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Regarding the work holding tangent: there are solutions to that problem, but that problem is not the culprit when it comes to an ill-fitted dovetail. A router only gets the parts of a dovetail joint into the right basic shape. The real fitting of the joint is done by hand. If you are expecting the parts to go together perfectly right after routing, that is an unrealistic expectation. So, sure, find solutions to your work holding problem while routing (they exist), but that won’t make your dovetail joints fit right. Several times now, I and others have recommended that you watch John Hall’s YouTube videos on fitting a dovetail. When you watch them, note whether you see John use any sort of vise or work holding jig while hand fitting the dovetail.

Tai,

If my questions came off as rude, that was absolutely not my intention. One of the great things about this forum is that it tends to be a safe and kind place to ask questions and discuss this stuff.

I tend to sound curt when I write and I can come off sounding like a d*ck. Writing is not one of my superpowers...

Again my apologies.

M

Under any reasonable set of use or storage conditions, mahogany is already among the most stable of woods. As long as you choose not oven-roast your instruments for prolonged periods of time, there is nothing to fear with a dovetail joint in the wood other than from the maker’s issues with execution.

We had a client that brought us a D-35 packed in several baggies and a couple boxes. The instrument had been in the back end of his over-packed minivan when one of his children found the spare key fob and popped the rear lift gate...at 75 mph on I-64 en route to the Outer Banks. The case, along with a few other items, ended up tumbling along the highway, striking a bridge overpass abutment at 50-60 mph. We did salvage the tuners for the client.

I could use this example of a ‘failure’ to find fault with Martin’s construction methods and materials, and to suggest that - had Martin just fabricated the instrument using exotic alloys and build-in airbag sensors and systems - the instrument would be more serviceable. But that would be silly, now, wouldn’t it?

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For the times they are a changin'

- Bob Dylan

Yes! Holding things is a giant deal, and an issue easily forgotten once one hasn’t had the issue in a while.
There are lots of ways to skin this cat. My method was to just use a neck jig (I have the LMII one). I’m not sure if shipping would be an issue. However it does the job of holding the neck tight, the template in the right place, and let’s you use a router to a more precise degree.



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There’s been a few mentions of the Gore neck joint in this thread. To the best of my knowledge, if we’re talking about a bolt-on neck using a square brass bar embedded in the neck heel, it is actually a Gilet design that dates back quite a ways.

The Gore/Gilet book describes Gilet’s joint and also describes Gore’s further development of the joint which introduces a bolt-down neck extension.

On the actual topic, Tai, I think your new design might not quite hit the mark, for many of the reasons others have outlined, but I respect your willingness to try something new. Keep it up.

There are free instructions on the StewMac website on how to build a dovetail jig that holds the parts for routing.

Or, it you really hate using a loud, unstable, mistake prone routers ...Try using a hand saw and chisel.

a little heating is not going to stop wood from shrinking on RH changes unless you do serious torrification.

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

You can also do a dovetail with hand tools, you can do it on a router table, or a tablesaw. Lots of different ways. Keep an open mind...

Tai, can you get your hands on the LMI neck jig? Or plans? Or plans for the Woolson neck jig, since that's basically what it is?

Alternatively, Tom Bills has a dovetail jig in his Luthier's Edge program that would be right up your alley as a machinest.

Seems like the Gore Gillet books do a step by step on doing a dovetail by hand (can’t remember the chapter)


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there are many videos on you tube about this but many do overthink this joint when they start. It is a simple interference joint.
Remember ACE
A angle
set the neck angle first
as you work the cheeks of the heel shim the tenon to tighten don't try adjusting it. AND USE A CLAMP TO PRESS IT IN
C center
Once the angle is set all you have to do is work the cheek of the heel on one side to true the neck to center

E elevation
Now that the neck is in position to angle and center you can work the tenon. Use chalk to mark the block and you can see the chalk , that tells you where you remove wood.

One thing to remember is the you only need the lower 1/3 of the neck tenon to bite and pull the tenon into the neck block. You should not ever really do anything at the neck block other that to chamfer the corners so you don't have the tenon held off and kept from seating.

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Thank you Mr Hall for taking the time to post this summary, you have always been very generous with your help and advice.
I might even have a try at a dovetail myself!

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

So it sounds like it’s better to make the neck tenon a slightly smaller angle than the pocket in the body? So the dovetail bites towards the bottom side more?

Is wood compression due to string tension even something to be concerned about?

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Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

IMHO, roughly 10,000,000+ well made dovetails vote NO to wood compression being something to be concerned about.
Just my humble opinion of course.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Any update on how this turned out?

Seems to work well, but then again not sure on the long term effects.

_________________
Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com