Neck Angle Question

[BudHa]

I have a simple question about neck angle. After a guitar is built and settles in, will neck angle changes be typically a result of the growth of the belly of the top?

I have a recently purchased 30 year old guitar. The neck relief is set at .006". There is a belly typical of a new Martin D-28. A 24" straight edge across the frets to the bridge sits about 1/16" below the top of the bridge. The saddle has been shaved to what I consider a maximum shave. The action of the low E at the 12th fret is 3/32". It seems to me the neck angle may not have been correct during the build process of this guitar. I would think there would an obvious belly bulge with all these other indications. What am I missing?

Thanks for any thoughts.

[Rudy4]

Originally Posted by BudHa

I have a simple question about neck angle. After a guitar is built and settles in, will neck angle changes be typically a result of the growth of the belly of the top?

I have a recently purchased 30 year old guitar. The neck relief is set at .006". There is a belly typical of a new Martin D-28. A 24" straight edge across the frets to the bridge sits about 1/16" below the top of the bridge. The saddle has been shaved to what I consider a maximum shave. The action of the low E at the 12th fret is 3/32". It seems to me the neck angle may not have been correct during the build process of this guitar. I would think there would an obvious belly bulge with all these other indications. What am I missing?

Thanks for any thoughts.

What you're missing is neck angle often changes over time, and a 30 year old guitar might be getting ready for a neck reset.

Your straightedge should be above the top edge of the bridge, so that's indicating typical neck angle change for a 30 year old Martin (or any other conventionally built acoustic guitar).

[BudHa]

Originally Posted by Rudy4

What you're missing is neck angle often changes over time, and a 30 year old guitar might be getting ready for a neck reset.

Your straightedge should be above the top edge of the bridge, so that's indicating typical neck angle change for a 30 year old Martin (or any other conventionally built acoustic guitar).

Thank you. You answered my fundamental question. I was not sure if neck angle could change independent of changes to the guitar top. I have always assumed there would be a measurable change in the belly bulge associated with neck angle changes over time.

[RonMay]

I have a 50 yr old Regal Jumbo Western, and mine has no belly bulge but the neck angle is about 1/32 below the top of the bridge.

I think it's time for a neck reset. it just happens over time and that's typical for old guitars, especially a 50 year old one.

It sounds like you have the same thing.

Ron

[redir]

Think of it this way, that the guitar is trying to close itself like a book right at the body joint. So belly bulge is certainly part of this equation but not the most significant part. If the bulge is excessive causing high action then you probably have other problems like loose braces or a cracked bridge plate. A neck reset would not 'fix' that problem.

[charles Tauber]

To be clear, the common reason for a neck reset is due to deformation of the body, particularly rotation of the upper bout of the guitar, as if trying to fold in half "into" the sound hole. The neck, being attached to the upper bout, goes with it. In so doing, it raises the height of the strings over the frets.

Excessive "bellying" of the lower bout of the top is rarely the cause of a neck reset. If bellying is excessive, its cause is usually related to loose braces, an un-glued bridge, cracked bridge plate or simply having been under-braced for the intended load.

A neck reset does not attempt to correct the deformation of the guitar body. Instead, it establishes a new neck angle that accounts for the deformation of the body, mostly of the rotation of the upper bout.

[BudHa]

I really appreciate all of the good information you folks have given on this subject. It is obvious I have never fully thought through the physics of neck angle changes over time. Thank you.