This is mostly just meant as a fun question.
My cigar box fiddle is pretty close to being done. I should be able to finish it in two weekends barring surprises or distractions like getting ready for Christmas. I panicked yesterday thinking I had screwed up the neck geometry (mostly height). But I forgot that the top plate needs to be somewhat high because the top is not arched. So the top height with respect to the neck may be off by 2 -- 3 mm, but that's okay. (As tested by rolling a #2 pencil across the fingerboard and comparing that with the bridge that was used previously with the neck.)
The "ribs" of the cigar box (sides of the cigar box) are about 41 mm high. Assuming I install the end pin in the center of the tail side (minus 1 mm!), then the tailgut will need to be longer than normal. I have a Wittner tailpiece with built-in tuners, but the nylon tailgut is not quite long enough.
My plan was to use a kevlar tailgut, as I think they are quite a bit longer and they are not expensive. So I ordered one yesterday evening along with a few other little things. But then I got a phone call today saying that they didn't have any kevlar tailguts and weren't able to find any from other sources.
I said that I didn't really need a kevlar tailgut, but that I needed a long tailgut for a cigar box fiddle. So they suggested using a silver wound gut cello string, I think a G string. The price is so low it's almost free except for the cost of mailing USPS. So I figured I have nothing to lose.
I don't remember for sure which model string it is, but the string I think it is has a tension of 10 kg = 22 lb as a musical string. If I use modern steel strings the tailpiece force will be easily 50--55 lbs. If the tension is split evenly between the two ends, that's 25 -- 28 lbs acting on the tailgut.
Clearly a big enough piece of gut would work, but it's not clear that a gut cello G string will work. And a big enough piece of gut is probably not going to fit through the holes on a Wittner composite tailpiece.
I should probably just get a nylon viola tailgut. Those should be long enough. That's what I thought I was doing when I ordered the kevlar string, as I think those are meant for use on violins or violas.
Plenty of people use wires as tailguts on cigar box fiddles, but I can't get excited about that.
I don’t think I’d trust a cello C string. Natural gut does look pretty, but I don’t use it myself because I’m very particular about the tailpiece afterlength. Gut stretches a lot over time, especially if it’s a thin strand, and the measurement gets distorted. I know some makers do use gut, but it’s not very common anymore unless it’s for a baroque setup.
If you look at old natural violin tailguts, you’ll find that they tend to be quite thick. If it’s necessary for the violin to have a tailgut that thick, imagine how a cello tailgut would compare.
If you want something easy to install, use a Sacconi tailgut. They’re nylon and work fairly well, although they can sag over time, and the threads can wear out, making the nuts slip off over time.
If you want something that will stay steady, use a braided steel tailgut or Kevlar. The former is an effective product, with the only caveat that the fairly thin cable can cut into a saddle like one of those survival cable saws you see at camping stores. The latter is my favorite. It takes a bit more time to install, and you need to learn a good knot, but it will stay in place. I’ve come across violins I set up years ago and the afterlength is still correct.
In the end, you won’t really see the tailgut much anyway, so I’d recommend going for function more than aesthetics.
Thank you for the thoughtful response, Rich!
I forgot that I had a nylon viola tailgut. It appears to be a good length. So I'll plan on using that. If for some reason that doesn't work I'll look harder for a Kevlar one.
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