Classical neck angle

Construction and repair of Classical Guitar and related instruments
blanks

Classical neck angle

Post by blanks » Sat Feb 16, 2013 3:04 am

First, let me start by admitting I'm a total beginner. I've been reading Courtnall's book and can't quite understand how the right neck angle is accomplished. I see where the solera has a relief of 3mm which would raise or create a forward tilt on the neck (flamenco), but I don't see when building the neck that the slot for the sides or the reduction of the soundboard platform allows for the forward tilt. Wouldn't the top and neck go back to a straight line after removing from the solera? What keeps the angle in place?

Thanks and sorry for asking what is obviously a very basic question for all.

Adam S. Vernon

Re: Classical neck angle

Post by Adam S. Vernon » Sat Feb 16, 2013 3:20 am

Yeah, Courtnall doesn't explain that very well. The implication is that you have to cut a sloped line on the inner part of the heel block where it attaches to the top. You have to cut this area to account for the thickness of the top anyway, and at that time you slope it as needed. At least that's my understanding, having not actually done it yet. :lol:

Cumpiano also does not explain it, either. Bogdanovich provides a picture and instructions, but not much explanation. I guess the authors think it's obvious. :roll:

Brad Heinzen

Re: Classical neck angle

Post by Brad Heinzen » Sat Feb 16, 2013 3:27 am

When you use a solera, you typically glue the back on last. Until the back goes on, the sides will flex, allowing you to alter the neck angle pretty easily. Since the guitar is held to the solera when glueing on the back, the neck angle is locked in when the back goes on. The neck extension on the solera can be shaved down or shimmed up to change the angle that the neck makes to the body. In effect, the neck angle of your completed guitar is set by how far out of plane your neck extension is, with shims on the nut end of the extension giving you a neck 'set-back,' and a shaved down extension giving you a neck 'set-forward.' I happen to use a zero, or neutral neck angle, but that's just the way it all works out for me, given the doming I build into the top, the thickness of my fingerboard, and the height of my saddle above the soundboard.

blanks

Re: Classical neck angle

Post by blanks » Sat Feb 16, 2013 4:41 am

Thank you all. That makes sense. That's why you learn by doing and a teacher and not from reading... :roll:

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Les Backshall
Luthier
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Joined: Wed Mar 21, 2007 5:12 pm
Location: Aylesbury UK

Re: Classical neck angle

Post by Les Backshall » Sat Feb 16, 2013 8:51 am

There are quite a few threads on the forum about neck angles and doming a solera which would repay reading - neck geometry is a subject that none of the standard books tackles well. Also, it has been pointed out here that the 3mm angle in Courtnall is a mistake (misprint?) and he actually uses 1mm.

Here's an equation which explains how the various elements interact.

SH=(FB+FR+(A*2))-(D+N)

SH = Saddle Height (12)
FB = Fingerboard thickness (6)
FR = Fret Height (1)
A = Action at F12 (3.5 @ E6)
D = Doming at bridge (2)
N = Neck Set (?)

If you punch in the numbers from Courtnall - (in brackets above), you will see that for the 12mm initial string height, the neck set would be zero. However, although you want a low action, which 3.5mm is, you might want to shoot for 4mm for some 'wriggle room' - so 1mm should be ok. Personally, I find that a 3mm dome and a dead flat neck works fine.


Les
Lester Backshall, Guitar Maker - Aylesbury UK

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Brian McCombs
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Joined: Mon Feb 07, 2011 7:55 pm
Location: Union City, Michigan

Re: Classical neck angle

Post by Brian McCombs » Sat Feb 16, 2013 1:21 pm

Cumpiano doesn't go into any detail because his method is a flat build. Tapers the fretboard.

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