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The butt joint does require a bit more heel. Hanger bolts instead of inserts lessen the effect. How important that is, is an individual choice. I seem to have fallen in the camp of not minding the extra size. I was just thinking that, by now, I could probably reduce the amount of wood I need having done several. But I kind of feel like I have settled into a particular look and don't feel like changing.

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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 that, what the heck, it works fine on my banjo. Lots of experimenting ahead.

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Hutch

Get the heck off the couch and go build a guitar!!!!

The extra beef in the heel for a buttjoint can be made to look ok. None of my clients have ever commented on it. Once you do a buttjoint though, you won't want to do it any other way. So simple!

As far as hardware goes, I greatly prefer the square-mortise bolt-bar described by Gore/Gilet and have abandoned treaded inserts, barrel nuts and hanger bolts since I started using it. There is the additional step of creating the square mortise in the heel but if you have a chisel mortiser drill press attachment it’s only a few minutes work to set it up, drill the hole and pack it away. If you have a dedicated chisel mortiser then it’s a breeze

However, I’m fairly committed to bolt-on necks. If you’re just wanting to try one out the threaded inserts or hanger bolts are the easiest way to go.

I have no idea what you're talking about.

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Hutch

Get the heck off the couch and go build a guitar!!!!

Sorry - maybe a picture would help. I don’t have a shot of my own handy showing the construction so I’m linking to one posted by another builder:



As you can see a bar with tapped holes is embedded in the heel - the heel cap is glued on to conceal it once installed. Bolts enter via the tenon in the usual way. This is more work to make than some other methods but very strong.

It's easy to see that in some idealized world, a tenon in a mortice is more sturdy than a butt joint, as the sides of the mortice can hold the sides of the tenon in the desired orientation. But in the real world, the sides of the neck tenon will not press significantly against the sides of the headblock mortice unless the neck assumes a notable angle to the guitar centerline -- and, at that point, it's too late. A tapered tenon, pulled into a tapered mortice by the bolt-on hardware would deal with this issue, but so would a carefully crafted butt joint. Dealer's choice.

I think one advantage of butt joints purely from the builders perspective is they’re a little easier to floss and fit vs tenon.


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I've been using hanger bolts with a 1/2" depth mortise and tenon (and dowel for the hanger bolts to bite into) for many years including on a couple of 34" scale bass guitars. Works great and I see no reason to change even though I haven't tried other systems. A long allen wrench allows me to tighten the furniture nuts by reaching through the endpin hole on archtops. I've put upper bout soundholes on my last ten guitars which sure helps on archtops and flat tops somewhat too when bolting things up. No pro by far but works for me.

Interesting discussion that I’m watching carefully because I haven’t settled on a preference for neck joints yet. Here’s my two cents worth — which may be an exaggeration of its worth …

Two bolts with threaded inserts and glued extension: I find it hard to get the bolts lined up perfectly with the inserts. Best success so far by drilling the neck block first and using a transfer punch to locate the spots to drill the neck tenon for the inserts. Still difficult to get the inserts in perfectly straight and often have to employ a lot of colorful language to bolt the neck on.

Gore/Gilet bolt-on/bolt-off design (I.e. 2 bolts through block into neck tenon and 2 more into the neck extension): I agree that the drilled/tapped bar in the square mortise works much better than threaded inserts but it also adds more weight. And maybe it’s just the way I built it and it doesn’t have to be this way, but my neck block and the tenon on the underside of the neck extension added a lot more wood and a lot more weight to the joint as well. On the plus side, I think the notes way up the fretboard sound out louder and clearer. On the downside, it’s all pretty heavy.

Just a couple of notes from my limited experience.

I had a similar headache, and I managed to resolve that problem and a bunch of others by making a floating tenon that gets glued into the neck after it's match-drilled in the neck block. The floating tenon is slipped into the neck block, two passes with the drill press, done. And it makes for dead-easy-for-me cutting the neck angle into the neck before gluing in the floating tenon. While the neck blank is still rectangular, make a pass through the table saw at the chosen angle, and there's a squared-to-the neck neck angle.

And the floating tenon is a sturdy crossgrain neck heel reinforcement, these heels will never crack.

My method for neck joints I bought from Luthier's Cool Tools (Dave Micheletti). I added the floating tenon, everything else is as so thoroughly outlined in the instruction set.

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Peter Havriluk

Same here, very strong, lots of wood to back it up from bolt pull.
I've also used aluminium (T6), which is ~1/3 the weight, but seems to be a similar shear strength.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

I don’t use the double bolted extension, just the bolt bar with glued fb extension, and it’s definitely a little heavier than say threaded inserts but we’re talking a few grams heavier. And that’s with a brass bar … you could use a lighter material … aluminium .. even titanium I guess!

That’s very interesting about improved volume up the neck with a bolt-on/bolt-off neck. I hadn’t heard that before and now I want to try it. A reliable sonic improvement is well worth a moderate weight penalty in my book.

Aha! Thanks Colin I’m actually running low on 3/8” brass bar so maybe it’s time to branch out and try these other materials.

there are many ways to do bolt ons and if you are doing a butt on I have seen them with short heels like martin.
they all used 2 bolts and if you do a true bolt on you may want to use the threaded inserts with the knife threads and they will hold very well.
what ever you choose be sure you select something that is structurally sound. 2 1/4 20 bolts will do very well. As for the extension that can also be a bolt on . Double sided tape is nothing I have ever seen that worked in over 20 years of this. The only time I saw it was on amature guitars. Taylor has a nice design and I am sure you can find many that are not complicated to make .

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I think this is a necessary evil, or positive characteristic (depending on your perspective), of any non-glued joint. The separate pieces (neck and body) have to individually have enough wood/metal to make the joint work well without glue. So, if reducing weight is a goal, a non-glued neck/body joint is not going to further that goal. But not everyone has that goal, or they live with the extra weight at this joint and try to go lighter elsewhere.

I think it is fair to say that deciding to have no glue at the neck/body joint necessarily increases the design and build time. It has to be a more complicated joint in order to work well. Getting comfortable with gluing down the fingerboard extension significantly simplifies the joint. Of course, then deciding to go without bolts increases complexity in the other direction, because then you are building with a dovetail joint. The bolted neck, glued fingerboard extension version of the neck/body joint is a great mix of performance and ease of construction. That’s why it’s so popular. I’m a dovetail guy at the moment, but I’ve built with a variety of neck/body joints, and the bolted neck, glued fingerboard extension version is a great way to go.

I should be more careful here - I'm a novice and have only made a few guitars. I shouldn't claim an improvement based upon a sample of 1! But I'd be really interested to know if others have found this.

I think it is easier to think about this in reverse. If the fingerboard extension is not solidly attached to anything, then notes can crap out, because the vibrations are being squandered instead of being fed into the whole of the guitar. That's the way I think about it, anyway.

Why?

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Jim Watts
http://jameswattsguitars.com

Another option is no heel at all.
Here is a Taylor Big Baby which shows the concept.

I have built some this way, as well as doing others with bolt on M&T with glued down fingerboard, and some bolt-on/bolt-down butt joints. All options work. This is arguably easier. It is certainly the lightest construction option. The neck block is bigger, with an extension under the soundboard thick enough for a routed pocket, but without a heel or the associated hardware it saves a lot of weight. It is plenty strong.

How do you attach it? Taylor screw it from the front - two screws straight through the fingerboard at the 16th fret. Effective but a bit inelegant. You can hide it all inside by bolting up through the block, like that picture that Herry posted earlier in this thread. Or you can do it through the back of the guitar (think stratocaster). That is what Martin do with their new SC13-E, and I did this with this bouzouki-guitar because it has f-holes so I couldn’t do internal bolts.

That type of attachment has been around for decades in one form or another. I have a 50's Truetone with the same attachment. Unfortunately, if building or especially, selling, a high end guitar, that heel less style just doesn't do it for most people/buyers.

Yes, if you are building to sell to the middle of the market you are better to stick to 1930s design principles. And if you want to try using more modern materials or methods you had better hide it all so that it still looks like the 1930s. But since we are having a conversation among builders, and we are interested in design, it is worth airing other options. Outside of North America there tends to be a bit more tolerance for “different”.

Hardware is always a stress riser in wood assemblies. The FAA has some pretty strict guidelines for the use of hardware in wood aircraft structures and things like propellers. Things like propeller bolts and the furniture dowel nuts have to be a tight fit in the holes to avoid stress risers: ideally they should be hammered in. A loose insert concentrates stress along a single line, and can split the wood. That happened to one of my students: he over tightened the neck bolts a bit, and then hit the head on a beam in the low ceiling picking the unstrung guitar up. The neck split at the top of the heel and the body fell to the floor. The damage wasn't too bad, but we made a new neck.

Part of the problem there was that we used short dowel screws that went in across the tenon. On the replacement neck, and subsequently, I've drilled in from the bottom of the heel perpendicular to the fingerboard surface, and put the dowel nuts in there. If the heel splits that way the tenon in the mortice prevents the pieces from separating, so the neck won't fall off; the design 'fails well'. Note that the dowel screws I get at the hardware store say they're 3/8", but they are really 10 mm in diameter.

I have the remains of a Taylor 12-string neck that split through the threaded insert. I've also seen those strip out. When I have used them I made a tap out of a wood screw with the correct thread to avoid creating a lot of compression stress in the neck heel, and then epoxied the insert in. So far...

This video shows how I do it. I made the drilling jig and I use it to drill out the head block (not in video) and then I use it to drill out the heel. Note that their is a cut off piece of the top wood used as a shim. This works perfectly for me every time. Prior to this I would do as you mentioned, using a transfer punch, but I could never get it right. Even so though it often only required expanding the holes by one size which is no biggie. But with this jig it's perfect.

https://www.tiktok.com/@piusone/video/7 ... 6608066053

As for the size of the heel, if you use a cross grain dowel to take the inserts you can actually get it pretty slim. And imho you should always use a dowel. I set the inserts in a bit farther than flush with the wood so that it can be flossed in the future for a neck reset. It seems to me that hangar bolts would get in the way of this process but perhaps that's easy enough to get around too?

Good call on mentioning the cross grain dowel in the heel. I do that too and think it is important. I have a matched set of drilling guides similar to yours. One for drilling the holes for the inserts and one fro drilling through the body for the bolts. It makes things a lot easier. I used hanger bolts for a while and felt fluke they got in the way of flossing the neck sink switched to inserts. Since then, I have started flossing eight the bolts in again, so I could go back to hanger bolts if I wanted. I guess that speaks to the fact that I am less concerned about shrinking my heels by a bit than I am about making a new drilling jig for hanger bolts.
Edit: JF, I think I remember reading that you do not relieve the bearing surface of your butt joints; going instead for full contact. So my comment on flossing with hanger bolts is misplaced. They would definitely be an issue for your method.

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Bryan Bear PMoMC

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