Official Luthiers Forum!

1. How much space between the two strings in each course?

2. On the bass courses, the octave string is smaller diameter than the regular string. Is set to be level with the top, or bottom of the thicker string, or is it level with the center? Hope I'm making myself clear here...

3. What guages are the octave strings?

I tried the search function, but there doesn't seem to be much info on 12 stringers...

Thanks,
Phillip

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Regards,
Phillip Patton

http://www.pattonblades.com

The bitterness of poor quality lingers long after the sweetness of low price has faded.

https://hoosierbladesmith.wordpress.com

Phillip: Have never built or worked on a 12 string but logic tells me that the bottoms of the two strings should be even or the same distance from the frets. This happens at the saddle so why not at the nut.
Tom

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A person who has never made a mistake has never made anything!!!

Here is a link to the D'Addario page with specs for a light gauge 12 string set including gauge and tension at pitch: http://store.daddario.com/category/1448 ... ring_10-47

D'Addario also has a nice PDF file of string tensions by string size and type for various instruments. Might print out a copy and keep it in your shop for reference.

Pair spacing...in the neighborhood of 3/32"...adjusted slightly for the larger diameter bass strings.

The slots in your nut should be all the same depth...ie: the string bottoms will all be the same height off the top of the frets.

If you can, you might wander into a "big" guitar store (no names used, but you get the idea) and take a close look at 12 string(s). Take a small machinists ruler with you and check out the string spacings on different brands if you can.

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Hank Mauel

Philip, Stewmac supply string spacing rule and as I remember may gave help in the instructions supplied with it for 12 stringers.
http://www.stewmac.com/shop/Tools/Special_tools_for:_Nuts_and_saddles/String_Spacing_Rule.html?tab=Details#details
Found 12 string online - at the bottom of the page -
http://www.stewmac.com/tradesecrets/promo/ts0028_spacingrule
(You can also use it for spacing at the bridge pins)
Hope that helps.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

I should clarify this:

"The slots in your nut should be all the same depth...ie: the string bottoms will all be the same height off the top of the frets."

I was refering to each "pair" of the 12 string groups, but didn't convey that. Of course, correct action will dictate that the "bass" strings will most likely be higher off the frets than the trebles. So, once you establish your action height for the "basic six strings", the octave or unison strings should match their partner string in action height.
Otherwise, you may have difficulty fretting the octave string paired with the E bass string (or any of the larger wound strings) due to the bass string contacting the fret before you get the octave string pressed down sufficiently. Results will range from a string buzz on the octave to a dead octave string as your finger flesh damps it while holding the bass string against the fret.

Hope that is better description.

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Hank Mauel

Thanks for all the answers everyone, you've been most helpful. Now here's another question.

Is there a good reason for having both strings on the high E and the B courses the same guage? Why not have them an octave higher also?

_________________
Regards,
Phillip Patton

http://www.pattonblades.com

The bitterness of poor quality lingers long after the sweetness of low price has faded.

https://hoosierbladesmith.wordpress.com

No reason you can't string 'em up any way you want as long as the box can take the tension. My 12 stings are built extra heavy for extra heavy strings.
Twelve strings can be strung with anything from the standard light to something like I use... .070-.015". There is a lot more experimentation going on with 12's. Many of the old 12 string blues players strung them every way you could imagine and every pitch from A to E, but mostly B, C or C#.

Not sure you would find a string that would take a pitch an octave above the first string E without breaking....at standard tuning.
If you drop the tuning down to the B or C range, you might get away with it.

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Hank Mauel

I was thinking of making my own octave strings for the two treble courses. I have some fine music wire left over from a hammer dulcimer project which might work. It's .009", which isn't too much smaller than the high E, but I guess it's worth a try.

Should be able to use it for the B course anyway...

_________________
Regards,
Phillip Patton

http://www.pattonblades.com

The bitterness of poor quality lingers long after the sweetness of low price has faded.

https://hoosierbladesmith.wordpress.com

The interesting thing is that two strings of the same material and length will both break at the same pitch (or very nearly so), no matter what diameter they are. Finer strings will tune _marginally_ higher: as I understand it, the strength is partly determined by the size of the largest flaw, and there's less room for flaws in a small string. In other words, the ones that woudn't work were weeded out for you because they broke during manufacture!

If you look at a typical 12 string set, the octave G is usually about a .009", iirc. It's darn close to it's usable breaking stress, which is about 75% of the ultimate stress that string 'should' be able to withstand. You have to allow a little for winding around the peg, for example: the outside of the bend is under more tension than the inside or the thing would make a straight line. Anyway, octave Gs break pretty frequently, so I don't think you'll get a string of normal length much above A.

One solution to that is to go to a shorter scale, but that makes the lower strings more prone to bending in normal play, and complicates the already tricky business of intonating a 12.

There are materials out there that can be made into a string that will tune an octave higher than a normal steel or nylon string at a given length. You'll find them in the fishing line section at the local store, and the give-way is that it looks like 12# test but it's labeled as 35#. It's a polymer; one brand is 'Spider Silk', so you get an idea of where that came from. Usually it's braided. The samples I've gotten are slippery as heck, don't stretch AT ALL, or so it seems, and between the high damping of the braided fibers and the light gauge don't put out much sound when you get them tuned. But they will sure tune high...

Being a big fan twelve string guitars I tell you that the octave strings on the lower courses are the same gauge as the strings on the higher courses. Correct me if I'm wrong, but if one makes the strings on the higher courses an octave higher your intonation will suffer greatly because the fret distance will be too great for such a high pitch. The reason why it works for the lower courses is that even at an octave higher than the strings they are coupled with, the notes are still in the tonal range. Personally I like the coupled string sound, being a mandolin player may have something to do with that though. On my personal twelve string, I would probably couple the g string as well, but that's just me....