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Hi Guys,
I'm finally getting around to working on the neck joint of my latest project and I need some advice. This sort of touches on the topic Andy brought up a few days ago, but I didn't want to hijack his tread. I'm tying a bolt-on double m&t joint. I like the idea of being able to complete construction and fretting before applying any finish. I seem to have difficulty avoiding nicks, dings and scratches after the finish is buffed out. The heelblock has a 1/2" thick by 2-3/4" qs mahogany tongue that buts up against the upper face brace. Right now the neck is attached with the conventional knock down hardware and the alignment is dialed in. I'm to the point where I can cut the mortise for the second tenon. I got to thinking that the joint might be stronger if I routed some of the neck away and had the tenon overlap both the body and the neck. Making sure that the tenon would be flush with the body, I could then glue the tenon to the neck, extend the truss rod slot, add some cf and finally attach the fretboard to the neck. After triple checking my measurements I made a jig that aligns off of the truss rod slot. I'm going to secure it with clamps and some double sided tape and cut the mortise with a 1/4" upward spiral cut bit. Lastly, since I'm mainly doing this to aid in construction I was going to glue the second tenon in after the finish is buffed out - although I do have the hardware for an all bolt setup. My question is, before I step out on a limb and take a router to my best work to date, is this sound thinking? Am I missing something/doing something stupid?? Candid feedback will be greatly appreciated.





Thanks for the help.

Bob K

I don't know if it's sound thinking or not but that's exactly how I do mine. I think it adds a lot of stability to the extension which is why I do it in the first place.I say go for it.

Hopefully Paul Woolson will chime in. I think he was designing an
overlapping tenon. I do like the idea because with a 2nd tenon
sometimes
you can still have a change at the neck body joint.
I personally make the 2nd tenon like Sylvan/John Mayes etc.
The 2nd tenon is glued to the bottom of the fretboard. T nuts are place
through it and bolt down through the fretboard extension on the neck
block

I was messing around with having the 2nd tenon actually part of the
original
neck material. This has advantages of having a perfectly straight neck. It
makes it hard to cut the 1st tenon and heel and get a good neck fit
because
the original board extends all the way out.



Dave White was also doing something like this. If I had a CNC, you could
cut this all out of a single piece and get a great fit.

_________________
Andy Z.
http://www.lazydogguitars.com

That was fast Paul
As I entered "hopefully Paul will chime in" you post actually preceeded
mine!!!!

_________________
Andy Z.
http://www.lazydogguitars.com

I don't know if this is what your looking for, but this website has lots of info on this type of neck joint. I think Mr. Wells is also a member of the OLF!


http://www.wellsguitars.com/Articles/Double_Tenon.htm

Sorry, I couldn't get the Click once button. You'll have to load it into your browser.BlueSpirit39035.8478587963

Cool,

Thanks for the "OK" guys. I've been borrowing bits and pieces for different methods and was just looking for some reassurance that I wasn't doing something boneheaded.

Thanks again.

I really like the idea of this kind of neck. What I don't understand is how the adjustment is done, given that the heel surface sits atop the body. Any change would seem to create a wedge shaped gap going one way or the other..

I remember that the Taylor neck had a mortise that the entire heel fit into. It also has a separate heel piece glued onto a neck board, enabling it to go all the way under the fretboard in one piece. This would make it easier to cut the heel angle and mortise, separately, but isn't too aesthetically appealing. They also routed two channels on either side of the truss rod and epoxied metal stiffener strips to reinforce the body joint area from the soundhole end of the neck down to about the 9th fret.

Anyway, I looked at the Wells joint, and still can't see how the heel surface can accomodate any adjustment.

What am I missing?

Scott

Scott,

I think, and am hoping, that my heel won't need any further adjusting. Currently my center alignment and action are where I want them, and I if I wanted to I could just finish it as a standard bolt-on. My thinking is that cutting the mortise in both the body and neck at the same time will help maintain the current neck angle. A reset in the future will be more difficult if I glue the second tenon. Don't most resets require the neck to be tipped back away from the bridge? If so that means a small gap between the fretboard and body at the upper frets. Not pleasing to the eye, but it could probably be minimized by thinning the second tenon a little. Or so I hope.

BobK

Bob, if I were you, I'd make the top tennon slightly thinner than the mortise from the start. That way, you are sure that the fingerboard is resting on the top instead of the tennon bottoming out in the mortise.
Scott, this is not a Taylor neck joint by any stretch of the imagination. To change the neck angle, you have to do a traditional neck reset. (removing material from the heal). What it does is give structure to the fingerboard extension which avoids the 14th fret hump.

Thanks for the feedback, Bob and Paul. I was partially referring to the statement on the Wells neck site that said a reset could be done in minutes with the Bourgeois neck joint, which I haven't seen.

Yes, most resets are needed when the angle between the heel and neck relaxes, allowing the neck to pull up, although the top pulling up can do it, too. That's why Taylor went with their "new technology" neck.

I designed a metal bracket made from a 4" x 1/4" angle iron that has one side going down as part of the heel's tenon, and the other, split like a two pronged fork, to accomodate the truss rod, going up the neck under the fretboard. It's a lot of work, but that angle will never bend. Now, if I could have an extension welded on that would go under the fb to the soundhole, it would provide the support of the carbon fiber rods and support the heel angle. One threaded hole would be enough to hold the extension in place.

I don't have any pics on my electronic camera (and have yet to figure out how to load them here--soon!) but there are photos of the neck bracket on my website, under the van Linge Guitars page.

Is anyone out there into making these out of aluminum? The tenon part could be set at an average angle, and the wood part of the tenon (I use 3/8" wood, 1/4" metal for the tenon) could be custom fit for any guitar. I haven't tried the Fox/Woolson jig, either, but that would still be great for getting the heel angle. I'm tired of fighting the hump, and will probably make one for my next guitar with a local welder. He can weld Al, too...

Scott

Here's an aluminum rig from eBay. The seller(not me) is Luthiers Cool Tools.

CrowDuck

_________________
Chris Nielsen
Soquel, CA.

The double mortise and tenon description on my web site does say that
adjustments can be made very quickly. The reason that is so is that the
neck can be removed within a minute or so from the body with absolutely
no damage to the box. The adjustments are done conventionally, i.e., by
adjusting the heel of the neck. It is NOT a Taylor style neck; rather a
method which can be done by most any guitarmaker with a minimum of
tools (a drill and a router). It has other benefits in that 1) it does away
with the popcycle brace; replacing it with a more substantial bracing of
the area under and around the fretboard eliminating those cracks seen on
older Martins; 2) the gluing of the block to the top during construction
provides a surefire method for aligning the top and insuring the distance
to the bridge is correct; and 3) some (not me) take the neck and fit it and
then take it off of the body and fret it, eliminating any potential scratches,
etc. from the finishing process.
The double mortise and tenon certainly did not originate with me - that is
why I credit Dana Borgeous (sp?) for where I first saw it used and John
Mayes for furthering to spread the method in the Lutherie community. I
posted the exact details which I believe are still only available at my web
site because I believe in the method and encourage others to try it, and
use it if it works for them.

_________________
Sylvan
http://www.wellsguitars.com

Chris,

I couldn't find Luthiers Cool Tools. Do you have a link?

Or, do you remember how far up the neck those Al bars go--to what fret? Both questions, really.

With all these joints, I just realized that the fretboard just lays over the top, with the mortise being narrower. How nice not to have to prepare the finish edges!! Way cool...

Thanks,

Scott

http://www.michelettiguitars.com/Images/Sales.htm#Bolt-on