[Originally posted on my old Urbanspinner blog, 28 July 2004]
Plies and fluffiness
Last month, someone on the Techspin mailing list asked about making fluffy yarns from a fleece that she'd bought. I made a couple of suggestions about fiber preparation, and then remarked that she could also use more than two plies, because this would also make a fluffier yarn. Several people asked for more information, because this didn't make sense to them. So here follows a little treatise on plies and plying that I hope will help illustrate why this is so.
On plies and plying or, How to use twist to get the yarn you want
It's a simple mathematical fact: the more plies you use in a yarn, the less twist you need in the singles, and the less plying twist you need when combining them into a finished yarn. This lower level of twist means the yarn will naturally be more lofty because the fibers are straighter and more relaxed.
Think about this example: let's say you wanted to make a yarn of a specific weight that had 12 twists per inch (meaning, there were 12 lumps per inch where the plies revolved around the central axis.) If you used just two plies to make that yarn, each ply would have to revolve around the central axis six times per inch to make that yarn.
2-ply yarn: In this example, the green strand of singles
has to curl around six times for every inch of yarn.
Now, if you used three plies to make that yarn, each single would have to revolve around the central axis only four times per inch to make that yarn. That's about 30% less twist than in the 2-ply yarn.
3-ply yarn: the pink strand of singles has to curl around four
times for every inch of yarn. Note how much
more open this coil looks.
Then, if you reduce the twist level slightly in the final yarn to, say, 9 twists per inch, the reduction of twist in the individual singles is even more dramatic
Softer 3-ply yarn:The purple strand of singles has to curl around
three times for every inch of yarn. By reducing the overall twist
(from 12 tpi to 9 tpi) and changing from a 2-ply to a 3-ply yarn,
your singles will be much more relaxed.
(50% fewer coils in the final yarn!)
How does twist relate to texture?
The less you coil the fibers together, the less they are jam-packed against each other, and the more room there is for each individual fiber to bloom into its natural crimp. This makes a loftier yarn.
In addition, coarse fibers like longwools and mohair actively resist being twisted. Look again at the illustration for the 2-ply yarn. Longwools would hate to be so tightly coiled! They harden up and make heavy, dense rope-like yarns with hairy bits sticking out everywhere. If you use more plies, the individual fibers can form more relaxed coils and the final yarn will more supple and smoother.
The biggest implication of all this on your daily spinning is this: if you want to make a 3-ply yarn, you must plan it from the start. If you take singles that were spun for 2-ply yarns and combine them into a 3-ply instead, you'll end up with a harder twisted yarn than you might have liked. (This assumes that you want to have a balanced yarn at the end, e.g. for knitting. If you don't need a balanced yarn, then all this theory goes out the window.)
End of my treatise
Several people on Techspin then asked me -- well, if you're making a 3-ply yarn, then how much twist is the correct amount for the singles? And the answer is... It depends! My little treatise above is only about the relationship of plying twist to spinning twist. All the measurements are relative. You have complete freedom to chose the overall twist level of the yarn you're making. Knitting yarns tend to be fluffy and low-twist, weaving yarns denser and high-twist, and fine threads for lace crochet should be tight and hard as steel wire. So figure out what you want to make with this yarn, then figure out how much twist you'll need to use.
A final word
When I spin yarn, I don't count treadles and I don't measure twist angles, either when spinning or plying. I did that for a little while, long ago when I first started spinning and found Mabel Ross's books on yarn design. But all that counting and measuring quickly drove me freaking nuts!
Instead, when starting a project, I sample a number of yarn structures (multiple thin plies vs. a few thick plies, differing levels of twist) until I find something I like. Then I wrap a sample of the singles tightly around my yarn gauge and use that for reference during the rest of my project. I compare things by eye and by feel. It's not magic. Your fingers are far more sensitive than I'll bet you realize. I'm sure you could distinguish between singles that were spun harder or softer than your reference sample, just from the way they feel. But all this is getting into stuff for another treatise on spinning styles, which I'll save for another rainy day!
Happy spinning everyone!
[Someone then asked this in the comments of the original blog post]
Where does Navajo plying fit into this? A twist somewhere between 2 and 3 ply?
Navajo plying is just a way to make 3-ply yarn. You spin the singles the same way as for a traditional 3-ply. The trick is to treadle slowly while you're plying, so that you don't add too much twist while you're fiddling with the loops.
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