutting the neck joint at a slight but critical angle" when you need to angle the neck above the front plane of the top.

What am I missing here?

Thanks for your help.

Sam,

The first style you describe is used by a number of builders including Torres. It requires you to taper the fretboard thickness as you mentioned.

The second style leads to a gap between the fretboard and the neck and top since the neck is rotated forward slightly relative to the plane of the top. This can be taken care of by planing a taper into the underside of the fretboard from the 12th fret to the soundhole, letting the fretboard to then fit into the neck-to-top angle,

Either way is used frequently. I've noted that guitars from some of the Granada builders have the neck pitched forward even more than the amounts you mentioned, requiring a fairly thick fretboard to allow for the taper and the fretboard-body join.

Jim

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Jim Kirby
kirby@udel.edu

p.s. The tilt of the neck does indeed imply that the sides aren't perfectly vertical at the heel joint, but this isn't noticeable.

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Jim Kirby
kirby@udel.edu

Hi Sam.

My personal method is to use the neck angle built into the solera.

It sounds like people are marking out their neck slots at 90 degrees to the neck.
I mark mine out at 90 degrees to the soundboard.

The set up of your solera will determine your neck angle.
The upper bout on my solera is flat.
The neck projection on my solera is 2 mm

Put your neck and heel onto the solera in its correct position, and clamp it on.
Put a square on the upper bout of the solera.
In line with the grain, not across the grain.
Line up your square adjacent with 12th fret on the heel block, and then pencil the line in.
You neck slot marks are always going to be at 90 degrees to the soundboard with this method.
Irrespective of the neck angle.
So the sides of the guitar are going to always end up square with the upper bout if the sundboard at the neck join.

Fingerboard neck angle gap:
I don't bother to plane the bottom edge of the fingerboard.
Its a headache.
There is an easier way of getting rid of the neck angle gap problem with a bit of care.

Pre slot your fingerboard.
The slot kerf gives the fingerboard a bit of play so that you can make it bend a little at the neck/body join when clamping it down during glueing.

Glue the fingerboard on.
This will give you a fingerboard with an angle at the 12th fret
But all is not lost.

Once its glued on and the glue is set then you can level the fingerboard.
I use a shooting board as a leveling tool.

Its not without its dangers but I find it the lesser of two evils.

I glue some aluminium oxide paper onto a flat straight shooting board and then when the whole thing is dry i clamp the shooting board onto a flat bench.
Move the job, and not the tool.
You get better control this way.
Be careful to protect the soundboard.
If you want you can put shims under the shooting board, which will help you alter the amount of string relief you want to build in.
Personally I like mine dead flat.

Be careful though
If you're one of these people who proflie the back of the neck after you have glued the fingerboard on, I would recomend profiling the back of the neck before you level the fingerboard as a risk management precaution just in case the neck decides to warp after you carve it.
Its happened to me.
Murphey's law.

I have used this method and i find that it works best.
I don't have any problems with intonation or with driving the fret tang into the slot on the 12th fret where the kerf has compressed, so long as i have used the approriate sized fret.

Cheers,
Claire

Jim - After reading your comment on tapering the fingerboard I looked at the chapters on making the fingerboard. Both books mention having to taper underneath the fingerboard as you mentioned. I had not read that before. The Courtnall book gives a more detailed explanation of how to do it than the other book.

Claire - Your method for the neck slots makes perfect sense. That looks like the way I'll do it. I'm thinking the books don't mention it because it is probably a very small difference in the placement of the slots as Jim mentioned. But your way is very easy to visualize and understand. Thanks for your detailed explanation of your entire process.

Does either method have any other effects on the guitar? Is it purely a matter of preference?

Claire - I taper the underside of the fingerboard as follows. I have a fingerboard-length block with the tilt of the neck relative to the solera planed into it. I double-stick the fretboard face down to this, and then pass the block and fretboard under a safe-T-planer, taking very light cuts until wood is removed back to a line indicating the 12th fret location on the fretboard bottom. Done. It's pretty easy. I'd rather do that than risk chip-outs on the fret slot edges while planing the top back to level.

Your guitars are oh-so-gorgeous, by the way.

Sam - I'm not experienced enough to say, but I think it's just preference.

Jim

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Jim Kirby
kirby@udel.edu

Im trying to understand the attractiveness of this second method.It seems more complicated and appears to give the untrussed classical neck a headstart at bending and imploding at the sound hole.........i must have missed something

Presently I'm using the combination of a domed solera, a somewhat smaller "lift" built into the neck of the solera, as well as fret board taper to achieve the right action/bridge height. The very slight springing of the back is also reduced somewhat to a negligable degree.
The use of only either the "lift" or tapering the board means the choice of an ungainly join at the neck/body or an overly thick fret board at the nut end.
I think the judicious use of all these techniques in concert imparts a more sophisticated geometry to the instrument.

http://www.guitarsbydavidlaplante.com

Claire, these are very good tips and I pretty much do it the way you have described with the addition of a carefully fitted and taped poster board "mask" to protect the top from ebony dust. I use an old wooden plane body with sandpaper to level and true the board.

One very interesting thing I learned by making a precise copy of the '37 Hauser a few years ago was the reason (I think) why he inserted a layer of ebony veneer cross grain in the underside of the fret board between the 12th fret and the soundhole end, this along with the fret slots makes the board extremely flexible in this area easily conforming to whatever angle is present at the neck/body join.

Best!

I do what Claire does.
Worksgreat for me !

I've fixed to many old Spanish guitars with super high action and no way to bring the strings down.
I have to either do one or two things to get them in playable condition.
A reverse taper of the f.b and a refret!
Or that combined with making the bridge a 12 holer to help get a angle
between the tieblock & saddle reestablished !
That way the lift knot a 6 hole bridge has is gone.

MIke

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Mike Collins

Sam, for a 3mm neck drop in your solera, a la Courtnall, results in only a .52 degree deviation from 90 degrees of your sides to your soundboard. At the bottom of your heel (assuming a heel depth around 90mm), this rotation translates into the bottom of your heel slots (worse case) being off around 1mm from a line normal to soundboard, half the width of your sides.

It's small. Not a very good picture but if you look closely the red vertical line shows the deviation from the front of the slot.

I use a mold, and a very tall one it is - I had to file a ramp of a couple mm to allow for that play otherwise it was very hard (and very unhealthy) to lower the neck.

It looks like the more I build, the less need i feel for a neck set. My last guitar had only 1-1.5mm and the next one will have zero . I used to plane the underside of the FB from 12th to 19th to make it fit, and after glue-up, i always needed to plane the 1st to 12th to achieve the geometry i am after. The end result was a more or less constant height FB from 1st to 19th! Lots of complications and detours to arrive where a short straight path would lead....

If I am not mistaken, the math is simple: Flat neck, 6mm FB - 3mm solera = 3mm distance between FB plane and top. 8mm bridge, 11mm distance from string to top. 8mm - 1mm (fret height) = 7mm / 2 = 3.5mm 12th fret action. You get the standard action, a constant height or near that FB which for many people looks better than a heavily tapered one, you get a good distance between strings and top. You also have sufficient saddle to achieve very low action if needed, or to correct a neck problem.

I think that necks with strong positive angles coupled with heavily domed soundboards are more or less time bombs. If the neck goes even higher in time, you have no saddle left to correct it, and you'll need to shave the bridge, or change the FB. There are players aware of this and usually reject a guitar with a tiny saddle.

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Build log

Steve,

Why did they start using a postive angled neck in Spain...don't now, but I could try to imagine. First of all, 50 or 100 years ago, there was no internet, no LMI, and they were far fewer builders. Most of them would have rather died instead of giving away any of their secrets. So you end up inspecting the guitar made by a master and you try to replicate his system. The domed soundboard is a problem, you can ask yourself was it intentional, or was it caused by the pull of the strings for the past xx years? And think that using a dished solera with forced in fan braces is not a very intuitive method, which is not used by everyone even today. Or maybe you just don't want to bother with it and want a flattop because you think it will sound better.
It is likely that not knowing about the dished solera, you'll start building with a flat top, maybe expect to bend it a little by forcing it in a scooped bridge (I read this is what Hauser devised when started copying Torres)
And such flattop guitars are unplayable unless using a monster tall saddle which of course is 5-fold no good.
The neck-set was a fix for this imagine.
and later they discovered the domed soundboard again, and the result is a flamenco bridge geometry on a classical.
It is interesting to look at the Romanillos solera. I believed it started as a regular set-neck, and later he modified it to have a higher positioned dish. The two deviations cancel each other and you get more or less the Torres flat.

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Build log

Thanks everyone for all the replies. I wasn't sure if my question made sense or not and you all got my point perfectly and answered my question.

I'm not sure yet how I'm going to approach the next guitar. I already have a bolt on like the other 2 in progress with the angle planed into the fingerboard and the neck and upper bout on the same plane.