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I build with a scarf joint--strong, easy, traditional (I build classicals), looks great, what's not to love?

I did warranty repairs for a company that made Hauser '37 copies. Hot hide glue at the v-joint, but really a Romanillos thru-v. Rosewood headplate w/white, black veneers. (No backstrap). I did plenty of crack repairs on tops and backs. Mostly humidity issues, but also some shipping damage. The Hauser model wasn't their main seller, but at least 60 went out the door during the five years I worked there. I covered the problems in everything they'd sold before I came on board. I saw a total of one failure in a neck-head joint.

That guitar was in its case when a car drove over it. The case was badly damaged (!), and the guitar was too. The neck was split in several places through the head joint. The head was still attached by a few slivers of wood. One of the butt-joint shoulders of the v-joint had let go, but the v itself, and the other shoulder were still intact. the cracks ran through the v-joint area, but the joint held.

Hide glue is strain-rate sensitive. The failure I saw was a fairly slow load. It was one example.

I build with scarf joints, but I think v-joints look great. I think they're plenty strong. I wouldn't hesitate to use a v-joint on any instrument--nylon string, steel string, twelve string, piano.

Hide glue of the day was probably just as good as one can buy now. We know that because there are literally thousands upon thousands of instruments that were constructed with it. You only have to look at the centre seams of Cremonese Violins (and tons of others) to know that they were using pretty good glue. Then there are all those Guitars made in the 18th and 19th century. The original glue is still holding. Further, Torres used a scarf joint and Hide glue, those joints are still good after 140 years.

[quote="grumpy"
Listen folks, so many of you misunderstood all of this that it truly boggles the mind! [/quote]

While trying to understand all this, I had an idea. Tiny shaped charge in the neck joint (whatever you want to use). Hard enough fall blows the headstock off and possibly catches the guitar on fire..........stuff happens, new neck minimum or a new build

Trevor, the only end grain in this joint are the shoulders, which comprise a tiny percentage of the total surface area of the joint. I haven't done the math on it, but the total surface area of the Vee itself is quite large.

I do a through-Vee, but use a slightly thicker headplate than on my one-piece necks, such that when done, it is effectively a covered-Vee, and since I use as much angle as I could get away with without it showing-through once the neck is carved, it is also a mechanical joint(it's a dovetail). I haven't done it, for many reasons, the biggest of which is that it would take a lot of time and not prove anything I don't already know, but if I fit the whole joint together, leveled the headplate surface flush, and then removed it all, glued the headplate in place, and put it all back, without glue, the guitar could be strung-up and played. Pretty much forever, I suspect. The string tension is such that it pulls the joint tighter together, and in this light, the shoulders, though they are end grain, provide structure by preventing the Vee from rotating upward.

Was the failed example a straight, or nearly straight, Vee?? If so, then yes, that would be a very bad design....

If it's such a good joint, why the thicker headplate?

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

Because it can't hurt, and since we do have two separate pieces of wood under the heatplate veneer with their grain running in slightly different directions, and in my case, two COMPLETELY different types of wood, if either one has any humidity related movement, even a minute amount, over the next century, it's less likely to telegraph through the glossy headplate if it's a wee tad thicker. And I'm not talking 1/2" thick here, I'm talking .060" to .070" VS the .040" I typically use.

I've also seen my share of failed scarf joints over the years, with the head only held on by the face veneer.

I don't see where a precise failure stress prediction is needed for this; it only has to be able to hold a reasonably higher than normal stress, and give 'way before the neck breaks. That seems like a pretty wide spread to me.

I'm sure the V-joint went out of use mostly because it takes too much skill to make by hand, and was hard to automate. Not being a factory, the fact that it takes fifteen or twenty minutes more to make than a scarf doesn't bother me, where I'm sure Bob Taylor would throw a fit.

My V-joints typically have pretty narrow shoulders, as little as 7mm wide. All it has to do is provide a stop. I've never been too keen on the Panormo style shoulderless V, although that's probably simply prejudice.

It's a shame I can't find the picture. The one I was railing about was on a classical, I would guess ~52/53mm at the nut, with the base of the V about 20-22mm, i.e. less than half the neck width, hence my ~50% end grain to end grain comment.

Again, wish I could find the pic; my recollection is that on the broken joint the V was a little proud of the underside of the headstock with the side fracture open ~1mm, strings still on. If it had been an effective covered V (like Michael N's pics) but covered by the headstock facing, my guess is that it would have just popped back together, which sorta implies it was more likely to have been a straight V, but very hard to be sure either way from the pic I saw.

Heated agreement! Mine's a beer, you're buying!

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

Hi Trevor,
With the "V" joint and the modified bridle joint (which is what I use) the "wood savings" comes from the fact that you can use a narrower piece of wood for the neck shaft. With a scarf joint the neck shaft is the same width as the maximum width of the peg head. With the early Martin style neck the volute is an extension of the maximum depth (thickness) of the neck, so again, no extra wood is used over what would be needed for the neck shaft itself.
I think all five of the joints mentioned, if properly done, have adequate strength and can look quite nice. Which is not to say that some aren't stronger than others. We picks our poison and takes our chances.

Heated agreement! Mine's a beer, you're buying!

I brew my own, so it'll have to be a homebrew. I have 3 different stouts on hand right now, and will be bottling a 4th batch today, followed by hopefully brewing another batch this evening, if I can get to the oven long enough to roast some barley; the missus is in the middle of making 9 loaves of spent-grain bread for one of her clients....

C'mon up!

Nice. I'm brewing today, too-a smoked porter. I have an English mild and a black IPA (or IBA or CDA...whatever you want to call it) on tap now and a Russian Imperial stout brewed with wild yeast that I'm bottling this week.

EDIT: Btw I've always done a scarf joint but plan to do a V on my next. I really like the look and have no real structural concerns with the joint so long as it's well fitted.

On a paddle headstock, with a top veneer and a backstrap, is there any reason why you couldn't incorporate wooden dowels to reinforce the joint? Yes , I know, the glue strength of dowels in cross grain is low, but if you angled them as much as possible, it could give significant reinforcement IMO ..

EDIT: FWIW I don't brew my own, I always purchase the excellent LIA FAIL Scottish dark beer, which can sometimes be had on offer at 1.5 GBP per 500 mll.

Well, yes, you can do it that way, but lots of people (including PRS amongst the factory builders) just put "ears" on the headstock; shown in "the book". Gives a much greater choice in available lumber and done well, almost invisible. Depending on the headstock shape and your start size, you can often get the "ears" from the off-cut from the neck taper, thus ensuring a good match.

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

Thanks for the invitation! Sounds marvellous! Almost worth the 17 hour flight (each way!). Almost...

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

I have done pegheads with "ears" but that was done to widen the peghead on an otherwise one piece neck. Scarf joining and adding ears both might make it look like a bit of a jig saw puzzle. With a front and back veneer I'm sure it could be made to look presentable, but that adds a lot of pieces.
I have worked out a way to cut the bridle joint with a table saw and router and a little bit of hand work, so I am happy to use it. I think all the joints if reasonably done are good enough. At some point good enough is good enough. Eventually I think we settle on our construction methods and just try to build better instruments. Both Hauser and Hernandez built fine guitars.
My home brewing has devolved to using the Muntons kits. I no longer sparge the wort. Maybe not world class brews, but easy and very drinkable.

I love this remark. Grumpy, you hit the nail right on the head. I love the looks of Taylor guitars otherwise, but simply detest the finger-joint application. Maybe I'm too picky, but I have declined to own one because of that design feature.

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I spent most of my money on women, guitars and whiskey, the rest I wasted.

Since this has gotten around to the design of headstock joints, could the more experienced here take a look at my hybrid laminate/scarf design and give me a opinion? It was designed to maximize strength and minimize material, a neck can be cut from a 2' length of 1x6. There's a photo essay of it in the Neck Lams thread, sorry but I don't know how to link to it.
Thanks,
RKnox

edit: viewtopic.php?f=10101&t=38393

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A man hears what he wants to hear, and disreguards the rest. Paul Simon

I'm not one of the experienced guys you're looking for an opinion from, but your scarf joint looks very interesting from a style and construction view point. What angle do you use for the scarf, and have you ever tried a combination of different woods for the lamination? After looking at the pictures from the Neck Lams thread a few times, it seems to be pretty staight forward to construct, and with the change of grain in the center lamination, much stronger than a regular scarf joint.

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

I use 10°, and frequently taper the center lamination. Here's one that's maple and mahogany with walnut accent strips.

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A man hears what he wants to hear, and disreguards the rest. Paul Simon

A properly done simple scarf will see the wood breaking before the joint gives, so your design can't be any stronger than that. I use a 15 degree angle for SS guitars and can get a neck out of a 600mm x 75mm x 25mm blank (2' x 3" x 1"), i.e. half the size you're using. Side off-cuts can be used as "ears" to widen the headstock, though yours might be too wide for the size of blank I use. I've done laminated necks in the past, but I don't think they offer any more stability than using a straight grained piece of a suitable species. Measured against your design objective (maximize strength and minimize material), it won't be any stronger than a well done simple scarf and you can use less material. Put together well, I don't see your design failing any time soon, though!

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

yes. because it is a difficult joint to master. best reason yet, am i correct?

If that we're important, I would just shop at guitar center. . .

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

hey....ya know, that's a great idea!!! nice rapping with you guys, i quit!

I have to agree with everything except the first statement, and that's a moot point anyway. I believe my design is stronger than a simple scarf due to the orientation of the grain. Just because the wood fails before the joint gives doesn't necessarily mean that's the maximum strength of the joint. A simple scarf is more than strong enough, so being stronger than strong enough is overkill.

I continue to use it because it's much easier to taper the center lamination for converging accent stripes, and I prefer it's "elegance" for lack of a better word, and the quality of the wood can be much lower and still provide adequate strength. By the way, when I first designed this about 12 years ago, I emailed a sketch to William Cumpiano for his evaluation. To my surprise, he replied to my email, and it was very similiar to your response.

Thanks for your evaluation.

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A man hears what he wants to hear, and disreguards the rest. Paul Simon