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Perhaps that's better than pulling the neck block out. Or not.

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formerly known around here as burbank
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http://www.patfosterguitars.com

Don't have the Sloane book, but yes, agreed.
A square dowel might be better than the round one for a start.

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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.

not a new design that fact is , the inserts usually fail from the wood shrinking. Amazing how hard people work to make a joint than cannot surpass a good dovetail. Learn to do the dovetail.

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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

This is probably your best bet. If inserts are too difficult to come by, just learn to do dovetails. I think the geometry in your idea is more complex than a basic dovetail; if you can pull this off you can definitely dovetail a neck.

I this new joint is a little too complicated to fit. That said, I’m always impressed by machining.


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My problem with dovetail is I had a few instances of them pulling itself out for no reason. The problem is you have no idea until years down the line.

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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.

Typhoon Guitars
http://www.typhoon-guitars.com

Yeah, I hate it when I make something poorly and it falls to bits as well.

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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.

We went through this in another recent thread. Those failures were not “for no reason.” You described how you made those dovetails, and it sounded pretty clear that you were leaving them too loose at the narrow end of the heel. You mistakenly concluded that a dovetail is just an inferior joint, when you should have concluded that you were not executing it right.

If you want to build a bolt-on, there is a decent design that I have already shared with you, and that avoids the use of barrel nuts: the Trevor Gore design. Another way to go is to drive hanger bolts into the tenon, like on a StewMac kit. Or, you can learn to cut a traditional dovetail.

This hunk of aluminum idea of yours just feels like a lot of over engineering. There are simpler and more reliable ways of attaching a neck. Innovation is fine, but this doesn’t feel like progress.

Not to pile on but this entire thread is laughable...

First what problem is it that you are trying to solve with this much too complicated solution looking for a problem? As John Hall rightly said a dovetail joint is a beautiful thing, period. At present I'm not aware or a more effective, long lasting, serviceable, light weight solution that does not depend on a stinkin mill or a hardware store to implement.

Also I take issue with your statement that your dovetails failed for no reason. I'm in the business of making dovetail joints that won't fail and so is everyone else I know who works in the trade. Like some of the others there is always a reason. Dovetails are not some mystery joint where you take your chances like buying a lottery ticket. They are rock solid and very predictable when done correctly and although there is a skill set to be developed to do this correctly it's been done tens of millions of times prior by thousands of folks.

I know you like using your mill Ti but it might just be that others who came before us worked out much of this and their solutions such as tried and true truss rod designs (you are making different truss rod nuts in another thread) and dovetail joints simply work. Innovation is fine but I see nothing at all practicable or desirable in this kind of neck joint. I'd take a simple bolt-on over this too.

By the way are you aware of the cries of heresy and calls to burn the traitors at the stake when Bob Taylor introduced his bolt on neck joint? Millions of hostile words were exchanged on forums by folks compensating for being sh**** players proclaiming that they could hear.... hear... a difference in the neck joint that Taylor was producing. To this very day some are still having arrested development over this issue.

Tai
not trying to make you feel bad but a dovetail is a master of simple wood joinery. So can yo post pictures of your joint, what wood and glue.
I have been doing this for a long time. Did over 1000 neck resets. So here are a few things I learned
A this is a simple interference fit.
When I am setting a dovetail i use a clamp and want the joint pushed together with the clamp. Hand strength won't do it. Some
do use a hammer I prefer the clamp. The point being the lower part of the tenon grabs and pulls the tenon in the mortise.
B Your angle on the tenon is critical. That lower 1/3 of the tenon has to touch the mortise first. That pulls it together. The angle of the tenon and cheeks are also important. Too flat you don't get a strong bite , too tight the edges fail. I use 9 degrees on tenon and cheeks. Same as Martin
C how you glue and clamp. I use a stout clamp on the tenon clamping straight to the mortise. I have seen some people thin that canting the clamp helps , and it doesn't . IF your joint it properly prepared you can see the heel pull into the block.
D Wood used is important. Plywood makes a horrible neck block for dovetails . I use mahogany and I run the grain direction the same as the side wood. Vertical graining can split. Also if the wood is not stored properly the wood may shrink in the tenon pulling itself loose.

There are reasons for failure but there is more success in this when mastered. I am not a fan of bolt on necks but have used them. I am more of a traditionalist in my building. I have seen so many here post pictures of the new improved bolt on designs and later have the same people posting the failures , it isn't the they are not smart but from an engineering standpoint you have to make the design to conform with the woods strength. The inserts often will apply more force than needed making the tenons fail. Martin uses a simple screw in insert that is very strong and efficient. The variable and weak link in this is that the metal joint loosens from wood shrinkage and vibration.

Either joint when executed properly is what makes them successful. The more variables you install into your system the higher the rate of failure. Keep it simple. Master your wood joinery and understand what glues work the best for the situation. I use only wood glues mostly Fish glue Hot Hide glue and tite bond original. No need to use any other wood glue.
Epoxies I may use in repair , super glue I seldom use anymore but it does have its uses.

You can learn more from a failure than you can success so take the time to understand why it failed and it will make you a better
builder. The difference between an expert and amateur , is we learned from the many mistakes we made. Best of luck and I know if you ask any one of us will be happy to help

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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

There's no need to avoid barrel nuts or threaded inserts or hanger bolts or even dovetails - just put the time into understanding how they are supposed to function and execute the joint correctly.

- Barrel nut M&T systems need cross-grain reinforcement - a trivial task quickly executed with table saw or router.

- Hanger bolts or inserts need face-grain mounting - a dowel is easily inserted into the heel for both tenoned and butted joints.

- Dovetailed necks need firm contact between the mating face of the tail and wall of the socket at both top and bottom of the joint - watch a couple videos if need be to understand how the joint is fitted.

To reiterate: most of the problems we see which trace back to design and workmanship faults stem from the maker's lack of understanding of either the functional requirements for or proper execution of a particular design or design element.

And to further beat a barely ambulatory member of an equine species, the dovetail is neither particularly difficult to make or to fit. Few other joints in woodworking can be so roughly hacked out with saw and chisel, fitted using shims (SHIMS!!!), then have the evidence of that butchery hidden away safe from prying eyes for decades of good service. We routinely pull stable, functioning necks on old instruments to fine a dog's dinner of a joint which is still functioning after being stored in an aged grandparent's crawlspace or attic...a neck reset allows another 70-80 years of trouble-free service.

As beaten into us by the boss and Mr. Morelli: master the simple stuff, if only to be able to repair what comes through the door (and the vast majority of factory-built instruments ALWAYS employ the simplest approach possible to achieve a given end result).

Edit: the Martin M&T joint IS NOT a bolt-on neck joint - it is more properly a glued mortise and tenon joint which employs a poorly engineered insert-and-bolt lash-up to hold things in place until the glue dries. Citing the Martin M&T joint as an example of the weakness of bolt-on neck joints is inaccurate.

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For the times they are a changin'

- Bob Dylan

Over the years participating here I have seen a number of complicated methods proposed and used to join the neck to the body, but few have met the disapprobation expressed here. Although I believe there are a number of improvements that can be made to the proposed method, I don't think it is the most complicated or silliest I have seen here. People go to great lengths to avoid the need to undo glue or to make a joint so strong it would survive the Gibson track hoe test.
The simple butt joint bolt on with a glued fingerboard extension has worked fine for me, and the tapered dovetail is elegantly simple and requires no mechanical fasteners and has the added benefit of being expected and traditional. With the advent of thin bladed oscillating tools even D.R. Youngs epoxied butt joint might be a viable alternative. Many people have said the joint held up fine, so being able to saw the neck off with little loss of length could work O.K. (with age a little loss of length is to be expected).
Many of the "improvements" to the guitar that have been espoused by their proponents, in the final analysis have proven to not be. Even some of those made by well known manufacturers have failed structurally or from lack of buyer acceptance.
A number of well known builders have employed idiosyncratic methods peculiar to their instruments, so if Tai wants to pursue the aluminium dovetail/ tenon "more power" to him.

In discussion with the big brains:

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For the times they are a changin'

- Bob Dylan

Problem statement: My dovetails do not always stay together.
Solution: Design a complex, multi-material, multi-part joint that relies on a glue's inherent low sheer strength and misguided ideas about toothing and glue. Hope this lasts a long time. Learn how to make and fit a solid dovetail joint.

History is a good thing. Dovetails have been around since about 3,000 B.C. thanks to the Egyptians. Probably one of the effective mechanical joints known to man and construction.

Specific to instruments, dovetails have been used for hundreds of years, beyond guitars. Harps for example. There are simpler joints to fashion for those that appreciate a good bolt-on neck with an M&T, for example. But no competent luthier will ever argue that a reasonably proper dovetail neck joint is lacking in structure or stability.

John Hall has a series of Youtube videos on the dovetail. I've not watched them so I can't comment specifically, but maybe a good place to start.

If the aluminum is necessary I would suggest a 'T' slot instead of the dovetail joint. I think the dovetail when tightened would act as a splitting maul and split the neck heel eventually.

I to use and like the traditional dovetail joint.

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Michael Lloyd

“I was born to ignorance, yes, and lesser poverties ...
I was born to privilege that I did not see ... I didn’t know it, but my way was paved” – John Gorka

One thing I like about a bolt on is that if the goal is to maintain optimal saddle height and low action throughout the entire neck the bolt on design allows minor neck angle tweaks to be done fairly easily as the guitar settles in.

With a glued dovetail altering the saddle height is the only option.

I only used glued dovetails on the first six or seven guitars I made so I would ask those with more experience like John, do you ever get a situation where a completed guitar settles in a little more than expected early on but not quite enough to warrant steaming off the neck and you are tempted to accept a less than optimal saddle height to achieve low action at 12?

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It's not what you don't know that hurts you, it's what you do know that's wrong.

The other question is, has there ever been a situation where you swore you made the dovetail solid, no looseness when pulling on it, then you completed the guitar, and 5 years later the heel pulled out?

Yes it does seem like a lottery to me sometimes because it's solid now, it stayed solid, but then years down the line it pulls out because perhaps the wood compressed (mahogany does compress rather easily) and maybe the guitar spent time in a hot car?

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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.

Typhoon Guitars
http://www.typhoon-guitars.com

It's more likely that the joint was loose, but being held in by glue alone, and the glue eventually failed...

Correct. Watch John’s dovetail series on YouTube paying attention to the dry fit.


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So that Martin D35 where the heel pulled loose due to heat on frets.com shouldn’t have happened if the joint were fitted better?

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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.

Typhoon Guitars
http://www.typhoon-guitars.com

I believe so.

Maybe, just maybe, the penny's beginning to drop?

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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.

Tai,
You've impressed me with your ability to handle the criticism of your idea in this thread -- and still stay civil and ask questions. It's a good quality. I will offer some criticism as well - you're workmanship seems to be a bit rough - the dovetail is not an easy joint to get correct and I believe the issues you have had are due to poor fit. Don't lose heart and keep at it - or try Trevor Gore's method. I use endgrain inserts and they are more than sufficiently strong for our purposes as luthiers. Lutherie requires a very high skill level for certain operations -- a perfect neck joint is one of those and something that I see even very experienced builders do poorly.

----

To a couple of you who posted -- Why the rudeness? I encourage you to keep the atmosphere here as kind as you can.

I think one of my biggest problem is workholding.

I hate routers for this very reason, it's like doing brain surgery with a chainsaw rather than a fine scalpel. Router templates slip, and when they do everything messes up and it's basically patchwork trying to fix what a router broke in a millisecond. I don't have a good way to clamp a template to a neck heel that will absolutely not slip, even though I use my laser to make templates with perfect accuracy. I can't use my milling machine (if I could I would) for this because my mill has a vertical work envelope of about 20 inches, and I am not sure I have enough room to maneuver and cut something into the neck, otherwise the fit would have been absolutely perfect. The aluminum insert however is a beautiful work of art in my opinion because even though a milling machine is a big heavy machine, doing work with it is like using a scalpel, if I move in a straight line. Using the digital readout I can dial it in to within .005mm which is probably 100 times more precise than any guitars are. I need to investigate this further and see if I can indeed fit a completed neck under my mill spindle because I rather do this than use a router. It's just cranking the knee is backbreaking labor.

I'm even going to make bridges with the mill and even use the laser to cut the bridge out (probably not, because lasers hate cutting ebony) just because I can be far more repeatable and precise with them rather than depending on screws and tape to not slip at the worst possible time. Or maybe just buy pre-made bridges from Taobao (they're really cheap).

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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.

Typhoon Guitars
http://www.typhoon-guitars.com

If you intend to slow-bake your instruments like casserole dishes in a medium oven - as that D-35 Mr. Ford mentioned most certainly was - you may wish to implement a range of changes to address that intended use:

- Convert to all-metal, heat-resistant construction
- Use adhesives rated to 100 deg C or perhaps welded/brazed construction
- Install a thermometer on the surface of the instrument to cue players to the need for oven mitts and heat-resistant clothing when playing

http://www.frets.com/FretsPages/Musician/GenMaint/Heat/73D35Heat/73d35heat.html

If on the other hand, you wish to address the failure of your dovetail joints under more reasonable use and storage conditions, I suspect the problem you must address is as Mr. The Cat has suggested - your understanding of and execution of a well-fitted (well done??? ) neck joint.

As to why the neck joint on that D-35 shifted slightly, that dovetail was oven-baked to dry for hours or more likely days, softening the adhesive and shrinking both the dovetail and neck block. Because mahogany shrinks about 100x more across the grain (tangential and radial directions) than along the grain, the dovetail shrank in width, allowing the neck joint to slip (the neck block also shrank in the cross-grain direction, but not in a direction which would have compensated for the dovetail). I suspect most other neck joints - including your own design - would see similar issues given that degree of heat stress, and perhaps more to the point, the rest of the guitar as well.

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For the times they are a changin'

- Bob Dylan

Has anyone thought to pre bake mahogany in order to make it more resistant to future shrinkage, or does it lead to additional problem?

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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.

Typhoon Guitars
http://www.typhoon-guitars.com