Proper neck set for a Martin 00-18

[Adam 12]

Hi Everyone,

I am building a replica of my old Martin 00-18. I have built several guitars using the pinned mortis and tenon neck joint from the Cumpiano and Natelson book. They all worked great, but I am building a replica and my old guitar has a dovetail neck joint.
I have not made a dovetail neck joint before, though I have made many practice dovetails. There are a few things that I could use help with: should I cut my heel block off at a 90 degree angle to the fretboard? Is there a better angle that will make it easier to set the neck? How long should the male part of the dovetail joint be?
Any help with this will be greatly appreciated.

Thanks!

Adam 12

[Skarsaune]

Originally Posted by Adam 12

There are a few things that I could use help with: should I cut my heel block off at a 90 degree angle to the fretboard? Is there a better angle that will make it easier to set the neck? How long should the male part of the dovetail joint be?

It needs to be a little off of 90 so your string height at the bridge location is high enough. On the dreadnoughts I’ve built & worked on, it comes out to 1 1/2 degrees, or 88.5.

On the guitars I’m most familiar with, the tenon is in the 5/8” range.

[Adam 12]

Hi Skarsaune,

I appreciate the input. That sounds about right; when I drew my plan it came out about 1 degree off 90. It looks like a tenon length of 5/8” will put it right under the 15th fret and allow removal at some future date.

Thanks again,

Adam 12

[murrmac123]

Hi Adam , and welcome to the forum !

You most likely are already aware of it, but just in case, you need to leave a small gap between the end of the tenon and the back of the neck-block mortise, to facilitate later removal, should it ever be needed.

Also, never put any glue on the tenon shoulders ( frequently misnamed as the tenon "cheeks").

[Adam 12]

Hi Murrmac 123

Thanks for your suggestions. I will leave about 3/32” clear at the end of the tenon; from what I am reading I gather that this will help with neck removal in the future.
As far as the shoulders go, are you referring to the part of the heel that will make contact with the body of the guitar?

Thanks again,

Adam 12

[Skarsaune]

Originally Posted by Adam 12

As far as the shoulders go, are you referring to the part of the heel that will make contact with the body of the guitar?

Thanks again,

Adam 12

That is correct. No glue there.

[Adam 12]

Got it.
Thanks for the help.

Adam