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I thought I would give a short explanation on how I made the bolt on section for the fingerboard extension on my latest build.
First thing to do is have the neck properly aligned with the body.




Next, cut out the mortise and attach a block under the fingerboard extension.
This block supports the extension and adds thickness for the threaded inserts.
The #8-32 socket head cap screws (SHCS) and brass threaded insert are shown in the pocket for truss rod access.



Next step is to drill holes through the fretboard and support black at a fret slot.
I used the 18th fret.
These small holes will be covered with fret wire.



Remove the neck. Now you have perfectly aligned holes. Enlarge the holes in the guitar to accept the #8-32 SHCS.



Enlarge the holes in the fretboard extension block to accept the #8-32 brass inserts.
Use a brad point drill. Do not brill through the fretboard!
Screw in the brass threaded inserts and the job is done.
How's that?



(The truss rod is not seated deep enough into the neck.)

What do you think about using only 2 bolts?
Any thought and comments are welcome.
Thanks!SteveS38868.4655324074

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"An adventure is only an inconvenience rightly considered. An inconvenience is an adventure wrongly considered." G. K. Chesterton.

Steve,

Thanks for the pics! I am about to attempt my first bolt-on extension on my current build. Where did you find the threaded brass inserts for the 8-32 screws?

As for using 2 screws, I recall a post by John Mayes where he mentions using 2 instead of 4. With this system, it seems pretty easy to go back and add 2 more if you find you need them.

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53% of all statistics are made up on the spot
http://driftwoodguitars.blogspot.com/

Wayne,
My local hardware store had the #8-32 screws and threaded inserts.

You can get the from Rockler.

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"An adventure is only an inconvenience rightly considered. An inconvenience is an adventure wrongly considered." G. K. Chesterton.

Wayne like Steve said Ace hardware has them every day and twice on Sundays

To answer an earlier question, I feel like two (2) bolts are ample. Of course, I've never done one of these, so this is not an experienced viewpoint. However, my brother's older system simply had one bolt holding the extension down. Worked fine...for a neck where the truss rod adjusts from the peghead, that is!

SK

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From Nacogdoches...the oldest town in Texas.

http://www.stephenkinnaird.com

Michael,

I have to admit I'm more likely to stop at one of the big box stores these days. I forget we even have an Ace hardware in town.

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53% of all statistics are made up on the spot
http://driftwoodguitars.blogspot.com/

I hadn't thought of drilling thru the f/b to align the holes...excellent trick! I've got 3 going together, so that's the way I'll do them! Thanx-a-million!   

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http://www.presnallguitars.com

Steve,

Nicely done. That is what I am going to try in the future. The current builds are going to have the traditional glued down fretboard, and bolted tenon.

Jeff

[QUOTE=L. Presnall] I hadn't thought of drilling thru the f/b to align the holes...excellent trick! I've got 3 going together, so that's the way I'll do them! Thanx-a-million!    [/QUOTE] Good luck with it. This is my second one. The other one I tried to align like John Mayes does. That didn't work out so good for me. This way, I can't even miss!

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"An adventure is only an inconvenience rightly considered. An inconvenience is an adventure wrongly considered." G. K. Chesterton.

I'm using two bolts (not side by side like yours, but in line to spread out
the load more evenly across the extension and tongue) now. Metric #4's
with T nuts (I've tried the inserts but had a few screw up) and they work
great. And I've never had a problem with alignment....

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John Mayes
http://www.mayesluthier.com

[QUOTE=John Mayes] (I've tried the inserts but had a few screw up)....[/QUOTE] How did they screw up?

BTW- If you are thinking about doing the bolt on fingerboard - Get John's DVD. It helped me a lot.

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"An adventure is only an inconvenience rightly considered. An inconvenience is an adventure wrongly considered." G. K. Chesterton.

I also use T nuts filed to fit the tenon. The advantage of the T nuts is that
they won't slip out if you torque too hard on the bolts

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

[QUOTE=azimmer1] I also use T nuts filed to fit the tenon. The
advantage of the T nuts is that
they won't slip out if you torque too hard on the bolts[/QUOTE]

Exactly. That is how the inserts messed up on me....

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John Mayes
http://www.mayesluthier.com

John and terken,

How do you use t-nuts? wouldn't you have to use Sylvan's "pointed bolt" to locate where to drill? I like Steve's idea as it is idiot proof. (I might even be able to do this). Thanks for your input.

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Dave Bland

remember...

"If it doesn't play in tune...it's just pretty wood"

yep I just use a bolt and then ground the head off it and to a sharp point.
It has always proved very accurate...

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John Mayes
http://www.mayesluthier.com

Thanks for the pics and explanations Steve, i might try that out on my no 3!

Serge

[QUOTE=azimmer1] I also use T nuts filed to fit the tenon. The advantage of the T nuts is that
they won't slip out if you torque too hard on the bolts[/QUOTE] T-nuts are better for not slipping out. The only trouble is, I can't think of a way to use them along with the drilling method that I use. I use CA to hold the inserts and I don't over tighten the bolts. I tighten them just enough to compress the lock washers.
John's method is great if you want to use T-nuts. I think this method is probably faster. YMMV

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"An adventure is only an inconvenience rightly considered. An inconvenience is an adventure wrongly considered." G. K. Chesterton.