Neck Angle

[Graham Long]

Hi,
Can anyone tell me what angle the neck should be set at on a steel string guitar. Most of the things I've read say they should be 90 degree or in other words co-planar to the body. I recently got a set of Martin D28 plans which shows the neck angle set at about 1.5 - 2.0 degrees.
Cheers
Graham

[Ron Wisdom]

Mine are very close to 2 degrees, maybe a hair over.

Ron

[Allen]

Depends on the top geometry. How much radius you build in. Mine are about 1.5 degrees.

[Nick]

As Allen stated, it very much depends on what top radius you are using. I use a 30' on my flat tops which, like Allen, seems to come in at 1.5 degrees. Best bet would be to physically measure the angle once the 'box' has been closed. Cutting the neck to a specific angle because "that's what everyone uses", then finding it differs from the actual angle formed between the top & neckblock could be frustrating

[kiwigeo]

Cutting the neck to a specific angle because "that's what everyone uses", then finding it differs from the actual angle formed between the top & neckblock could be frustrating

It can turn into a disaster..don't ask me how. The important thing is to understand the geometry of the top and realise that how the strings lie relative to the top of the bridge should be used as the indicator that you've arrived at the correct neck rake angle.

[ozwood]

Hi,

I always use a Bolt on Neck System , Cause I don't want to Commit to a neck angle till I have Finished the Box , and can Place the bridge in the Sound board and do my final adjusment from there .

Learnt that lesson the hard way.

Cheers,

[peter.coombe]

Measure with the bridge in place, then measure again just to be sure, then cut the neck angle on the neck to the measurement. Don't worry about what it measures because it will depend on how much you dome the top, but my 3 guitars have been around 1.5deg.

[Trevor Gore]

The best way to set the neck angle is...not to measure the angle!

You are primarily interested in two things - the string height above the twelfth fret (say 2.5mm for the 4th string) and the string height above the soundboard at the saddle position (say 14mm at the 4th string). However this knocks on into a whole stack of other things, like the doming of the top, bridge height, saddle protrusion, effect of relief on action, etc. etc..

You don't have to do it this way, but many builders, including me, like to have the top of the neck coplanar with the upper bout, so you can glue a straight fretboard down flat. So, in fact, it is the longitudinal tangent of the upper bout projected over the saddle position that determines the neck angle, not any angle the heel makes with the sides. That angle just needs to be fitted to suit. If one of the standard top domes is used, e.g. ~8m or ~10m you will end up with a string height above the saddle that is too high (well, higher than the 14mm I use). So you need to flatten the upper bout (usually by reducing the curvature on the upper transverse brace) until the projection of the tangent over the upper bout comes out at ~2.5mm at the saddle position. Then when you add the fretboard, the frets and the strings at the right action you get to the target string height above the saddle. Keeping to a tight target helps give you consistency in the sound.

If you prefer to play with a fair amount of relief in the neck, the relief effect normally adds to the action, so you have to take into account the relief effect. If you don't, and just add relief to a system that's been computed around straight lines, you will get either a higher action or lower string height at the saddle than you wanted. Further, if you drop the saddle height to get the right action this gives you a "ski-jump" effect on the end of the fretboard, which you then have to remove if you're looking for outstanding playability.

Classicals are a different story altogether!

Most books don't explain any of this stuff or how to do it "properly".

[Graham Long]

How much influence does the shape of the fret board have?
Should the radius be consistent over the fret boards length or should it be graduated from the nut to the sound hole.

[Trevor Gore]

How much influence does the shape of the fret board have?
Should the radius be consistent over the fret boards length or should it be graduated from the nut to the sound hole.

Once the radius of the fretboard is greater than ~16" it doesn't matter - the difference between a constant radius fretboard and a compound radius fretboard is smaller than the build tolerances that you can expect to work to.

At the other end of the scale, about the smallest nut radius that doesn't give fret-out problems on big bends is ~10". A typical compound radius would then be 10" at the nut, 12" at the 12th and 14" at the saddle on the acoustic guitar string spreads that I use.

Depending on the strings you're using, it often pays to have the saddle a slightly smaller radius than the fretboard because the centre strings (3rd and 4th) frequently need a little more action. For string height above the soundboard at the saddle I usually reference the centreline (that's the 14mm in my previous post).

[woodrat]

The best way to set the neck angle is...not to measure the angle!
.

I love empirical extrapolation!

Thanks Trevor, I am just playing with this at the moment with my latest batch. It is extremely subtle I think and I am glad that someone in a book actually told you what is happening instead of the vagueness that we have had to endure until now....

John

[woodrat]

The best way to set the neck angle is...not to measure the angle!
.

I love empirical extrapolation!

Thanks Trevor, I am just playing with this at the moment with my latest batch. It is extremely subtle I think and I am glad that someone in a book actually told you what is happening instead of the vagueness that we have had to endure until now....

John

I have just completed the neck building/carving/fitting/alignment on two of my latest cutaway Journeyman guitars using the procedure that is outlined in the G/G book and I have to say that it made the whole process much faster and consistent and accurate...altogether a much pleasanter experience now that I have some rock solid methodology...
The fingerboard is beautifully straight projecting over the body using this method and should result in being very close to the target height for the "Perfect Guitar" that the book guides you towards.



John