The dovetail joint is borrowed from furniture making where it used to create a visually attractive connection that incorporates the pressure of wedge geometry to reduce play and creep, creating a tremendously firm and rigid joint. The mortise and tenon are glued together to better seat the halves. A guitar neck’s dovetail joint differs greatly from those used in furniture in that the joint incorporates empty space within it so that the luthier can dial in the perfect neck angle as the neck is seated (there is no “air” in a furniture dovetail joint, normally). Still, adherents claim that the dovetails tightness results in greater tone as a more rigid neck will absorb fewer vibrations from the string. The fact that they were used on coveted, vintage Martin and Gibson guitars is reason enough to employ a dovetail joint for many. On the negative side, seating a dovetail joint can be far more difficult and time consuming than a bolt-on, and when it comes time to do a neck reset on the guitar (to correct the action), loosening a dovetail joint involves the relatively difficult maneuver of injecting steam into the joint using a narrow, hollow pin inserted into a hole drilled (inconspicuously) into the appropriate fret slot above the joint.
The “pros” of using a bolt-on neck are implied by the negatives of the dovetail! It’s much easier to set-up and rout the mortise and tenon, to seat the neck and to repair the joint, if need be. In a factory or busy shop, time is money and because of this, the bolt-on neck’s popularity has grown steadily over the years.
Some argue, that the sound of these guitars is not as robust as in a dovetail instrument, but there are many who strongly disagree with this opinion. In reality, there is just as much solid wood contact in a bolt-on joint as in a dovetail joint. In the end, it can be difficult to point out exactly what is creating an improvement or decline in tone quality with so many factors at play in any one instrument and with the supposed differences between them being so subtle.
One thing is for sure though. The sometimes daunting job of routing either a dovetail joint or a bolt-on mortise and tenon joint, with all its particular geometry, is made much, much easier when using LMI’s clever Neck Joint Jig, designed by Robbie O’Brien. Click the link below to learn why this tool is so popular with today’s luthiers.