Intregral Neck Extension And The One Piece Archtop Guitar Neck.

[Gilbert Fredrickson]

I have the perfect piece of wood for a one piece neck with an intregral neck extension. Any suggestions on how to carve and join this neck to the body? I'm using the Epiphone Spartan plans. The original scarf joint neck extension does seem to work well, however.

[Chris Richards]

I would have thought it's not possible, I can't see how you could cut a dovetail with the neck extension in place. The only thing I could think that you could do is use a different type of joint maybe something with dowels? My other thought would be go ahead and cut the neck out of the one-piece sized wood that you have then saw the neck extension off, cut the dovetail and then glue the extension on again...At least all the grain would match and the joint would be pretty much invisible.

[Mario Proulx]

Do a simple bolted "butt joint".

[Gilbert Fredrickson]

Yes, a simple bolted butt joint, like a Baroque violin neck joint, would do well. Since I am using all hand tools, this is an attractive option. I feel that I might be able to do a straight mortise and tenon, though for this guitar, I will probably use some regular neck stock and go with the scarf joint glue-on neck extension as shown in the plans.

[Chuck Tweedy]

So, this is how I did what you are talking about, but for a flat-top guitar. I built about 3 or 4 this way.
It has a continuous FB extension, with a mortise and tenon joint at the body.
I used a CNC mill to make the tenon joint to the neckshaft. It's all fit perfectly and generates an amazingly strong structure in the end, but it is a lot of work.

3 parts of the neck: shaft, tenon and heel

Tenon in neckshaft

View from the underside of the extension

Assembled, but not glued together in this shot

This is the guitar, with no heel cover on the tenon in this shot

[Michael Lewis]

The one piece neck used to be more common, but there are other ways of achieving the structure. Typically it was a hand carved dovetail made with sharp chisels, and it may take several attempts to get it right if you have never done on previously.

Personally I think that with good glue and a close fit that your parts can be made separately and glued together, yielding a sturdy structure. It is quicker to rout a dovetail than to carve it, and generally more accurate, though time and experience can blur the differences.

[Gilbert Fredrickson]

That is an epic neck construction, Chuck. Really a beautiful thing, it reminds me of Bob Taylor and Lemon Grove.

[Mark Swanson]

Yes that is really good work Chuck!

[Chuck Tweedy]

Hey, thanks guys!
It's one of those things that you do because the idea won't leave you alone. I haven't built one like that in a long time now, but I could always go back.
And it is, certainly, a method that would work very well for an archtop.
Heck, you guys are already doing a ton of work to build one of those things, so what's a bit more?!?

[Alan Carruth]

I just use my normal neck joint, which is similar to a dovetail, but only tapered in the vertical direction: a 'single tapered mortise and tenon'. If you can carve a top and back, you can cut this.

[Joe Lanza]

"similar to a dovetail, but only tapered in the vertical direction"

Do you mean a sliding dovetail with straight (parallel) sides?

[Alan Carruth]

"Do you mean a sliding dovetail with straight (parallel) sides?"

From the top view the sides of the tenon are parallel, In the end view they are tapered: wider at the top and narrower at the heel.

I made a few with straight tenons, until somebody pointed out that they might be hard to steam apart. As you introduce water the wood of the tenon would swell, and it could lock in place. The single tapered mortise comes apart the same as a dovetail, but the glue lines on the side of the tenon are in shear, rather than (possibly) tension.

Also, there's more glue area at the flat bottom of the tenon, and I under cut that so that it locks in rotation to keep the neck from moving. Often the usual dovetail is not well fitted in that area, and that's where most of the stress is.

[Randolph Rhett]

From the top view the sides of the tenon are parallel, In the end view they are tapered: wider at the top and narrower at the heel.

...

So what holds the neck to the neck body? If I am visualizing this correctly, the tenon would slip into the mortise and out. Do you have mechanical fasteners (screws, eg) or does glue alone do the job?

[Alan Carruth]

I usually glue in the neck. In terms of it's mechanical strength, it's much the same as a violin neck, except that most of the interesting stuff is out of sight. You can also bolt this, of course, and I've done that, although, in that case, there's no reason to taper the tenon.

[Gilbert Fredrickson]

I was just reading Arthur Overholtzer's book. He includes a good section on neck construction and various neck attatchment methods. The electric guitar "set-neck" method is a straight sided mortise and tenon.