Although its mechanics are invisible on most acoustic guitars, the neck joint in guitar making provides fodder for endless discussions among musicians and luthiers. Three designs and their variations dominate acoustic guitar construction – dovetail, the mortise and tennon and the bolt-on. All three approaches are found on guitars of all price and quality levels.
A dovetail neck joint is a traditional woodworker’s joint. On a guitar, the usually the tapered dovetail is used it takes the form of a V-shaped (the tapir) , flared tenon on the neck’s heel, which is fitted into a matching mortise in the body’s neck block. Properly fitted, a tapered dovetail joint is very strong and lightweight, as well as, the way the joint is constructed, the gluing area is increased somewhat and the way it fits. results in a very reliable, stable and strong joint. The fact that it offers a larger area of direct wood-to-wood contact between the neck and the body, it positively affects a guitar’s tonal properties.
The bolt-on approach uses hardware to attach the neck to the body. In most cases, the bolts run parallel to the fingerboard and pass through the neckblock, meeting threaded inserts in the neck’s heel. Some designs also bolt the fingerboard extension to the top of the body. The biggest advantage to a bolt-on neck is that it makes repairs and adjustments very easy, because the neck can be removed without any complicated procedures.
The mortise and tennon joint that consists of a tennon that would be cut on the neck, that is straight, with no tapirs or angles that fits into a mortice that would be the ‘square hole’ that would be cut into the neck block. This, in the more traditional construction, would be locked in by putting a pin through the joint inside the guitar through the neck block. This too, could make repairing or adjusting easier as it could make the removal of the neck easier. This and the bolt on rely on good workmanship to ensure a good reliable joint