12 string guitar

[John Rice]

Hi everybody, just like to ask if anyone knows where I might get a plan for a 12 string guitar. I would like to try one,maybe when you get plotting Charlie you might have one for sale.

[Mark Swanson]

You can alter just about any 6 string plan for a 12 string too.

[John Rice]

I had a feeling that was the case Mark but I like to work with drawings, I know the top and the braces are heavier and the head stock is longer but what about the neck, how much wider or stronger should it be, what about the bridge how are the holes set out, so many questions that a plan would answer.

[Mark Swanson]

A plan would help for sure, but by asking those questions here you have the resources of all the members, and it's pretty easy to get those answers just by asking. Our Library Archive is also up and running and I think you'll find references there too.

[John Rice]

Thanks Mark, I was looking for the lazy way out

[Alan Carruth]

The last couple of 12s I've made went pretty well. I used a Small Jumbo platform, 16" wide. One was a 12-fret neck, and one 14: I'd suggest 12 frets for stiffness, or really careful choice of wood. The nut width on the latest is 1-7/8", string spread at the bridge is 2-3/8" outside to outside. I like the StewMac slothead machines, but would really like to see them come out with Waverlies for the 12, using the same spacing. For the top, you can use your normal bracing pattern, but make the top itself about 25% thicker than you would for that wood on a 6-string. Make the bracing a little wider and 25% taller. You'll need a larger bridge plate and bridge, of course.

I built a beam test rig with a movable 'nut' and 'saddle' to set up the intonation for each string at both ends. It worked really well: this is the first 12 I've worked with that really in tune above the 7th fret, and the octaves don't get crunchy.

Alan Carruth / Luthier

[Freeman Keller]

I have built two twelves, a short scale OM sized body and a very long scale ladder braced 000 (basically a Stella clone), and own one more. There are many factors that go into a good 12 string design - how you plan to string and tune it, what sort of sound you are looking for. My Martin D12-28 has exactly the same non scalloped 5/16 bracing as a standard D28 and the same top thickness (after 30 years it developed a pretty good belly). Taylor makes the top plate thicker and adds a third tone bar. The LKSM is much wider braces and deeply scalloped (of course it is designed for C# tuning).

On my OM I made the top plate 0.115, non scalloped 5/16 with a third tone bar and a larger bridge plate. It is usually strung with lights and tune down two semi tones.

If you want to look at one set of plans, Ultimate Guitar has a grand auditorium 12 string that looks very much like a Taylor clone. It would probably be a very good starting point for a generic all around 12 - just like an x55 series Taylor.

[John Rice]

Thanks Alan that is a great starting point now I can start to draw a plan. Freeman they are pretty neat guitars I love the OM this is one of my favourite shapes.

[Mark Morris]

Freeman, did you increase the body depth on your OM? If yes how much? I'm looking at modifying my 6 string OM plans for 12 string and this thread is quite helpful especially the top and brace info.

[Freeman Keller]

Freeman, did you increase the body depth on your OM? If yes how much? I'm looking at modifying my 6 string OM plans for 12 string and this thread is quite helpful especially the top and brace info.

Yes, I went with 4 inches at the neck heel ad 4-7/8 at the end block (out to out). Can't really tell you why I settled on those values - of course it means that it won't fit a normal case (Cedar Creek to the rescue). I used Martin short scale for the lower tension, but if I was to do it again I would use 25.4 (it is always downtuned).

Here is a shot of the inside - I added third tone bar and moved the other two slightly towards the bridge plate. I think the top is 0.115, I can mic it if you would like.



Guitar is designed for fingerstyle - is well balanced across the strings with none of the boomyness of the dread. Btw - I did make a drilling jig for the paddle head tuners (mini Grovers, standard Martin spacing) - I would loan that if anyone needs it. The Stella clone was a slot head usin the StewMac tuners

[Mark Morris]

Thanks Freeman the photo and input is helpful.