Sanity Check: Neck Joint Design

[Rob Carty]

This looks like it'll work in my head, but surely I'm not the first to attempt it.

I want to build something akin to a Les Paul Junior. There are a few things about LPJ neck pockets that I don't like. First, if you rout a neck pickup cavity, it can compromise the neck joint. Second, because there's no top, you have to use a pickguard or some other artifice to conceal the tenon. I'd like a nice top without a pickguard. I want a neck pickup. And I want something simple.

I've been thinking about ways to do this, and I came up with something like this, which is basically a super-extended tenon underneath a top:
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You might be wondering why I don't just do a neck-through at this point. I love neck-through guitars, but not this time.

Anyway, let me set this up. Here are the main parts, except the top. This drawing assumes a 5° neck angle.
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In the first step, I envision routing a big long neck channel in the body, using the 5° angle:
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Then I'd glue the neck into the channel, and shave the protrusion until it's flush with the body:
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Finally, I'd add the top, rout the pickup cavities, etc., and affix the fretboard:
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I don't know how much this will improve neck-joint stability over the traditional LPJ, but the body will be thicker and the tenon will be longer, so I have to think there'll be some improvement. The top will also conceal the joint and look pretty.

Has anyone seen this before? Either way, can you see any material drawbacks? Thanks, everyone!

--Rob

[Barry Daniels]

Your drawings show something much greater than a 5 degree angle.

[Bob Gramann]

I don’t think you’ve solved the problem of the neck pickup rout taking the strength out of the joint. You can experiment with cheap wood until you get something you’re satisfied with.

[Freeman Keller]

Rob, Melvyn Hiscock has a good discussion on LPJr/SG neck joints and their weaknesses. I think there are several things that can be done to improve the design. Certainly running the tenon under the neck pickup as is done on LP's gives more gluing surface. I question the need for 18 or 19 frets clear, you loose a lot of side support on the neck,.

Having built a number of set neck electric guitar I think the hardest part will be setting the neck geometry. I think you'll find the angle will be less than five degrees but that depends of course on your bridge and the amount of overstand you choose. It can be calculated either graphically as you are doing or consider RM Motolla's new calculator.

So yes, I think it will work, but it will be a lot more work and has several potentials to go wrong.

[Freeman Keller]

I'm sure you have seen this, a LP style neck with a little bit of the tenon extending under the neck pickup.

What I think you are proposing is to extend that to the bridge and however much farther it need to be so you and make it flat and then cover it with your veneer. Obviously much easier to do with a flat top than carved and you will need to introduce some overstand but certainly doable.

[Rob Carty]

Thanks, Freeman. Yes, it was Melvyn's discussion that brought the problem home to me; until I read his book, I'd honestly never given it any thought. (RIP Melvyn! He and I connected on Facebook back around 2012 and I considered him a friend.) I'm not wedded to the five-degree angle -- that may change and I've just used it here for demo purposes -- but I've done full-scale drawings based on the bridge I'll be using and it definitely works.

[JC Whitney]

Stemming from my concerns regarding: grain runout on the angled approach…. Perhaps consider doing a full depth thru neck with grain parallel to the face of the guitar instead (along the lines of the “hippie sandwich” approach, or Melvin’s eight string bass build)? Could conceal with front and back face laminations if desired.

[Rob Carty]

Thanks, JC. Runout is definitely a consideration, but here it doesn't bother me much. My neck pitch will likely turn out shallower than five degrees (again, that assumption is just for demo and drawing purposes), and the neck will be laminated with quarter-sawn boards. I've done neck-through guitars with similar specs and they've turned out really stout. Here, the neck "tenon" would taper (unlike a neck-through), but it would also be encased in a hard body and top. It's interesting ... I was expecting someone to respond with "Brand X tried that years ago and it [exploded horrifically or worked fine]." Surely I can't be the first!