Members knockwood Posted March 15, 2005 Members Posted March 15, 2005 Anyone familiar enough with this type of neck construction to know how/whether it impacts a guitar's sound and overall quality vs. dovetail? I do not notice a difference, which is to say that generally when I pick up a guitar and play it, I cannot strum out a few chords and tell you what type of neck construction I'm playing on. But I would be interested in others' opinions. Wondering why this construction seems generally not used for Martin's high end models.
Members Jerry NT Posted March 15, 2005 Members Posted March 15, 2005 Mortise: a space hollowed out in a piece of wood to receive a projection (tenon) (According to Webster's) Most of the thought on Dove Tail construction is that more wood contacts the body and thus more sound gets through. True?I've read luthiers sites that stated the only reason some use dove tail is that it is expected of better guitars and that bolt on necks work just fine and would be easier when the guitar needs a neck reset (which nearly all will eventually.) I dunno. The only neck joint used on most high quality guitars is dove tail.
Members daddyO Posted March 15, 2005 Members Posted March 15, 2005 A mortise and tenon are both rectangular. A dovetail is angle to lock in. A mortise and tenon joint (ie: Taylor) relies on a bolt(s) to hold the joint tight. From a scientific viewpoint, there is no reason a good MT joint is worse than a dovetail joint. But a dovetail is harder to make so the cachet of quality is there. My Larrivee has a dovetal joint and I like it.
Members bjorn-fjord Posted March 15, 2005 Members Posted March 15, 2005 Mortise and Tenon: http://www.stewmac.com/shop/Bodies,_necks,_wood/Acoustic_guitar:_Necks/1/Bolt-on_Acoustic_Necks/Pictures.html#details Dovetail:http://www.stewmac.com/shop/Bodies,_necks,_wood/Acoustic_guitar:_Necks/1/Dovetailed_Acoustic_Necks/Pictures.html#details I agree with what everyone else has said about the efficacy of these two types of neck/body joints. As a builder, I think I can add a little more. In my opinion, the idea that there is more wood to wood contact in a dovetail joint is a fallacy. I believe that the opposite is true. This contention (more contact) is true when we are talking furniture joinery but the guitar neck/body joint is different. Let me explain.When the heel and neck block are routed for the dovetail, the proper neck angle is routed into the heel but the neck block is routed "straight". This creates a small amount of "play" in the joint that allows small adjustments to be made to neck angle. To solidify the joint small wood shims are wedged into the areas of the joint that are not making contact. When anyone speaks of "fitting" a dovetail or a "hand-fitted" dovetail, this is what they mean. In a dovetail neck/body joint, the primary area of contact is these small veneer wedges. In a mortise and tenon joint, especially a bolt-on, the neck can be installed and removed ad infinitum before final assembly so the fit of the neck can be cut to much smaller tolerances, hence more wood to wood contact.
Members Jerry NT Posted March 15, 2005 Members Posted March 15, 2005 And a dove tail is extremely hard to reset. Getting them to fit again is a difficult task. I've done it.
Members knockwood Posted March 15, 2005 Author Members Posted March 15, 2005 Many thanks for the replies. All interesting and very useful information.
Members bigmo66 Posted March 16, 2005 Members Posted March 16, 2005 Originally posted by knockwood What the Frig is Mortise/Tenon It's what I get playing my dreadnaught for 4 hours straight
Members digitalsnipe Posted March 16, 2005 Members Posted March 16, 2005 Originally posted by bigmo66 It's what I get playing my dreadnaught for 4 hours straight
Members guitarcapo Posted March 16, 2005 Members Posted March 16, 2005 I always assumed that a dovetail was angled and a mortise/tenon joint was straight. Most of these straight wood joints would need a bolt also. I wouldn't trust just glue there. I've also heard of using a locking pin (Cumpiano's book) to hold the neck in but that seems kind of elaborate and a neck reset nightmare.
Members Andrewrg Posted March 17, 2005 Members Posted March 17, 2005 Originally posted by guitarcapo I always assumed that a dovetail was angled and a mortise/tenon joint was straight. Most of these straight wood joints would need a bolt also. I wouldn't trust just glue there. I've also heard of using a locking pin (Cumpiano's book) to hold the neck in but that seems kind of elaborate and a neck reset nightmare. The bolt in Martins M&T joint is only to hold the neck and body together while the glue sets.Aside from that it performs no mechanical function.Both my M&T jointed guitars(CEO5 and CEO4R)sound fantastic.The tonal difference is due to the modified bracing used as opposed to,say,my D28.
Members bjorn-fjord Posted March 17, 2005 Members Posted March 17, 2005 Originally posted by Andrewrg The bolt in Martins M&T joint is only to hold the neck and body together while the glue sets.Aside from that it performs no mechanical function.Both my M&T jointed guitars(CEO5 and CEO4R)sound fantastic.The tonal difference is due to the modified bracing used as opposed to,say,my D28. Are you certain that the joint itself is glued? Of course the fretboard is glued down to the soundboard (except w/ Taylors) but it makes no sense to glue a bolted joint. One of the main advantages of a M/T is that it can be easily taken apart. Glue would negate this advantage. Not to mention that gluing a bolted joint would be overkill. Just askin'.
Members B. Adams Posted March 17, 2005 Members Posted March 17, 2005 Originally posted by bjorn-fjord Are you certain that the joint itself is glued? Of course the fretboard is glued down to the soundboard (except w/ Taylors) but it makes no sense to glue a bolted joint. One of the main advantages of a M/T is that it can be easily taken apart. Glue would negate this advantage. Not to mention that gluing a bolted joint would be overkill. Just askin'. Technically speaking, bolting a glued joint is overkill, since a glued joint is stronger than a bolted joint. Not that I disagree with you on the rest, I'm just saying... FWIW, I did a search, and found this page, where a guy shows a way to turn a mortise and tenon neck into a bolt-on. Not that it's incredibly relevant, but I found it kind of interesting.
Members Andrewrg Posted March 17, 2005 Members Posted March 17, 2005 Originally posted by bjorn-fjord Are you certain that the joint itself is glued? Of course the fretboard is glued down to the soundboard (except w/ Taylors) but it makes no sense to glue a bolted joint. One of the main advantages of a M/T is that it can be easily taken apart. Glue would negate this advantage. Not to mention that gluing a bolted joint would be overkill. Just askin'. If you read my post again you will see I said that the bolt is only there to hold the joint while the glue sets,afterwards it is redundant and could be removed with no issues.Todays glues are extremely strong compared with hide glues in the past.And yes,I am quite certain the joint is glued!
Members bjorn-fjord Posted March 18, 2005 Members Posted March 18, 2005 Originally posted by Andrewrg If you read my post again you will see I said that the bolt is only there to hold the joint while the glue sets,afterwards it is redundant and could be removed with no issues.Todays glues are extremely strong compared with hide glues in the past.And yes,I am quite certain the joint is glued! I understood your previous post, I'm just surprised to hear a joint would be both glued and bolted. It seems odd that a bolt would be used simply to hold everything in place while the glue dried. Traditional dovetail neck/body joints are clamped. Why would a m/t be different. And if the joint is bolted, why bother with glue?I should have elaborated on my perspective. I am a luthier with years of experience in the industry. I have never heard of a neck/body joint that is glued AND bolted. I'm not trying to be a smart-ass or to prove anyone wrong. I'm just curious as to why Martin would do this. What has led you to believe the joint is glued? And in reply to B. Adams: Cumpiano is not illustrating how to convert a mortise and tenon to a bolt-on. He is explaining the construction of a bolt-on mortise and tenon in comparison to his design for a pinned mortise and tenon. They are both mortise and tenon joints. To my knowledge, nobody is building guitars with a m/t joint without either bolting or pinning the joint. With the amount of transverse stress on the joint combined with the natural expansion and contraction of wood in conditions of changing humidity, no amount of space-aged glue is going to hold that sucker together for very long.
Members B. Adams Posted March 18, 2005 Members Posted March 18, 2005 Just for the sake of arguement, a mortise and tenon joint wouldn't be a mortise and tenon joint if it didn't have either a pin, a bolt, or something else through it. That's inherent in the definition. Otherwise it would be like a dovetail, except square, and that would be silly. Anyway, what I was referring to was this statement, "By the way, I've actually converted a pinned mortise and tenon neck and headblock to this system, aftermarket, so to speak: I made a little drilling jig to slip over the tenon to guide the drills for the barrel and bolt holes, and then spotted and drilled the 3/8" holes in the headblock through the headblock mortise." That's all I was saying, just because I found it interesting.
Members bjorn-fjord Posted March 18, 2005 Members Posted March 18, 2005 Cool. William Cumpiano wrote what is considered to be the bible of guitar construction about 25 years ago. Apparently the biggest complaint he received had to do with the difficulty in constructing his pinned mortise and tenon joint. Since bolt-ons have become so widely used by respected builders he has developed his own method of constructing a bolted m/t. And it really is quite innovative. Most bolt-ons have a threaded anchor embedded in the end-grain of the heel. The problem with this design is that the end-grain is inherently quite weak. Anchors can pull-out quite easily. With Cumpiano's system this problem is eliminated. I could go on but this is probably boring as hell.
Members JasmineTea Posted March 18, 2005 Members Posted March 18, 2005 Originally posted by bjorn-fjord With Cumpiano's system this problem is eliminated. I could go on but this is probably boring as hell. Not at all. Please, tell me more.
Members JasmineTea Posted March 18, 2005 Members Posted March 18, 2005 One thing I'd like to add to this thread (I've learned a few things here btw, thanks) is, apparently there are a few luthiers hanging out on this board. If you all could "compare" methods vs argueing about them, I think it'd be better for everyone. PLEASE, carry on..
Members olyeller Posted March 18, 2005 Members Posted March 18, 2005 Martin , on some guitars, say they use their "patented mortise/tenon" neck joint. I wonder what is so unique about it that it is patented?
Members bjorn-fjord Posted March 18, 2005 Members Posted March 18, 2005 Originally posted by olyeller Martin , on some guitars, say they use their "patented mortise/tenon" neck joint. I wonder what is so unique about it that it is patented? Yeah, I wonder that too. I cannot find any info on the specifics of this joint on their website or in any of their brochures. For that reason they might have trouble prosecuting me for patent infringement if my sytem happens to be the same as theirs! Taylor is the same (although there is a microscopic photo on their site). I know that Taylor has figured out a way to attach the neck in such a way that it can be completely removed in 5 minutes.
Members Andrewrg Posted March 20, 2005 Members Posted March 20, 2005 Bjorn,the information I got regarding the joints was from the Unofficial Martin Guitar Forum and was posted by one of Martins reps.I agree though that the logic of gluing and bolting a joint is lost on me!
Members shecky Posted March 20, 2005 Members Posted March 20, 2005 Glued mortise and tenon joints (without pinning or screws) exist. I've seen them with some Asian guitars, where the neck is glued on with a epoxy of some type. I think some Ovations are made this way, too. Yes, this makes resets a big pain in the butt. Some repair techs simply won't take on such a job. Some saw the neck off flush with the body and use bolts to re-attach. I believe some relatively modern Spanish classicals have abandoned the traditional neck joint for a glued mortise/tenon. A dovetail can be viewed as a mark of a skilled builder... if it's cut and fitted by hand. I suspect most builders, even small time ones, would use a jig to do the job, however. The dovetail is interesting in that it doesn't actually need glue to remain in place. Some old timers like Stromberg even made them without glue at all, where the neck could be removed by cutting the strings and whacking the joint in just the right way. Sonically, I don't think there's any difference, as long as the joint is secure.
Members bjorn-fjord Posted March 21, 2005 Members Posted March 21, 2005 To Andrewrg and Shecky Thanks for the info! I guess if a Martin rep said their Mortise and Tenon is glued then it must be so. Live and learn. I agree that the type of joint used does not influence tone much (if at all),as long as it is solid. I would advise everyone to avoid guitars with a glued (but not bolted) M/T joint. It just doesn't make sense. Speaking of Ovations (hiss!) I once did a repair that included a full soundboard replacement and I was shocked at the way the original top was affixed to the salad bowl (sorry, Ovation fans). It was attached with some kind of black goo that had never really hardened. It was some kind of mastic crap that looked like something you would use to repair your roof. I'm no traditionalist but COME ON!
Members guitarcapo Posted March 22, 2005 Members Posted March 22, 2005 I think Taylor guitars (up until recently when they introduced their improved neck joint) would glue the fretboard to the top and just bolt the neck onto the body without glue. To remove the neck, you would just heat the fingerboard to loosen that glue and unbolt. Taylor's new necks have the fingerboard extension and neck as a single modular unit, that fits into a pocket routed in the body block. No glue anywhere between the neck and body. Just bolt to the body. Neck resets are just a matter of unbolting the neck and installing shims. The advantage would be that the fingerboard extention is always aligned with the rest of the fingerboard after a neck reset. No more planing the fingerboard straight and refretting. I visited the Martin factory one time and saw a woman pour glue all over a bolt on neck's joint and then bolt it on. Seemed kind of silly to me in that I thought the whole point of a bolt on neck was to make neck resets easier. My guess is that Martin might just like the joint because it's simpler to make and is more uniform to duplicate from guitar to guitar.
Members shecky Posted March 22, 2005 Members Posted March 22, 2005 Originally posted by bjorn-fjord Speaking of Ovations (hiss!) I once did a repair that included a full soundboard replacement and I was shocked at the way the original top was affixed to the salad bowl (sorry, Ovation fans). It was attached with some kind of black goo that had never really hardened. It was some kind of mastic crap that looked like something you would use to repair your roof. I'm no traditionalist but COME ON! Actually, I think this would be a reasonable type of adhesive as long as it does the job: holds two materials (wood and plastic) securely. If the gooey stuff couldn't hold the materials together, obviously it'd be a poor choice. But if it does adhere well, and is easy to remove when needed, I'd say this would be a good thing. I'm not familiar with Martin's screw/glue joints. I'm assuming this is on their lower end models. Presumably, Martin is uncomfortable with just a screwed joint and prefers to have some glue in there. In such a case, it may make sense, since the screws function as a clamp. This might eliminate a construction step of having to store the guitar clamped while glue sets, and then remove the clamp after glue has set. Using the screws, the guitar goes from the glue step to the next step. If all this is true, however, I wonder why they don't just engineer a suitable screw-only joint? Screw joints have long proven themselves.
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