Official Luthiers Forum!

In the repair world we often run into a neck where someone has attempted a dovetail reset prior and hacked it up beyond recognition.

In our trade we have the unfortunate reality of people thinking that they understand some of these operations when they don't and they dive in and ruin what might otherwise be an heirloom instrument with a century of service or more.

It's so bad... the poor prior work that it is perhaps the second major consideration at times beyond what is actually wrong with the instrument but I digress.

When this happens we have two choices. We can do something similar to what you did and reconfigure the dovetail to a bolt-on or rebuild the dovetail and pocket by adding wood in the form of glued on shims and then refitting as a dovetail is intended to be.

When we have to do a bolt on our preference has been a bolt-on butt joint as simple as it gets.

My concern about the bolt on point being in the heel cap area is two fold. One the torque on the joint is highest at the furtherest point from the pivot point which for the forces acting on a neck with string tension over time is near the fret board. Call that our hinge as the neck tries to fold into the body.

Second not only are the forces we need to counter with our bolt greatest at the base of the heel the amount of wood there depending on your heel design may be the most minimal.... Is that a term, most minimal

Most of what I see folks here do and I did on my bolt-on guitars was putting the two bolts through the neck block where there is more heel to grab onto.

Not trying to reengineer your joint and thanks for the description I just have never seen anyone place a bolt in the heel cap area and when they did it was for a strap button which is also problematic for the same reason less wood leading to it failing and coming loose. The guitar also has a tendency to flip on its face with a heel mounted strap button so we won't place them there.

Maybe consider just going to a bolt-on butt joint which is an excellent joint in my view and the simplest one out here?

Same applies to bridges....

_________________
Peter Havriluk

I didn’t explain myself very well. I’m just doing a normal dovetail joint. I figured out a way to hold it in place with a bolt rather than glue. The joint is structural all by itself. I’m just considering holding it from moving with a bolt.

Your point about future maintenance of a dovetail is noted. I can only imagine what you’ve seen.

Here’s a question. How good do you think carbon fiber rods are at preventing the need for neck resets?

Thomas—

You might want to look into how Grit Laskin does dovetail neck joints. A number of guitar makers do it this way, having learned it from him. After fitting the dovetail in a traditional manner, he drives a screw through the body’s headblock into the face of the dovetail tenon. Threads are created in both pieces of wood, not just the tenon, so the two pieces of wood do not pull together. The point of the screw is not to act as a screw, but rather to act as a pin that is easy to put in and take out, due to being threaded. The pin keeps the tenon from sliding out of the mortise in the only direction of movement available to it. This replaces the glue otherwise used in the dovetail joint. Glue is only used under the fingerboard extension. It is a proven method of using a traditional dovetail neck joint, but avoiding the use of glue in the joint, thereby making future neck resets less traumatic for the guitar. I don’t speak from personal experience with this method; I’ve used glue in the dovetails I have made. But I’ve read a lot about it, and Grit Laskin is a pretty big name, so if he uses it, it probably works.

Thanks, I’ll look into that. I had discounted using a screw from the neck block, because I thought it would pull the joint together. I hadn’t considered threading the neck as well.

Actually one of the major pro finishers does exactly that finish with the neck set and attached to the body. Lots of builders here who have used this finisher in the past had our guitars finished this way and I had some done early on by this finisher too.

I moved away from it in 2007 for the reasons I state in my posts here it reduces serviceability, the SQ if you will and it makes neck resets more prone to require additional finish touch-up.

Oddly this finisher has a method that he says makes it not difficult to finish with the neck attached and this of course includes the sanding in the joint area. I agree with the separate finishing camp and think it would be much harder with the neck attached.

Guild did it too back in the day and combined with Guild's very thin heel that commonly breaks in the reset process they are a real PITA and some shops avoid them.

Thomas I'm chucking here because we all do what you just did and that is consider how we might make the need for a neck reset be delayed or avoided all together.

I used CF in 50 or so of my Heshtone guitars to do exactly this and the jury is still out on how successful my implementation of CF usage has been. None of the neck angles have changed in 20 years so far on my Heshtone guitars.

My strategy was simple and kept as much of the traditional acoustic guitar design as I could because I would rather have to do a neck reset than play a guitar that sounds like a bucket of bolts and weighs 6lbs for decades hating every moment of it.

I used 0.020" CF sheet sandwiched in my UTB (upper transverse brace) coupled to reverse kerf linings but without the loads transmitted any other way anywhere else which might have been a good idea but it added complexity. I also used a neck block that is massive and twice the depth or a typical neck block. My OMs still came out under 4lbs most of the time depending on the back and side woods, etc.

Will it work? Who knows I'm 68 and so far so good

But there are hundreds perhaps thousands of different ways that others have employed CF to try to build a better mouse trap and the jury is still out on their implementations too. I'm not keen to like ep*xy in a guitar beyond pore filling and ep*xy often goes along with CF use, not always but frequently.

Howard Klepper is someone to check out his use of CF and butress implementations too. Some will use CF rods to transfer loads from the neck block area to the tail block and so on and so forth.

I don't object to most of these implementations but I've seen CF use cause other problems that were expensive for the owner to undo. CF neck reinforcements when too stiff can render a truss rod ineffective and/or even encourage it to break. I've seen both with the ineffective part being most common. Necks need to be flexible to counter RH swings, different gauge strings, different tunings, etc.

Not to commit heresy here (it wouldn't be the first or last time for me... ) but what's wrong with learning to use and set a proper dovetail joint and then when neck reset day comes 32 years from now and we are still kicking but in our PJs with feet in them craping on our selves all day resetting the neck when it needs it? It's really not that hard, the reset.... especially if the dovetail was set correctly and the luthier did not pour a bucket of glue in there and glue the cheeks to the sides.

Here is a link to what Howard does and his workmanship is as beautiful as it gets.

http://www.klepperguitars.com/about.html

Another innovative builder RIP was my friend Rick Turner. He is who challenged me to learn repair work nearly 20 years ago. I like a challenge...

Rick was a fan of tops that were not domes but cylinders like the ole Howe Orme guitars that he collected. The Cylinder is uber strong and permitted the top to transfer loads from the neck to the tail block and further distribute the loads to the rim.

Rick built under commission a guitar that successfully went to Antartica and was gigged there. Pretty cool. He also built Jerry Garcia's peanut guitar and many of the guitars that Lindsey Buckingham of Fleetwood Mac uses to this day. Rick had a customer list that reads like my iTunes play list.

He once told the OLF that many of us here were building "GLOs" standing for guitar like objects....

My experience has been that the most successful implementations that seem to work using CF are a combination of CF, design, engineering and history. I say history because both Klepper and Turner pulled from historic instrument with the butress and cylinder top ideas but also employed CF judiciously following engineering best practices to direct and transfer loads.