Official Luthiers Forum!

Does anyone know of any references for building a 12 string that they
could pass along?

Thanks,
Tom.

Tom, the Steel String Guitar book by David Russell Young has most of the patterns and measurements for a 12 string as I recall.

I wouldn't take the advice given about such things a gluing on necks and stuff with epoxy though.

Are you just looking for plans, or something to walk you through the process?

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Dave Rector
Rector Guitars

something to walk me through the process, I quess. I am building an
archtop right now form benedetto's book.

Tom,

I think the best source of info might be a mirror, a flash light and a good ruler. If you can poke around in some 12 strings you will learn a lot about their construction. Look inside a Martin, a Guild and a Taylor if that is possible to you. By and large, they are quite similar to their 6 string (weaker) brethren. You will note how the different companies have beefed up their instruments in those areas of greatest need.
I had to do this as there is a scarcity of info out there on just these points. And Dave is right about the neck joint. You need something mechanical there---something stronger than a butt joint.

Good luck,
Steve

_________________
From Nacogdoches...the oldest town in Texas.

http://www.stephenkinnaird.com

Tom,

As many here will know I'm currently putting together the plans to build a 12-string Parlour guitar so I have been talking to a number of luthiers over here. They all say that a bolt on mortice and tenon is quite man enough for the job but that I should also incorporate a couple of carbon fibre rods in the neck to increase stiffness and that head block extensions are a good idea. One area that you should obviously take great care of is top bracing, it needs to be man enough to take the additional tension. This isn't such a problem in fact with the Parlour body size I'm using but for anything bigger, and I assume you're not nuts like me so will be using a Jumbo or D size body. The luthier over here that I respect most uses AXX bracing on all his 12 strings replacing the tone bars with an additional X brace. Taking care obviously on its position relative to the bridge, as has been rehearsed in a separate discussion here.



Also consider a slot head, this is what I'll be using as many people pointed out that a solid head 12 string can get a bit heavy (don't forget you can use mini tuners.)

ColinColin S38416.2114699074

_________________
I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

I don't really see why a butt-joint wouldn't work just as well as a mortise/tenon bolt-on if it's well executed, to be perfectly honest.

As to CF rods, I always use the things. Cheap insurance. And I'm thinking of adding a small foot extension to my headblocks in addition to the fingerboard 'tounge' I'm already using.

Mattia, my problem wasn't with the butt joint itself, but with Young's method of attachment. He simply glues the butt-jointed neck on with epoxy. That would be a nightmare for future neck resets.

I don't see a problem with a butt joint either, as long as it is properly bolted on.

Just wanted to clarify this a little.

_________________
Dave Rector
Rector Guitars

Dave and Mattia--
Let me clarify what I meant by a butt joint. Basically just that, one which uses the epoxy glue as the only gripping / holding agent. I have lots of respect for epoxy-- but not that much. At my first GAL convention I spoke with a respected repairman who stated he had worked on a number of those types of neck joints which had all failed in time. And Dave's point about future neck resets is well taken.
As for a butt joint with bolt-on inserts, that is a different beast which has a mechanical strength to it. Needs no glue. I use this all the time, and did so on the 12 string I built. I also do something like Mario, in that I run a 1/2" Honduras (sorry Colin) mahogany dowel down the heel which not only strengthens the heel, but gives the inserts something to bite into other than end grain of the neck.

Steve

_________________
From Nacogdoches...the oldest town in Texas.

http://www.stephenkinnaird.com

[QUOTE=Steve Kinnaird]
I also do something like Mario, in that I run a 1/2" Honduras (sorry Colin) mahogany dowel down the heel which not only strengthens the heel, but gives the inserts something to bite into other than end grain of the neck.

Steve[/QUOTE]

Don't worry Steve I do that as well, but I now use barrel nuts that go across the tenon rather than screw in inserts, but I still put the dowel in, It's called "belt and braces"! The dowels that I use though are Ash I can't seem to find the right mahogany ones. I expect that's because you've got them all.

Colin

_________________
I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

Colin, if you have a lathe it's pretty easy to make your own dowels. And, you can make them out of any wood you happen to have laying around.

_________________
Dave Rector
Rector Guitars

[QUOTE=Colin S]
Don't worry Steve I do that as well, but I now use barrel nuts that go across the tenon rather than screw in inserts, but I still put the dowel in, It's called "belt and braces"! The dowels that I use though are Ash I can't seem to find the right mahogany ones. I expect that's because you've got them all.

Colin[/QUOTE]

Colin--great time to experiment. Try different wood dowels and tell us which one makes the better sounding guitar!

"Belt and braces"... I think we would say belt and suspenders?

Tell us more about your neck fastening system. (Or is that old news?)

Steve

_________________
From Nacogdoches...the oldest town in Texas.

http://www.stephenkinnaird.com

Dave,

I don't have a lathe I'm afraid but I do have enough Ash Dowels to last me about 20 years! It's the wood they use to make the best snooker cues.

ColinColin S38417.3401967593

_________________
I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

[QUOTE=Steve Kinnaird] [QUOTE=Colin S]
Don't worry Steve I do that as well, but I now use barrel nuts that go across the tenon rather than screw in inserts, but I still put the dowel in, It's called "belt and braces"! The dowels that I use though are Ash I can't seem to find the right mahogany ones. I expect that's because you've got them all.

Colin[/QUOTE]

Colin--great time to experiment. Try different wood dowels and tell us which one makes the better sounding guitar!

"Belt and braces"... I think we would say belt and suspenders?

Tell us more about your neck fastening system. (Or is that old news?)

Steve[/QUOTE]

Steve I wouldn't dare say "suspenders", over here suspenders are what women use to hold up stockings! Believe me I don't use them!

I thought that most people used barrel nuts now, They are a cylinder that goes right across the tenon with the thread in the side that the bolt goes in to. You drill a hole across the tenon and pop the nut in then another hole goes from the end of the tenon for the bolt. (It's the main reason I still use a tenon rather than just a butt joint.) The pressure then pulls aginst the wood rather than trying to pull the nut out of the wood. I drill the cross hole so that it half cuts into the side of the dowel for extra strength. If you look at Paul's Patriot Guitars site he has a good picture of them in his neck detail in the 'Builders' section.

ColinColin S38417.3391319444

_________________
I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

I've got both barrel nuts and inserts, and I think both work well. If they fit well (and if they've got some cross-grain material to bite into) the inserts can work wonderfully well. I've got a bunch from Lee Valley now, similar to the ones I can get from my local hardware store, but much, much, much, much more affordable in bulk quantities. Look like the ones Mario posted a picture of a very long time ago on the MIMF. Slightly tapered, bite nicely, and pretty much just stay put. I'm going to try a tenon'd/adjustable neck experiment on my next, and I'll use barrel bolts there because they can rotate and 'wiggle' themselves into the optimal alignment as the angle changes, which inserts, well, can't.

Colin--the language has trouble going this way, too. A friend of mine in London tells a hilarious story about coming to an American grocery store looking for cookies. Only he kept asking for biscuits, which are nearly identical to your scones. A frustrating yet humorous exchange.

Thanks for the direction to Paul's site. Helpful and inspiring. And, Paul, nice work and nice site!

Steve

_________________
From Nacogdoches...the oldest town in Texas.

http://www.stephenkinnaird.com