"Slightly mortised butt heel"

[Dave Bagwill]

I picked this subject up from another thread.

For a first time neck builder - is this an attainable neck joint, compared to a m&t?

It would be really cool to see a diagram or set of pictures or specs that would show in detail what the various suggested parameters are.


Edit: Here is one luthier's approach. What do you think?
http://www.liutaiomottola.com/construction/Bolton.htm

[Dan Pennington]

Here's my first try at this Taylor-ish bolt on neck joint. I don't mean to completely take over this thread, but it takes a bunch of photos to explain how I got to the point of making this neck joint work for me.

I first saw this joint last summer at a guitar builder's gathering in northern Minnesota. Grant Goltz, one of the prime movers on the Luthier Community forum (luthiercom.org) did a demo of this neck joint. He used a mortise and tenon joint. And he used a spring plate under one of the bolts so that he could adjust the neck angle by tightening that bolt. This is a photo of his joint.



Grant had made a test model of the joint a year or two earlier and it had circulated among the forum members. So, that was what I did. I made my own model using a reject Martin neck blank and an orphan side piece. Except that I used a butt joint. I played with it till I got it to fit the way I wanted it to. I'd recommend anyone trying this joint, make your own model first.





Then I started making the real thing. I was doing an all cedar build-along on the luthier forum.com. The neck was a scarf joint with a built up heel with an extension to support the fingerboard extension.





It took a bit of head scratching, fiddling, and adjustment, but it came together. The cedar neck was pretty soft, so it has a two way truss rod and two carbon fiber rods under the fingerboard to stiffen it up.



Here's the completed guitar so you can see that the neck joint is pretty well hidden in the mortised sides.

[Dave Bagwill]

Thanks for the pictures. That gives me a much better idea of what we are talking about.

The mortise depth is a matter of choice?

[Dan Pennington]

Depth of the mortise - I started with just the depth of the side wood, but then cut another 1/32 deeper at the bottom of the heel - tapering the cut from the top of the neck block downward. Does that make sense?

[Dave Bagwill]

Probably. I have yet to think the thing through, let alone make a model. :-)
I think I would put the 88.7 degree angle on the cheeks and go flat against the headblock, seems like a sure fire way to get the right fb slope. But as I said, I'm a noob with this kind of joint.

[Dan Pennington]

Sorry, I forgot to say that I did start with the heel at 88.5 degrees - just like the usual build.

[Dave Bagwill]

Thanks