Plying
On the surface of it, these little skeins don't look very different from each other.
The skein on the right is a 2-ply from the moorit CVM. The skein on the left is a 3-ply of the same fiber. In general, the singles that I prepared for each test skein were as similar as I could get them because I wanted to see the difference between a two ply and a three ply yarn made from the same singles.
When I put them together side by side like this, they don't look very different. At least I don't think so. So it was time to switch my camera into macro mode and take a much closer look.
Comparing them like this, I began to see more of a difference. The 3-ply had a rounder, puffier quality, even though it didn't seem to have a dramatically different diameter.
If you look right down the yarn, what's going on with the twist becomes much more pronounced. I created the singles with Z-twist, so the singles were plied together in the S-twisting direction. Looking at this picture, I was struck, once again, by the fact that it seemed like the 3-ply yarn was rounder and had more depth. This reminded me of a comment Toni Neil made when we were last out at the Fold -- 2 ply yarn is a 2-dimensional yarn, while 3-ply yarn is 3 dimensional. At the time, I didn't really understand that comment completely, but it came home better when I was looking at these pictures. In a two ply yarn, the singles are always side by side. There's always one horizontal plane, no matter where you are in the yarn. But once you get to 3- (or more) ply yarn, the singles are still side by side, but they are arranged such that there are three horizontal planes formed by the three plys at any time.
This might be more clear if I show you some pictures...
Imagine you are looking right down the center line of the yarn you are plying. If you were to draw just one line that went through the center of each circle (which represents one single), you have one plane. No matter how you rotate the plies, there's still just one plane. Though the plane does change it's angle relative to the center of the yarn as the twist is put into it. (My arrows indicate the direction of the twist). Thus the yarn is always two dimensional.
But a three ply yarn gets more complicated...
Once again, imagine you are looking right down the center line of the yarn you are plying. Now when you go to draw a straight line through the centers of any two adjoining circles (plies), you'll find you need 3 lines. Thus there are three planes no matter where you are in the twist cycle. Three planes takes you into three dimensions. And the yarn develops that quality of having more depth. And this also demonstrates why you don't see much difference in the diameter of the yarn. The 3 ply does have more depth, but because of the way the plies "pack" it doesn't increase the diameter of the yarn as much as you might think it would. (I was tempted to make some more pictures showing the math for this (i.e drawing the smallest possible circle around the two and three ply illustrations and calculating the diameter), but I figured nobody needs to be confronted with too much basic geometery early on Friday morning -- the exercise is left for the reader to try at home if you really don't believe me).
As a final test of the yarn, I determined the wraps per inch (WPI) of each yarn. The 2 ply came out to about 21 WPI, putting it in the category of "fingering" weight yarn. The 3 ply came out to about 15 WPI, putting it in the category of "sport weight yarns", but just on the edge between sport weight and DK. That's still a little finer than I would like it to be. I'd like to have a 3-ply yarn that's solidly in the DK range (12-14 WPI), which means I need to increase the diameter of my singles. I'm going to look through my stash to find a DK-weight three ply yarn so that I can get a feeling for what the single should look like in hopes that my eyes can convince my fingers to make the single a bit bigger. So there is definitely more sampling ahead on my road to the perfect yarn for my moorit CVM.
Coming out of lurkerville to say - Wow. That's... that's wildcrazyawesome! Like, I'm sure if I'd sat and scratched the ol' noggin long enough, I'd have figured that out too, but man am I glad you saved me the trouble!
Suddenly the difference between two different sock yarns I've been playing with is crystal clear, even though they don't /look/ any different, they sure /feel/ different in my hands.
Knitting + Science = Awesome!
Very well done post, Theresa! I especially appreciated the graphics of the difference between the 2 and 3 ply yarns! Thank you!
See, that's why I like Lorna's Laces better than Koigu any day of the week.
Seriously, though - I don't spin, I probably won't for at least another few years (I'm a college student with too many expensive hobbies - knitting, fishkeeping, and worst of all, reading. God, books are expensive) and usually I'm just not a fan of spinning blogs or spinning posts. But yours I look forward to!
Great grahpic! I thought I was nerdy with the chromatography and the dyes, but the geometry is even better. My students don't believe me that I use math and science in my hobbies. They are learning stoichiometry now and I can't convince them that I even use that in my fiber adventures.
I have loved my two ply so much, I haven't thought of doing a three ply yet.
Very interesting, and the graphics were great, and the 2-dimension/3-dimension thing made perfect sense.
But.
Does that mean that 4-ply would be 4-dimensional?
Finally, a way to power my time-machine!
As a math junkie I could leave this alone so I spent a few minutes playing around ane did some of the math. if the plies are 20units in diameter 2 ply would make a yarn with a radius of 40, 3 ply would be a radius of 43 and a 4 ply has a radius of about 48. Of course that is assuming the plies are fairly rigid, which they aren't. I think the plies squish into each other and more plies would actually take even less space than my trial showed.
OK, my geek is definately showing here, sorry.
The bottom line is in the 'hand', ie. how it feels to me, I choose yarns mostly by how they feel as I knit. Therefore, I am a process knitter not necessarily a project knitter. (I have been known to spend a couple months knitting an item just to 'dispose' of it when it is completed because the thrill was gone.
*basking in the geekiness of it all*
a sock story http://knittingunderway.blogspot.com/2006/03/dad-take-one-with-help-from-flitgirl.html
Great post! I, too, never fully understood why 2 versus 3-ply would make much of a difference because they look so much the same in your hand. Thanks!
Your information and way of presenting it always impresses me. Thanks!
Thanks for this great discussion on three vs two ply!
I think I'll try three-plying the singles I'm spinning now just to experience this, I've only two-plyed before.
Do you Navajo ply or did you ply from three bobbins?
-Sarah.
This may be a dumb question, but humor the inexperienced :) When you make a three ply, do you do it the same as two ply but with three singles at once? When I've done two ply I hold one single in each hand, so do you have to juggle a bit to make that work? Very interesting description of how the plies sit.
Lurker here de-lurking for a comment. I use the Spinner's Control Card (NAYY) to help me determine the size single I need to spin for a specific size finished yarn. This is a small acrylic(?) card with lines on it representing different sizes of spun or plied fiber. You use it by multiplying the number of plies by the finished yarn size to find out how big to spin you singles. (EX: You want a 2 ply 12wpi yarn so you would spin a 24wpi single.) Find the line representing (or closest to) the size single you want to get an idea how thin/thick that is.
I check my singles against the card occasionally to make sure I'm still in the range. Not very scientific I suppose, but it works pretty good for me - I usually come very close or right on the finished size I want. BTW, the smallest size on the card is 40wpi, so it is limited in how small a single you can use it for.
Deb -- if you define planes as passing through the parallel "cores" of the yarn plies, two-ply yarn gives you one plane. One plane has two dimensions. Three-ply yarn gives you three non-coplanar planes. Three suck planes define a space. A space has three dimensions. Four-ply yarn gives you six non-coplanar planes, which still define a space of three dimensions.
Thus, if you take Theresa's analysis to somewhat accurately reflect what one "feels" in a yarn, a fourth ply shouldn't feel like it's giving the yarn any more "dimension", only more detail. It would be an experiment to perform -- I haven't done so.
*sigh* Too bad four-ply won't power a time machine. Think of the amazing sheep we could bring back!
Your graphics feed the geek in me!
Family Sock Challenge Update - Hubby b-day socks finished! I'm going on a sock hiatius for a month - my hands are getting the tingleys. But I'll be shopping for sister b-day socks!
You've made my day. I've been thinking about whether and why to three-ply, and I'm going to try it. I've got someone willing to dye me up some Wensleydale, and I'd like it to be a bit more substantial than I'm currently able to spin with, say, Shetland.
Since I'm practically spinning cobweb singles with Shetland, anything would be more substantial than that, but nevermind :-)