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The point I'm making is that it is relatively easy to design a guitar to take minor mistreatment without it falling apart. "Safety valves" are fine, provided you can set them to the right pressure.

Of course! But, we haven't discussed the possibility that the joint on the guitar in question, itself, was poor, did we? Nope. You just jumped-in with both feet and decided then and there that this type of joint with this type of glue is bound to fail.

But it isn't. Not when well done. Yes, it should release before wood breaks, if subjected to a big enough "hit", which is what I assume happened. Of course, it may have been a minor 'hit', and failed because of poor joinery. I'm playing the Devil's advocate here; since we don't know the builder, haven't seen the quality of the joinery, and NOBODY can tell how bad the impact was, or even how well the guitar fit its case, or how good the case was. I have to assume the luthier had good joinery chops, and that the guitar received a severe blow. That the case looked fine is of no consequence; the biggest, baddest impact a guitar can possibly take in a fall is when the case lands completely flat. In this scenario, the case will show NO DAMAGE, because the case absorbed none of the impact's energy. That left the poor guitar, inside, the take the "hit". Go back to my example of the new car VS the old car relative to accidents. The old cars were big, stiff, strong machines; they could bounce off trees and laugh, but their poor passengers bore the brunt of the hits. The new cars are designed to crumple; they look awful after even mild impacts, but they bore the brunt of the impact, not the passengers. Your example of your guitar's 3 week journey is another perfect example; the case bore the brunt of the abuse, and the guitar was fine. This isn't magic; it's basic engineering...

And again, if the joinery was poor, then it could well have been a minor hit that caused the joint to fail, but once again, that is NOT the fault of the V joint's design nor that of HHG's characteristics. There have to be tens, if not hundreds, of thousands of steel and nylon string guitars with a V joint that have held perfectly for decades and even Centuries(Old Martins..), yet you jumped to a conclusion after ONE failed example? Pretty sad, especially given the weight your word and reputation carries.

I once tried to separate a through V by steaming the thing for 30 minutes or so. It did nothing. I wasn't happy with the joint that I had done so it had to come off. Glued with HHG. In the end I took a piece of 2 x 2 inch turning blank of Bubinga, placed the head part in the vice and gave the back of the neck a substantial hit. No go until I resorted to the baseball technique. That's what you get when you pre size HHG joints. Sizing correctly is key when dealing with HHG and this type of joint as much of it is end grain.
The Fussen (so called Hauser) joint has greater mechanical integrity and more liable to split wood.

No offense, but designing something to break is not good engineering from my perspective.I would much rather concentrate my efforts on designing and building something that will not break. As for hhg at headstock joints, does disassembly really matter here? I mean how many Headstocks have you had to steam off in your life?

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Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

No one is saying that steaming headstocks is a regular occurrence. I fail to see your point.
The discussion is really about how much of an impact a head joint should withstand (before failure) and the subsequent ease of repair. I maintain that the V joint is capable of withstanding considerable force without letting go. That being dependent on how well the joint is executed, method of gluing and the particular type of V joint.
These type of joints have been around since at least the 16 th century. They never really went out of fashion but the scarf joint gained popularity in the late 19 th century, probably because it is much easier and quicker to execute.

Isn’t designing something to fail a common design strategy? This is why we have brass nuts on the elevneteen thousand steel Gibson style truss rods. Most of our workshops probably have fuses (or breakers) because they are easier to fix than the wires inside the walls. . . Not to mention all the talk about which glue to use to facilitate future repairs. . . At any rate, this thread has made me comfortable enough to work towards a goal of using this on a SS guitar (someday). I think the fact that in this thread and the same thread on another forum, have brought up exactly two examples of this joint failing, speaks to its suitability.The worst thing that can happen here is I get some practice with the chisels and some day have to re glue one; ah the luxury of being an amateur.

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Bryan Bear PMoMC

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

i'd like to try martin's old bridle joint some day...kinda looks like a split tongue and groove v joint

I've never done a bridal joint but always thought they looked really cool - and hard to do correctly.

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Steve Smith
"Music is what feelings sound like"

All the broken headstocks I have seen have not failed at a joint. Gibson's are the most common and they are sawn from a single billet. HHG has 75% the strength of the best PVA. In a lab test a 90 degree bridle joint in typical cabinet frame stock HHG was able to support on average better than 1500 lbs before the joint yeilded. That's a lot of force, 450 PSI +. The best HHG joint supported almost 1900 lbs before failure,almost 600 PSI. In examining the failures only the strongest woods or the poorest fit joints managed to cause shear along the glue line, most failures were of the surrounding wood fibers. The reason for a brass nut on a truss rod is a completely different scenario. That is a part that is meant to be serviced due to wear and use, that design criteria does not exist at a headstock joint. I had one of my guitars dropped about 4 feet onto a concrete floor the other year. I hit on the tail, bounced about 2 feet high and landed on it's face. Bent two tuners to the point of no return and removing them was no real fun. The headstock however remained perfectly intact with the exception of cosmetic damage. Personally I'm happy I engineered it to survive rather than break on impact.

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Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

The only headstock design that I have seen that was worse than a Gibson was a japanese acoustic from the 60's which had its truss rod access slot machined ACROSS the headstock to allow the use of an open ended spanner on the nut.
It really should not have been intact with the minimal amount to wood left there.

I think well made scarf or v joints are both quite adequate. I do think that some scarf joints where the scarf is made to a full thickness neck blank and the joint ends up in the back of the headstock are just as vulnerable to short grain breaks as a one piece neck.

The point of having the V joint fail on the glue line is to have it fail right before the wood would have failed. If the joint were any stronger, the neck would have broken. A poorly designed and fitted V joint fails much too soon but a proper one does not. It's like a fuse in an electrical circuit.

In the V joint designs that I've seen Al do and most others as well, the bulk of the glue surface is along the V and the shoulders are not a big part of the strength. It's the V that makes it work. If you just did a simple 15 degree miter, you'd be asking for trouble. There have been debates on this joint about where you cut the 15 degree angle. Do you put it on the read stock or do you put it on the neck shaft? I've seen both. One is supposed to be easier to rough cut on a table saw but I don't recall which one.

I wouldn't mind seeing some more pictures of V joints if anyone else has some to share.

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Formerly known as Adaboy.......

B,Howard wrote:
"No offense, but designing something to break is not good engineering from my perspective. I would much rather concentrate my efforts on designing and building something that will not break."

But _anything_ can be broken. The idea is to get it to break in the least harmful way when it does. I know guys that work at a local gun factory, and they routinely blow up guns; theirs and ones from other manufacturers, to see where the pieces go. Better they should fly _away_ from the guy holding the gun...

I can attest that the through V will break before the neck. A friend of mine was teaching an adult ed class for beginner guitarists, using an archtop I'd built him with a V-joined head. One of the students had an old box with seriously high action, and he traded guitars for the evening. At the end, as he was erasing the board, she evidently decided she couldn't wait, stood his guitar up on a chair, and left. The first he knew of it was when he heard it fall. He put a chair over the wreckage while he finished wiping the board, and swept it into the case without looking at it any more than he had to. The next morning he was camped out at my door when I arrived at the shop.

It had evidently hit on the back of the headstock, and the HHG joint had simply fractured along the glue line. I washed the old glue off with warm water, so the shoulders would go together tightly, and re-glued it. He was out the door in less than two hours, although I told him not to string it up until later in the evening. He's been playing it ever since, and that was about fifteen years ago. You'd have to look pretty closely to see that it had been broken. I have to wonder what might have broken if the head joint did not: maybe the neck?

The Martin modified bridle joint is an interesting one. Julius Borges showed us how that was done at a local luthiers meeting some years ago. It's actually a fairly easy joint to make with some simple table saw jigs. Once the parts are cut, all the fitting is done by thinning the headstock piece from the back until it just seats, and then you glue it. It's tricky to get it apart, and I can't see it breaking cleanly along the glue line without losing some wood, so I'm not sure I'd make it, even if I had a table saw.

Here's an early 19 th century original V joint that is typical of french romantic guitars. Very pointy. Note that it's not a through and it's wedged:

I'm with Trevor on this one. Too much end grain in the design. It should take a harder hit for it to fail. Other joints would, without doing damage to other parts of the guitar. As was stated before if it was a better design you would see it more.

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

How many times have you hit one? I've actually done it and I know what it's capable of. Partly the reason why it's not so common is because the difficulty in execution and the ease of the scarf joint. It's not a weak joint if done well!

Well, I searched for the pic of the headstock in question on the other site - sorry, no joy. So both of us will have to trust my memory. The failed joint looked well enough made in terms of closeness of fit. It appeared to be a through-V of typical proportions covered by a head plate. And the typical proportions bit is where the problem lay with THAT joint design. Each side of the V there was ~25% of the neck width that was end grain to end grain. Now perhaps you could do what Michael N. suggests and size the end grain with HHG and then you can't smash the joint with a baseball bat. No safety valve there. Or you can just glue up and hope that it holds the "right" amount. But how would you ever know? All you have is a joint that might fail under some unpredictable load. What is the point of that? A keystone of good engineering design is to not have things fail unpredictably and to be able to survive up to a specific load condition. IF you can do that with this type of V joint and suitable gluing technique, fine, you get a design pass. But I'd suggest mostly a design fail given the typical variability of the wood, end grain porosity, the fit, the glue mix, clamping technique etc. etc..

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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

Trevor, that was ONE fail.

One

Un

Uno

I have had zero fails, and yes, I've tested them, though not with a baseball bat. One of my new models uses a western red cedar headstock with a spanish cedar neck(all for the sake of weight reduction), and with this one, I did try to break a sample of it, and couldn't. It IS one strong joint, if done right. And no, I don't size my joints with HHG; never did, can't see a reason to(with zero fails, why should I?).

Listen folks, so many of you misunderstood all of this that it truly boggles the mind! Nobody suggested that anyone should build instruments that should fall apart. All that was suggested was that if an instrument took a fall and the V joint failed, cleanly, then that was a blessing in disguise, because it acted as the weakest part of the instrument and prevented more severe damage. Back in my younger days, I would build cars, "hot rods", even drag raced a time or two. Still own an original '87 Grand National.... Anyhow, as anyone who's ever built anything similar can attest to, once you get more power out of the engine, it's only a matter of time before something breaks in the driveline. Maybe just a U joint at first. So you buy a heavy duty U-joint, and the next time you drop the clutch at 6500 RPM, you take the rear diff out. In goes a truck rear end, and now you're looking at twisting the driveshaft, frying the clutch, or taking out the transmission. See where this is going? There has to be a weak link somewhere, so maybe you would have been better off replacing the U-joint with a stock until and just forgetting going ape sh!t with the 6500 rpm clutch drops, eh? Yup! So that same here; if the blow was hard enough to sheer a well made V joint at the glue line, it was pretty severe! So if the joint had held, quite likely, something else would have failed, something much more catastrophic, like the entire neck, the neck joint, or the heel. Do enough repairs in the real worlds, and you'll see all of these walk through your shop at one time or another; promise.

If the fall was truly minimal and innocent, then the joint wasn't done well enough. Period. A joint can look clean and well done, in a photo, but nobody got to really see how well it all fit together before gluing. And anyone who's done, or seen, one of these joints knows there are many compound angles that all need to fit precisely together for it to work as one unit. If any -one- angle is "off" by even a wee bit, the whole thing is compromised.

Sounds like more design problem if it's that reliant on perfect execution.

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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 like them!

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

Sounds like more design problem if it's that reliant on perfect execution.


But isn't perfect execution what we all strive to attain? No matter the joint, it needs to be executed to perfection, no? A sloppy scarf joint ain't nuthin' to be proud of, nor will it be overly reliable.

Perfection sure is my goal, each and every time, with everything I do, be it a simple butt joint, edge joint, or a complex compound angle V joint. And it should be everyone's goal! We should NOT rely on crutches like excessive clamping, epoxy, fillers, gap-filling glues, etc..., correct? Correct! Thereby, a luthier who chooses to use a V joint should have the chops to do it correctly, and if not, practice until he/she attains the chops to do it correctly. Once again, and for the final time, stop blaming the joint!

i will speculate that there were two main reasons that type joint was ever popular:
1)it was economical, as far as not wasting wood is concerned. lord knows labor was basically free in the 17-1800s. and good wood surely was not wasted on frivolous stuff such as musical instruments. saws were crude and there was no electricity, so all dimensional lumber would have been highly valued.
2)the hide glues of the day were impractical and untrustworthy, and possibly expensive, which ruled out today's popular scarf joint, which depends 100% on glue.
2a)no one really had air conditioning, which meant that the natural climate conditions would dramatically affect the hide glue joints
2c)Leo Fender was not yet born

If I may quote a mountain climber who had just gotten back to base camp after conquering one of the toughest climbs known to man, and was greeted by a reporter who asked "how hard was the climb?", he just looked at the clueless interviewer and said "well, if it was easy, everyone would be doing it...".

The same can be said about the V joint. It's a hard one to master, but that makes it all the more worthwhile conquering. It's also very elegant(look at Waddy's examples!), classic(in some circles), and very strong. It is, after all, and when properly done, a mechanical joint, where a simple scarf joint relies 100% on the glue... If you want all-out strength, at all costs, then you should be promoting a finger-joint scarf, like Taylor chose. It has all the elegance of an orange crate, but she's one tough joint! And dead-simple; just choose the right cutters for the shaper, and go to town....

Hmmm. Not sure that one passes muster. If you look at Michael N's pic above you'll see that you need around 50% more wood thickness in the neck shaft to get the V in. More economical than cutting from solid, though, but uses a lot more wood than a scarf. Given the reliance on glue for so many other joints on a stringed instrument, it's hard to see why the scarf took so long to catch on.

Sorry, but no one's is going to tell me that a joint with 50% end grain to end grain in bending (design application) is a good design, when there are numerous alternatives. And if it takes much of a load outside its "design" regime we have TWO examples of failure discussed in this thread. If you want to show off your woodworking chops (and your customers want to pay for it), there's the covered dovetail V (Michael's pics) with very little end grain gluing. The through V is just a poorly engineered version of that joint.

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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 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.