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I've read Cumpiano's book a dozen times or more and a book by Jim Williams which is more like a shop manual. I've made a prototype neck out of some walnut I had around my garage, but I am an extreme novice at woodworking and I had a question.

Spanish heel, bolt on, pinned tenon, dovetail, or some other way to attach the neck to the body--what is best for a steel string? Dreadnought, scale length will be around 25.6, I think. Spanish heel looks easiest, but it can't be repaired . . .

Thoughts?

p.s.--I'm glad I found this forum. Just what I've been looking for. I've been wanting to build an acoustic for years and I'm finally taking the plunge. I'm a CNC machinist by trade.

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Adam

Welcome aboard Carl,

Which neck joint is "best" I think you'll find is rather subjective. All of them can be made to work well and sound good but, I don't think that many makers are using Spanish heels on steel strings. I'll go out on a limb and say that most i.e. 50%+1 or more, guys are using some form of bolt on.

The tenon type neck joint is pretty popular as is the straight old butt joint. Butt joint is easier to make (obviously). As to fitting, I've only done M&T so I'm not sure if the butt is easier or harder in that respect.

p.s. there's a CNC section on the board you should visit. I just bought a small CNC router myself!

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Welcome . I agree with Andy , You will get multiple answers here . I prefer a Mortise /tennon joint . I bolt and glue . The only real reason for the bolt is mounting during the build to check for fit and c/line and to hold it secure while gluing .

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FWIW I started off doing dove tail joints (cut by hand) and switched to flush mount bolt on neck. The heal is flush to the body and wood inserts glued into the heal to accept the bolts. Not only do I find this to be the easiest joint to set up, get the neck angle right, and with a clean look but I also have never seen one fail in ten years. I would not recommend the Cumpiano method in his book. It's an incredibly cool joint that would last for ever but it's very difficult to implement especially for a novice.

Good luck, when I started building my only wood working skills were from building a tree fort with my friends in the woods when we were kids

+1 for a bolt on system...

If you use a spanish heel on a steel string the guitar will become useless in 10-20 years. Removable joints are used on steel strings because the soundboard will lift up eventually from the string pressure, and the neck angle will need to be reset to make it playable. Spanish heel can be used on nylon string instruments because they do not lift up like steel strings.

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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.

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Here's that revised Cumpiano joint http://www.cumpiano.com/Home/Articles/Special%20interest/headblock.html
I use it. It's not too hard to cut and drill (way easier than a dovetail, at least), and works well. I'm thinking about trying a butt joint with inserts on my next build though. Less cutting, and only two holes to drill.

The only time I really wouldn't want to use a butt joint, is on a cutaway. I like low-profile heels in that case so you can play bar chords at high positions, and the butt joint needs a longish heel so there's plenty of room inside for the inserts. Not an issue without a cutaway though, since your hand runs into the body before your thumb runs into the heel anyway.

I'm a big fan of Spanish heels for the ease of cutting, guaranteed coplanar upper bout when using a headblock that extends all the way to the upper transverse brace, ability to shape the outside heel however you want (especially on cutaways, like the photo, although that's a factory guitar), and the low weight compared to having metal bolts in there. But the disadvantages just aren't worth it, I think. Either you brace the top heavier to safeguard against ever needing a neck reset, resulting in less sound quality, or you risk having to do a lot of difficult and potentially destructive heel slip resets in the future. Or worse, your instruments end up stuffed in a closet, abandoned and unplayed due to the difficulty of the repair. Although the tap tuning thread has me thinking about switching to carbon fiber reinforced bracing to reduce long-term deformation so I can get away with integral necks.

For what it's worth, Ervin Somogyi is probably the most famous steel string builder in the world right now, and uses what effectively amounts to a Spanish heel (actually a pinned and permanently glued mortise and tenon). I think he's running at about 1% of guitars needing a reset so far, and has been building for 40 years. So, it is possible to make great sounding guitars that don't die young.

Most of the problems with spanish heel, dovetail, pinned tenon, floating tenon, and glued mortise and tenon with a bolt-on have to do with the increased cost and/or difficulty of future neck resets. Spanish heels and floating tenons (sometimes called a spline joint) are fine for classical guitars but not for the increased tension of steel string guitars. Some noted classical guitar makers such as Randy Reynolds are even using bolt-ons with threaded inserts. I used to use the bolt and barrel fasteners for a mortise and tenon joint like Cumpiano, but the tenon needed to be larger than what I wanted for the type of heel I make. Some people use a full bolt-on neck where the fingerboard extension is also bolted on making resetting very easy. Some have adjustable necks like Doolin and Kent Chasson which don't need neck resetting. Chris Jenkins has an adjustable neck that is much like an electric guitar which gives on the fly action adjustment and more access to the upper frets as an added benefit. Harvey Leach has a hinged collapsable neck joint on his travel guitars.

A bolt-on butt joint with threaded inserts and a glued fingerboard extension is what I mostly do these days. It's solid, easy to line up, doesn't add much weight and can be flossed for a neck reset. It's a good place to start for beginners too.

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Ken Franklin
clumsy yet persistent
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After making the jigs (the hard part) I have this M&T w/bolt on (the easy part)
It should make any future neck resets very easy, just something to consider.

Wow. Thanks everyone for the comments and suggestions.

To recap, it looks like tenon/bolt-on is the way to go. Just to make sure I understand it correctly, you are glueing the tenon to the headblock and basically using the bolts to keep it in place while it dries. Right? It makes sense that it's super strong since a properly glued joint is stronger than a piece of wood anyway.

This may be a stuipid follow-up questoin, but how do you set the angle of the neck at that point? Is it the same as in Cumpiano's book?

Ken: nice quitars at your site. I particularly like Elsie. I have been wondering what an oak bodied guitar would sound like. I'm going to try it one of these days. She looks beautiful.

Thanks again everyone!

_________________
Adam

One more question. With the tenon/bolt-on system, do any of you angle the cheeks of the tenon like Cumpiano or do you keep them flat?

Thanks!

_________________
Adam

Nope, WudWerkr is in the minority there. To me, half the point of the bolts is so I DON'T have to glue the tenon. As Ken says, it's very nice to be able to leave the fingerboard glued down while you remove the bolts, tilt the neck out just enough to slip a piece of sandpaper in the crack, and then drag it back out to sand the heel (this is called flossing).


You can set the angle pretty much whenever you like. I conservatively estimate it when cutting the tenon in the first place, and then refine it as soon as the box is closed up (before gluing the fingerboard onto the neck, since it's easier to floss when you can pull a long strip of sandpaper continuously through the crack). Then do one final check and any adjustment needed after the fingerboard is glued to the neck, but before gluing down the extension and bolting to the body.


Not sure what you mean... they don't look angled to me. Mine are all square.

If you angle the cheeks initially the neck angle will increase as you carve the heel. I find it better to set the neck angle with the cheeks at 90 degrees first, carve the heel and then chisel some relief about 3/16 inch in from the edges of the heel toward the tenon. Then I can floss for a good fit easily. I only angle the cheeks if the body is curved rather than flat.

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

To set the angle I finish the box and take the measurement with an angle finder. My radius is 30' so it's usually 1.2-1.5 degrees. If I wanted to set it first I would use 1 degree because it's easier to remove wood from the cheek at the bottom of the heel.

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

Adam: No need to glue the Cumpiano mortice and tenon. Even the fingerboard extension just need a small amount of weak glue and that just to prevent rattles.Good luck in the adventure.
Tom

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I use the threaded screw in inserts to hold the neck tenon bolts rather than the round things that go in from the side....

Jigs wise - never used them yet... You can do all the cuts for both the mortise and tenon with a big box store hand saw, a good sharp chisel, and a plane.... Just carefully draw out your layout lines with a high quality adjustable square...

Remember that a super duper tight fitting mortise and tenon is actually harder to make everything in the neck set line up properly than if you leave a little slop.... Remember - The only thing the mortise and tenon does is to help you keep things lined up before you set the neck angle and glue the fretboard down...

If you are going to do the top bracing the same way as Cumpiano - then you probably ought to set the neck angles the same way as he does.... It will save you some time.. Remember that all the geometry is worked out more or less correctly if you follow his directions....

Thanks

I just prefer a glued joint . I use the bolt as a building tool . As time goes on and I get more experience I may change my approach , its just what im comfortable with now.

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The Shallower the depth of the stream , The Louder the Babble !
The Taking Of Offense Is the Life Course Of The Stupid One !
Wanna Leave a Better Planet for our Kids? How about Working on BETTER KIDS for our Planet !
Forgiveness is the ability to accept an apology that you will probably NEVER GET
The truth will set you free , But FIRST, it will probably Piss you Off !
Creativity is allowing yourself to make Mistakes, Art is knowing which ones to Keep !
The Saddest thing anyone can do , is push a Loyal Person to the point that they Dont Care Anymore
Never met a STRONG person who had an EASY past !
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Once again, thanks for all the good words. After all the advice, I'm going to shoot for the Cumpiano bolt-on method with just the little glue under the soundboard. If it doesn't work for me, I can always pull the neck off and glue the whole thing later.

As a quick side note, I made a prototype neck out of walnut to walk myself through the process and found that I really, really, really needed a skew chisel. I, however, am thrifty and I made my own out of an old chisel. I'll try to post pics tomorrow.

Thanks for all the help. I'll be sure to post pics when I get my first batch of wood and chronicle the build. I could not be more excited.

Thanks again.

_________________
Adam

If you are going to use the barrel nut instead of threaded inserts then for extra strength you should add shims to the sides of the tenon before you drill.

_________________
Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

Another thing...

Unless you wrecked the Walnut test neck - why not use it? Walnut is fine neck material so long as it is pretty straight grained and not warped/twisted....

Thanks

Why not use the walnut test neck? I made a few errors in the cut and the scarf joint and stacked heel were done in a pretty sloppy manner. I'm looking forward to refining the process.

_________________
Adam