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I have built three beautiful acoustic guitars over the past four years. I've been using a close friend who owns MOZE Guitars here in San Diego, as my mentor. I've been unable to establish any repour with local builders, and I'm looking for assistance with building this 12 string. I've already ordered the plans, and I have the top already done (sitka spruce), and the sides (Rosewood) will be done soon. My questions are with the neck build and joint to the body, and a company that sells the bridge and nut for a 12 string. Using my (bible) good book by David Russell Young I should be off and running. I've never used this Forum before, and I may have some difficulties with handling this site?? Tanks, Greg

Hi Robert,

You should be able to use the same neck joint for a 12 string that you do for a 6 string.

Do you mean saddle instead of bridge? You should be able to use the same saddle on a 12 that you do for a 6.

If you're looking for a preslotted 12 string nut, I'd look into Graphtech.

Robert, I no knowledge to offer, but I sure would like to watch build process.
Dan

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IIRC Young's book has an epoxied butt joint which has been pulled off successfully many times I'm sure but is sort of nontraditional shall we say. The butt joint is one of the easiest joints to make and in fact that's what I do but instead of just epoxying most who do that joint style bolt it on. Just a suggestion.

Greg, I have built two 12 strings and own an old Martin. The Martin has a dovetail which has been reset, my OM-12 has a dovetail and my Stella clone has a M&T bolt on. Both of those neck joints work fine - you have about 50 percent more tension on a 12 that a 6er. I do mostly bolted M&T now but you do need to plan for the future when you'll reset it.

You can buy commercial 12 string bridges or make your own. One question will be whether to put the primaries or octaves pins closest to the saddle - there are arguments for either. You will also see some 12's with two strings under one pin - I think thats a bad idea. On the Stella clone I did a tailpiece but since it is ladder braced I didn't want the rotational torque on the top.

Most people up the thickness of the top slightly and use either slightly taller or often unscalloped braces. It is fairly common to add a third tone bar. Bracing considerations follow from the way you intend to string and tune it - my OM is tuned two semi tones down, the Stella clone is tuned to B or C#.

I don't understand the question about the nut - make your nut to fit your neck and your desired string spacing - both within the course and between courses. You can also decide whether to make the bottoms of the slots level or the tops of the strings (again, there are arguments for both.

Here are 36 strings



and the bolt on neck for the Stella clone

FWIW . If this will help .I met david russel young when he was running a bow making shop in N hollywood ca in 1990. If you have a question about 12 strings he might be able to answer it . He moved to longmont co in the early 1990/s PS I have a jumbo 12 string built in 1973 by michael Dunn in van couver bc . it uses a spanish foot LOL. and has a compensated bridge saddle to account for the extra octave strings which are much thinner.It is made of brazilian rosewood and WRC. He might be another resource with useful information. He used to teach guitarmaking.He is still building in new westminister BC

David Freeman, another Canadian builder, also uses a Spanish foot for all of his guitars including his steel string 12. When I asked him about it he said they never need a reset.

Also, if you make your saddle slot extra wide you can easily compensate each string of each course individually. Sort of looks like a rip saw blade but it will play more in tune up the neck. I think Taylor is doing that now (with their cnc saddle mill)

David: Thanks for the reply and info. I may sound a little behind, but what is a spanish foot LOL. Taylor does use the compensated bridge a lot. I made my own for the second guitar and it worked well. My third guitar, which I kept for my own use, doesn't have a compensated bridge saddle. I probably wouldn't know the difference as I'm not a good player, and a just liked the action I have so well, that I didn't want to change it. David - how do I reply to the other fellows on this forum. I'm not too cool with computers and this is the first time I've ever used a forum?? I'd like to send a photo or two of the instrument I have right now, and I don't know how to do that either. Greg

Greg, there might be a little confusion about "David" My first name happens to be Freeman, thats what I go by here. There is a great Canadian luthier with the same last name as my first - David Freeman. As far as I know he doesn't post here but he does have ads in American Lutherie and has shown guitars at the GAL convention. One of them was a 12 string with what is fondly called a Spanish heel or Spanish foot.

Spanish heel is the construction method for most classical guitars. The neck has an extension that goes inside the guitar - its all one piece rather than a separate neck block. There are two slots cut in the sides of that extension and the sides go into those slots. So the neck is basically built into the guitar and is not separate. One big disadvantage is that it cannot be disassembled and reset (easily). It is commonly thought to be strong enough for a classical but not for a steel string and certainly not for a 12 string. However, it looks like a few people do use it.

OK, next, there was some discussion of an epoxied (or bolted) butt joint - again, that is a somewhat unorthodox joint but some folks make it work. You won't find it on commercially manufactured 12 strings.

I then suggested either a conventional dovetail (Martin style) or a conventional mortise and tenon with a couple of bolts thru it (Taylor style). Both these are strong enough for the additional tension of a twelve string (about 250 pounds depending on strings and tuning) and both are easily resettable when needed. If you have built sixers you have probably used one of these - it should be good for your twelve (Martin and Guild 12's have dovetails, Taylors have the NT bolt on necks).

You will want to compensate your saddle - whether you decide that doing it to each string is worth it or not might be too much trouble. However the usual slanted saddle with about 1/16 on the high E and maybe 3/16 extra on the low will work well for your 12.

You said in your first post that you have ordered plans for you 12 string - may I ask what you are getting? I spent a lot of time poking around inside many 12 strings before I built mine - I might be able to help you with some of the differences.

As far as how the forum works - you can click the quote button on any posting and reply to that. You can simply post a reply and we'll figure out who you are talking too. If you want to chat off the regular forum you can send a personal message to one individual by clicking that "pm" button. Most of the time its best to keep in on the forum itself, however, as others may want to comment.

Lastly, each forum has different ways to post pictures - most of the time you need to "host" them at another site and then embed them is your discussion - it is a bit geeky. I use Photobucket as my hosting site. There might be far easier ways to do it - some forums just let you stick them in but I don't think this one does.

Most neck resets are not needed because of problems with the neck itself or the neck joint: it's usually distortion of the body that causes the neck to rise and the action to get too high to correct. I used to build 12s with a Spanish heel, but not any more.

Keep in mind the strength per se is not generally the limiting factor in the top structure; it's stiffness. I can't think of too many guitars I've seen over the years where the top broke in normal use (aside from humidity cracks), but I've seen plenty that were too lightly built and distorted beyond all hope of salvation. If strength were the problem, you'd need to make the top 50% thicker and the bracing 50% taller to get the strength you need for a 12. However, stiffness goes as the cube of the top thickness/brace height, so in theory all you have to do is make them about 15% thicker/taller to get the stiffness you need. The last few 12s I've made I increased things by about 20%, just to be on the safe side. The top ends up being little heavier in proportion than that, since the bridge and bridge plate also need to be a bit larger. Still, it works out pretty nicely. Remember that the power in the strings at a given amplitude is proportional to the tension, so you've got something like 50% more power, going into a structure that might be 25% heavier. The result is a LOUD guitar.

It's well worth while to compensate both the nut and saddle on a 12 for each string. You'll need a saddle that's at least 3/16" wide on top. What I do is make the saddle with a flat top to begin with, just rounding off the back edge a bit. I string the guitar up, and get the setup otherwise correct, including at least most of the anticipated nut compensation if I'm going to use that. Then I find the correct break point on the saddle top, using the 'cross wire' method. This consists of putting a short length of a cutoff string end under the string on top of the saddle, and moving it back and forth until the point is found that produces an exact octave between the string open and fretted at the 12th fret. This normally produces two lines of marks, one near the front edge of the saddle, and one behind that from the G string down at a greater angle.

When I've got that marked I take out the saddle and file a V groove along it, so that the back edge of the groove comes down sharply in front of the rear line, and it angles off less steeply behind the front line. The front edge of the bridge is also filed back with a steep break to the front line, and the back rounded off behind the rear line. Then the two ridges are notched out beneath the strings that are not supposed to touch: the rear line being the stop for the main strings, and the front line for the octaves.

The first one I did this way ended up with every note within 3 cents of 'perfect' pitch all the way up. When I got the strings on it I immediately noticed a decided lack of the usual 12-string 'crunch' sound, and wondered how the player would react. He liked it: now, when he's recording, he doesn't have to stop and re-tune between the A part in the first position and the B part further up the neck. Of course, if somebody wants that crunchy sound it's easy enough reduce the amount of compensation and give it to them. It sure is nice having the choice.

Alot of good stuff in this thread. Thanks to all for sharing.

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I am watching this discussion with interest. I've never built a 12-string but I'm gathering information because I hope to build one a few guitars from now.

It's possible for two strings to share one bridge pin, as described here: http://www.anzlf.com/viewtopic.php?t=354

Freeman, earlier in this thread you said you didn't think this was a good idea. I'd be interested in your reasons for this, since I have no experience making either bridge type. The only 12 I ever owned had the usual 1 pin per string.

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Just spent 15 minutes trying to ask another question to you guys out there. Still don't know how to use this forum yet??? I have a very large piece of old spruce which was to be used for a concert stringed instrument, and the man gave it to me. My question is - can I use spruce for the head and tail block in my 12 string guitar, instead of mahogany. Russell Young says only mahogany, and yet on my plans, Scott Antes say either can be used. Also which bracing pattern can be used for a 12 that will give a good sound? I have plans for one by Antes, and another by Russell Young. I've seen several from Taylor as well. Just wondered which one is best? Greg (I'm no sound engineer or a premium builder; just looking for suggestions) Thanks!!!

Greg, some questions before I answer yours. First, what kind of neck joint do you plan to use and what kind of neck wood? For the tail block I don't think it matters. If you are going to do a dovetail I think you want to use the same kind of wood as the neck. If you are going to do a bolted joint I'm not sure how well spruce would stand up to the compression of the bolts. Short answer - I've always used mahogany - if you are using mahogany for your neck you probably will have some cutoffs that will work for the neck block or buy one from LMI for a couple of dollars.

Now the more important question about bracing a 12 string. It starts with how you plan to string, tune and play it. Remember that in general a 12 string does not have twice the tension of a sixer but more like 150% - most 6 strings are in the 160-180 pound range, 12's are 250 or 260 (that can change a lot however). Many 12 string players do not tune to concert pitch and 12 string "light" gauge strings are frequently 0.010 to 0.046 or so.

I own three 12 strings and they are all braced differently (and strung and played differently). When I built my OM sized 12 I spent a fair amount of time poking around in different commercial models - here are some generalities. I'm going add that I think that Guild and Taylor are building some of the better modern 12 strings but you might prefer something else.

- the most common sizes for 12 strings are dreads and jumbos. Dreads seem to sound muddy when tuned down so you might consider jumbo or a smaller body

- spruce top thicknesses seemed to range from about 0.110 to 0.125 - so slightly thicker than a 6. Taylors in particular make a point of telling you that the tops are thicker. I would be careful about using woods other than spruce, however Seagull does make a nice little cedar topped 12.

- some 12's (Martins in particular) have bracing like a heavily braced 6. My old D12-28 has non scalloped 5/16 braces just like some D28's. It had a larger bridge patch but otherwise nothing special. It also developed a pretty significant belly in the lower bout.

- some 12's (Taylors) have a third tone bar and finger brace along with being non scalloped. They seem to have less structural problems that Martins.

- the wonderful Taylor LKSM has very wide and deeply scalloped braces (the legend is that Leo scalloped a prototype with a pocket knife and sent it back to Taylor). Remember that the LKSM is intended for tuning to C# with fairly heavy strings.

- there is, of course, the whole 'nother world of ladder braced 12 strings. They are frequently tuned several steps down and have their own wonderful sound. My Stella clone attempts to capture that sound, if you want further information we can talk about it

- scale lengths are all over the place. In my opinion, if you are going to tune to concert you might consider Martin short scale (24.9). My 24.9 D12-28 is OK at D but starting to sound muddy. My OM12 is long Martin scale (25.4) and seems better when tuned down because of the slightly higher tension. My Stella clone is 26.5 and I tune it to C or sometimes lower.

As far as plans - I have the Ultimate Guitar 12 string plans and while I haven't built from it, it does seem to be pretty close to a Taylor jumbo which I think is one of the best commercial 12's. The guitar in the plans is 25-1/2 scale, three 5/16 tone bars and I'm pretty sure the top is called out as 0.125 but I can't find the thickness on the drawing. By the way, he does comment that the neck block is "very important" and should be vertical grain mahogany.

Freeman: Thanks for the reply. I'll go ahead and use mahogany. My neck joint is a simple MT joint. It will have two hanging screws/bolts that will fit thro the head block and will bolt into place. I've already finished shaping the neck, and the rosewood fingerboard is the 25.4 scale. I just tune my guitars like everyone else, and I'm not sure what key that is. (I'm not much of a technical musician) I will probably start off with the lightest available strings until the neck 'sets in'. Mine is going to be a dread, as that is the shape of the mold I made; also the sides are already shaped. the top is sitka spruce (bear claw) 0.136 thickness (unsanded). It rings 'like a bell'. I'm not sure what LKSM is, but I played several Taylors. I love the SeaGull that MOZE guitars has, and am thinking of buying it to play while I'm building. Moze is presently my mentor and is helping me as well. 'Great guy.' I made a bid for $50 for an Aria 12 for parts on e-bay, too. Figure I can mess around with it while building mine. My Scott Antes plans show only 2 tone bars with a brace above, outlining a hugh reinforcing plate. I'd rather go with Russell Young's design with 3 tone bars and a smaller reinforcing plate. Seems to me that would have a better sound. My bracing materials are all vertical grain adirondeck (spelling). My neck is two pieces of vertical grain mahogany with a 1/2 inch center strip of hard maple. Hope this helps? Greg (i only wish I knew how to submit photos?)

You'll be fine. I like bolted necks - it does let you mess with the angle if needed. Consider tuning each string two semi tones below what is considered normal - that would be DGCFAD from low to high. The octaves are tuned an octave above each primary. The LKSM is the Leo Kottke sig model - Kottke is a dynamic 12 string player who tunes down three or more semi tones.

I haven't seen either of those plans so I can't comment - I know that Antes' parlor plans are thought to be overbraced. Here is the insides of my OM 12, the bridge plate is angleds slightly so the pin holes don't run right along the grain (don't know if thats a good idea or not, someone suggested it).

Freeman

Great advice - by the way, what is the wood on your bridge-plate.

I have used Cherry and Walnut for neck and tail blocks because

1) they have similar density to mahogany
2) they were laying around the shop

Great thing about guitar building is the small amount of wood needed - ukulele's even less

Ed

It's maple, that's all I use for bridge plates and it was probably something laying around the shop.

fwiw I have two old Martins (one is the D12-28) from the "over built" 1970's that both had the heavy rosewood plates. Both have had neck resets and at that time I had the b/p's replaced with smaller maple ones. Its hard to tell the difference, if any, on the 12 string but my wife's comment about the sixer when it came back was "you are playing louder". Didn't think I was and that certainly is not a controlled test, but it does lead me to using smaller lighter plates (that can still withstand the wear of the strings).

I have the sides of my guitar already bent, profiled, and the top and bottom blocks are in place. I started with bracing the top today. I'm going to use maple for the reinforcing plate and I was wondering what thickness you would recommend? In the past with the six string guitars I've made, there has always been an arch in my tops. I usually sand my lower braces and tone bars with a 25' radius. It works out nice and seems to make the top even stronger. Would you recommend I do the same with this 12 string, or should I keep the top flat? Wanted to know if the tome bars are to end at the kerfling? I'm going to try to go to the Taylor Factory for the tour today. I hope they will talk with someone like me who is building their own guitars? Will wait to see!! Greg

Freeman: A lot has changed since I asked the first questions. I have since then purchased a 10 yr old Taylor GA 12 string. It's an all wood guitar (no laminates) and sounds great. On the guitar I'm building: I have finished making the guitar body and we are routing out the top and bottom for the purfling. The above neck turned out to be too short, and I've made a completely new neck from Port Orford Cedar, from the town in Oregon. It was a beautiful piece of wood. I laminated a 1/2 inch strip if hard maple down the center. It's almost done. My question is in setting the neck angle for a 12 string. I figure I will need at least a 2 to 3 degree angle downward of the neck (with the unit right side up). Many just mount the neck straight, but I'm not sure if that would be adequate? I did reenforce the inside of the body as mentioned: i.e. braces not scalloped, and the top was straight. Would appreciate any suggestions?? Thanks, Greg

I set the neck angles on a 12 string exactly the same as a sixer - a straight edge on the fretted f/b just kisses the top of the bridge. I set the action on my 12's the same as a 6 - roughly 0.060 on the treble course to 0.080 or so on the bass, maybe 0.004 relief. That gives me about 1/8 of saddle sticking out of the bridge which seems like a good starting point.

I happen to have an old Guild 12 on my bench right now. It recently had a reset and in my opinion the neck was over set for the bridge that is on it (by my measurements the bridge has been shaved at one point). The end of a straightedge is 1/16+ off the top of the bridge, the saddle is tipping towards the sound hole. The owner wants a UST installed - I told him he is asking for trouble.

Right. Somogyi makes that claim too. Guess what, it ain't true.



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Mountain Song Guitars www.mountainsongguitars.com

My teacher Rob Girdis built 80+ ss with Spanish heel with no known failures yet. (Although no way to keep track of them now) I think some are over 35 years.

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Pat

Here's some info on a recent 12-string build:
http://luthiersforum.com/forum/viewtopic.php?f=10101&t=48565
Neck joint is mortise & tenon with threaded inserts.