In yesterday's post I mentioned the yarn 'profile' as being sawtoothed, and I began to wonder if people would know what I was referring to. So I worried about it for a while and decided the best thing to do was manipulate the image a bit. And, while I was at it, see if I could gain an understanding of the thickness of the yarn.
The 2/20 is on the left, the 2/10 on the right. What that means is that the yarn is made up of two strands twisted together (or plied). The 20 refers to the number of yards/pound which is 20 x 840 = 16,800 divided by 2 (for the number of threads in the 2 ply yarn) for a total of 8,400 yards per pound. Approximately.
The 2/10 is thicker with 10 x 840 = 8,400 yards per pound divided by 2 or 4,200 yards per pound. Approximately,.
Nominally, then, you would expect the 2/10 to be twice as thick as the 2/20, right?
Well, no matter how many times I try to measure the two, the 2/10 is not twice the thickness of the 2/20. Which kind of affirms what a very experienced spinner suggested would be the case when I consulted with her when I did the original samples for the article I'm (still) working on.
I have not done any further 'testing' of the yarn to try and determine numbers of twist in the singles and the plied yarn but I suspect that if I were to take the yarn apart I would discover the singles for the 2/20 are more tightly twisted than the 2/10. The finer the yarn, the 'weaker' it can be, so additional twist can be added to add a little 'backbone' to the yarn so that it can perform as warp more easily. The thicker the yarn, the more strength it will have - united we stand, divided we fall, and all that.
I just beamed the sample warp for these yarns yesterday. (it's the 2/20 for warp) I wound the beam quite tightly - more tightly than I've been using for the 2/16, in part because I could, in part because I wanted to make sure the yarn was 'sound'. I did not have one single broken end during beaming. I have a nicely beamed warp that will need to be re-sleyed a couple times, and re-threaded once (according to my most recent set of scratch notes). It also needs to withstand a pretty significant change in weaving width, which will stress the outside ends, so I wanted to make sure it wasn't going to fall apart on the stress of the deflection as the weaving width changed. I don't remember that I had any issues when I wove the original set of samples, but this is a new lot of yarn so I wanted to improve my chances by increasing the tension on the warp as I wound it.
These samples have to be to the magazine by the end of August. So my goal today is to begin threading and try to weave all the samples this week. August 12 I have my next back injection and need to do 3 days of 'light duties'. Seems like a good time to polish off this batch of samples and polish the two article on cotton are due 'next' so I can mail everything in one box...
1 comment:
It shouldn't be twice as thick, because it is a circle, so it increases according to the formula for the radius 2 (pi) r. So a circle twice the radius of another is roughly 6 times the area (2 pi), which would be roughly 6 times the weight. A circle with twice the area as another (so twice the weight) would only need to be about a third bigger, which is close to the quarter bigger you found, and would be affected by how tightly spun it is. I hope this helps a little!
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