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lizzard 05-03-2016 06:54 AM

Neck Joints
 
Who still uses a traditional "dove-tail" neck joint? I know Bob turned the world to bolt-ons but...

Anyone?

Chris

LeightonBankes 05-03-2016 07:00 AM

people were doing bolt-on necks long before Taylor started making them on cnc machines. The NT neck is sweet, but I wouldn't call it a real innovation (the interchangeable shims are nice though)

Brad Goodman 05-03-2016 07:28 AM

Over the years I have used Spanish slipper foot (on steel strings)
glued mortise and tenon
bolt-on mortise and tenon
bolt-on butt joint
dovetail

At the present time, I am using dovetail joints.

It's a toss up for me between the dovetail and bolt-on butt joint.

They both have their pros and cons.

Neil K Walk 05-03-2016 08:18 AM

Quote:

Originally Posted by LeightonBankes (Post 4923260)
people were doing bolt-on necks long before Taylor started making them on cnc machines. The NT neck is sweet, but I wouldn't call it a real innovation (the interchangeable shims are nice though)

I think they pretty much perfected the bolt on joint though. Given Martin's history of fingerboard humps and ramping bridges I really like the idea of having a removable neck that bolts along two axes: namely into the neck block along the lengthwise axis and "downward" from the underside of the fretboard extension into an extension of the neck block.

I have a Norlin era Epiphone Texan FT-160N that is technically a bolt on but it's clearly not a good design for a steel string acoustic - least of which a 12 string. It's more of an adaptation of a solid body electric guitar design where the neck fits into a "pocket" in the top of the guitar and there is no heel to speak of.

Bruce Sexauer 05-03-2016 10:10 AM

My traditional HHG dovetail neck to body connection ain't broke, so I ain't fixin it. Bob's bodacious bolt on ain't broke neither, they say, but it may require occasional attention. :)

Tim McKnight 05-03-2016 10:46 AM

Necks that require attention are not the fault of the neck joint but rather a result of body / side / back deformation.

LouieAtienza 05-03-2016 11:51 AM

Quote:

Originally Posted by LeightonBankes (Post 4923260)
people were doing bolt-on necks long before Taylor started making them on cnc machines. The NT neck is sweet, but I wouldn't call it a real innovation (the interchangeable shims are nice though)

The main thing with the Taylor NT joint is that there is a contiguous piece of wood that continues through the fretboard extension, which helps prevent the "rising tongue" that can occur at that area. The innovation is that the fretboard AND heel are pocketed into the body, which allows the use of shims without it being noticeable as such. I thought it was a 5-axis CNC, but it's actually a 3-axis CNC with an aggregate 90 degree head that mills the heel pocket.

Bruce Sexauer 05-03-2016 02:47 PM

Quote:

Originally Posted by Tim McKnight (Post 4923545)
Necks that require attention are not the fault of the neck joint but rather a result of body / side / back deformation.

When I was following contemporary "state of the art" industrial woodworking (free magazine for many years) I learned that threaded fasteners WILL eventually back themselves out in a stressed vibrating application, which sure sounds like a guitar to me . . . Oh, we're talking about a Taylor . . . ;)

I have been called upon a few times to tighten loose bolt-on necks, but it may not be the rule. While I am a dovetail guy and have no intention of changing, I do not mind what others choose to do. A bolt on may or may not be as good as an HHG dovetail, but I am as certain as I am of anything that it is not better where aesthetics and performance are concerned.

jessupe 05-03-2016 07:26 PM

bolts is nuts :D the only bolts I've ever seen that I liked is Parkers,and that was for changing projection... but I'm sure it can be just fine....personally I'm a mortice cut attached to the back via the button kind of guy, like, thats right, a violin or cello :)

LouieAtienza 05-03-2016 07:53 PM

Quote:

Originally Posted by Bruce Sexauer (Post 4923778)
When I was following contemporary "state of the art" industrial woodworking (free magazine for many years) I learned that threaded fasteners WILL eventually back themselves out in a stressed vibrating application, which sure sounds like a guitar to me . . . Oh, we're talking about a Taylor . . . ;)

I have been called upon a few times to tighten loose bolt-on necks, but it may not be the rule. While I am a dovetail guy and have no intention of changing, I do not mind what others choose to do. A bolt on may or may not be as good as an HHG dovetail, but I am as certain as I am of anything that it is not better where aesthetics and performance are concerned.

I do like McPherson's solution, where a brass dowel in the heel receives the bolts from the body, which have Belleville washers, I believe rated at 250lbs force each, which allow movement of wood while still retaining their hold.

Stephen Strahm 05-03-2016 10:38 PM

I use a traditional dovetail neck joint. It's what I learned to use during my time at the Santa Cruz Guitar Company and it works for me.

Jimmy Caldwell 05-04-2016 05:36 AM

Traditional tapered dovetail for me. It's not how I started out, but it's where I wound up. I build very traditional guitars and it's what I'm comfortable with.

MC5C 05-04-2016 06:23 AM

Owning two guitars where the traditional dovetail joint failed, albeit after 70 years, and having the repair on one fail and have to be redone, I am using bolt on necks with a tightly fitting mortise and tenon. Things made of wood and glue that are under constant stress fail with enough time, it's what they do. Just because I won't be the guy fixing it 70 years from now doesn't mean, to me at least, that I shouldn't design the thing so it can be fixed or adjusted easily and neatly.

I have a dozen antique chairs - circa 1900 to 1930's - in my house that are in constant use. Every single one of them has failing joints. In a lot of cases it's the wood itself that has failed, but the wood is part of the joint...

Guest 1928 05-04-2016 06:36 AM

Quote:

Originally Posted by LouieAtienza (Post 4923599)
The main thing with the Taylor NT joint is that there is a contiguous piece of wood that continues through the fretboard extension, which helps prevent the "rising tongue" that can occur at that area. The innovation is that the fretboard AND heel are pocketed into the body, which allows the use of shims without it being noticeable as such. I thought it was a 5-axis CNC, but it's actually a 3-axis CNC with an aggregate 90 degree head that mills the heel pocket.

IME the "rising tongue" is nearly always an underset neck and the fretboard extension only appears to be rising if you look at it from the wrong reference point.

The Taylor N/T joint is wonderful for manufacture and repair, but the whole thing adds considerable mass to that area of the guitar. It works, but it's not what I'd consider elegant construction.


Quote:

Originally Posted by MC5C (Post 4924284)
Owning two guitars where the traditional dovetail joint failed, albeit after 70 years, and having the repair on one fail and have to be redone, I am using bolt on necks with a tightly fitting mortise and tenon. Things made of wood and glue that are under constant stress fail with enough time, it's what they do. Just because I won't be the guy fixing it 70 years from now doesn't mean, to me at least, that I shouldn't design the thing so it can be fixed or adjusted easily and neatly.

I have a dozen antique chairs - circa 1900 to 1930's - in my house that are in constant use. Every single one of them has failing joints. In a lot of cases it's the wood itself that has failed, but the wood is part of the joint...

Failed how? What was the brand(s)? I'm curious to know whether the instruments needed neck resets to correct the neck angle, or if the joints actually failed, as in came apart.

MC5C 05-04-2016 07:03 AM

Hi Todd. I guess it depends on a definition or two, but I consider a joint failure one where the body of the instrument has not shifted measurably and the neck has started to pull out of the mortise, creating a gap at the joint and letting the neck tip forward. I don't really differentiate between a glue failure or a wood failure, they are both part of the joint to me. The first one is my 1946 Epiphone Zephyr. Neck joint failed, allowing the lower heel to come out from the body about 1/16" clear gap, and the fretboard extension to dip down and start to touch the body. Much of the glue was still good, the joint had to be steamed apart. Recall that this era of Epiphone had the "pusher" truss rod with the adjusting end under the fret board extension - that was what had contacted the top of the body. The bridge height had fallen to the point that the original bridge topper had been discarded and a new, shorter, one been made to replace it. Recall also that the bodies of these guitars, being their first electric models, were made of three ply spruce laminate and are extremely stable - the body had not move to a measurable degree. The first repair was done wrong, rushed, and failed due to a shim moving when the neck was reglued and coming out of place. So far the second repair has held up. It was repaired before I was building guitars, by a professional luthier who really specializes in repair, not building. I let him redo the work (for free) since his first try failed within 3 months.

The second guitar is a 1935/6 ish Regal-made Dobro, round neck, again the heel of the joint has pulled away from the body. Again an extremely robust (like 1/4" thick) laminate body that hasn't moved to a measurable degree. This model Dobro, being the entry level student model, does not have the traditional resonator "stick" neck extension inside the body, but has a dovetail neck joint. The neck has also bowed considerably, relief is around .060". I could reset the neck and get the action down, I could pull the fingerboard and straighten the neck and do a reset, but for now I just keep it put away with loosened strings and pull it out, tune it to low bass open G and get my fix of bottleneck blues. I can play open position chords, but nothing above the third fret - but that old resonator has a sound of it's own, very distinctive, and it flat out loves a slide...

I thought of a third one. My 1957 Hofner Senator had the neck reset 25 or 30 years ago, when it was around 30 years old. I had just bought it, and with no truss rod and heavy strings, the neck had bowed a bit, it needed frets and the neck had pulled out of the body considerably. My friend was learning lutherie and guitar repair and wanted to have a go at it. He pulled the neck off, found the joint was a questionable design in the first place, repaired it and I suspect redid the joint design, and that guitar has been perfectly stable ever since (he also planed the fretboard and installed new frets, of course). Again a fully laminate body. I do need to dress the frets on it, the neck has risen past the fret board extension and the action is too high as a result.

So my three oldest guitars that have dovetail joints all had joint failures to some degree or other, some with extenuating circumstances (the Dobro sat under a bed, strung at full tension, from around 1942 to 2012, without being played. Young Canadian soldier took it off to war, and only the guitar got shipped back to his family. My neck would be bowed after that, so I don't blame it a bit). Having written this I am forced to wonder about all of these instruments having laminate bodies and two of them being archtops. I strongly suspect that they can be far more stable (the Epiphone archtop doesn't even have top bracing) than solid wood guitars, so if a failure occurs it might be less likely to be the body moving.


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