Official Luthiers Forum!

On this last classical I put a 1/4" by 1/4" CF rod in the neck. Probably overkill. My question is, would a 1/8" x 3/8" single CF rod down the center be sufficient for a classical guitar? Seeing as you can build them with nothing in the neck I'b betting single 1/8" x 3/8" would be fine, but thought I'd ask.

Ron,
Your right, obviously you don't need any, and one would be better than none in my opinion. I think the in addition to building a stable neck, it really helps to even out the sound and elimintae dead spots along the neck.
Try building one of each and see what you like best.

_________________
Jim Watts
http://jameswattsguitars.com

a 1/8 x 3/8 on it's edge would be much stronger than a .250x.250

_________________
John Mayes
http://www.mayesluthier.com

Here's an alternative to CF, if you'd rather use wood instead:

I use a 1/4" strip of ebony as a neck reinforcement on my 10-string classicals. The necks are actually laminates, with the ebony sandwiched between the two pieces of neck wood. The reinforcement strip butts up flush with the bottom of the fingerboard, forming a "T" in cross-section. I have found this to be an extremely rigid method for neck reinforcement. Sometimes, if my fingerboard blanks are wide enough, I can use an offcut for the reinforcement strip. Otherwise, I'll cut up a fingerboard blank for the reinforcement strips. Either way, it's probably a bit cheaper than CF, as well.

Best,

Michael

_________________
Live to Play, Play to Live

John is right that 1/8 X 3/8 is stiffer than 1/4 X 1/4.
Here's the formula for I (moment of inertia)of a rectangle, I is the stiffness generated by the geometery or in other words it's resistance to bending, the bigger the I the stiffer the geometery.
I=b*h^3/12
b = width
h = height
I think there are other factors to consider other than just stiffness however including:
- The stability factor of the material.
- Sound transmission through the material which is a function of its density and modulus of elasticity (stiffness). Carbon fiber transmits sound differently than wood,(much faster).
I'm not advocating one over the other, just pointing out that I think there's more to it than just stiffness.



Jim_W38878.6267361111

_________________
Jim Watts
http://jameswattsguitars.com

Many thanx gentlemen

I will try the 1/8" x 3/8" and see how I like it.

I really like Mr. McBroom's idea. I will definately be trying that somewhere down the road.

Jim is that width times height cubed divided by 12?

A truss rod is an interesting addition to a classical. Theres more than one
famous classical maker installing truss rods and tensioning them up
before planing fretboard. Apparently the tensioned up truss rod enhances
the sound of the instrument.

Havent tried it yet but the next classical will have a truss rod.

I've recently made a classical neck from cedar and put an ebony reinforcement in it to stiffen the neck, but I put it on the back side of the neck so that it adds decoration as well. This neck was just an experiment initially as I had no intention of building a classical, well of course I am now in the middle of building one an 'homage' to FE19.



ColinColin S38879.2980208333

_________________
I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

Colin,

Strat "skunk stripe" huh, you old rocker you

_________________
Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

[QUOTE=kiwigeo] A truss rod is an interesting addition to a classical. Theres more than one
famous classical maker installing truss rods and tensioning them up
before planing fretboard. Apparently the tensioned up truss rod enhances
the sound of the instrument.

Havent tried it yet but the next classical will have a truss rod.[/QUOTE]

I've got a "Fleta" inspired guitar here that has a trussrod and bolt on neck.