This is for my woodworking nerds out there: converting a bolt-on into a set neck.
Our buddy Anders Osborne comes to our store pretty regularly with unique requests, but this one takes the cake. He had a custom-made Delaney guitar built with a cypress siding from the house he’s been hanging on since the devastation of Hurricane Katrina. Mike Delaney used the cypress for the top and Honduran mahogany for the neck and body. The guitar sounds amazing and means a lot to Anders – especially since it was built to replace his stolen 68 Les Paul Deluxe. But there was always something lacking in the feel and sustain of the instrument, and he believed this was because the guitar had a bolted neck, as opposed to a traditional Gibson-style mortise and tenon saddle neck. So he brought it into play to talk about converting a bolt-on neck to a set neck.
There is nothing wrong with the screwed neck construction, but it has different sonic properties than a set neck. A bolt-on has a lighter, more snappy attack at the front end of a note because the string vibration is transmitted via four metal screws and a metal plate. It’s a great sound that is synonymous with that classic Fender sound, but it lacks the resonance and sustain that a set neck has when the two pieces of wood are joined by glue. Anders was looking for the latter on this guitar, so I found a way to make this a reality for him.
I removed the neck and sketched a plan for cutting a tenon in the neck pocket. Then I sanded the area flat to give the obstructing neck heel a square mating surface.
I made the first irreversible cut with our proven Festool plunge milling machine. Point of no return.
That was the easy part. The next phase was the creation of a neck ledge / tenon. I decided to make two small dovetail joints that flank the truss rod, so I glued a three-piece, quarter-sawn Honduran mahogany block together to match the existing neck lamination.
Then I cut the dovetail channels in the neck and tenon block. These cuts have to be right, otherwise the laminations of the neck and heel would not line up and that is of no use.
Once the dovetails fit, I cut and shaped the tenon into the other side of the block.
After I clicked the test seat into place and it looked good and well fitting, I glued the peg to the neck.
Setting a tenon and tenon neck angle is basically the same process as setting a dovetail joint on an acoustic guitar. On this guitar, I adjusted the angle of the heel to line up with the Tune-O-Matic bridge at its nominal point on the up and down stroke, and centered the action of the strings to be symmetrical with the edges of the neck.
Once I had the corner of the neck where I wanted it, I carved and shaped the heel of the neck. This is much easier to do before gluing the neck to the body.
Since it used to be a screw-on, I just used the existing screws and holes to glue and clamp the connection. It worked perfectly!
I let the glue line sit over the weekend then took out the screws and neck plate and doweled the holes by first countersinking a 1/8 “dowel rod and then covering the holes with mahogany dowels following the grain pattern.
A few coats of gun oil later and you’re good to go!
The conversion definitely made a noticeable sonic difference, and now the guitar has the Les Paul vibe that Anders was aiming for. What a fun project and a cool guitar!