As a guitar repairman, I glue a lot of headstocks back onto guitar necks.  In many cases the guitar has been dropped, or has fallen from a stand, and the headstock has snapped on impact.  More often than not, it will be hanging on by its headcap.

This diagram represents a side view of a one-piece neck.  As you can see, the grain is aligned with the direction of the neck. So when it comes to the headstock, the grain is very short and can snap easily.  To compound the issue most acoustic and many electric necks are made from mahogany, which already has relatively short fibres.  This means that the area around the headstock is really weak.

Another way to construct a neck is to use a scarf joint.  This way, you have good, long grain in the weakest point. The neck is therefore much stronger.

What I don’t like about this joint is that you can see the “shark’s nose” shape that the joint leaves on the neck.  Most players won’t even notice it, but I’m fussy when it comes to joints. I prefer to hide them.

This third diagram shows the method that I use for the custom guitars that I build. By doing this, I am able to hide the joint with a rear headcap.  This headcap also adds strength.  I figured that if a broken-off headstock often hangs by the  headcap, then a rear headcap is likely to help prevent it breaking in the first place.

I also think it looks great.  This rosewood headcap hides the joint nicely, and really accentuates the contour of the volute.

What do you reckon?