Developments - New Neck Joint
In the past I’ve used 3 different types of neck joints-
1. Slipper heel neck joint- derived from the classical way of building nylon strung guitars, but I did it so that it was slotted and the neck went on after the body was built up
2. Bolt on- smaller instruments
3. Dove tailed- the way most of my instruments have been made
All these joints are successful, very strong and have great transfer of energy. However, I’m always looking to develop on things, so I wanted to revisit the Bolt-on neck. I feel for longevity there is an added benefit of having a neck which is totally removable and has a glue-less joint. Because there is a lot of tension in the neck of a guitar, this can create a lot of problems in terms of neck angles changing over time or the belling of the top making the once correct neck angle wrong. If the neck is removable then these things can be addressed easily. For me this was only a small benefit when thinking about neck joints. Without talking about neck material, very important consideration when designing any instrument. The most important thing is energy transfer between the neck and highly responsive body. If the neck absorbs vibrations you lose sound quality and if the joint isn’t solid or its to small the same thing happens.
Q - I wanted the joint to be bigger, I also wanted the heel to be much thinner A - Put the heel inside the body.
Using the wonders of a dovetail joint and a mortise and tenon this can be achieved. It is now glue-less, 2 bolts will take the neck off, but I have made it so that there is a greater amount/area of wood joining the neck to the body. In theory and principle, the energy transfer is better as there is more physical contact between the woods. The mass of the joint is greater and the heel can be thinned.
In terms of making- it is much harder to make than the dove tail because the joint is twofold. There is an extension which runs out underneath the end of the fretboard, past the 12th and 14th fret, down to the 18th fret. That is the critical point of the glue-less joint. It’s easy to bolt the neck onto the heel but it is difficult to tie the fretboard extension down without any glue. This area must be tied to the body as over time the joint would rise upwards under the string tension. Bolts could be used but why when the dovetail will do it as well?
I achieved this by putting a tilted fret board extension onto the neck, which slides onto the locating Dove tail housing joint on the guitar’s body. When the joint is first put together and the fret board comes down onto the body, the tilted extension means it doesn’t slide across the face of the guitar. This is important as you don’t want to scratch the lacquer on the nice shiny guitar you’ve just made. Then, there is threaded inserts into the heel block, and two bolts in which you attach it on. The tighter the bolts the more solidly the dovetail houses.
So, the major benefits to this joint,
solidity
removability
Slimmer Heel for access to high frets
Increased wood contact from a standard Dovetail therefore increased energy transfer
Longevity of instruments life being increased
I get to machine a beautiful joint and it makes me very happy!
I love moving forward on designs and ideas that ulitimatily make the instruments sound better and make them even more playable.