Potentially dumb question: Reverse tapered dovetail?

[Drew Streip]

So, guitar and mandolin necks tend to pull forward / upward under tension. Because the traditional tapered dovetail is set from the top down, it releases upward (if it releases on purpose or by accident).

Has anybody ever created an upside down tapered dovetail where the neck sets from the bottom, therefore “tightening” under string tension?

I understand that it would require either putting the top on first — or doing really good measurements — to get the neck plane in line with the top. Would that be a problem?

Tell me why this idea is bad in practice, because in theory it seems like it’d be the ultimate self-tightening joint. But I’ve never had a truly unique or revolutionary idea so I know I’m missing something.

[Dale Ludewig]

Well, that's an interesting idea. But, it's flawed reasoning from my experience (80 + builds). I think I understand your idea. But, in regular mandolin builds, the top goes on first anyway. On a guitar, the whole body is usually done independently and the neck joint is either a mortise/tenon or a dovetail. To come from the backside with the dovetail "upside down" would require the back to be removed before you could do a neck reset, which is very rare on a well made modern mandolin. On most modern guitars, a neck reset is required because the top has warped and there's no need to pull the back off. Normally.

[j. condino]

I like the idea from a structural standpoint; if it was well done, you could have a removable neck design that only relied on string tension to keep it secure.

One obvious problem: as mandolin nerds, we are addicted to the smallest possible stiletto heel. Reversing the dovetail would present a giant heel that the crusty crusty old grumpy crowd would never tolerate....

The biggest thing that I can point out with whatever dovetail method you decide is that no matter the choice, all beginners will struggle with it. Pick one, practice it 100 times until you get it perfect, then repeat and stick with what you know will work well. During the struggle phase, they all suck. Once you get it down well and have made as many as Dale, every one is fun....

As an early mention, I'll be giving a dovetail workshop and demonstration at the upcoming Association of String Instrument Artisans Symposium at East Stroudsburg State U. in mid June.

Here is one from 1927 that I posted on facebook earlier this week:

[sebastiaan56]

This joint is commonly used on Ouds. Saz and the like. It makes a lot of sense and removes the waste associated with a heel. But as has been noted tradition is more powerful than good engineering.

[belbein]

truly unique or revolutionary idea

I'm not an expert builder, so my opinion doesn't account for much. Whether your idea is truly unique and revolutionary AND WILL WORK I can't say. But I like the fact that you're thinking outside the box (no pun intended). My bet is that the reason that we use dovetails is that there was some sort of old-time-technological or cultural reason for it (like no screws, or poor glues, or it was luthiers showing off for the amateurs like me). But just because what we do today has stood the test of time doesn't mean that it's the only way to do things, or even the best way. You'll note that there are both first quality guitars and first quality mandolins that use bolt-on necks, and even more that use mortise and tennon. That there are mandolins made out of carbon fiber. That there are people doing really high quality inlay using computerized routers. I'm kind of a traditionalist, but I would not ever confuse "traditional" with "best" or "only way." So I'd say: go for it. Give it a shot and see what happens. And remember, the Wright brothers had never built an airplane before they ... built an airplane.

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Saz

Saz?

[belbein]

one from 1927

Golly, GCM. I didn't know that you were that old.

[Marty Jacobson]

This joint is commonly used on Ouds. Saz and the like. It makes a lot of sense and removes the waste associated with a heel. But as has been noted tradition is more powerful than good engineering.

I'm in love. It's not ideal, there's a reason why the normal dovetail is perpendicular-ish to the fretboard surface. But still, this is a very nice solution and opens up a lot of possibilities.

Saz?

Saz who?

[Jess L.]

Saz?

First saz hit on YouTube:


(or direct link)

[tom.gibson]

This joint is commonly used on Ouds. Saz and the like. It makes a lot of sense and removes the waste associated with a heel. But as has been noted tradition is more powerful than good engineering.

I used this joint when I made a bowlback because I couldn't see any other good way to attach the neck (except making it integral with the block). It seems perfectly strong and secure.

[j. condino]

I use a horizontal dovetail like that with some of my electric guitar builds rather than the basic lap joint on a Les Paul junior.

Neck angle adjustments and resets are no fun, but I have a lot of confidence in it when jumping around on & off stage into the mosh pitt.....

[belbein]

Saz who?

I thought about that, but then I thought better of it.

[belbein]

Wow. Thanks. Nice piece of music ... and beautiful instrument. Can you post more pix of the instrument? Is it a bowlback? Do i see right that it's 8 strings? How's it tuned?