Thread: Neck Joints
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Old 05-04-2016, 07:03 AM
MC5C MC5C is offline
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Location: Tatamagouche Nova Scotia
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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.
__________________
Brian Evans
1935 Dobro model 25 resonator
1943 Paramount (made by Kay) mandolin
1946 Epiphone Zephyr electric archtop
1957 Hofner Senator archtop
1962 Gibson Melody Maker electric
1963 National Dynamic lap steel
1996 Landola jumbo
1998 Godin Artisan TC electric
1998 Epiphone SG electric
2010 GoldTone PBR-CA resonator
2015 Evans electric archtop
2016 Evans archtop

Last edited by MC5C; 05-04-2016 at 07:16 AM.
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